Head Segments Research Articles

A New Species of Szeptyckitheca (Collembola, Symphypleona, Sphyrothecinae) from Brazil

A new species of the genus Szeptyckitheca is described from the Biological Reserve of Serra do Japi, São Paulo State, Brazil. All species of the genus present trochanteral spine on the first and third legs, cephalic chaeta A1 often absent. The presence of spine in all trochanters, chaetal row F in head, and abdominal and antennal segments with long bristles with capitate apex are relevant features that distinguishes the new species from all known species of the genus. A key to the identification of the species of Szeptyckitheca is presented.

Bicoid signal extraction: Another powerful approach

This belief has been widely accepted that Bicoid (Bcd) protein distributes in a concentration gradient that organizes the anterior/posterior axis of the Drosophila embryo. Segment polarity protein provides positional cues for the development of head and thoracic segments. Therefore As a result of its essential role, modeling the Bicoid gradient has been welcomed by many researchers in various scientific fields. In this paper, We present investigation of gene expression profiles by means of Singular Spectrum Decomposition (SSD), an optimizing version of Singular Spectrum Analysis for filtering and extracting the bicoid gene expression signal. The results with strong evidence suggest that the proposed technique is capable of eliminating noise and can be considered as an acceptable method for filtering gene expression.

Reliability of posturographic measures obtained during instrumental assessment of trunk control using inertial sensors in individuals with spinal cord injury

The seated position is the most frequent and fundamental for patients with Spinal Cord Injury (SCI). There are tests for clinically assessing seated postural control in SCI, most of them rely on distance related parameters. However, clinical assessment of trunk control in SCI is not enough sensitive to detect and/or describe a possible improvement. Hence, there is a need for practical, objective and reliable assessment tools to demonstrate the efficacy of different interventions in clinical practice. Therefore our objective was to establish the reliability of distance related measures obtained from inertial sensors (IMUs) to assess trunk control in SCI subjects. A cross-cutting study was performed where 15 non SCI subjects and 22 SCI subjects who fulfilled inclusion criteria were recruited. After signature of informed consent, there was held a concurrent application of the trunk control test (TCT) and the instrumental assessment (using IMUs attached to head and trunk of subjects) with repeated measures three times of static and dynamic control selected items, in an interleaved and random manner. IMUs 3D orientation was obtained during all time. Distance related parameters on transverse plane were obtained after applying IMUs 3D orientation to a biomechanical model of head and trunk segments. Dimensions were normalized to body segments. One hundred twenty-four distance related measures were calculated. Test-retest reliability was measured by intraclass correlation coefficients (ICC) of items with repeated measures. High reliability (ICC > 0.5) was found on 10 distance related measures in both areas of static and dynamic equilibrium of TCT, measured on both the head and the trunk of SCI and non SCI subjects. It was demonstrated that the IMU usage has high reliability when measuring distance related parameters of static and dynamic control of the trunk.

Influence of Sitting Positions and Level of Trunk Control During Reaching Movements in Late Preterm and Full-Term Infants.

In order to acquire reaching and independent sitting, refinement of trunk control is needed by gradually and progressively incorporating the head, thoracic, lumbar, and sacral segments. Previous studies have evaluated trunk control in a segmental way, standardizing the level of manual support in the infants' trunk during reaching. The aim of this study was to identify the level of trunk control and to analyze the influence of the difference sitting positions in late preterm and full-term infants between 6 and 8 months of age during reaching. Therefore, 36 infants born full term (control group)—FTG and 20 late preterm infants at a corrected age (experimental group)—PTG were evaluated. Most of the infants started the study at 6 months and they were evaluated monthly until 8 months of age (longitudinal study) in a total of 1–3 visits. The Segmental Assessment of Trunk Control was used to identify the level of trunk control in a segmental way, as well as to verify the capacity of the infant to maintain or regain the vertical position while sitting. Kinematic analysis was used for reaching. The infants were in a ring sitting position and at 90° of flexion. To elicit reaching, an attractive object was presented at the infant's midline and at 45° to the right and left. We found that PTG infants presented lower trunk control scores, i.e., worse control. For both groups, the ring sitting position and at 90° of flexion did not influence most kinematic variables during reaching because accurate manual support was provided for the infants' trunk. The PTG group presented less trunk displacement when at 90° of flexion. Compared to the FTG, even with accurate trunk support, the PTG group presented more immature reaches. These results suggest that accurate manual trunk support favored more stability of the trunk during the reach. Thus, early intervention is suggested for PTG infants and reaching in this age group should be trained in the ring sitting position with their trunk accurately manually supported. SATCo is an effective tool for segmental trunk evaluation.

Different lasers and techniques for proliferative diabetic retinopathy.

Different lasers and techniques for proliferative diabetic retinopathy.

Sidestep-induced neuromuscular miswiring causes severe locomotion defects in Drosophila larvae.

Mutations in motor axon guidance molecules cause aberrant projection patterns of motor nerves. As most studies in Drosophila have analysed these molecules in fixed embryos, the consequences for larval locomotion are entirely unexplored. Here, we took advantage of sidestep (side)-mutant larvae that display severe locomotion defects because of irreparable innervation errors. Mutations in side affected all motor nerve branches and all body wall regions. Innervation defects were non-stereotypical, showing unique innervation patterns in each hemisegment. Premature activation of Side in muscle precursors abrogated dorsal migration of motor nerves, resulting in larvae with a complete loss of neuromuscular junctions on dorsal-most muscles. High-speed videography showed that these larvae failed to maintain substrate contact and inappropriately raised both head and tail segments above the substrate, resulting in unique 'arching' and 'lifting' phenotypes. These results show that guidance errors in side mutants are maintained throughout larval life and are asymmetrical with respect to the bilateral body axis. Together with similar findings in mice, this study also suggests that miswiring could be an underlying cause of inherited movement disorders.

Classifications in Brief: The Pipkin Classification of Femoral Head Fractures.

Classifications in Brief: The Pipkin Classification of Femoral Head Fractures.

Progressive derivation of serially homologous neuroblast lineages in the gnathal CNS of Drosophila.

Along the anterior-posterior axis the central nervous system is subdivided into segmental units (neuromeres) the composition of which is adapted to their region-specific functional requirements. In Drosophila melanogaster each neuromere is formed by a specific set of identified neural stem cells (neuroblasts, NBs). In the thoracic and anterior abdominal region of the embryonic ventral nerve cord segmental sets of NBs resemble the ground state (2nd thoracic segment, which does not require input of homeotic genes), and serial (segmental) homologs generate similar types of lineages. The three gnathal head segments form a transitional zone between the brain and the ventral nerve cord. It has been shown recently that although all NBs of this zone are serial homologs of NBs in more posterior segments, they progressively differ from the ground state in anterior direction (labial > maxillary > mandibular segment) with regard to numbers and expression profiles. To study the consequences of their derived characters we traced the embryonic lineages of gnathal NBs using the Flybow and DiI-labelling techniques. For a number of clonal types serial homology is rather clearly reflected by their morphology (location and projection patterns) and cell specific markers, despite of reproducible segment-specific differences. However, many lineages, particularly in the mandibular segment, show a degree of derivation that impedes their assignment to ground state serial homologs. These findings demonstrate that differences in gene expression profiles of gnathal NBs go along with anteriorly directed progressive derivation in the composition of their lineages. Furthermore, lineage sizes decrease from labial to mandibular segments, which in concert with decreasing NB-numbers lead to reduced volumes of gnathal neuromeres, most significantly in the mandibular segment.

Gliding and Quasi-harmonic Tremor Behaviour of Raung Volcano: November 2014 Crisis Period Case Study

DOI: 10.17014/ijog.5.1.13-21The seismic activity of Raung Volcano was raised on 11 November 2014. As many as 1709 tremors were recorded followed by continuous tremors appearing in late November 2014. Quasi-harmonic and gliding tremors appeared in a spectrogram on 12 November 2014. The quasi-harmonic tremors refer to tremors that have no fully harmonic form in spectrum. The gliding harmonic tremors refer to harmonic tremors that have frequency jumps with either positive or negative increment. After signal restitution processing, the Maximum Entropy Spectral Analysis (MESA) method was applied in Raung recordings resulting the spectrum and the spectrogram of tremors. The quasi-harmonic tremors have the monotonic spectrum in its head and centre segment, and the harmonic one in its tails. There are twenty-four spectrums that show frequency changes between the monotonic and harmonic. The similarity between the fundamental frequency range of the monotonic and harmonic ones suggests that both signals are excited from a common resonator. The alternating of monotonic and harmonic respectively over this period is qualitatively similar with Julian’s synthetic time series about the nonlinear oscillator model. It is suggested that Raung Volcano magma pressure is sizeable to make a chaotic vibration. A pressure increasing in Raung magmatic conduit causes the increasing of P-wave velocity and makes a positive gliding frequency.

Self-assembly of model short triblock amphiphiles in dilute solution.

In this work, a molecular theory is used to study the self-assembly of short diblock and triblock amphiphiles, with head-tail and head-linker-tail structures, respectively. The theory was used to systematically explore the effects of the molecular architecture and the affinity of the solvent for the linker and tail blocks on the relative stability of the different nanostructures formed by the amphiphiles in dilute solution, which include spherical micelles, cylindrical fibers and planar lamellas. Moreover, the theory predicts that each of these nanostructures can adopt two different types of internal organization: (i) normal nanostructures with a core composed of tail segments and a corona composed of head segments, and (ii) nanostructures with a core formed by linker segments and a corona formed by tail and head segments. The theory predicts the occurrence of a transition from micelle to fiber to lamella when increasing the length of the tail or the linker blocks, which is in qualitative agreement with the geometric packing theory and with experiments in the literature. The theory also predicts a transition from micelle to fiber to lamella as the affinity of the solvent for the tail or linker block is decreased. This result is also in qualitative agreement with experiments in the literature but cannot be explained in terms of the geometric packing theory. The molecular theory provides an explanation for this result in terms of the competition between solvophobic attractions among segments in the core and steric repulsions between segments in the corona for the different types of self-assembled nanostructures.

Thermal Analysis of Viscoelastic Propellant Grains with Developed Axisymmetric Finite Elements using Herrmann Formulation

Solid Rocket Motor (SRM) is developed based on casting method where solid propellant grains are cast into a composite or metallic casing. Generally, SRMs are exposed to extreme loading scenarios during storage, transportation, and firing, leading to cracks in the solid propellants. In this paper, Computational Finite Element Analysis is performed with developed 8 node quadrilateral, 9 node quadrilateral and 6 node triangular elements using Herrmann formulation to analyze stress and strain variations in the head and mid segments of the SRM subjected to thermal loading. The obtained results are compared with commercially available Finite element software

Expression and function of the zinc finger transcription factor Sp6-9 in the spider Parasteatoda tepidariorum.

Zinc finger transcription factors of the Sp6-9 group are evolutionarily conserved in all metazoans and have important functions in, e.g., limb formation and heart development. The function of Sp6-9-related genes has been studied in a number of vertebrates and invertebrates, but data from chelicerates (spiders and allies) was lacking so far. We have isolated the ortholog of Sp6-9 from the common house spider Parasteatoda tepidariorum and the cellar spider Pholcus phalangioides. We show that the Sp6-9 gene in these spider species is expressed in the developing appendages thus suggesting a conserved role in limb formation. Indeed, RNAi with Sp6-9 in P. tepidariorum leads not only to strong limb defects, but also to the loss of body segments and head defects in more strongly affected animals. Together with a new expression domain in the early embryo, these data suggest that Sp6-9 has a dual role P. tepidariorum. The early role in head and body segment formation is not known from other arthropods, but the role in limb formation is evolutionarily highly conserved.

Upper body accelerations during planned gait termination in young and older women

Transitory tasks, such as gait termination, involve interactions between neural and biomechanical factors that challenge postural stability and head stabilization patterns in older adults. The aim of the study was to compare upper body patterns of acceleration during planned gait termination at different speeds between young and older women. Ten young and 10 older women were asked to carry out three gait termination trials at slow, comfortable and fast speed. A stereophotogrammetric system and a 15-body segments model were used to calculate antero-posterior whole-body Center of Mass (AP CoM) speed and to reconstruct the centroids of head, trunk and pelvis segments. RMS of three-dimensional linear accelerations were calculated for each segment and the transmission of acceleration between two segments was expressed as a percentage difference. Older women reported lower AP CoM speed and acceleration RMS of the three upper body segments than young women across the three speed conditions. A lower pelvis-to-trunk attenuation of accelerations in the transverse plane was observed in older compared to young women, and mainly in the medio-lateral direction. As possible explanations, older women may not need to reduce acceleration as young women because of their lower progression speed and the subsequent acceleration at upper body levels. On the other hand, older women may prioritize a decrease in the whole body progression speed at expense of the involvement of upper body segments. This limits the attenuation of the accelerations, particularly in the transverse plane, implying an increased dynamic unbalance in performing this transitory task.

Ancient genetic redundancy of eyeless and twin of eyeless in the arthropod ocular segment

Pax6 transcription factors are essential upstream regulators in the developing anterior brain and peripheral visual system of most bilaterian animals. While a single homolog is in charge of these functions in vertebrates, two Pax6 genes are in Drosophila: eyeless (ey) and twin of eyeless (toy). At first glance, their co-existence seems sufficiently explained by their differential involvement in the specification of two types of insect visual organs: the lateral compound eyes (ey) and the dorsal ocelli (toy). Less straightforward to understand, however, is their genetic redundancy in promoting defined early and late growth phases of the precursor tissue to these organs: the eye-antennal imaginal disc. Drawing on comparative sequence, expression, and gene function evidence, I here conclude that this gene regulatory network module dates back to the dawn of arthropod evolution, securing the embryonic development of the ocular head segment. Thus, ey and toy constitute a paradigm to explore the organization and functional significance of longterm conserved genetic redundancy of duplicated genes. Indeed, as first steps in this direction, recent studies uncovered the shared use of binding sites in shared enhancers of target genes that are under redundant (string) and, strikingly, even subfunctionalized control by ey and toy (atonal). Equally significant, the evolutionarily recent and paralog-specific function of ey to repress the transcription of the antenna fate regulator Distal-less offers a functionally and phylogenetically well-defined opportunity to study the reconciliation of shared, partitioned, and newly acquired functions in a duplicated developmental gene pair.

Unraveling Pancreatic Segmentation.

Limited pancreatic resections are increasingly performed, but the rate of postoperative fistula is higher than after classical resections. Pancreatic segmentation, anatomically and radiologically identifiable, may theoretically help the surgeon removing selected anatomical portions with their own segmental pancreatic duct and thus might decrease the postoperative fistula rate. We aimed at systematically and comprehensively reviewing the previously proposed pancreatic segmentations and discuss their relevance and limitations. PubMed database was searched for articles investigating pancreatic segmentation, including human or animal anatomy, and cadaveric or surgical studies. Overall, 47/99 articles were selected and grouped into 4 main hypotheses of pancreatic segmentation methodology: anatomic, vascular, embryologic and lymphatic. The head, body and tail segments are gross description without distinct borders. The arterial territories defined vascular segments and isolate an isthmic paucivascular area. The embryological theory relied on the fusion plans of the embryological buds. The lymphatic drainage pathways defined the lymphatic segmentation. These theories had differences, but converged toward separating the head and body/tail parts, and the anterior from posterior and inferior parts of the pancreatic head. The rate of postoperative fistula was not decreased when surgical resection was performed following any of these segmentation theories; hence, none of them appeared relevant enough to guide pancreatic transections. Current pancreatic segmentation theories do not enable defining anatomical-surgical pancreatic segments. Other approaches should be explored, in particular focusing on pancreatic ducts, through pancreatic ducts reconstructions and embryologic 3D modelization.

Patient-adapted respiratory training: Effect on navigator-triggered 3D MRCP in painful pancreatobiliary disorders

PurposeTo compare the image quality of navigator-triggered (NT) 3D MR cholangiopancreatography (MRCP) with and without a patient-adapted respiratory training, in clinical patients with painful pancreatobiliary disorders. Materials and methodsWith institutional review board approval, hospitalized patients with painful pancreatobiliary disorders who were scheduled for MRCP study were prospectively enrolled. The numerical rating scale (NRS) of abdominal pain during the examination was recorded. Special patient-adapted respiratory training was conducted before the examination. A control group of patients was enrolled with the same criteria, who received ordinary instructions only (n=60 for each group). A subgroup of patients (n=10) underwent MRCP studies with ordinary instructions first and with patient-adapted training later. Acquisition time was recorded. General image quality, degree of artifacts and visualization of 12 segments of the pancreatobiliary tree were rated on a five-point scale and compared between the groups. ResultBoth groups had similar NRS of pain. There was a significant improvement in image quality (p<0.01) as well as visualization of right posterior hepatic duct (p=0.045), left lateral hepatic duct (p=0.037), and pancreatic duct (p<0.01 for head, body and tail segments) in patients receiving respiratory training. The other segments showed no significant differences. The percentage of patients with severe and extensive imaging artifacts decreased from 18.3%(11/60) to 8.3%(5/60). The acquisition time was shorter (175±54s vs 249±67s, p<0.01) in patients with respiratory training. ConclusionPatient-adapted respiratory training improves the image quality of NT-MRCP in patients with painful pancreatobiliary disorders.

Reliability of Head, Neck, and Trunk Anthropometric Measurements Used for Predicting Segment Tissue Masses in Living Humans.

Soft and rigid tissue mass prediction equations have been previously developed and validated for the segments of the upper and lower extremities in living humans using simple anthropometric measurements. The reliability of these measurements has been found to be good to excellent for all measurement types (segment lengths, circumferences, breadths, skinfolds). However, the reliability of the measurements needed to develop corresponding equations for the head, neck, and trunk has yet to be determined. The purpose of this study was to quantify the inter- and intrameasurer reliability of 34 surface anthropometric measurements of the head, neck, and trunk segments. Measurements (11 lengths, 7 circumferences, 11 breadths, 5 skinfolds) were taken twice separately on 50 healthy, university-age individuals using standard anthropometric tools. The mean inter- and intrameasurer measurement differences were fairly small overall, with 64.7% and 67.6% of the relative differences less than 5%, respectively. All measurements, except for the right lateral trunk, had intraclass correlation coefficients (ICCs) greater than 0.75, and coefficients of variation (CVs) less than 10%, indicating good reliability overall. These results are consistent with previous work for the extremities and provide support for the use of the defined surface measurements for future tissue mass prediction equation development.

Upper body accelerations during walking are altered in adults with ACL reconstruction

This study was designed to assess and compare the pattern of acceleration from the lower trunk, neck and head regions for individuals with reconstructed ACL compared to healthy controls during walking. Participants with unilateral ACL reconstruction and matched control persons participated in the study. Accelerations were collected using three triaxial accelerometers attached to the head, neck, and lower trunk. Measures of amplitude and signal regularity of the acceleration data were performed. Similarities were seen between both groups with regards to the general acceleration patterns in all three axes. However, the results also revealed that the individuals with ACL reconstruction had significantly greater peak power in the AP direction at higher frequencies, indicating a reduced ability to attenuate frequency signals. Further, the ACL group had a reduced ability to control head motion during gait, as indicated by reduced regularity in VT. Both groups demonstrated a similar pattern of gait-related oscillations across the head, neck and trunk segments. However, adults with a reconstructed ACL demonstrated a reduced capacity to compensate for the higher frequency components of the gait signal, which may have led to a decline in head control. Overall, these findings indicate that previous damage to the ACL is not simply localized to the knee joint, but influences upper body control, too.

Sedimentary differences between different segments of the continental slope-parallel Central Canyon in the Qiongdongnan Basin on the northern margin of the South China Sea

Submarine canyons have been the subject of intense studies in recent years because of their academic significance to studies of climate signals, eustasy and tectonic movement of the neighbouring area and their economic significance for hydrocarbon exploration in deep-water areas. The Central Canyon in the Qiongdongnan Basin runs parallel to the continental slope, and has a length, width and depth of 520 km, 2–15 km and 270–800 m. Using seismic and well log data, we analyses the sedimentary differences and controlling factors of the sediments in the different segments of the Central Canyon. The sediments within the Central Canyon can be subdivided into five phases of the secondary canyon filling. The most typical features of each phase of the secondary canyon are high- and low-density turbidity currents developed in the phase 1–2 of the secondary canyon, the muddy debris flows, turbidity currents and mass transport deposits in the phase 3, the high-density turbidity currents in the phase 4, the hemi-pelagic mudstone and mass transport deposits in the phase 5. There are four depositional models corresponding to the head area, upstream segment, middle reaches and downstream segment of the Central Canyon were established. It is characterized by muddy matrix-supported conglomerates and thickly massive sandstones with the feature of upward fining and thinning deposited in the head area, the thickly high net to gross sandstone infilled in the upstream segment, the thinly interbedded sandstones and mudstones and muddy mass transport deposits developed in the middle reaches, and the extensive hemi-pelagic mudstone infilled in the downstream segment. The transformation of the debris flows into turbidity currents and high-density turbidity currents into low-density turbidity in the head and upstream segment, supersaturated filling in the upstream segment, extensive development of mass transport deposits in the middle reaches, under-compensation filling and widely development of canyon wall collapse in the downstream segment are the main reasons contributing to the sedimentary differences between different segments of the Central Canyon.

Expression and function of spineless orthologs correlate with distal deutocerebral appendage morphology across Arthropoda

The deutocerebral (second) head segment is putatively homologous across Arthropoda, in spite of remarkable disparity of form and function of deutocerebral appendages. In Mandibulata this segment bears a pair of sensory antennae, whereas in Chelicerata the same segment bears a pair of feeding appendages called chelicerae. Part of the evidence for the homology of deutocerebral appendages is the conserved function of homothorax (hth), which has been shown to specify antennal or cheliceral fate in the absence of Hox signaling, in both mandibulate and chelicerate exemplars. However, the genetic basis for the morphological disparity of antenna and chelicera is not understood. To test whether downstream targets of hth have diverged in a lineage-specific manner, we examined the evolution of the function and expression of spineless (ss), which in two holometabolous insects is known to act as a hth target and distal antennal determinant. Toward expanding phylogenetic representation of gene expression data, here we show that strong expression of ss is observed in developing antennae of a hemimetabolous insect, a centipede, and an amphipod crustacean. By contrast, ss orthologs are not expressed throughout the cheliceral limb buds of spiders or harvestmen during developmental stages when appendage fate is specified. RNA interference-mediated knockdown of ss in Oncopeltus fasciatus, which bears a simple plesiomorphic antenna, resulted in homeotic distal antenna-to-leg transformation, comparable to data from holometabolous insect counterparts. Knockdown of hth in Oncopeltus fasciatus abrogated ss expression, suggesting conservation of upstream regulation. These data suggest that ss may be a flagellar (distal antennal) determinant more broadly, and that this function was acquired at the base of Mandibulata.