Evaluation of tomato cultivars to Helicoverpa armigera using two-sex life table parameters in laboratory

Helicoverpa armigera (Hübner) is one of the most important pests of a wide range of agricultural crops worldwide. Resistance of 10 tomato cultivars (‘Primoearly,’ ‘Riogrand,’ ‘CaljN3,’ ‘Kingstone,’ ‘Earlyurbana,’ ‘Petomech,’ ‘EarlyurbanaY,’ ‘Mobil,’ ‘Imprial’ and ‘Petoearly’) to H. armigera was evaluated under laboratory conditions at 25 ± 1 °C, 60 ± 5% RH and a photoperiod of 16:8 (L:D) hours using age-stage, two-sex life table parameters. The larval period ranged from 19.96 on ‘Riogrand’ to 24.58 days on ‘Imprial.’ The insects reared on ‘Imprial’ had the longest total preoviposition period (44.80 days) and those reared on ‘Riogrand’ had the shortest one (35.44 days). The longest adult longevity for female and male was observed on ‘EarlyurbanaY’ (14.40 days) and ‘Kingstone’ (15.00 days), respectively. Using age-stage, two-sex life table, the value of the net reproductive rate (R₀) varied from 7.8 on ‘Imprial’ to 186.9 offspring per individual on ‘Petomech.’ The lowest value of the intrinsic rate of increase (r) and finite rate of increase (λ) was on ‘Imprial’ (0.0410 and 1.0423 day^− 1, respectively) and the highest was on ‘Petomech’ (0.1274 and 1.1359 day^− 1, respectively). The mean generation time (T) on different cultivars varied from 39.9 to 48.2 days. The results revealed that ‘Petomech’ was the most susceptible (suitable) and ‘Imprial’ was the most resistant (unsuitable) cultivar to this pest among the tomato cultivars tested.     

Musculoskeletal-see-through mirror: Computational modeling and algorithm for whole-body muscle activity visualization in real time

In this paper, we present a system that estimates and visualizes muscle tensions in real time using optical motion capture and electromyography (EMG). The system overlays rendered musculoskeletal human model on top of a live video image of the subject. The subject therefore has an impression that he/she sees the muscles with tension information through the cloth and skin. The main technical challenge lies in real-time estimation of muscle tension. Since existing algorithms using mathematical optimization to distribute joint torques to muscle tensions are too slow for our purpose, we develop a new algorithm that computes a reasonable approximation of muscle tensions based on the internal connections between muscles known as neuronal binding. The algorithm can estimate the tensions of 274 muscles in only 16 ms, and the whole visualization system runs at about 15 fps. The developed system is applied to assisting sport training, and the user case studies show its usefulness. Possible applications include interfaces for assisting rehabilitation.     

Effect of plant spacing on the growth,flowering and bulb production of four lachenalia cultivars

A 2-year field experiment was performed with lachenalia (‘Namakwa’, ‘Ronina,’ ‘Rosabeth’ and ‘Rupert’) to study the effects of planting density on leaf formation, inflorescence quality and bulb production. Bulbs 6.0 cm in circumference were planted at a spacing of 2.0 × 5.0 cm, 3.0 × 7.0 cm and 5.0 × 10.0 cm, and cultivated in the open air in Polish conditions in 2009 and 2010. The spacing affected the number of leaves only in lachenalia ‘Namakwa’ in 2010. In the other cases, the bulbs formed 2–3 leaves. Plant height increased with the high-density treatment, but flower yield and the total time to the beginning of flowering were independent of planting density. The cultivars proved to differ in terms of the time of blooming: ‘Namakwa’ and ‘Ronina’ flowered earlier (after 63–73 days) than ‘Rosabeth’ and ‘Rupert’ (after 82–90 days). Plant arrangement had little effect on inflorescence length and the number of florets. Irrespective of the spacing, lachenalia ‘Rupert’ seemed to be the most floriferous — one bulb produced even 30 flowers. Lower planting density influenced advantageously the quality of bulbs (circumference and weight), without affecting their quantity (number of bulbs from one plant).     

Impact of temperature on olive (Olea europaea L.) pollen performance in relation to relative humidity and genotype

Olive varieties ‘Koroneiki’, ‘Kalamata’, ‘Mastoidis’ and ‘Amigdalolia’ were employed in two experiments for 3 years to assess the effect of temperature on olive pollen germination and tube growth in relation to relative humidity and genotype. Pollen samples were subjected to pre-incubation at 10, 20, 30 or 40 °C in combination with decreased air relative humidity – 80, 40, 30 or 20%, respectively – for 24 h to simulate temperature stress that is observed during pollen dispersal; and subsequently in vitro cultured. In the second experiment, pollen was exposed at 15, 20, 25 and 30 °C for 24 h in vitro to evaluate pollen response in conditions of water and nutrients availability and to determine the optimum pollen germination and tube growth temperatures for each cultivar. The highest pre-incubation temperature treatment (40 °C) prevented pollen germination in ‘Koroneiki’ and ‘Mastoidis’, with the less affected varieties (‘Amigdalolia’ and ‘Kalamata’) having average germination percentages of only 7.6 and 2%, respectively. Pre-incubation at 30 °C had a negative impact on pollen germination in ‘Koroneiki’ (?65%), ‘Kalamata’ (?20%) and ‘Amigdalolia’ (?72%) compared to the control (20 °C). Pollen pre-incubation at 40 °C decreased significantly the pollen tube length in ‘Kalamata’ (?50%) and ‘Amigdalolia’ (?52%). In the second experiment, in vitro pollen germination increased after incubation at 25 °C for ‘Koroneiki’ (+6%), ‘Mastoidis’ (+52%), ‘Kalamata’ (+10%) and ‘Amigdalolia’ (+10%) compared to the control (20 °C). At 30 °C germination percentages for ‘Mastoidis’, ‘Kalamata’ and ‘Amigdalolia’ were 8, 6 and 14% higher, respectively, compared to the control (20 °C). Pollen tube length also increased with incubation temperature for all of the studied cultivars. Based on the cumulative stress response index (CSRI) that was calculated for high temperature stress the varieties were classified: ‘Mastoidis’ and ‘Kalamata’ as tolerant and ‘Koroneiki’ and ‘Amigdalolia’ as intermediate at 30 °C while all studied cultivars were sensitive at 40 °C. The observed strong genotype-differentiated response in high and low temperature stress could be exploited by plant breeders towards producing new tolerant olive varieties.     

Analysis of different effects on longevity in four sheep breeds of northern Germany

The lifetime performance of female sheep is one of the most important economic traits in sheep husbandry. In this investigation, a Weibull model was used to study the effects of ‘breed’, ‘number of lambings’, ‘age at first lambing’, ‘type of birth’ and ‘farm’ on the length of productive life (LPL). The data included records of 5191 female sheep of four different breeds on 236 breeding farms in northern Germany. The observation period in which the sheep were born or were removed from the farm ranged from January 2003 to December 2007. About 12% of the records were right-censored. All variables had a significant effect on LPL at a level of p < 0.001 except ‘type of birth’. The German Blackheaded Mutton breed showed the lowest risk ratio with 0.77 (SE = 0.17), while the Texel had the highest hazard rate (1.00). The relative culling risk initially decreased from the first (5.73, SE = 0.09) to the seventh lambing (0.36, SE = 0.12), and then increased until lambing number nine. The highest relative culling risk was calculated at an age of 395 to less than 455 days at first lambing (1.00). Animals younger than 395 days at first lambing showed the lowest risk ratio (0.56, SE = 0.05). The culling risk for the effect ‘farm’ ranged from 0.3 to 3.1. A differentiation of environmental, housing or management effects was not feasible with this data. But the results offer some interesting options for further studies.     

Study of morphological and phenological diversity in chestnut trees (‘Judia’ variety) as a function of temperature sum

Morphological and histological adaptation of chestnut leaves at the different altitudes and edaphoclimate conditions were shown. The study was carried out on Castanea sativa Mill. var. ‘Judia’. The growth range altitudes of ‘Judia’ were between 709 m a.s.l. and 860 m a.s.l. (above sea level), corresponding to a variation in the sum of temperatures (expressed in degree-day values – °D) of 2751 °D to 2316 °D in 2006 and 2338 °D to 1700 °D in 2007, between May and October. In 2007 the thickest leaves (319.9 μm), the highest stomata density (469.1 stomata mm⁻²), one of the largest leaf areas (69.2 cm²) and the highest fruit size (71.7 fruit kg⁻¹) were observed in Alfândega da Fé (759 m a.s.l., 2186 °D, during the May–October period) whereas in 2006 the highest fruit size (86.8 fruit kg⁻¹) was observed in Valpaços (860 m a.s.l., 2316 °D, during the same period).Additionally, the leaves of the trees grown in this locality (Valpaços) displayed one of the largest areas (57.0 cm²). Overall results suggest that annual climate conditions do significantly influence both fruit and leaf biometric characteristics, and that the range of temperatures from 2100 °D to 2300 °D (between May and October) correspond to the optimal temperature sum, which can be ascribed to different places, depending on the year in question. Concerning the molecular characterisation using nuclear microsatellites, the individuals more distant are those from Macedo de Cavaleiros and Alfândega da Fé (genetic distance = 0.227), while the ecotypes with closer similarities were those collected in Murça and Vinhais (genetic identity = 1.171). The current results suggest that the morphological and phenological differences among ecotypes are not related to the small genetic differences, but are simply phenotypic adaptations to diffent climatic conditions.     

Cation selectivity of the plasma membrane of tobacco protoplasts in the electroporated state

Cation selectivity of the cellular membrane of tobacco culture cells (cell line ‘bright yellow-2’) exposed to pulsed electric fields in the millisecond range was investigated. The whole cell configuration of the patch clamp technique was established on protoplasts prepared from these cells. Ion selectivity of the electroporated membrane was investigated by measuring the reversal potential of currents passing through field-induced pores. To this end the membrane was hyper- or depolarized for 10 ms (prepulse); subsequently the voltage was driven to opposite polarity at a constant rate (+ 40 or ? 40 mV/ms, respectively). The experiment was started by polarizing the membrane to moderately negative or positive voltages (prepulse potential ± 150 mV) that would not induce pore formation. Subsequently, an extended voltage range was scanned in the porated state of the membrane (prepulse potential ± 600 mV). IV curves in the porated and the non-porated state (obtained at the same prepulse polarity) were superimposed to determine the voltage at which both curves intersected (‘Intersection potential’). Using a modified version of the Goldmann–Hodgkin–Katz equation relative permeabilities to Ca^2 + and various monovalent alkali and organic cations were calculated. Pores were found to be fairly cation selective, with a selectivity sequence determined to be Ca^2 + > Li⁺ > Rb⁺ ≈ K⁺ ≈ Na⁺ > TEA⁺ ≈ TBA⁺ > Cl^?. Relative permeability to monovalent cations was inversely related to the ionic diameter. By fitting a formalism suggested by Dwyer at al. (J. Gen. Physiol. 75 (1980), 469–492) the effective average diameter of field induced pores was estimated to be about 1.8 nm. Implications of these results for biotechnology and electroporation theory are discussed.     

A critical evaluation of salivary testosterone as a method for the assessment of serum testosterone

Although salivary testosterone (T) is often used in clinical studies accuracy is mostly questionable. State of the art data for men is sparse and for women absent. Our objective was to perform a critical evaluation of salivary T (Sal-T) as a method for indirect assessment of serum T using state of the art methods. Saliva was collected via ‘Salivette’ and ‘passive drooling’ methods. Sal-T and free T in serum after equilibrium dialysis were measured by LC-MS/MSResultsEvaluation of Sal-T results versus free T by equilibrium dialysis (ED-T) for men gave: ‘Salivette’ Sal-T = 0.05 + 0.88x ED-T, r = 0.43; ‘passive drooling’ Sal-T = 0.17 + 0.91x ED-T r = 0.71. In women, correlation was comparable but values are higher than free T: ‘passive drooling’ Sal-T = 0.12 + 2.32x ED-T, r = 0.70. The higher than expected T values in saliva, appear to be explained by T binding to salivary proteins. Iso-electric focusing of saliva proteins, followed by fractionation and LC–MS/MS assay of T showed marked testosterone peaks at pH 5.3 and 8.4, providing evidence for T binding in saliva to proteins such as albumin and proline rich protein (PRP).ConclusionsPassive drooling is the collection method of choice for testosterone in saliva. Sal-T is not directly comparable to serum free T due to T binding to saliva proteins, which substantially affects the low Sal-T in women but not the higher Sal-T in healthy adult men.     

Mitochondrial biogenesis related endurance genotype score and sports performance in athletes

We determined the probability of individuals having the ‘optimal’ mitochondrial biogenesis related endurance polygenic profile, and compared the endurance polygenic profile of Israeli (Caucasian) endurance athletes (n = 74), power athletes (n = 81), and non-athletes (n = 240). We computed a mitochondrial biogenesis related ‘endurance genotype score’ (EGS, scoring from 0 to 100) from the accumulated combination of six polymorphisms in the PPARGC1A-NRF-TFAM pathway. Some of the variant alleles of the polymorphisms studied were so infrequent, that the probability of possessing an ‘optimal’ EGS (= 100) was 0% in the entire study population. However, the EGS was significantly higher (P < 0.001) in endurance athletes (38.9 ± 17.1) compared with controls (30.6 ± 12.4) or power athletes (29.0 ± 11.2). In summary, although the probability of an individual possessing a theoretically ‘optimal’ genetic background for endurance sports is very low, in general endurance athletes have a polygenic profile that is more suitable for mitochondrial biogenesis.     

Unweighted state as a sidestep preparation improve the initiation and reaching performance for basketball players

The preparatory motion of a defensive motion in contact sport such as basketball should be small and involve landing on both feet for strict time and motion constraints. We thus proposed the movement creating a unweighted state. Ten basketball players performed a choice reaction sidestepping task with and without the voluntary, continuous vertical fluctuation movement. The results indicated that the preparatory movement shortened the time of their sidestep initiation (301 vs. 314 ms, p = 0.011) and reaching performance (883 vs. 910 ms, p = 0.018) but did not increase their peak ground reaction force or movement velocity. The mechanism of the improvement was estimated to be the following: in the preparation phase, the vertical body fluctuation created the force fluctuation; after the direction signal, the unweighted state can shorten the time required to initiate the sidestepping (unweighted: 279 ms; weighted: 322 ms, p = 0.002); around the initiation phase, the dropping down of the body and weighted state can contribute to the reaching performance. We conducted additional experiment investigating muscle–tendon-complex dynamics and muscle activity using ultrasound device and electromyography. The result suggests that the building up of active state of muscle might explain the improvement of sidestepping performance.     

Diminished sub-maximal quadriceps force control in anterior cruciate ligament reconstructed patients is related to quadriceps and hamstring muscle dyskinesia

The aim of this study was to determine the effects of anterior cruciate ligament reconstruction (ACLR) on sub-maximal quadriceps force control with respect to quadriceps and hamstring muscle activity. Thirty ACLR individuals together with 30 healthy individuals participated. With real-time visual feedback of muscle force output and electromyographic electrodes attached to the quadriceps and hamstring muscles, subjects performed an isometric knee extension task where they increased and decreased their muscle force output at 0.128 Hz within a range of 5–30% maximum voluntary capacity. The ACLR group completed the task with more error and increased medial hamstring and vastus medialis activation (p < 0.05). Moderate negative correlations (p < 0.05) were observed between quadriceps force control and medial (Spearman’s rho = −0.448, p = 0.022) and lateral (Spearman’s rho = −0.401, p = 0.034) hamstring activation in the ACLR group. Diminished quadriceps sub-maximal force control in ACLR subjects was reflective of medial quadriceps and hamstring dyskinesia (i.e., altered muscle activity patterns and coordination deficits). Within the ACLR group however, augmented hamstring co-activation was associated with better quadriceps force control. Future studies should explore the convergent validity of quadriceps force control in ACLR patients.     

Differential protein expression for geothermal Agrostis scabra and turf-type Agrostis stolonifera differing in heat tolerance

Heat stress is a major factor limiting the growth of cool-season grasses in warm climatic regions by affecting many physiological processes, including protein metabolism. Protein degradation often occurs with increasing temperatures, but certain specific proteins such as heat shock proteins (HSPs) may be induced or enhanced in their expression under supraoptimal temperatures. The objectives of this study were to determine the critical temperature that causes protein induction or degradation in two Agrostis grass species differing in heat tolerance and to compare protein profiles between the two species under different temperature regimes. Plants of heat-tolerant Agrostis scabra and two cultivars of heat-sensitive Agrostis stolonifera (‘L-93’ and ‘Penncross’) were exposed to constant day/night temperatures of 20, 30, 35, 40, or 45 °C for 14 d. Leaf photochemical efficiency (Fv/Fm), chlorophyll and carotenoid contents, and soluble protein content declined with increasing temperatures. The decreases were the least severe for A. scabra, intermediate for ‘L-93’, and the most severe for ‘Penncross’, indicating interspecific and intraspecific variations in heat tolerance in Agrostis species. Protein degradation was observed at 30–45 °C in both cultivars of A. stolonifera, and at 40–45 °C in A. scabra.HSPs were induced or enhanced at 35–45 °C in ‘L-93’ and A. scabra, and at 40–45 °C in ‘Penncross’. Immunoblotting also revealed stronger expressions of HSP60 and HSP70 in A. scabra or ‘L-93’ than in ‘Penncross’ at 35–45 °C after 3 d. The results suggested the superior heat tolerance of Agrostis grass species and cultivars could be attributed to the early induction of HSPs, particularly small molecular weight (23 kDa), at a lower level of heat stress and the maintenance of protein thermostability, particularly high-molecular weight proteins (83 kDa and large units of Rubisco).     

The structural definition of some novel adducts of stoichiometry CuX:dpex:MeCN (2:1:1)(n), X = (pseudo-) halogen,dppx = Ph2E(CH2)xEPh2, E = P,As, Sb

Single-crystal X-ray studies have defined the structures of a number of novel adducts of the form CuX:dpex (2:1), X = (pseudo-)halide, dpex = bis(diphenylpnicogeno)alkane, Ph₂E(CH₂)_xEPh₂, E = P, As, of diverse types, solvated with acetonitrile. CuBr:dpem (2:1)₂. 2MeCN (E = both P, As) are tetranuclear, derivative of the familiar ‘step’ structure, while CuCl:dpph (MeCN solvate) and CuBr:dppe (MeCN solvate) yield one-dimensional polymers (i.e., x = 1, 2, 6 for dppx, x = m, e, h), as also does CuSCN:dpam (MeCN solvate). In CuI:dpsm:MeCN (3:1:2) (‘dpsm’ = Ph₂Sb(CH₂)SbPh₂), CuI:dpsm (2:1)₂ ‘step’ units are connected into an infinite ‘stair’ polymer by interspersed (MeCN)CuI linkers.     

Comparaison entre les modes d’acquisition 2D et 3D en TEP au FDG

AimSome positron emission tomography (PET) cameras offer the possibility of choosing between the 2D and 3D acquisition modes. Due to the lack of comparative and objective data in the litterature between the two modes in clinical routine conditions, we have performed a comparative study based on the assessment of qualitative and quantitative parameters.Materials and methodsA series of 33 FDG PET studies has been prospectively selected in the nuclear medicine department. All studies have been performed with a Discovery ST^® camera (GE healthcare) first in the 2D or 3D mode according to the usual criteria of the department. Then a new single step was acquired on a pathological region using the other mode. The same single slice was chosen and analyzed in the two modes (blindly and in random order) by seven nuclear physicians in terms of qualitative and quantitative parameters.ResultsThe 2D mode is significantly better than 3D concerning the overall image quality for patients with a body mass index (BMI) > 27.5 (p = 0.006) and concerning the confidence in lesion reporting for patients with a BMI > 25 (p = 0.01). The mean number of detected lesions is not affected by the acquisition mode but it is significantly correlated with the image quality and the confidence in lesion reporting (p = 0.07 and p = 0.013, respectively).ConclusionWith the Discovery ST PET-CT, the 2D mode gives better results than 3D for overweight and obese patients in terms of image quality and confidence in lesion reporting.     

Algorithmic detection of the beginning and end of bipolar electrograms: Implications for novel methods to assess local activation time during atrial tachycardia

Activation mapping is required to effectively ablate atrial tachycardia (AT). Conventional tools to assess local activation time (LAT) are based upon the peak of the bipolar electrogram (B-EGM, LAT_Peak) and the maximal negative slope of the unipolar electrogram (U-EGM, LAT_Slope). Bipolar electrograms are influenced by wavefront direction, bipole orientation, and inter-electrode spacing causing ambiguity in peak detection, whereas unipolar electrograms are disturbed by the presence of far-field signals. We developed a new algorithm to detect the beginning and end of bipolar electrograms (t_begin and t_end). Then, we introduced new LAT methods related to the onset of B-EGMs (LAT_Onset), the center of mass of B-EGMs (LAT_CoM), and the slope of U-EGMs within a pre-defined window (LAT_Slope-hybrid).In total 3752 recordings from 31 AT patients were retrospectively analyzed. The signal-to-noise ratio (SNR) for B-EGMs was calculated to differentiate algorithmically high from low quality electrograms (HQ and LQ). In a subset of 328 B-EGMs, five experts validated the t_begin as determined by the algorithm by visual rating. The newly developed LAT methods were compared to the conventional LAT methods and to one another (Bland–Altman plots) in both HQ (n = 3003) and LQ EGMs (n = 749).The t_begin algorithm was accurate (deviation < ±10 ms) in 96 ± 4% of HQ and 91 ± 8% of LQ B-EGMs. BA plots revealed the following difference (bias) and variation in HQ and LQ EGMs respectively: (1) LAT_Onset vs. LAT_Peak: 27 ± 30 ms and 24 ± 62 ms; (2) LAT_CoM vs. LAT_Peak: 0 ± 16 ms and 2 ± 38 ms; (3) LAT_Slope-hybrid vs. LAT_Slope: 1 ± 32 ms and 15 ± 110 ms; (4) LAT_Onset vs. LAT_CoM: 22 ± 24 ms and 18 ± 22 ms; (5) LAT_Onset vs. LAT_Slope-hybrid: 16 ± 18 ms and 13 ± 22 ms; and (6) LAT_CoM vs. LAT_Slope-hybrid: 5 ± 20 ms and 4 ± 18 ms.In the present study, we introduced three new methods to assess local activation time in AT, based upon an algorithm detecting accurately the beginning and end of the B-EGM complex. BA analysis of the new methods showed similar variation in high and low quality EGMs, suggesting that they introduce less ambiguity than the conventional peak method. LAT_Onset consistently yielded an earlier activation moment. LAT_Slope-hybrid – by blanking far-field potentials – seems to be the optimal method for detection of the maximal negative slope in U-EGMs. Interestingly, LAT_CoM in B-EGMs coincided with the maximal negative slope in U-EGMs, suggesting its physiological sense and future use. The new LAT methods can be implemented in real-time mapping applications.     

Effects of gender and age on median and ulnar nerve sensory responses over ring finger

ObjectiveTo analyze the effect of gender on median nerve (MN) and ulnar nerve (UN) sensorial responses over ring finger (RF).Materials and methodsResults of individuals admitted to our ENMG laboratory between June 2011 and March 2012 for nerve conduction studies (NCSs) were retrospectively analyzed. Sensory NCSs were performed by standard antidromic technique.ResultsTotally, 112 normal recordings belong to 100 patients were included. Mean antidromic sensory conduction velocity of MNs (wrist-to-second finger) or UNs (wrist-to-fifth finger) was not different between two genders. Mean sensory nerve action potential (SNAP) amplitude of MN from second finger was also not different between two genders. However, mean SNAP amplitude of UN from fifth finger was higher in females. In RF’s sensorial response studies; mean peak latency of MN was similar between females and males (3.05 ± 0.25 ms vs. 3.14 ± 0.29 ms, p = 0.111), whereas one of UN was shorter in females (2.86 ± 0.22 ms vs. 3.04 ± 0.31 ms, p = 0.001). MN to UN latency difference to RF was greater in females than males (0.19 ± 0.15 ms vs. 0.10 ± 0.16 ms, p = 0.007). Mean SNAP amplitude of MN and UN were both higher in females than males (17.9 ± 7.1 μV vs. 14.1 ± 5.5 μV, p = 0.011 and 18.5 ± 8.0 μV vs. 12.9 ± 6.1 μV, p = 0.0009, respectively). All data of NCSs were re-analyzed after adjustment for age, and obtained findings regarding effect of aging are also included.ConclusionGender has a prominent effect on RF’s sensorial responses. Normative values regarding them should be prepared with adjustment for gender.     

Quantifying ‘normal’ shoulder muscle activity during abduction

The purpose of this experiment was to obtain electromyographic (EMG) activity from a sample of healthy shoulders to allow a reference database to be developed and used for comparison with pathological shoulders. Temporal and intensity shoulder muscle activation characteristics during a coronal plane abduction/adduction movement were evaluated in the dominant healthy shoulder of 24 subjects. Surface and intramuscular fine wire electrodes recorded EMG activity from 15 shoulder muscles (deltoid × 3, trapezius × 3, subscapularis × 2, latissimus dorsi, pectoralis major, pectoralis minor, supraspinatus, infraspinatus, serratus anterior and rhomboids) at 2000 Hz for 10 s whilst each subject performed 10 dynamic coronal plane abduction/adduction movements from 0° to 166° to 0° with a light dumbbell. Results revealed that supraspinatus (?.102 s before movement onset) initiated the movement with middle trapezius (?.019 s) and middle deltoid (?.014 s) also activated before the movement onset. Similar patterns were also found in the time of peak amplitude and %MVC with a pattern emerging where the prime movers (supraspinatus and middle deltoid) were among the first to reach peak amplitude or display the highest %MVC values. In conclusion, the most reproducible patterns of activation arose from the more prime mover muscle sites in all EMG variables analysed and although variability was present, there emerged ‘invariant characteristics’ that were considered ‘normal’ for this group of non pathological shoulders. The authors believe that the methodology and certain parts of the analysis in this study can be duplicated and used by future researchers who require a reference database of muscle activity for use as a control group in comparisons to their respective pathological shoulder group.     

Torque-onset determination: Unintended consequences of the threshold method

Background: Compared with visual torque-onset-detection (TOD), threshold-based TOD produces onset bias, which increases with lower torques or rates of torque development (RTD). Purpose: To compare the effects of differential TOD-bias on common contractile parameters in two torque-disparate groups. Methods: Fifteen boys and 12 men performed maximal, explosive, isometric knee-extensions. Torque and EMG were recorded for each contraction. Best contractions were selected by peak torque (MVC) and peak RTD. Visual-TOD-based torque-time traces, electromechanical delays (EMD), and times to peak RTD (tRTD) were compared with corresponding data derived from fixed 4-N m- and relative 5%MVC-thresholds. Results: The 5%MVC TOD-biases were similar for boys and men, but the corresponding 4-N m-based biases were markedly different (40.3 ± 14.1 vs. 18.4 ± 7.1 ms, respectively; p < 0.001). Boys–men EMD differences were most affected, increasing from 5.0 ms (visual) to 26.9 ms (4 N m; p < 0.01). Men’s visually-based torque kinetics tended to be faster than the boys’ (NS), but the 4-N m-based kinetics erroneously depicted the boys as being much faster to any given %MVC (p < 0.001). Conclusions: When comparing contractile properties of dissimilar groups, e.g., children vs. adults, threshold-based TOD methods can misrepresent reality and lead to erroneous conclusions. Relative-thresholds (e.g., 5% MVC) still introduce error, but group-comparisons are not confounded.     

Spectral K-edge subtraction imaging of experimental non-radioactive barium uptake in bone

PurposeTo evaluate the feasibility of using non-radioactive barium as a bone tracer for detection with synchrotron spectral K-edge subtraction (SKES) technique.MethodsMale rats of 1-month old (i.e., developing skeleton) and 8-month old (i.e., skeletally mature) were orally dosed with low dose of barium chloride (33 mg/kg/day Ba²⁺) for 4 weeks. The fore and hind limbs were dissected for imaging in projection and computed tomography modes at 100 μm and 52 μm pixel sizes. The SKES method utilizes a single bent Laue monochromator to prepare a 550 eV energy spectrum to encompass the K-edge of barium (37.441 keV), for collecting both ‘above’ and ‘below’ the K-edge data sets in a single scan.ResultsThe SKES has a very good focal size, thus limits the ‘crossover’ and motion artifacts. In juvenile rats, barium was mostly incorporated in the areas of high bone turnover such as at the growth plate and the trabecular surfaces, but also in the cortical bone as the animals were growing at the time of tracer administration. However, the adults incorporated approximately half the concentration and mainly in the areas where bone remodeling was predominant and occasionally in the periosteal and endosteal layers of the diaphyseal cortical bone.ConclusionsThe presented methodology is simple to implement and provides both structural and functional information, after labeling with barium, on bone micro-architecture and thus has great potential for in vivo imaging of pre-clinical animal models of musculoskeletal diseases to better understand their mechanisms and to evaluate the efficacy of pharmaceuticals.     

Novel formulation of a double threshold algorithm for the estimation of muscle activation intervals designed for variable SNR environments

The aim of this work is the development of an improved formulation of the double threshold algorithm for sEMG onset–offset detection presented by Bonato and co-workers. The original formulation, which keeps the threshold fixed, suffers from performance degradation whenever the SNR changes during the analysis. The novel approach is designed to be adaptive to SNR changes in either burst or inter-burst zones of sEMG signals recorded in static and dynamic conditions. The detection parameters (i.e. detection and false alarm probabilities) are updated on the basis of an on-line estimation of the SNR. The proposed formulation has been assessed on both simulated and real sEMG data. For constant SNR the performance of the original formulation is confirmed (for SNR > 8 dB, bias and standard deviation less than 10 and 15 ms, respectively; detection percentage higher than 95%), while the novel implementation performs better with time-varying SNR (for SNR varying in the range 10–25 dB the standard approach detection percentage decreases at 50%). Detection on signals recorded during isometric contractions at different force levels confirms the performance on simulated signals (StD = 134 ms; FP = 22%, and StD = 42 ms; FP = 2%, respectively for standard and novel implementation calculated as average on five experimental trials). The pseudo real-time detection allowed by this formulation can be profitably exploited by biofeedback applications based on myoelectric information.