1,240 research outputs found
‘Retournement’ of the aedeagus in Curculionidae (Coleoptera, Curculionoidea)
Retournement or turning of the aedeagus about its longitudinal axis through about 180o during development is known in Chrysomeloidea (Coleoptera). This change in the orientation of the organ may be observed during the postembryonic development. This change produces certain morphological effects. By observing these morphological features in the imago the retournement may be inferred. Such morphological features in Curculionidae (Coleoptera) are here recorded. From this it has been inferred not only that retournement of the aedeagus is included in the ontogeny of curculionids, but also that the change of orientation of the organ occurs by the same mechanism as in Chrysomeloidea. These inferences attest the notion of a close phyletic relationship between the superfamilies Curculionoidea and Chrysomeloidea
Exploring Convolutional Networks for End-to-End Visual Servoing
Present image based visual servoing approaches rely on extracting hand
crafted visual features from an image. Choosing the right set of features is
important as it directly affects the performance of any approach. Motivated by
recent breakthroughs in performance of data driven methods on recognition and
localization tasks, we aim to learn visual feature representations suitable for
servoing tasks in unstructured and unknown environments. In this paper, we
present an end-to-end learning based approach for visual servoing in diverse
scenes where the knowledge of camera parameters and scene geometry is not
available a priori. This is achieved by training a convolutional neural network
over color images with synchronised camera poses. Through experiments performed
in simulation and on a quadrotor, we demonstrate the efficacy and robustness of
our approach for a wide range of camera poses in both indoor as well as outdoor
environments.Comment: IEEE ICRA 201
Atomic-level structure characterization of an ultrafast folding mini-protein denatured state
Atomic-level analyses of non-native protein ensembles constitute an important aspect of protein folding studies to reach a more complete understanding of how proteins attain their native form exhibiting biological activity. Previously, formation of hydrophobic clusters in the 6 M urea-denatured state of an ultrafast folding mini-protein known as TC5b from both photo-CIDNP NOE transfer studies and FCS measurements was observed. Here, we elucidate the structural properties of this mini-protein denatured in 6 M urea performing 15N NMR relaxation studies together with a thorough NOE analysis. Even though our results demonstrate that no elements of secondary structure persist in the denatured state, the heterogeneous distribution of R2 rate constants together with observing pronounced heteronuclear NOEs along the peptide backbone reveals specific regions of urea-denatured TC5b exhibiting a high degree of structural rigidity more frequently observed for native proteins. The data are complemented with studies on two TC5b point mutants to verify the importance of hydrophobic interactions for fast folding. Our results corroborate earlier findings of a hydrophobic cluster present in urea-denatured TC5b comprising both native and non-native contacts underscoring their importance for ultra rapid folding. The data assist in finding ways of interpreting the effects of pre-existing native and/or non-native interactions on the ultrafast folding of proteins; a fact, which might have to be considered when defining the starting conditions for molecular dynamics simulation studies of protein folding
Study of E. coli Hfq's RNA annealing acceleration and duplex destabilization activities using substrates with different GC-contents
Folding of RNA molecules into their functional three-dimensional structures is often supported by RNA chaperones, some of which can catalyse the two elementary reactions helix disruption and helix formation. Hfq is one such RNA chaperone, but its strand displacement activity is controversial. Whereas some groups found Hfq to destabilize secondary structures, others did not observe such an activity with their RNA substrates. We studied Hfq’s activities using a set of short RNAs of different thermodynamic stabilities (GC-contents from 4.8% to 61.9%), but constant length. We show that Hfq’s strand displacement as well as its annealing activity are strongly dependent on the substrate’s GC-content. However, this is due to Hfq’s preferred binding of AU-rich sequences and not to the substrate’s thermodynamic stability. Importantly, Hfq catalyses both annealing and strand displacement with comparable rates for different substrates, hinting at RNA strand diffusion and annealing nucleation being rate-limiting for both reactions. Hfq’s strand displacement activity is a result of the thermodynamic destabilization of the RNA through preferred single-strand binding whereas annealing acceleration is independent from Hfq’s thermodynamic influence. Therefore, the two apparently disparate activities annealing acceleration and duplex destabilization are not in energetic conflict with each other
Polycystic ovarian syndrome and insulin resistance: a South Indian study
Background: Polycystic ovary syndrome (PCOS) is a common endocrine disorder in women of reproductive age. Some studies have characterized different aspects of women presenting with PCOS. In this study we characterise the association of insulin resistance (IR) in patients with PCOS in the southern Indian state of Andhra Pradesh.Methods: A total of 50 women diagnosed to have PCOS according to Rotterdam criteria were studied. IR was estimated using Homeostatic model assessment - insulin resistance (HOMA-IR) and clinical characteristics were recorded.Results: The prevalence of IR among the study population was 36%. All PCOS patients with IR were overweight or obese, and had impaired glycaemic status, 75% of PCOS patients with IR also had features of hirsutism.Conclusions: Considering the prevalence of IR, obesity and impaired fasting glucose in women with PCOS, early institution of treatment by lifestyle changes or medication would lead to improvement in reproductive and metabolic abnormalities
Non syndromic synchronous multiple odontogenic keratocysts in a western Indian population : a series of four cases
Odontogenic keratocysts (OKCs) are developmental odontogenic cysts affecting the maxillofacial region and their association with a syndrome especially Naevoid basal cell carcinoma syndrome (NBCCS) is a common occurrence in comparison to non syndromic multiple OKCs. In a first, we present a series of four non syndromic cases with multiple OKCs in western Indian population. The presence of multiple OKC in our present case series may be because of the multifocal nature of the lesion rather than its association with any syndrome. Thus, a comprehensive evaluation of any patients reporting with multiple cysts/OKCs always has to be undertaken and the dental practitioner may be the play a key role in early detection and subsequent follow-up
Placental transfer of pesticides in humans
Transfer of organochlorine pesticides from mother to fetus has been studied in 100 women. The concentrations of organochlorine pesticides were examined in maternal blood, placenta, and umbilical cord blood of the same mother/child pair. Residue levels of dichlorodiphenyl trichloro ethane (DDT) and its metabolites, isomers of benzene hexachloride (BHC) and aldrin were detected in all the samples analyzed, indicating their transfer from mother to the fetus. A correlation was found to exist between the pesticide concentration and age, dietetic habits and area of residence of pregnant women
Long-term occupational exposure to DDT
Blood serum of twenty workers occupationally exposed to DDT for an average duration of 14 years was analysed for organochlorine pesticides by gas-liquid chromatography with an electron capture detector. Significant levels of BHC, p,p'-DDT, p,p'-DDD and p,p-DDE were detected. A higher incidence of total DDT equivalent, about 10 times, was observed in DDT exposed workers when compared with a comparable sample of unexposed persons from the general population. Levels of DDT in serum of occupationally exposed workers were more than the permitted level of 200 ppb. The daily intake was computed to be about 10 mg/man/day as against 0.25 mg-the acceptable daily intale. Abnormal nerve conduction was encountered in a few cases of DDT sprayers. No significant correlation was observed between the total DDT equivalent in serum and duration of occupational exposure in workers. Levels of BHC in controls was 2.3 times the level in exposed workers, possibly due to induction of hepatic drug metabolising enzymes by high levels of DDT in the latter group. Findings are discussed in the light of existing knowledge of the bio-chemical effects evoked due to residual intoxication of DDT during occupational exposure
- …