54 research outputs found
miRNA-34 and miRNA-210 target hexamerin genes enhancing their differential expression during early brain development of honeybee (Apis mellifera) castes
No full textDuring the honeybee larval stage, queens develop larger brains than workers, with morphological differentiation appearing at the fourth larval phase (L4), just after a boost in nutritional difference both prospective females experience. The molecular promoters of this caste-specific brain development are already ongoing in previous larval phases. Transcriptomic analyses revealed a set of differentially expressed genes in the L3 brains of queens and workers, which represents the early molecular response to differential feeding females receive during larval development. Three genes of this set, hex70b, hex70c and hex110, are more highly transcribed in the brain of workers than in queens. The microRNAs miR-34, miR-210 and miR-317 are in higher levels in the queens' brain at the same phase of larval development. Here, we tested the hypothesis that the brain of workers expresses higher levels of hexamerins than that of queens during key phases of larval development and that this differential hexamerin genes expression is further enhanced by the repressing activity of miR-34, miR-210 and miR-317. Our transcriptional analyses showed that hex70b, hex70c and hex110 genes are differentially expressed in the brain of L3 and L4 larval phases of honeybee queens and workers. In silico reconstructed miRNA-mRNA interaction networks were validated using luciferase assays, which showed miR-34 and miR-210 negatively regulate hex70b and hex110 genes by directly and redundantly binding their 3'UTR (untranslated region) sequences. Taken together, our results suggest that miR-34 and miR-210 act together promoting differential brain development in honeybee castes by downregulating the expression of the putative antineurogenic hexamerin genes hex70b and hex110.No Full Tex
Developmental pattern of esterases in Apis mellifera L honey bees. I. Stage-dependent changes of esterase isoenzymes in Africanized workers
No full textInternational audienc
Development of a KBE application to support aerodynamic design and analysis: Towards a next-generation multi-model generator
No full textThe aviation industry faces a number of challenges: it needs to produce safer, quieter and more efficient aircraft to meet the demands of the airlines and increasingly strict regulations. At the same time, engineers are becoming more scarce because the retirement age of the `baby-boom generation' is approaching. The department of Systems Engineering and Aircraft Design (SEAD) at Delft University of Technology has been developing methods to support aircraft design in order to meet these challenges for the future. One example of such a method is a generic aircraft modeling application, based on Knowledge-Based Engineering (KBE) techniques, called a Multi-Model Generator (MMG). The ICAD system was used in the past to create such an MMG. Unfortunately, this system has been discontinued. To continue research in this area, there was a need at the SEAD research group to develop a new MMG. The research group has selected GDL as a new KBE system. This system has been used to develop a new MMG. By starting the development work of the MMG as a clean-sheet design, opportunities existed to improve the modeling capabilities of the MMG. One such improvement is the modeling of fully curved wings in a practical way. A wing design procedure has been developed which is intuitive to aircraft designers, based on the planform shape of the wing and its dihedral and twist distribution. Airfoils of any shape can be used in any orientation on the wing. Accurate wing surfaces can be created for several aircraft configurations, including unconventional ones like the box wing and blended wing-body (BWB). The MMG also offers the capability to produce consistent analysis models. The foundations for aerodynamic and structural analysis modules have been laid. For this thesis work, an interface to the 3D panel code VSaero has been developed and tested for clean wings. Procedures to model wings with moveables and 'intersected' wings (e.g. wings with a pylon or fin attached to them) have been developed. With the new MMG, a large reduction in design time can be achieved. It enables the designer to obtain more knowledge about a design in an early phase of its development and eliminates repetitive, non-creative tasks. This is a step towards the further development of unconventional aircraft configurations, which have the potential to become the aircraft for the future.Aerospace Design, Integration & OperationsAerospace Engineerin
Mispatterning in the ommatidia of Apis mellifera pupae treated with a juvenile hormone analogue
No full textTo further understand the function of morphogenetic hormones in honeybee eye differentiation, the alterations in ommatidial patterning induced by pyriproxyfen, a juvenile hormone (JH) analogue, were studied by scanning and transmission electron microscopy. Prepupae of prospective honeybee workers were treated with pyriproxyfen and the effects on ommatidial differentiation were described at the end of the pupal development. The results show that the entire ommatidia, i.e., the dioptric as well as the receptor systems, were affected by the JH analogue. The wave of ommatidial differentiation, which progresses from the posterior to the anterior region of the pupal eyes, was arrested. In treated pupae, the rhabdomeres only differentiated at the apical axis of the retinula, the secondary and tertiary pigment cells did not develop their cytoplasm protrusions, and the cone cell quartet did not pattern correctly. Simultaneously, an intense vacuolization was observed in cells forming ommatidia. In a previous study we showed that pyriproxyfen exerts an inhibition on pupal ecdysteroid secretion. In this sense, the arrested ommatidial differentiation in pyriproxyfen-treated pupae could be due to a secondary effect resulting from an alteration in pupal ecdysteroid titers. J. Morphol. 249:89-99, 2001. (C) 2001 Wiley-Liss, Inc.Univ São Paulo, Fac Filosofia Ciências & Letras Ribeirao Pret, Dept Biol, BR-14040901 São Paulo, BrazilUniv Estadual Paulista, Fac Ciências Agr & Vet, Dept Morfol & Fisiol Anim, São Paulo, BrazilUniv Estadual Paulista, Fac Ciências Agr & Vet, Dept Morfol & Fisiol Anim, São Paulo, Brazi
Reasons to Ban? The Anti-Burqa Movement in Western Europe
No full textOriginally published at http://www.mmg.mpg.de/en/publications/working-papers/2012/
'Our Working Papers are refereed and may be downloaded from this site by individuals, for their own use, subject to the ordinary rules governing the fair use of professional scholarship. Working Papers may be cited without seeking prior permission from the author.
Sonomyographic responses during voluntary isometric ramp contraction of the human rectus femoris muscle
No full textThis paper aims to investigate the relationship between torque and muscle morphological change, which is derived from ultrasound image sequence and termed as sonomyography (SMG), during isometric ramp contraction of the rectus femoris (RF) muscle, and to further compare SMG with the electromyography (EMG) and mechanomyography (MMG), which represent the electrical and mechanical activities of the muscle. Nine subjects performed isometric ramp contraction of knee up to 90% of the maximal voluntary contraction (MVC) at speeds of 45, 22.5 and 15% MVC/s, and EMG, MMG and ultrasonography were simultaneously recorded from the RF muscle. Cross-sectional area, which was referred to as SMG, was automatically extracted from continuously captured ultrasound images using a newly developed image tracking algorithm. Polynomial regression analyses were applied to fit the EMG/MMG/SMG-to-torque relationships, and the regression coefficients of EMG, MMG, and SMG were compared. Moreover, the effect of contraction speed on SMG/EMG/MMG-to-torque relationships was tested by pair-wise comparisons of the mean relationship curves at different speeds for EMG, MMG and SMG. The results show that continuous SMG could provide important morphological parameters of continuous muscle contraction. Compared with EMG and MMG, SMG exhibits different changing patterns with the increase of torque during voluntary isometric ramp contraction, and it is less influenced by the contraction speed. © 2011 The Author(s).published_or_final_versionSpringer Open Choice, 28 May 201
Mucous membrane grafting for cicatricial entropion repair: review of surgical techniques and outcomes
No full textMucous membrane graft (MMG) is used for moderate-to-severe cicatricial entropion repair either in primary or recurrent cases. We conducted a review to comprehensively summarize the various surgical techniques, outcomes, and complications of using MMG for cicatricial entropion. Though the comparison between different techniques is limited by multiple factors like small numbers of cicatricial entgropion patients, variable severity and success criteria across studies, and different underlying cicatricial entropion etiologies, the author has brought forth the nuances of the use of MMG for cicatricial entropion repair along with its outcomes and complications. MMG use in moderate-to-severe cicatricial entropion gives favourable outcomes. The shortened tarsoconjunctiva is lengthened using MMG, which is used either with terminal tarsal rotation or anterior lamellar recession (ALR) or tarsotomy alone. Non-trachomatous entropion has poor outcomes compared to trachomatous entropion. The most common source of MMG is labial or buccal mucosa and the exact size of MMG harvested is variable according to the defect, and very few prefer oversizing the graft by 10–30%. The outcomes of ALR+MMG appear similar to tarsal rotation and MMG for severe cicatricial entropion. The recurrences of trichiasis or entropion can occur for up to one year after surgery, irrespective of the technique used. Factors affecting the outcomes of cicatricial entropion repair are not well known. There is a non-uniformity in data reporting across literature; hence, future studies with details on severity of entropion, ocular surface changes, forniceal depth and ocular surface inflammation, and the degree of dry eye disease would be informative.</p
Hormonal control and target genes of ftz-f1 expression in the honeybee Apis mellifera: a positive loop linking juvenile hormone, ftz-f1, and vitellogenin
No full textFtz-f1 is an orphan member of the nuclear hormone receptor superfamily. A 20-hydroxyecdysone pulse allows ftz-f1 gene expression, which then regulates the activity of downstream genes involved in major developmental progression events. In honeybees, the expression of genes like vitellogenin (vg), prophenoloxidase and juvenile hormone-esterase during late pharate-adult development is known to be hormonally controlled in both queens and workers by increasing juvenile hormone (JH) titres in the presence of declining levels of ecdysteroids. Since Ftz-f1 is known for mediating intracellular JH signalling, we hypothesized that ftz-f1 could mediate JH action during the pharate-adult development of honeybees, thus controlling the expression of these genes. Here, we show that ftz-f1 has caste-specific transcription profiles during this developmental period, with a peak coinciding with the increase in JH titre, and that its expression is upregulated by JH and downregulated by ecdysteroids. RNAi-mediated knock down of ftz-f1 showed that the expression of genes essential for adult development (e.g. vg and cuticular genes) depends on ftz-f1 expression. Finally, a double-repressor hypothesis-inspired vg gene knock-down experiment suggests the existence of a positive molecular loop between JH, ftz-f1 and vg
On the determination of Hydrodynamic Coefficients for Real-Time Ship Manoeuvring Simulation
No full textFor the real-time simulation of ship manoeuvring, it is required to estimate the hydrodynamic forces with high accuracy. Current methods to determine the hydrodynamic coefficients prove to be time consuming and labour intensive. In this thesis, a method based on Singular Value Decomposition is proposed to determine the hydrodynamic coefficients from a manoeuvre executed by a vessel. The method applies Singular Value Decomposition (SVD) on the equations of motion in the horizontal plane using estimated propeller and rudder forces. With use of numerical differentiation the velocities and accelerations of thevessel are calculated. The set of coefficients determined by the method is based on low aspect ratio lift theory. By comparing the trial manoeuvres simulated with results from the MMG method, it shows that the manoeuvres agree well with the MMG results. However since the method is only tested on simulated trial manoeuvres there are still some problems to be solved such as influence of measuring errors, determining the set of coefficients to be predicted and the search for the best manoeuvre(s) to predict the coefficients.Marine Technology | Ship Hydromechanic
Ergonomic analysis of Company XYZ's de-palletizing workstation
No full textPlan BCompany XYZ is in the beverage industry producing, bottling, and distributing a variety of products. The starting point of the bottling process begins at the de-palletizing workstation where employees manually unload new cases of bottles from a pallet onto a conveyor. Workers at this station were complaining of discomfort in the shoulders/neck, elbows, hands, wrists, and lower back from excessive overhead reaching at the beginning of a new pallet and forward bending toward the end of the unloading process. The purpose of this study was to identify, via ergonomic assessment, if workstation design and work practice risk factors were exposing employees to injuries and illnesses at XYZ Company’s de-palletizing workstation. This ergonomic assessment was performed in three steps. First, the researcher began by identifying the extent of the employees discomfort by utilizing work-related musculoskeletal disorder symptom surveys. These results indicated the severity and location of the employee’s distress and informed the researcher of the extent of the problem. In the second step, the researcher video-recorded an employee’s bodily postures while performing job duties at the de-palletizing workstation. The body angles and posture measurements were incorporated into three ergonomic methodologies to reveal the severity and amount of intervention required by Company XYZ. The results from the symptom surveys and products of the methodologies revealed that the de-palletizing workstation is in fact exposing the employee’s to risk factors that lead to the onset of work-related musculoskeletal disorders (WMSD’s). The final step in this process was to recommend suitable engineering controls that will reduce or eliminate those risk factors, while protecting and preserving Company XYZ’s employees and preventing future worker compensation expenditures
- …
