bluuebunny/crossref_metadata_2025 huggingface dataset:
Tests of two physically based filters for base flow separation
Authors: Furey Peter R. , Gupta Vijay K.
Published: October 2003

A physically based filter for separating base flow from streamflow time series is tested using a simple dynamical model of streamflow generation from a hillslope. The model is a modified version of an integral water balance model developed for hillslopes and small basins. It does not include Hortonian overland flow, but it represents the physics of runoff generation from a hillslope better than the physics used in developing the filter. Rainfall time series data are used to run the model. The filter is applied to streamflow simulated from the model and filter estimates of base flow are compared to model‐simulated base flow. The filter performs well on average, but base flow estimates include a strong high‐frequency component that is not found in simulated base flow. The filter assumption that overland flow and recharge are constant fractions of rainfall is found to be a main source of estimation error. A new filter is developed using the modified model in which recharge is a delayed and attenuated response to rainfall because it is a function of integrated soil moisture. Comparing this new filter with the original one shows that base flow estimates only marginally improve, based on one criterion, for streamflow data from a first‐order basin. However, this new filter provides time series estimates of integrated soil moisture and estimates of soil moisture are similar to observed trends in the basin. The formulation of this filter provides a new framework for developing better filters for estimating time series of base flow and integrated soil moisture.
Search strategy for groundwater contaminant plume delineation
Authors: McGrath William A. , Pinder George F.
Published: October 2003

The definition of the boundary of a groundwater contaminant plume can be best viewed as a search strategy objective. To this end, a new approach to plume boundary identification based upon the goal of a stepwise reduction in the overall uncertainty in the location and geometry of the boundary can be used. Through the sequential selection of investigatory well locations based on the criteria of maximizing plume boundary uncertainty reduction and on updated field information, a least cost plume boundary investigation can be realized. The effectiveness of this approach can be investigated using a realistic hypothetical example and demonstrated via a field application.
Plane‐of‐sky simulations of interplanetary shock waves
Authors: Sun W. , Deehr C. S. , Fry C. D. , Dryer M. , Smith Z. , Akasofu S.‐I.
Published: October 2003

We present simulated plane‐of‐sky maps of the shock waves in interplanetary space from several representative solar events by using the Hakamada‐Akasofu‐Fry solar wind model (HAFv.2). This kinematic model uses a three‐dimensional approach to construct plane‐of‐sky maps of interplanetary shock waves initiated by solar flares and CMEs. The simulated plane‐of‐sky maps are in a form that can be directly compared with assimilated optical observations of shock waves from Earth‐orbiting and interplanetary satellites. Combining these simulations with observations would provide a new tool for monitoring the propagation of interplanetary shocks in interplanetary space and for predicting the arrival of shock waves at Earth.
Internal solitary waves of elevation advancing on a shoaling shelf
Authors: Klymak Jody M. , Moum James N.
Published: October 2003

A sequence of three internal solitary waves of elevation were observed propagating shoreward along a near‐bottom density interface over Oregon's continental shelf. These waves are highly turbulent and coincide with enhanced optical backscatter, consistent with increased suspended sediments in the bottom boundary layer. Non‐linear solitary wave solutions are employed to estimate wave speeds and energy. The waves are rank ordered in amplitude, phase speed, and energy, and inversely ordered in width. Wave kinetic energy is roughly twice the potential energy. The observed turbulence is not sufficiently large to dissipate the waves' energy before the waves reach the shore. Because of high wave velocities at the sea bed, bottom stress is inferred to be an important source of wave energy loss, unlike near‐surface solitary waves. The wave solution suggests that the lead wave has a trapped core, implying enhanced cross‐shelf transport of fluid and biology.
Evidence of possible sea‐ice influence on Microwave Sounding Unit tropospheric temperature trends in polar regions
Authors: Swanson Richard E.
Published: October 2003

Spencer and Christy have analyzed data derived from the Microwave Sounding Unit (MSU) series of satellite instruments to assess climate change. This report presents data which suggests a source of error in their MSU/AMSU TLT product. A comparison of data for high latitudes in the Southern Hemisphere demonstrate that the TLT product does not represent the seasonal cycle of temperature in the lower troposphere, as seen in radiosonde data from Antarctica. The difference appears to be the result of the yearly sea‐ice cycle, thus trends in the sea‐ice cycle may impact the TLT product. The Arctic data could also be influenced. These observations question of the validity of the TLT product as a measure of climate change at high latitudes.
Water vapor enhancement in the polar summer mesosphere and its relationship to polar mesospheric clouds
Authors: Hervig Mark , McHugh Marty , Summers Michael E.
Published: October 2003

Polar mesospheric water vapor exhibits a strong seasonal cycle, with summer mixing ratios dramatically higher than in winter. It is generally accepted that vertical transport from ∼50 km altitude towards the mesopause is one driver behind this change, however, upwelling alone cannot explain observed H2O changes. H2O near 83 km increases from 1 ppmv in winter to over 8 ppmv in summer, and upwelling accounts for roughly half of this increase. It has been suggested that evaporation of polar mesospheric clouds (PMCs) should produce a layer of enhanced water vapor. This idea was explored using particle measurements from the Halogen Occultation Experiment (HALOE) to derive the equivalent gas phase H2O contained in PMCs. Comparing these estimates to HALOE water vapor measurements suggests that PMC evaporation is a large component in H2O enhancement near 83 km during summer.
An evaluation of the time of observation bias adjustment in the U.S. Historical Climatology Network
Authors: Vose Russell S. , Williams Claude N. , Peterson Thomas C. , Karl Thomas R. , Easterling David R.
Published: October 2003

The U.S. Historical Climatology Network (HCN) database contains statistical adjustments that address historical changes in observation time at each observing station in the network. A paper in 2002 suggested that these adjustments cause HCN temperature trends to be “spuriously” warm relative to other datasets for the United States. To test this hypothesis, this paper evaluates the reliability of these “time of observation bias” adjustments in HCN. The results indicate that HCN station history information is reasonably complete and that the bias adjustment models have low residual errors. In short, the time of observation bias adjustments in HCN appear to be robust.
An alternative to radiative forcing for estimating the relative importance of climate change mechanisms
Authors: Shine Keith P. , Cook Jolene , Highwood Eleanor J. , Joshi Manoj M.
Published: October 2003

Radiative forcing is widely used to measure the relative efficacy of climate change mechanisms. Earlier general circulation model (GCM) experiments showed that the global‐mean radiative forcing could be used to predict, with useful accuracy, the consequent global‐mean surface temperature change regardless of whether the forcing was due to, for example, changes in greenhouse gases or solar output. More recent experiments indicate that for changes in absorbing aerosols and ozone, the predictive ability of radiative forcing is much worse. Building on a suggestion from Hansen and co‐workers, we propose an alternative, the “adjusted troposphere and stratosphere forcing”. We present GCM calculations showing that it is a significantly more reliable predictor of this GCM's surface temperature change than radiative forcing. It is a candidate to supplement radiative forcing as a metric for comparing different mechanisms and provides a framework for understanding the circumstances in which radiative forcing is less reliable.
Systematic global mixing and melting in lunar soil evolution
Authors: Pieters C. M. , Taylor L. A.
Published: October 2003

We present a revised model of soil evolution constrained by the recent LSCC data for lunar soils. In addition to an observed universal increase in feldspathic components in the finer fractions of soils [Taylor et al., 2001, 2003a, 2003b], both differential melting and lateral mixing processes appear to be required during the evolution of lunar soils. We propose mare‐highland mixing of a significant glass component along with a preferential melting sequence for agglutinitic glass formation of: glass > plagioclase > pyroxene ≫ ilmenite.
Shallow horizontal groundwater flow in peatlands is reduced by bacteriogenic gas production
Authors: Baird Andrew J. , Waldron Susan
Published: October 2003

We tested the extent to which horizontal hydraulic conductivity (Kh) below the water table in near‐surface peats is affected by the accumulation of biogenic gas bubbles. We found: (1) Immediately after water table rise the peat is not saturated. Levels of initial undersaturation were between 1 and 9 percent. (2) The production of biogenic gas bubbles below the water table causes large reductions (typically more than a factor of two) in Kh.
Multiple magnetic clouds: Several examples during March–April 2001
Authors: Wang Y. M. , Ye P. Z. , Wang S.
Published: October 2003

Multiple magnetic cloud (Multi‐MC), which is formed by the overtaking of successive coronal mass ejections (CMEs), is a kind of complex structure in interplanetary space. Multi‐MC is worthy of notice due to its special properties and potential geoeffectiveness. Using the data from the ACE spacecraft, we identify the three cases of Multi‐MC in the period from March to April 2001. Some observational signatures of Multi‐MC are concluded: (1) Multi‐MC only consists of several magnetic clouds and interacting regions between them; (2) each subcloud in Multi‐MC is primarily satisfied with the criteria of isolated magnetic cloud, except that the proton temperature is not as low as that in typical magnetic cloud due to the compression between the subclouds; (3) the speed of solar wind at the rear part of the front subcloud does not continuously decrease, rather increases because of the overtaking of the following subcloud; (4) inside the interacting region between the subclouds, the magnetic field becomes less regular and its strength decreases obviously, and (5) β value increases to a high level in the interacting region. We find out that two of three Multi‐MCs are associated with the great geomagnetic storms (Dst ≤ −200 nT), which indicate a close relationship between the Multi‐MCs and some intense geomagnetic storms. The observational results imply that the Multi‐MC is possibly another type of the interplanetary origin of the large geomagnetic storm, though not all of them have geoeffectiveness. Based on the observations from Solar and Heliospheric Observatory (SOHO) and GOES, the solar sources (CMEs) of these Multi‐MCs are identified. We suggest that such successive halo CMEs are not required to be originated from a single solar region. Furthermore, the relationship between Multi‐MC and complex ejecta is analyzed, and some similarities and differences between them are discussed.
Numerical modeling of the halo electrons in the fast solar wind
Authors: Chen Y. , Esser R. , Hu Y. Q.
Published: October 2003

A one‐dimensional magnetohydrodynamic solar wind model is constructed to describe the behavior of the halo electrons in the fast electron‐proton solar wind, assuming that the electrons are composed of two populations: the core and halo. The halo component is separated from the core electrons by increasing the heat deposition. It is shown that the model including only Coulomb collisions yields a much faster halo drift than observed if the halo temperature is in agreement with measured values. This supports the previous argument that some anomalous frictional processes caused by microinstabilities and/or wave‐particle interactions exist in the solar wind. We show that these anomalous frictional processes can be approximated by enhanced Coulomb collisions together with a heat deposition that has a very large damping length. We find that beyond a certain heliocentric distance, say 20 RS, the anomalous frictional forces acting on the halo population are more important than the electric field force and the Coulomb collisional forces and become the dominant factor inhibiting the core‐halo drift.
Signatures for magnetospheric substorms in the geomagnetic field of dayside equatorial region: Origin of the ionospheric component
Authors: Sastri J. Hanumath , Kamide Y. , Yumoto K.
Published: October 2003

An event‐based study is made of the conditions that lead to the ionospheric current component in the geomagnetic field signature for magnetospheric substorms in the dayside dip equatorial region. The substorm activity studied here is characterized by two onsets separated by ∼40 min: The first one occurred during steady southward interplanetary magnetic field (IMF) and steadily increasing cross‐polar cap potential and enhanced energy input into the magnetosphere, while the second one occurred in close association with a northward transition of IMF and a rapid reduction of the polar cap potential and energy input into the magnetosphere. Earlier studies using multispacecraft data as well as ground‐based optical, radar, and magnetic recordings ascertained the first onset to be associated with a pseudo‐breakup and the second onset with a “true” breakup. Magnetometer recordings from a meridional network of stations in the Indian and Pacific sectors revealed the response of daytime equatorial H‐field to the pseudo‐breakup to be weak and not readily identifiable. In contrast, a distinct negative bay‐like disturbance with an unambiguous dip equator enhancement prevailed in the H‐field starting with the onset of the expansive phase of the fully developed substorm. This behavior indicative of a significant contribution of ionospheric currents to the negative H‐field bay is seen both in the Indian and Pacific sectors covering the 1200–1600 LT region. The present case study thus suggests that a sudden and prominent reduction in the cross‐polar cap potential at the substorm expansive phase is responsible for the prevalence of the ionospheric current component in the geomagnetic disturbance in the dayside equatorial region. It is also found for the first time that the amplitude of the negative H‐field disturbance in the afternoon sector exhibits a marked hemisphere asymmetry at midlatitudes: It is higher by a factor of about 3 in the summer hemisphere than in the winter hemisphere. The equatorial enhancement of the negative H‐component disturbance is interpreted as the signature of the “over‐shielding” effect, namely, direct penetration of the perturbation component of the large‐scale electric field associated with the rapid reduction in convection at the onset of the substorm expansion phase. The marked summer‐winter asymmetry of the H‐field disturbance at midlatitudes is suggested as the outcome of the competing magnetic effects of field‐aligned currents and polar origin DP2 currents.
Numerical experiments on the inner magnetospheric electric field
Authors: Garner T. W.
Published: October 2003

Inner magnetospheric electric fields are often complicated by a reduction of the total electric field at low‐latitudes called shielding and an intensification of the electric field equatorward of the auroral oval called a subauroral polarization stream (SAPS). To better understand the stormtime behavior of these electric fields, computer experiments have been conducted using the Rice Convection Model (RCM). The RCM computes the Region‐2 Birkeland currents and the inner magnetospheric electric field and particle distribution. It uses as input a magnetic field and the plasma sheet pressure and energy distribution and assumes that particle loss is negligible. The base or control run used realistic model inputs, while the experiments varied fundamental model inputs to test the electric field's sensitivity to magnetospheric conditions. The first experiment is a high‐pressure or dense plasma sheet run, where the boundary density and pressure are a factor of three higher than in the base run. The high‐pressure run produced better shielding and a stronger SAPS. The second experiment is a cold plasma sheet run in which the plasma sheet temperature was reduced by a factor of thirty, while the pressure remained constant. In this run, the gradient and curvature drift is small compared with the × drift. With particle transport similar to ideal MHD, the cold plasma sheet run produced excellent shielding and strong Region‐2 currents. This is in contrast to the weak shielding and Region‐2 currents produced by global MHD codes. In addition, the SAPS feature is significantly strengthened. The final experiment held the magnetic field constant. This run produced marginally better shielding. However, the magnetospheric signature of SAPS is very weak, suggesting that magnetic field variations are important in SAPS formation.
Stable paths of the Kuroshio south of Japan determined by the wind stress field
Authors: Kurogi Masao , Akitomo Kazunori
Published: October 2003

To investigate the role of the wind stress field in determining stable paths of the Kuroshio south of Japan, we have executed numerical experiments with a two‐layer, wind‐driven ocean model, changing zonal and meridional wind stress distributions. Four types of path (two straight and two meandering paths) have been found, and their appearance has been classified into three categories. In category I, straight and meandering paths coexist (multiple equilibrium); only a meandering (straight) path appears in category II (III). A meandering path tends to appear when the Sverdrup transport along the southern coast of Japan decreases downstream strongly and the wind stress curl is anomalously negative in the western region near Japan, whereas a straight path is apt to occur with the positive anomaly. Detailed examination of the results has revealed the following mechanism determining stable paths of the Kuroshio. The wind stress field first determines the pressure difference Δp* between the two ends of the southern coast of Japan. When Δp* is smaller than a certain threshold, only a meandering path can exist since the along‐coast pressure decrease in a straight path state is much larger than Δp* (category II). Conversely, when Δp* is larger than another threshold, only a straight path is consistent with the larger Δp* (category III). Both paths can appear when Δp* is between the two thresholds (category I). The climatological wind stress field in the North Pacific subtropical region has been suggested to be in category I.
Tropospheric distribution of ozone and its precursors over the tropical Indian Ocean
Authors: Saraf N. , Beig G. , Schultz M.
Published: October 2003

To evaluate the atmospheric ozone measurements of the Indian Ocean during the dry winter season from January to March, an analysis of ozone and its precursors has been made using the Model of Ozone and its Related Tracers (MOZART‐2), a global chemical transport model. The ozonesonde measurements were made on board the ship Sagar Kanya during the Indian Ocean Experiment 1999 (INDOEX‐99), which covered the region from 11.3°N to 20.2°S and from 62.3°E to 75.8°E. These measurements reveal surface ozone values on the order of 20–50 ppb over the oceanic region and increasing concentrations in the midtroposphere in the range 50–100 ppb, followed by a steep gradient (>120 ppb) near the tropopause. The model qualitatively reproduces most of the broad features observed in the ozonesonde measurements. The low value of O3 over the ocean is characterized by the low concentration of NOx and CO as simulated by the model, but the relationship between O3 and NOx breaks down toward the continent where NOx increases sharply and O3 does not follow the steep gradient. The variation in CO from ocean to continent is closely related to the O3 variation. The model reproduces the latitudinal variation of CO in this region well but underestimates the CO concentration by 30–50%, probably because of underestimated emission values. The latitudinal distribution of ozone over the marine boundary layer shows a decrease from north of the equator to the south as the CO‐rich air from the continent spreads toward the ocean, thereby reflecting the inflow of pollutants to the pristine marine region during the dry winter season.
Lightning electric field intensity at high altitudes: Inferences for production of elves
Authors: Rakov V. A. , Tuni W. G.
Published: October 2003

Distant electric fields predicted by the transmission line (TL) model and by the modified transmission line model with exponential current decay with height (MTLE) are examined as a function of polar angle (elevation) and return stroke propagation speed. The lightning return stroke current waveform was approximated by a step function. The resultant electric field waveform for the TL model is also a step function, while for the MTLE model the field instantaneously rises to the same value as for the TL model and then decays exponentially. The exponential current attenuation with height in the MTLE model results in a considerable reduction in the electric field intensity within 1 μs after the initial peak, particularly for smaller polar angles (larger elevations) and higher propagation speeds. Combinations of current and speed (as a function of polar angle) that are conducive to the production of transient optical emissions (elves) in the lower ionosphere are examined. According to the TL model, for a typical negative first‐stroke current of 30 kA, elves would be produced only if the return stroke speed were greater than about 2.5 × 108 m/s. For the MTLE model, considerably larger currents are needed for the production of elves than for the TL model.
Downstream coarsening in headwater channels
Authors: Brummer Chris J. , Montgomery David R.
Published: October 2003

Field data from four mountain drainage basins in western Washington document systematic downstream coarsening of median bed surface grain size (D50) and a subsequent shift to downstream fining at a drainage area of about 10 km2. Analyses of network‐wide patterns of unit stream power derived from both channel surveys and digital elevation models reveal maximum unit stream power that in all four study areas roughly corresponds with both the grain size maxima and an inflection in the drainage area‐slope relation thought to represent the transition from debris flow‐dominated channels to fluvially dominated channels. Our results support the hypothesis that basin‐wide trends in D50 are hydraulically controlled by systematic variations in unit stream power in addition to lag deposits forced by mass‐wasting processes. The similar relations found in our four study areas suggest that the tendency for downstream coarsening may be ubiquitous in headwater reaches of mountain drainage basins where debris flow processes set the channel gradient.
Reforming the wastewater treatment sector in Italy: Implications of plant size, structure, and scale economies
Authors: Fraquelli Giovanni , Giandrone Roberto
Published: October 2003

In the context of the restructuring of the water industry, this work examines the treatment processes of urban wastewaters in Italy, with reference to costs, size, and technology. The operating cost function of 103 plants confirms scope economies from vertical integration and strong economies of scale for the smaller structure, confirming the benefits coming from the aggregation of the existing little firms. A minimum efficient size at about 100,000 inhabitants, however, inhibits the creation of large monopolies at a local level and enables the maintenance of indirect competition. Among the explanatory variables of running costs, the pollution load of the input wastewater takes on a high statistical significance and suggests environmental prevention, while the strong impact of sludge concentration means it should be considered in the new tariff systems. The recent introduction of advanced treatments is expensive, but the costs are balanced by a notable improvement in the pureness of the effluent waters. As for general environmental policies, it is necessary to find a good compromise between the need to improve the effectiveness of the existing plants and the investments in areas where the water treatment service is still inexistent.
Fractal mobile/immobile solute transport
Authors: Schumer Rina , Benson David A. , Meerschaert Mark M. , Baeumer Boris
Published: October 2003

A fractal mobile/immobile model for solute transport assumes power law waiting times in the immobile zone, leading to a fractional time derivative in the model equations. The equations are equivalent to previous models of mobile/immobile transport with power law memory functions and are the limiting equations that govern continuous time random walks with heavy tailed random waiting times. The solution is gained by performing an integral transform on the solution of any boundary value problem for transport in the absence of an immobile phase. In this regard, the output from a multidimensional numerical model can be transformed to include the effect of a fractal immobile phase. The solutions capture the anomalous behavior of tracer plumes in heterogeneous aquifers, including power law breakthrough curves at late time, and power law decline in the measured mobile mass. The MADE site mobile tritium mass decline is consistent with a fractional time derivative of order γ = 0.33, while Haggerty et al.'s [2002] stream tracer test is well modeled by a fractional time derivative of order γ = 0.3.
Root debridement of single‐rooted teeth with a diamond‐ coated sonic scaler insert during flap surgery
Authors: Kocher Thomas , Plagmann Hans‐Christian
Published: October 2003

Abstract. In our laboratory, we modified inserts of a sonic scaler to increase effectivity of root surface instrumentation during flap surgery. The present clinical study investigates whether use of this diamond‐coated, thickened insert facilitates more rapid root debridement compared to hand instruments and whether clinical wound healing is influenced by the type of instrument used. In 13 patients with moderate to advanced periodontal destructions, flap surgery was carried out on single rooted teeth with probing depth of ≥6 mm. The mean amount of time saved by root debridement with the diamond‐coated insert was 60% over curets. Regardless of the used instrumentation method probing depths and attachment level changes were altered and remained unchanged for 2 years after surgery. In conclusion the newly‐developed, diamond‐coated sonic scaler insert facilitates more rapid root debridement during flap surgery than hand instruments without disadvantageously affecting clinical healing.
Increased release of elastase from in vitro activated peripheral neutrophils in patients with adult periodontitis
Authors: Figueredo C. M. S. , Gustafsson A. , Âsman B. , Bergström K.
Published: October 2003

Abstract. The main object of this study was to determine if there was a difference between patients with adult periodontitis and healthy controls in the release of elastase. We also wanted to test the release of α1‐antitrypsin and lactoferrin from in vitro‐activated peripheral neutrophils. A leukocyte‐rich preparation from venous blood was made by lysing the red blood cells. The leukocytes were stimulated for 1 h at 37°C with opsonized Staphylococcus aureus and the released elastase was measured with a chromogenic substrate. The release of elastase after stimulation with bacteria was significantly higher in patients than in controls. The amounts of elastase from unstimulated cells, i.e., both released extracellularly and extracted from the pellet, were similar in the 2 groups. However, after stimulation, the amount of elastase in the patient group, but not in the control group, was significantly increased. Similar releases of α‐1‐antitrypsin (A1AT) and lactoferrin were found in both groups of subjects. In conclusion, this study shows that peripheral neutrophils from patients with adult periodontitis release more active elastase after in vitro activation compared to healthy controls. The release of A1AT and lacto‐ferrin showed no differences, indicating that the increased elastase activity was not due to a impaired inhibition by A1AT and that the differences in degranulation were limited to the primary granula.
Calcitonin gene‐related peptide in gingival crevicular fluid in periodontal health and disease
Authors: Lundy Fionnuala T. , Shaw Christopher , McKinnell Judith , Lamey Philip‐J. , Linden Gerard J.
Published: October 2003

Abstract. The aims of the present study were to investigate whether calcitonin gene‐related peptide (CGRP) was present in gingival crevicular fluid in both periodontal health and disease and to study the relationship with periodontal inflammation. Gingival crevicular fluid (GCF) was collected from a healthy, a gingivitis and a periodontitis site in 18 subjects with periodontitis and from a healthy site in 19 subjects without periodontitis. The volume of GCF was measured and each sample subsequently analysed for CGRP by radioimmunoassay. In subjects with periodontitis, CGRP immunoreactivity (CGRP‐IR) was not detected in any periodontitis sites, nor in 67% of gingivitis and 28% of periodontallyhealthy sites. The total amount of CGRP‐IR was significantly elevated in periodontally healthy (p=0.0015) and gingivitis (p=0.027) compared with periodontitis sites. CGRP‐IR was present in 89% of the healthy sites sampled in control subjects at comparable levels to those in healthy sites in periodontitis subjects. It is concluded that in periodontal inflammation, particularly in deep pockets, constituents of GCF process and degrade CGRP.
Expression of VLA‐integrins and their related basement membrane ligands in gingiva from patients of various periodontitis categories
Authors: Gürses Nurcan , Thorup Alis K. , Reibel Jesper , Carter William G. , Holmstrup Palle
Published: October 2003

Abstract. Periodontitis is characterized by destruction of dento‐gingival fibers and apical migration of the junctional epithelium. Tissue destruction may be associated with altered interactions between epithelium and connective tissue mediated by integrins localized in the basement membrane zone. We examined the expression of α2β1, α3β1, α4/α5β1, α6β4 and their related extracellular matrix (ECM) ligands: laminin‐1, laminin‐5, and collagen type IV in untreated periodontitis sites of various categories. The expression and location of ECM proteins along the basement membrane were found to be similar between clinically healthy and periodontitis affected tissues. However, ECM proteins were more diffusely distributed in connective tissue (CT) of periodontitis tissues as streak‐like/fibrillar/granular stainings, particularly beneath the pocket epithelium (PE) and around the blood vessels. This may reflect an increase in inflammatory cell migration. The more widespread distribution of integrins α2β1, α3β1 in PE of periodontitis specimens may be related to disease activity and increased rate of keratinocyte proliferation and migration. Moreover, the weaker expression of α6β4 in junctional epithelium (JE) of periodontitis affected tissues may be related to the epithelial detachment from the tooth surface. Clarification of expressions of integrins and their ligands in relation to known clinical disease susceptibility factors may provide information on the onset and progression mechanisms of periodontal disease destruction.
Effect of different frequencies of preventive maintenance treatment on periodontal conditions
Authors: Rosén Birgitta , Olavi Gran , Badersten Anita , Rönström Anders , Söderholm Göran , Egelberg Jan
Published: October 2003

Abstract. The protocol for this study was designed to evaluate the effects of supportive recall treatments provided with different frequencies, viz. at 3‐, 6‐, 12‐ and 18‐month intervals. The subjects for the study were recruited from patients attending a public, general dentistry clinic. Prior to baseline, the subjects were given necessary dental treatments to provide a proper baseline for the study. Baseline, intermittent and final recordings included scores of dental plaque, bleeding on probing, probing depth and probing attachment level. Results were evaluated statistically by intergroup comparisons of changes for the various parameters from baseline to final examination after 5 years. The analyses showed some advantage to shorter recall intervals for plaque and bleeding scores. Although not statistically significant, there was a trend suggesting some rebound of sites >6 mm deep at the end of the study for the 18‐month group, but not for the other groups. Similarly, there was a trend that the 18‐month group showed a higher percentage of buccal/lingual furcation sites with attachment loss ≥1.0 mm than the other groups. Apart from these trends, the analyses failed to demonstrate differences between the groups for either changes of probing depths or probing attachment levels. The negative observations included identification of individuals with ‘disease progression’ in the various groups, using a series of arbitrary definitions for this parameter. The results of this trial suggest that recall intervals extended to a year may be acceptable for the purpose of reducing periodontal disease progression in individuals with a history of limited susceptibility to the disease.
The effects of mouth rinses and dentifrice‐containing magnesium monoperoxyphthalate (mmpp) on oral microflora, plaque reduction, and mucosa
Authors: Scully Crispian , El‐Kabir Mohamed , Greenman John , Porter Stephen R. , Mutlu Serdar , Barton Ian , Adair Richard
Published: October 2003

Abstract. The effects of a magnesium monoperoxyphthalate (MMPP) mouthrinse, with or without sodium lauryl sulphate (SLS), and an MMPP dentifrice, on salivary counts of bacterial flora and yeasts, and on supragingival plaque scores were investigated in 131 healthy oral candida carriers over a 9 week double blind study. There were no changes in the salivary counts of bacteria studied (anaerobes, streptococci, fusobacteria, Actinomyces, Viellonella) in the test or placebo groups. A significant increase in salivary candida counts was seen in subjects using an MMPP rinse and dentifrice compared with placebo subjects and this phenomenon was not influenced by the presence of SLS. A significant reduction in plaque was seen in subjects using an MMPP rinse and dentifrice compared with placebo subjects. Frank candidosis was observed in only 2 subjects (1 in the placebo rinse group and 1 in the MMPP dentifrice group) but erythematous lesions, with subjective reports of soreness, dryness or burning sensation, were recorded and observed more frequently in the experimental groups than in the placebos, especially in those also using SLS. The substantial plaque reduction achieved with MMPP in the absence of tooth staining but with the increase in salivary Candida counts suggests that further studies of MMPP are warranted.
In vivo comparison of synthetic osseous graft materials
Authors: MacNeill Simon R. , Cobb Charles M. , Rapley John W. , Glaros Alan G. , Spencer Paulette
Published: October 2003

Abstract. The purpose of this study was to compare the in vivo osseous healing response of 4 commercially‐available synthetic bone grafting materials; hydroxylapatite (HA), calcium sulfate (CaSO4) plus autogenous bone, or a bioactive glass ceramic: with particle size of 300–360 μm (BG1) or 90 to 710 μm (BG2). 4 osteotomy sites were prepared in each tibia of 10 adult male rabbits. One unfilled osteotomy site served as negative control (NC) and another site filled with autogenous bone was the positive control (PC). All animals received BG1 in 2 sites and BG2 in 2 sites. 5 animals received HA and five CaSO4 plus autogenous bone in the remaining 2 sites. Animals were sacrificed at 28 days post‐surgery, histologic sections obtained and the % surface area of new bone formation for each material was determined by computerized image analysis. All graft sites showed evidence of bone formation, i.e., (NC) 41.95%; (PC) 50.41%; (BG1) 41.82%; (BG2) 40.36%; (HA) 41.83% and (CaSO4) 58.83%. Statistical analysis using an ANOVA with repeated measures on the materials common to all animals (excluding HA and CaSO4 groups) showed significant differences between materials in surface area of bone, with positive controls better than negative controls, and BG1 and BG2 not significantly different from the negative control. These results indicate that synthetic graft materials can support new bone formation in surgically prepared defects. The utility of a rabbit model for studying physiologic osseous turnover and healing is questioned for studies of slowly resorbing synthetic graft materials.
Influence of OAS‐1000 on mediators of inflammation
Authors: Scherl D. S. , Afflitto J. , Gaffar A.
Published: October 2003

Abstract. OAS‐1000 is a semisynthetic derivative of pseudopterosine A, isolated from sea whip (Pseudopterogorgia elizabethae), that has been shown to have topical anti‐inflammatory activity. The purpose of this research was to investigate OAS‐1000 for potential use as an anti‐inflammatory agent for topical oral application, and to begin to investigate a mechanism of action. OAS‐1000 was therefore evaluated as an inhibitor of 4 enzymes of the arachidonic acid metabolic pathways (prostaglandin G/H synthase I (PGHS‐1, COX‐1), prostaglandin G/H synthase II (PGHS‐2, COX‐2), arachidonate 5‐lipoxygenase (5‐LOX), and arachidonate 15‐lipoxygenase (15‐LOX)). It was found that OAS‐1000 inhibits PGHS‐1 activity with an IC‐50 value of 80.3 μM, but had much less activity versus PGHS‐2 enzyme and no activity versus the 15‐LOX enzyme. 5‐LOX activity showed some inhibition, but only at a high OAS‐1000 concentrations. Additionally, OAS‐1000 was tested for it's ability inhibit 1 ng/ml IL‐1b stimulated PGE2 production in a cell culture system. Inhibition of 46% was seen at an OAS‐1000 concentration of 22.4 μM. Taken together, these experiments suggest that at least some of the topical anti‐inflammatory activity of OAS‐1000 may be attributed to inhibition of the arachidonic acid metabolites that have been shown to be important in inflammation and tissue destruction.
Gingival crevicular fluid osteocalcin in adult periodontitis
Authors: Lee Allison J. , Walsh Trevor F. , Hodges Stephen J. , Rawlinson Andrew
Published: October 2003

Abstract. This study aimed to detect the levels of osteocalcin in gingival crevicular fluid (GCF) from healthy (≤3 mm sulcus depth and non‐bleeding) and diseased sites (≥6 mm probing depth and bleeding) in subjects with adult periodontitis, in order to further investigate its potential as a possible marker of the disease process. Periodontal probing depths, attachment levels and gingival indices were recorded from one healthy and one diseased site in each of 20 subjects with adult periodontitis. Both GCF accumulated in the periodontal pocket or sulci and GCF flowing into the periodontal pocket or sulci over a three‐minute interval were sampled. The amounts of osteocalcin in each GCF sample was determined using immunoassays. A mean of 2.34 ng/site (2.7 μg/ml) osteocalcin was found at diseased sites and a mean of 2.47 ng/site (5.47 μg/ml) was found at healthy sites for the accumulated GCF collection method. A mean of 0.17 ng/site (2.17 μg/ml) osteocalcin was found at diseased sites and a mean of 0.14 ng/site (1.85 μg/ml) at healthy sites for the flow method of GCF collection. There were no statistically significant differences between osteocalcin levels in diseased and healthy sites in subjects with adult periodontitis.
Tissue necrosis after subgingival irrigation with fluoride solution
Authors: Sjöström S. , Kalfas S.
Published: October 2003

Abstract. Irrigation of periodontal pockets with fluoride solution after scaling and root planing is occasionally recommended to inhibit the growth of pathogenic bacteria in the periodontal pocket. At the same time, irrigation enables mechanical removal of loosely adhering plaque and debris. Due to its toxicity, fluoride solution deposited in the periodontium may lead to tissue damage. We report in this paper, a case of extensive periodontal tissue necrosis and permanent loss of alveolar bone after irrigation of periodontal pockets with stannous fluoride solution. The literature on the toxic effects of fluoride on the local tissues is briefly reviewed and arguments for a re‐evaluation of the use of stannous fluoride for pocket irrigation are provided.
Metronidazole susceptibility testing of anaerobic bacteria associated with periodontal disease
Authors: Poulet P. P. , Duffaut D. , Lodter J. Ph.
Published: October 2003

Abstract. The aim of the present investigation was to determine the susceptibility of Prevotella intermedia, Porphyromonas gingivalis, Fusobacterium and Peptostreptococcus micros to metronidazole in vitro. Two methods were applied on each isolated strain: agar dilution and epsilometer Etest®. A total of fifty three wild test strains (13 P.intermedia, 14 P.gingivalis, 14 F.spp and 12 P.micros) were isolated from patients with periodontitis. The Etest® appears to be a simple, rapid and reliable method for the metronidazole susceptibility testing. The results show that all P.intermedia, P.gingivalis and F.spp strains were susceptible to metronidazole. The mean values of minimal inhibitory concentration obtained with the agar dilution method were, respectively, 0.98 μg/ml, 0.122 μg/ml and 0.242 μg/ml. For P. micros, the minimal inhibitory concentration was of 12.14 μg/ml. Comparatively to break points, only 60% of P.micros strains seem to be susceptible, in vitro, to metronidazole. This study demonstrated the excellent activity of metronidazole against P.intermedia, P.gingivalis, F.spp except perhaps for P.micros.
The periodic acid‐Schiff stain in diagnosing tinea: should it be used routinely in inflammatory skin diseases?
Authors: Al‐Amiri Amina , Chatrath Vandana , Bhawan Jag , Stefanato Catherine M.
Published: October 2003

Background:  The clinical presentation of tinea is usually, but not always, characteristic. The purpose of this study was to determine whether the routine use of the periodic acid‐Schiff (PAS) stain in inflammatory skin disorders is requisite for identifying clinically undiagnosed tinea cases and to ascertain whether there are histopathologic clues that suggest the diagnosis of a dermatophyte infection.

Methods:  Hematoxylin and eosin (H&E)‐stained slides from 60 PAS‐positive tinea cases were examined histologically by two observers. One observer, aware of the diagnosis of tinea, searched for hyphal elements and also recorded in detail epidermal, dermal, and follicular changes. The second observer, not aware of the diagnosis beforehand, reviewed the same slides, together with randomly mixed slides from 21 non‐tinea cases, recording the same parameters as the first reviewer.

Results:  Of the 60 cases of tinea, only 45% were diagnosed clinically. Histologic examination of H&E sections by the two observers disclosed the presence of hyphal elements in 68 and 45%, respectively. No significant histologic differences, except for the presence of hyphae, were observed between tinea and non‐tinea cases.

Conclusions:  The finding that only 57% of PAS‐positive cases of tinea showed hyphal elements on H&E examination alone, together with no other differentiable histologic characteristics, lends strong support for the routine use of PAS‐staining for inflammatory skin disorders.
Expression of insulin‐like growth factor‐binding protein 2 in melanocytic lesions
Authors: Wang Huamin , Shen Steven S. , Wang Hua , Diwan A. Hafeez , Zhang Wei , Fuller Gregory N. , Prieto Victor G.
Published: October 2003

Background:  Insulin‐like growth factor‐1 (IGF‐1) is one of the most critical proteins required for the survival, migration, and growth of melanoma cells. IGF‐binding protein 2 (IGFBP2), which binds and regulates the function of IGF‐1, is upregulated in a dose‐dependent manner in melanoma cells treated with IGF‐1, suggesting a possible role of IGFBP2 in the pathogenesis of melanoma.

Methods:  Tissue microarrays were constructed using formalin‐fixed, paraffin‐embedded archival tissue blocks from 94 melanocytic lesions: 20 benign nevi, 20 dysplastic nevi, 23 primary melanomas, and 31 metastatic melanomas. IGFBP2 expression was evaluated immunohistochemically using a polyclonal antibody against the C‐terminus of IGFBP2. The number of cells and labeling intensity were assessed semiquantitatively.

Results:  Positive IGFBP2 labeling was observed in 5.0% of benign nevi, which was significantly lower than in dysplastic nevi (35.0%), primary melanomas (52.2%), or metastatic melanomas (54.8%) (p < 0.05). Among the IGFBP2‐positive cases, moderate‐to‐strong immunostaining was observed in 64.7% of metastatic melanomas and 33.3% of primary melanomas. But none of the dysplastic nevi had moderate‐to‐strong immunostaining (p < 0.05).

Conclusions:  Our study shows that IGFBP2 expression increases from benign and dysplastic nevi to primary and metastatic melanomas and suggests that it may play a role in melanoma progression.
Expression of desmosomal proteins in squamous cell carcinomas of the skin
Authors: Kurzen Hjalmar , Münzing Ivonne , Hartschuh Wolfgang
Published: October 2003

Background:  Desmosomal proteins are well established markers of epithelial differentiation. Down‐regulation of desmosomal proteins has been suggested to be a sign of reduced adhesiveness in metastasizing cells.

Methods:  We examined actinic keratoses, Bowen's disease, and squamous cell carcinoma (SCC) of the skin for the expression of desmosomal proteins using isoform‐specific antibodies on paraffin‐embedded sections. Evaluation was performed qualitatively in comparison to the epidermis and semiquantitatively using an area‐intensity‐score.

Results:  We found no qualitative correlation of desmoplakin or plakoglobin expression with risk of metastasis. Plakophilin 1, desmoglein 1, and the desmocollins 1–3 were found to be heterogeneously expressed in all neoplasms without significant correlation to aggressive tumor behavior. Plakophilin 2 was not expressed in any of the neoplasms examined. As most striking finding, desmoglein 2 was up‐regulated qualitatively in half of all neoplasms examined and showed a significant higher proportion of positive cells in high‐risk SCC than in low‐risk SCC.

Conclusions:  Desmosomal proteins are highly regulated in cutaneous SCC. Only desmoglein 2 expression correlates with risk of metastasis. Desmosomes may still be functional in metastasizing tumor cells.