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Featured Application: The present study intends to help and support clinicians and specialists in the decision process concerning the length and type of stems to use in case varus–valgus deformity is present in a patient. Hinged total knee arthroplasty (TKA) is a valid option to treat patients during revision of an implant; however, in case of varus/valgus deformity, the force transmission from the femur to the tibia could be altered and therefore the performance of the implant could be detrimental. To be able to evaluate this, the goal of this study was to investigate, using a validated finite element analysis, the effect of varus/valgus load configurations in the bones when a hinged TKA is used. In detail, short and long stem lengths (50 mm, and 120 mm), were analyzed both under cemented or press-fit fixation under the following varus and valgus deformity: 5°, 10°, 20°, and 30°. The main outputs of the study were average bone stress in different regions of interest, together with tibio-femoral contact pressure and force. Results demonstrated that changes in the varus or valgus deformity degrees induce a change in the medio-lateral stress and force distribution, together with a change in the contact area. The effect of stem length and cement do not alter the tibio-femoral contact biomechanics but its effect is mainly localized in the distal femoral region, and it is negligible in the proximal regions., SCOPUS: ar.j, info:eu-repo/semantics/published

Researchers have long sought to predict the mechanical behavior of polyethylene from its microstructure. In particular, the yield strength and yield kinetics have been reported to be dependent on crystallinity and crystal thickness, but the relative importance of these two microstructural attributes has not been shown. In the present work, a series of microstructures was obtained through a combination of controlled quench rates from the melt and inclusion of various amounts of hexene comonomer. The yield strength for a wide range of strain-rates was linearly dependent on the crystallinity, and independent of crystal thickness (chain stem length), both measured by Raman spectroscopy. Similarly, yield kinetics described by a Ree-Eyring two-process stress activated model showed linear dependence on crystallinity and no dependence on crystal thickness. The results of the present work call into question models of yield kinetics dependent on screw dislocation nucleation, which depend on crystal thickness.

Adequate fixation is a requisite for hinged Total Knee Arthroplasty (TKA): consequently, several stem solutions are currently available. However, there are no evidence-based biomechanical guidelines for surgeons to determine the appropriate stem length and whether to use cemented or press-fit fixation. The objective of this study is therefore to compare, using a validated finite-element model, bone stresses and implant micromotions in different configurations., SCOPUS: ar.j, info:eu-repo/semantics/published

Introduction: No evidence-based guidelines are available to determine the appropriate stem length, and whether or not to cement stems in revision total knee arthroplasty (TKA). Therefore, the objective of this study was to compare stresses and relative movement of cemented and uncemented stems of different lengths using a finite element analysis. Materials and methods: A finite element model was created for a synthetic tibia. Two stem lengths (95 and 160 mm) and two types of fixation (cemented or press fit) of a hinged TKA were examined. The average compressive stress distribution in different regions of interest, as well as implant micromotions, was determined and compared during lunge and squat motor tasks. Results: Both long and short stems in revision TKA lead to high stresses, primarily in the region around the stem tip. The presence of cement reduces the stresses in the bone in every region along the stem. Short stem configurations are less affected by the presence of cement than the long stem configuration. Press-fit stems showed higher micromotions compared to cemented stems. Conclusions: Lowest stresses and micromotion were found for long cemented stems. Cementless stems showed more micromotion and increased stress levels especially at the level of the stem tip, which may explain the clinical phenomenon of stem-end pain following revision knee arthroplasty. These findings will help the surgeon with optimal individual implant choice., SCOPUS: ar.j, info:eu-repo/semantics/published

Conventional breeding programmes on common vetch (Vicia sativa L.) are based on knowledge of relationships between forage yield components and economically important characteristics. To improve this knowledge, a small-plot trial was carried out in 2005 and 2006 at Rimski Sancevi, Serbia, with fourteen common vetch accessions from the Novi Sad Vicia collection of diverse geographic origin and collection status. Results showed significant variability in forage yield components and related characteristics. Two-year average values of forage dry matter (DM) yield ranged from 8.0 t ha(-1) (cvs. Armantes and Labari) to 10.2 t ha(-1) (cv. Slavej). The highest 2-year average concentration of crude protein (CP) was for cv. Armantes (239 g kg(-1) DM). Highly significant positive genetic correlation coefficients were found between time from sowing to first flowering and main stem length (0.938) and between number of stems per plant and CP content in the forage DM (0.910). Significant positive phenotypic correlation coefficients were detected between main stem length and time from sowing to first flowering (0.830). A cluster analysis showed four main groups of cultivars based on the recorded forage yield components and related characteristics. It is concluded that common vetch represents a stable and reliable source of protein-rich forage for regions such as the Balkans area of SE Europe. Genetic variability within common vetch and knowledge of the tested cultivars offer a basis for further improvement and developing novel cultivars.

A study was carried out to explore the effect of length of stem and stage of harvest on vase life and display quality of tuberose. As regards stem length, 90 cm stem length (L4) had longest vase life, maximum uptake of water, minimum loss-uptake ratio, maximum fresh weight and percentage of opened florets, and, lowest percentage of abscised floret; whereas, 60 cm stem length (L2) enhanced longevity of individual florets. In the case of stage of harvest, significantly high vase life, least loss of water, minimum loss-uptake ratio and lowest physiological loss of weight were recorded in two-florets open stage (S3). Maximum percentage of opened florets and lowest percentage of abscised florets were observed in three-florets open stage (S4), whereas, maximum uptake of water and fresh weight of spike were seen in one-floret open stage (S2). Interaction effect of stem length and harvest stage was also found to be significant showing that 75 cm of stem length with one-floret open stage (L3S2) was superior for maximum vase life of spike as well as lowest physiological loss of weight.

A study was carried out to explore the effect of length of stem and stage of harvest on vase life and display quality of tuberose. As regards stem length, 90 cm stem length (L4) had longest vase life, maximum uptake of water, minimum loss-uptake ratio, maximum fresh weight and percentage of opened florets, and, lowest percentage of abscised floret; whereas, 60 cm stem length (L2) enhanced longevity of individual florets. In the case of stage of harvest, significantly high vase life, least loss of water, minimum loss-uptake ratio and lowest physiological loss of weight were recorded in two-florets open stage (S3). Maximum percentage of opened florets and lowest percentage of abscised florets were observed in three-florets open stage (S4), whereas, maximum uptake of water and fresh weight of spike were seen in one-floret open stage (S2). Interaction effect of stem length and harvest stage was also found to be significant showing that 75 cm of stem length with one-floret open stage (L3S2) was superior for maximum vase life of spike as well as lowest physiological loss of weight.

During production of plug transplants, high plant density and small cell size increases seedling height. The resulting tall, weak-stemmed, plants are difficult to transplant and can be easily damaged. One technique that can prevent excessive seedling elongation is irrigation with cold water. Seedlings of tomato, pepper and eggplant were planted in cell plug trays in greenhouses and irrigated daily, in the morning, with water at different temperatures. The temperatures tested were 3°C, 9°C and tap water (15.5-16.5°C). Irrigation with cold water reduced seedling stem height by 48-58% in tomato, 24-42% in pepper and 17-36% in eggplant. Cold water irrigation significantly affected stem diameter, number of leaves, shoot and root dry weights and leaf chlorophyll content. These results show that irrigation with cold water can effectively control plant height in plug-grown seedlings.

During production of plug transplants, high plant density and small cell size increases seedling height. The resulting tall, weak-stemmed, plants are difficult to transplant and can be easily damaged. One technique that can prevent excessive seedling elongation is irrigation with cold water. Seedlings of tomato, pepper and eggplant were planted in cell plug trays in greenhouses and irrigated daily, in the morning, with water at different temperatures. The temperatures tested were 3°C, 9°C and tap water (15.5-16.5°C). Irrigation with cold water reduced seedling stem height by 48-58% in tomato, 24-42% in pepper and 17-36% in eggplant. Cold water irrigation significantly affected stem diameter, number of leaves, shoot and root dry weights and leaf chlorophyll content. These results show that irrigation with cold water can effectively control plant height in plug-grown seedlings.

In many plant species, including chrysanthemum, a strong positive correlation between internode length and DIF [difference between day (DT) and night (NT) temperature] has been observed. However, Langton and Cockshull (1997, Scientia Horticulturae 69: 229–237) reported no such relationship and showed that absolute DT and NT explained internode length rather than DIF. To investigate these conflicting results and to clarify the validity of the DIF concept, cut chrysanthemums (Chrysanthemum ‘Reagan Improved’) were grown in growth chambers at all 16 combinations of four DT and four NT (16, 20, 24 and 28 °C) with a 12 h daylength. Length of internode 10, number of internodes and stem length were measured on days 5, 10, 17, 22 and 27 after starting the temperature treatments. Internode length on day 10 showed a positive linear relationship with DIF (R2 = 0?64). However, when internodes had reached their final length in all treatments (day 27), a much stronger positive linear relation was observed (R2 = 0?81). A model to predict final internode length was developed based on the absolute DT and NT responses: both responses were optimum curves and no significant interaction between DT and NT occurred [final internode length (mm) = –32?23 3?56DT 1?08NT – 0?0687DT2 – 0?0371NT2; R2 = 0?91, where TD is day temperature and TN is night temperature]. It is shown that DIF can predict final internode length only within a temperature range where effects of DT and NT are equal in magnitude and opposite in sign (18–24 °C). Internode appearance rate, as well as stem length formed during the experiment, showed an optimum response to DT.