Efficient use of lactose for the lac promotercontrolled overexpression of the main antigenic protein of the foot and mouth disease virus in Escherichia coli under fed-batch fermentation conditions

Abstract: Derivatives of the lac promoter (tac, pac, rac) belong to the strongest bacterial promoters which are frequently used for the induced overexpression of foreign genes in Escherichia coli . However, their use in fermentation processes is strongly restricted because of the high cost of the inducer iso-propyl-β-D-thiogalactopyranoside (IPTG). The aim of this work was to investigate the possibility of using lac-derived promoters in high cell density processes resulting in a high yield of the induced recombinant protein if glucose is the main carbon and energy source. Lactose is tested as inducer of the main antigenic coat protein (VP1) of the foot and mouth disease (FMD) virus in a T7-RNA polymerase expression system. It was shown that lactose is able to induce the expression of the recombinant gene to an amount of the VP1 protein corresponding to 20% of the total cell protein.     

Human talus bones from the Middle Pleistocene site of Sima de los Huesos (Sierra de Atapuerca,Burgos, Spain)

Here we present and describe comparatively 25 talus bones from the Middle Pleistocene site of the Sima de los Huesos (SH) (Sierra de Atapuerca, Burgos, Spain). These tali belong to 14 individuals (11 adult and three immature). Although variation among Middle and Late Pleistocene tali tends to be subtle, this study has identified unique morphological characteristics of the SH tali. They are vertically shorter than those of Late Pleistocene Homo sapiens, and show a shorter head and a broader lateral malleolar facet than all of the samples. Moreover, a few shared characters with Neanderthals are consistent with the hypothesis that the SH population and Neanderthals are sister groups. These shared characters are a broad lateral malleolar facet, a trochlear height intermediate between modern humans and Late Pleistocene H. sapiens, and a short middle calcaneal facet. It has been possible to propose sex assignment for the SH tali based on their size. Stature estimates based on these fossils give a mean stature of 174.4 cm for males and 161.9 cm for females, similar to that obtained based on the long bones from this same site.     

The relationship between plantar pressure and footprint shape

Fossil footprints preserve the only direct evidence of the external foot morphologies and gaits of extinct hominin taxa. However, their interpretation requires an understanding of the complex interaction among foot anatomy, foot function, and soft sediment mechanics. We applied an experimental approach aimed at understanding how one measure of foot function, the distribution of plantar pressure, influences footprint topography.     

Bringing the “General Strike” Back In: DuBois,Slavery and Emancipation

ABSTRACT

The “general strike” of slaves in the Civil War was a direct action that involved millions of small and large acts of defiance by slaves. These actions pushed President Lincoln from hesitation to full on military action, although this chapter of history has been neglected. The work of W.E.B. Du Bois reinserted the agency of slaves in their own liberation through the “general strike” but this analysis has also been pushed to the margins. David Roediger's “Seizing Freedom: Slave Emancipation and Liberty for All' is an important corrective to this historical omission.     

Segmental foot and ankle kinematic differences between rectus,planus, and cavus foot types

The presence of multiple foot types has been used to explain the variability of foot structure observed among healthy adults. These foot types were determined by specific static morphologic features and included rectus (well aligned hindfoot/forefoot), planus (low arched), and cavus (high arched) foot types. Unique biomechanical characteristics of these foot types have been identified but reported differences in segmental foot kinematics among them has been inconsistent due to differences in neutral referencing and evaluation of only select discrete variables. This study used the radiographically-indexed Milwaukee Foot Model to evaluate differences in segmental foot kinematics among healthy adults with rectus, planus, and cavus feet based on the true bony alignment between segments. Based on the definitions of the individual foot types and due to conflicting results in previous literature, the primary study outcome was peak coronal hindfoot position during stance phase. Additionally, locally weighted regression smoothing with alpha-adjusted serial t-test analysis (LAAST) was used to compare these foot types across the entire gait cycle. Average peak hindfoot inversion was −1.6° ± 5.1°, 6.7° ± 3.5°, and 13.6° ± 4.6°, for the Planus, Rectus, and Cavus Groups, respectively. There were significant differences among all comparisons. Differences were observed between the Rectus and Planus Groups and Cavus and Planus Groups throughout the gait cycle. Additionally, the Planus Group had a premature peak velocity toward coronal varus and early transition toward valgus, likely due to a deficient windlass mechanism. This assessment of kinematic data across the gait cycle can help understand differences in dynamic foot function among foot types.     

Correlations of pelvis state to foot placement do not imply within-step active control

Experimental studies of human walking have shown that within an individual step, variations in the center of mass (CoM) state can predict corresponding variations in the next foot placement. This has been interpreted by some to indicate the existence of active control in which the nervous system uses the CoM state at or near mid-stance to regulate subsequent foot placement. However, the passive dynamics of the moving body and/or moving limbs also contribute (perhaps strongly) to foot placement, and thus to its variation. The extent to which correlations of CoM state to foot placement reflect the effects of within-step active control, those of passive dynamics, or some combination of both, remains an important and still open question. Here, we used an open-loop-stable 2D walking model to show that this predictive ability cannot by itself be taken as evidence of within-step active control. In our simulations, we too find high correlations between the CoM state and subsequent foot placement, but these correlations are entirely due to passive dynamics as our system has no active control, either within a step or between steps. This demonstrates that any inferences made from such correlations about within-step active control require additional supporting evidence beyond the correlations themselves. Thus, these within-step predictive correlations leave unresolved the relative importance of within-step active control as compared to passive dynamics, meaning that such methods should be used to characterize control in human walking only with caution.     

Validity and reliability of a shoe-embedded sensor module for measuring foot progression angle during over-ground walking

Wearable systems are becoming increasingly popular for gait assessment outside of laboratory settings. A single shoe-embedded sensor module can measure the foot progression angle (FPA) during walking. The FPA has important clinical utility, particularly in populations with knee osteoarthritis, as it is a target for biomechanical treatments. However, the validity and the day-to-day reliability of FPA measurement using wearable systems during over-ground walking has yet to be established. Two gait analysis sessions on 20 healthy adults were conducted. During both sessions, participants performed natural over-ground walking in a motion capture laboratory and on a 100 m linear section of outdoor athletics track. FPA was measured in the laboratory via marker trajectory data, while the sensor module measured FPA during the outdoor track walking. Validity was examined by comparing the laboratory- and sensor-measured average FPA. Day-to-day reliability was examined by comparing the sensor-measured FPA between the first and second gait analysis sessions. Average absolute error between motion capture and sensor measured FPA were 1.7° and 2.1° at session 1 and 2, respectively. A Bland and Altman plot indicated no systematic bias, with 95% limit of agreement widths of 4.2° – 5.1°. Intraclass correlation coefficient (ICC_2k) analysis resulted in good to excellent validity (ICC = 0.89 – 0.91) and reliability (ICC = 0.95). Overall, the shoe-embedded sensor module is a valid and reliable method of measuring FPA during over-ground walking without the need for laboratory equipment.     

Initial contact and toe off event identification for rearfoot and non-rearfoot strike pattern treadmill running at different speeds

The purpose of this study was to determine the validity of kinematic based initial contact (IC) and toe-off (TO) identification algorithms for rearfoot and non-rearfoot runners across a broad range of treadmill running speeds. 14 healthy active participants completed six 20–60 s treadmill running trials at 6 speeds: 2.24, 2.68, 3.13, 3.58, 4.02, and 4.48 ms⁻¹. 3D kinematic data were collected for the last 20 s of each trial. Force plates (FP) were used as the gold standard to determine ICFP and TOFP for each step. Three algorithms for finding IC, IC_Milner, IC_Alvim, IC_Alvim-mod, and one algorithm for finding toe off, TO_Fellin, were chosen for analysis. Root mean square errors (RMSE) and difference scores with 95% confidence intervals were computed for IC, TO and stance time (ST). IC_Alvim RMSE ranged from 0.175 to 0.219 s. ST_Alvim RMSE ranged from 0.168 to 0.216 s. IC_Alvim-mod RMSE ranged from 0.105 to 0.131 s. ST_Alvim-mod RMSE ranged from 0.108 to 0.129 s. IC_Milner RMSE ranged 0.012 to 0.015 s. ST_Milner RMSE ranged 0.019 to 0.024 s. IC_Milner accuracy was inversely related to speed. IC_Milner corrected with a linear regression equation reduced differences to- 0.006 ± 0.012 s with 86% of foot strikes identified within 20 ms and 58% with 10 ms. TO_Fellin RMSE ranged from 0.012 to 0.016 s. IC_Milner adjusted for speed and TO_Fellin can be used to predict IC and TO within a broad range of treadmill running speeds (2.24–4.48 ms⁻¹) and for rearfoot and non-rearfoot strikers.     

Comparison of the hindfoot axes of a multi-segment foot model to the underlying bony anatomy

Musculoskeletal models used in gait analysis require coordinate systems to be identified for the body segments of interest. It is not obvious how hindfoot (or rearfoot) axes defined by skin-mounted markers relate to the anatomy of the underlying bones. The aim of this study was to compare the marker-based axes of the hindfoot in a multi-segment foot model to the orientations of the talus and calcaneus as characterized by their principal axes of inertia. Twenty adult females with no known foot deformities had radio-opaque markers placed on their feet and ankles at the foot model marker locations. CT images of the feet were acquired as the participants lay supine with their feet in a semi-weight bearing posture. The spatial coordinates of the markers were obtained from the images and used to define the foot model axes. Segmented masks of the tali and calcanei were used to create 3D bone models, from which the principal axes of the bones were obtained. The orientations of the principal axes were either within the range of typical values reported in the imaging literature or differed in ways that could be explained by variations in how the angles were defined. The model hindfoot axis orientations relative to the principal axes of the bones had little bias but were highly variable. Consideration of coronal plane hindfoot alignment as measured clinically and radiographically suggested that the model hindfoot coordinate system represents the posterior calcaneal tuberosity, rather than the calcaneus as a whole.     

Aeroecology meets aviation safety: early warning systems in Europe and the Middle East prevent collisions between birds and aircraft

The aerosphere is utilized by billions of birds, moving for different reasons and from short to great distances spanning tens of thousands of kilometres. The aerosphere, however, is also utilized by aviation which leads to increasing conflicts in and around airfields as well as en‐route. Collisions between birds and aircraft cost billions of euros annually and, in some cases, result in the loss of human lives. Simultaneously, aviation has diverse negative impacts on wildlife. During avian migration, due to the sheer numbers of birds in the air, the risk of bird strikes becomes particularly acute for low‐flying aircraft, especially during military training flights. Over the last few decades, air forces across Europe and the Middle East have been developing solutions that integrate ecological research and aviation policy to reduce mutual negative interactions between birds and aircraft. In this paper we 1) provide a brief overview of the systems currently used in military aviation to monitor bird migration movements in the aerosphere, 2) provide a brief overview of the impact of bird strikes on military low‐level operations, and 3) estimate the effectiveness of migration monitoring systems in bird strike avoidance. We compare systems from the Netherlands, Belgium, Germany, Poland and Israel, which are all areas that Palearctic migrants cross twice a year in huge numbers. We show that the en‐route bird strikes have decreased considerably in countries where avoidance systems have been implemented, and that consequently bird strikes are on average 45% less frequent in countries with implemented avoidance systems in place. We conclude by showing the roles of operational weather radar networks, forecast models and international and interdisciplinary collaboration to create safer skies for aviation and birds.