Bathymetry Change of Lake Svitiaz in 1929–2012

W pracy przedstawiono zmianę batymetrii jeziora Świtaź, będącego jednym z największych na Ukrainie. Na podstawie przeprowadzonych badań terenowych w lipcu 2012 roku wyznaczono aktualny plan batymetryczny tego akwenu. Uzyskane dzięki temu dane, odnoszące się do parametrów morfometrycznych przyrównano z informacjami z lat 20. XX wieku. Wynika z nich iż w okresie ponad 80 lat nastąpiło zmniejszenie powierzchni o 305,8 ha, objętości o 14558 tys. m3 oraz skrócenie linii brzegowej o 7300 m. Na podstawie rozkładu izobat, ustalono iż podatna na zanik jest wschodnia (płytsza część akwenu) gdzie nastąpiło znaczne wypłycenie misy jeziora. У роботі представлено зміни батиметрії озера Світязь, яке є одним із найбільших в Україні. На підставі польових досліджень, проведених у липні 2012 року, з’ясовано сучасні батиметричній план водойми. Отримані дані порівняли з результатами досліджень 20-х років ХХ ст. Вони засвідчують, що протягом понад 80 років виявлено зменшення площі на 305,8 га, об’єму – на 14 558 тис. м3 і довжини берегової лінії – на 7300 м. За результатами розподілу ізобат виявлено вразливість східних мілководних частин водойми, де постерігається значне обміління озера.The article deals with bathymetry changes of lake Svitiaz, which is one of the largest lakes in Ukraine. On the basis of field studies done in June 2012, a current bathymetrical chart of the lake was made. The obtained data were compared with the results of the studies dating back to 1920-s. They testify that within the period of more than 80 years the area of the lake reduced by 305.8 ha, its volume decreased by 14558 000 m3, and the length of the shore line by 7300 m. According to the results of isobath distribution, vulnerability of the eastern shallow parts of the lake, where considerable shallowness is observed, was found out.Praca wykonana w Instytucie Geografii Fizycznej i Kształtowania Środowiska Przyrodniczeg

Dew Point Temperature Affects Ascospore Release of Allergenic Genus Leptosphaeria

The genus Leptosphaeria contains numerous fungi that cause the symptoms of asthma and also parasitize wild and crop plants. In search of a robust and universal forecast model, the ascospore concentration in air was measured and weather data recorded from 1 March to 31 October between 2006 and 2012. The experiment was conducted in three European countries of the temperate climate, i.e., Ukraine, Poland, and the UK. Out of over 150 forecast models produced using artificial neural networks (ANNs) and multivariate regression trees (MRTs), we selected the best model for each site, as well as for joint two-site combinations. The performance of all computed models was tested against records from 1 year which had not been used for model construction. The statistical analysis of the fungal spore data was supported by a comprehensive study of both climate and land cover within a 30-km radius from the air sampler location. High-performance forecasting models were obtained for individual sites, showing that the local micro-climate plays a decisive role in biology of the fungi. Based on the previous epidemiological studies, we hypothesized that dew point temperature (DPT) would be a critical factor in the models. The impact of DPT was confirmed only by one of the final best neural models, but the MRT analyses, similarly to the Spearman's rank test, indicated the importance of DPT in all but one of the studied cases and in half of them ranked it as a fundamental factor. This work applies artificial neural modeling to predict the Leptosphaeria airborne spore concentration in urban areas for the first time

Evaluation of laxity tests with a musculoskeletal model of total knee arthroplasty

Introduction Musculoskeletal models are emerging as potential tools for the use in many clinical applications. One important example is aid to the clinical decision in the orthopaedic field. Recently, a patient-specific model of Cruciate-Retaining Total Knee Arthroplasty (CR-TKA) was presented and validated with respect to knee joint forces and kinematics [1]. However, the ligament restraints were not calibrated and inaccuracies in knee kinematic predictions were present. The objective of this study was to evaluate the effect of ligament calibration on the performance of simulated laxity tests. Methods A musculoskeletal model of CR-TKA was previously described [1]. The model comprised the musculoskeletal architecture of a TKA patient and a force-dependent model of the prosthetic knee and patellofemoral joint. Ligament restraints were modelled using non-linear springs and contact was solved using a rigid formulation. To calibrate the ligament parameters we simulated anterior/posterior, valgus/varus and endo-/exorotation laxity tests. Each test was performed at four different knee flexion angles (0, 30, 60, 90 deg). The anterior (respectively posterior) laxity load consisted of a 35 N force applied on the tibia at a distance of approximately 15 cm from the surface of the tibial component, pointing anteriorly (respectively posteriorly). Valgus (respectively varus) test was simulated by applying a force on the tibia at a distance of approximately 15 cm from the ankle joint, pointing laterally (respectively medially) so that the resulting moment was equal to 10 Nm. For the endo- (respectively exo-) rotation a 1.5 Nm torque was applied to the longitudinal axis of the tibia. Laxity envelopes for each test were calculated as the difference between the values obtained in the two opposite directions of the test. Manual changes to ligament insertion site, stiffness, and reference strain were made iteratively in order to obtain laxity envelopes close to those reported in the literature for cadaveric tests on a CR-TKA [2]. All the laxity tests were eventually simulated with the same ligament configuration. Results The results for all simulated laxity tests and the reference values from the literature are summarized in Table 1. 0° 30° 60° 90° AP (M) 3.5mm 4.2mm 1.0mm 1.0mm AP (L) 1.5mm 5mm 4mm 4.5mm VV (M) 0.9° 4.3° 2.6° 1.5° VV (L) 3.0° 6.0° 7.0° 7.0° EE (M) 7.0° 16.5° 4.0° 5.5° EE (L) 6.5° 22.0° 21.0° 23.0° Table 1: AP: Anterior/Posterior, VV: Valgus/Varus, EE: Endo-/Exorotation, M: Model prediction, L: Literature value Discussion The laxity envelopes predicted by the model were in partial agreement with those reported in the literature. The largest differences were noted for 60-90 degrees of knee flexion for all laxity tests, where the model showed considerably less laxity. These deviations may be attributable to actual differences between the implant design and subject geometry currently simulated and those used in the cadaveric tests. In future studies we aim to simulate surgical variations such as implant size and positioning, joint line elevation and ligament restraint. This musculoskeletal model of TKA has potential as a pre-operative planning tool for orthopaedic interventions. References Marra et al, J Biomech Eng, 137, 2015 Saeki et al, Clin Orthop Relat Res, 392:184-189, 200

The effect of posterior tibial slope on simulated laxity tests in cruciate-retaining TKA

INTRODUCTION: Tibial slope can affect the outcomes of Total Knee Arthroplasty (TKA). More posterior slope potentially helps releasing a too tight flexion gap and it is generally associated with a wider range of post-operative knee flexion. However, the mechanism by which tibial slope affects the function of TKA during dynamic activities of daily living is rather complex and not well documented. The aim of this study was to investigate the effect of tibial slope on the kinematics of the tibiofemoral (TF) contact point, quadriceps muscle forces, and patellofemoral (PF) joint contact forces during squat. In addition, we studied the effect of anterior tibial cortex-referencing (ACR) versus center of tibial plateau-referencing (CPR), as two possible techniques to obtain the desired degree of tibial slope. METHODS: A previously validated musculoskeletal model of a 86-year-old male subject, having a cruciate-retaining (CR) TKA prosthesis, was used to simulate a squat activity [1]. Motion-capture data were input to a motion optimization algorithm to find the full body kinematics. Quadriceps muscle forces were then calculated using inverse-dynamics. The kinematics of the TF contact point and PF joint contact forces were simultaneously calculated using force-dependent kinematics. A baseline case with 0° tibial slope was simulated, plus four additional cases with anterior (-3°), and posterior (+3°, +6°, +9°) tibial slope using the ACR technique (Fig. 1a), and four using the CPR technique (Fig. 1b). RESULTS: Compared to the baseline, more posterior tibial slope with ACR technique resulted in a larger excursion of the TF contact point, which shifted to a more anterior position, on the lateral side, and a more posterior position, on the medial side, in extension (Fig. 2). With the CPR technique, the contact point in extension shifted gradually more posterior on both sides with more posterior slope, and in flexion it shifted gradually more posterior mainly on the lateral side. The peak quadriceps force decreased on average by 1.7 and 1.2 % BW per degree of more posterior slope, with the ACR and CPR techniques, respectively. However, due to the different relative position of patella and femur, the peak PF contact force was mainly reduced by increasing the posterior slope with the CPR technique (-3.9 % BW/degree), rather than with the ACR technique (-1.5 % BW/degree) (Fig. 3). DISCUSSION: Increasing the tibial slope using the ACR technique produced large changes in the TF kinematics: the pattern of the contact point became more unstable, with a larger AP movement observed on the lateral side, denoting increased anterior-posterior laxity. On the other hand, variations of tibial slope with CPR technique resulted in more stable TF kinematics, more posterior position of the TF contact point, and a greater reduction of the PF contact forces. It is advisable to pre-plan the desired amount of tibial slope and execute it using the CPR technique. The surgeon should be very careful applying too much tibial slope with the ACR technique in CR-TKA, as it may have devastating effects on the TF kinematics, laxity and PF forces. SIGNIFICANCE: This study provides new insights into the effect of variation of tibial slope in TKA using different surgical techniques, which were not documented before, and used a highly controlled and parameterized study design and dynamic loading conditions. Orthopedic surgeons can directly use these results as an indication for the clinical practice. The presented tool can also be very useful for educational/medical training purposes

The effect of tibial slope on the biomechanics of cruciate-retaining TKA:a musculoskeletal simulation study

INTRODUCTION: Tibial slope can affect the outcomes of Total Knee Arthroplasty (TKA). More posterior slope potentially helps releasing a too tight flexion gap and it is generally associated with a wider range of post-operative knee flexion. However, the mechanism by which tibial slope affects the function of TKA during dynamic activities of daily living is rather complex and not well documented. The aim of this study was to investigate the effect of tibial slope on the kinematics of the tibiofemoral (TF) contact point, quadriceps muscle forces, and patellofemoral (PF) joint contact forces during squat. In addition, we studied the effect of anterior tibial cortex-referencing (ACR) versus center of tibial plateau-referencing (CPR), as two possible techniques to obtain the desired degree of tibial slope. METHODS: A previously validated musculoskeletal model of a 86-year-old male subject, having a cruciate-retaining (CR) TKA prosthesis, was used to simulate a squat activity [1]. Motion-capture data were input to a motion optimization algorithm to find the full body kinematics. Quadriceps muscle forces were then calculated using inverse-dynamics. The kinematics of the TF contact point and PF joint contact forces were simultaneously calculated using force-dependent kinematics. A baseline case with 0° tibial slope was simulated, plus four additional cases with anterior (-3°), and posterior (+3°, +6°, +9°) tibial slope using the ACR technique (Fig. 1a), and four using the CPR technique (Fig. 1b). RESULTS: Compared to the baseline, more posterior tibial slope with ACR technique resulted in a larger excursion of the TF contact point, which shifted to a more anterior position, on the lateral side, and a more posterior position, on the medial side, in extension (Fig. 2). With the CPR technique, the contact point in extension shifted gradually more posterior on both sides with more posterior slope, and in flexion it shifted gradually more posterior mainly on the lateral side. The peak quadriceps force decreased on average by 1.7 and 1.2 % BW per degree of more posterior slope, with the ACR and CPR techniques, respectively. However, due to the different relative position of patella and femur, the peak PF contact force was mainly reduced by increasing the posterior slope with the CPR technique (-3.9 % BW/degree), rather than with the ACR technique (-1.5 % BW/degree) (Fig. 3). DISCUSSION: Increasing the tibial slope using the ACR technique produced large changes in the TF kinematics: the pattern of the contact point became more unstable, with a larger AP movement observed on the lateral side, denoting increased anterior-posterior laxity. On the other hand, variations of tibial slope with CPR technique resulted in more stable TF kinematics, more posterior position of the TF contact point, and a greater reduction of the PF contact forces. It is advisable to pre-plan the desired amount of tibial slope and execute it using the CPR technique. The surgeon should be very careful applying too much tibial slope with the ACR technique in CR-TKA, as it may have devastating effects on the TF kinematics, laxity and PF forces. SIGNIFICANCE: This study provides new insights into the effect of variation of tibial slope in TKA using different surgical techniques, which were not documented before, and used a highly controlled and parameterized study design and dynamic loading conditions. Orthopedic surgeons can directly use these results as an indication for the clinical practice. The presented tool can also be very useful for educational/medical training purposes. REFERENCES: [1] Marra MA, Vanheule V, Fluit R, et al. A Subject-Specific Musculoskeletal Modeling Framework to Predict In Vivo Mechanics of Total Knee Arthroplasty. ASME. J Biomech Eng. 2015;137(2):020904-020904-12 ACKNOWLEDGEMENTS: The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013) / ERC Grant Agreement n. 323091 awarded to N. Verdonschot

The effects of meteorological factors on the occurrence of Ganoderma sp. spores in the air

Ganoderma sp. is an airborne fungal spore type known to trigger respiratory allergy symptoms in sensitive patients. Aiming to reduce the risk for allergic individuals, we analysed fungal spore circulation in Szczecin, Poland, and its dependence on meteorological conditions. Statistical models for the airborne spore concentrations of Ganoderma sp.—one of the most abundant fungal taxa in the area—were developed. Aerobiological sampling was conducted over 2004–2008 using a volumetric Lanzoni trap. Simultaneously, the following meteorological parameters were recorded: daily level of precipitation, maximum and average wind speed, relative humidity and maximum, minimum, average and dew point temperatures. These data were used as the explaining variables. Due to the non-linearity and non-normality of the data set, the applied modelling techniques were artificial neural networks (ANN) and mutlivariate regression trees (MRT). The obtained classification and MRT models predicted threshold conditions above which Ganoderma sp. appeared in the air. It turned out that dew point temperature was the main factor influencing the presence or absence of Ganoderma sp. spores. Further analysis of spore seasons revealed that the airborne fungal spore concentration depended only slightly on meteorological factors

Spatial and Temporal Variations in the Annual Pollen Index Recorded by Sites Belonging to the Portuguese Aerobiology Network

This study presents the findings of a 10-year survey carried out by the Portuguese Aerobiology Network (RPA) at seven pollen-monitoring stations: five mainland stations (Oporto, Coimbra, Lisbon, Évora and Portimão) and two insular stations [Funchal (Madeira archipelago) and Ponta Delgada (Azores archipelago)]. The main aim of the study was to examine spatial and temporal variations in the Annual Pollen Index (API) with particular focus on the most frequently recorded pollen types. Pollen monitoring (2003–2012) was carried out using Hirst-type volumetric spore traps, following the minimum recommendations proposed by the European Aerobiology Society Working Group on Quality Control. Daily pollen data were examined for similarities using the Kruskal–Wallis nonparametric test and multivariate regression trees. Simple linear regression analysis was used to describe trends in API. The airborne pollen spectrum at RPA stations is dominated by important allergenic pollen types such as Poaceae, Olea and Urticaceae. Statistically significant differences were witnessed in the API recorded at the seven stations. Mean API is higher in the southern mainland cities, e.g. Évora, Lisbon and Portimão, and lower in insular and littoral cities. There were also a number of significant trends in API during the 10-year study. This report identifies spatial and temporal variations in the amount of airborne pollen recorded annually in the Portuguese territory. There were also a number of significant changes in API, but no general increases in the amount of airborne pollen