Rod-like Bodies Research Articles

STUDY OF THE UNLOADING AND SELECTION PROCESS OF ENERGY WILLOW CUTTINGS FOR THE CREATION A PLANTING MACHINE

The article highlights the problems of ensuring continuous unloading of energy willow cuttings from slotted bunkers. During the free discharge of rod-like bodies, such phenomena as crypt formations, distortions, pinching occur, which stop the discharge under the action of gravity. Finding such parameters, under which the system will work evenly and without stops, will make it possible to automate many processes related to working with such material, in particular, when developing a piecemeal selection mechanism for a planting machine. The study revealed and analyzed the possible forms of vaults that are formed during unloading from creating obstacles to movement. As a hopper model, for unloading cuttings, a slotted hopper in the form of two walls located at angles to the horizontal plane is considered. These walls form an unloading slot with adjustable width of the unloading window and an adjustable tilt angle. During the study, vaults were recorded, which are formed at different parameters of the bunker during free unloading. As research has shown, in order to ensure uninterrupted unloading of cuttings, there is such a width of the unloading window of the hopper, which will ensure uniform pouring of cuttings without crypt formations and stops associated with this process. The analysis of continuous discharge of rod-like material established that for cuttings of energy willow, the width of the window, which ensures continuous discharge, is 8-12 cm.

Synthesis and characterization of hairy aminated nanocrystalline cellulose

HypothesisThe synthesis and characterization of aminated nanocrystalline cellulose (ANCC), a new member of the hairy nanocellulose family, is reported. Hairy nanocelluloses consist of a crystalline rod-like body with amorphous cellulose chains (“hairs”) at both ends, on which various functional groups can be accommodated. In ANCC these groups are reactive primary amine groups, which are useful for bioconjugation- and Schiff base-centered modifications. We hypothesize that a two-step oxidation-reductive amination of cellulose fibers followed by hydrothermal treatment will result in the formation of rod-like hairy ANCC. ExperimentsANCC was prepared by converting the aldehyde groups in cellulose, introduced by a periodate oxidation, to primary amines using ammonia and sodium borohydride, followed by a hot water treatment, during which diamine modified cellulose fibers were converted to ANCC. ANCC was characterized by AFM, TEM, DLS, ELS, FTIR, NMR, XPS and conductometric titration. Antibacterial activity of ANCC was assessed by the viable cell counting method. FindingsANCC, with an amine content of 5.5 mmol g−1 is a bare nanocolloid (i.e. non-coated, without adsorbed polyelectrolytes or surfactants) which, as far as we know, has a positive charge density larger than any other bare cationic nanocolloid. It was observed that ANCC particles have a needle-like morphology with a width of ~ 5 nm and a length ~ 120 nm. DLS results proof that ANCC is hairy. Spectroscopic analysis confirmed the introduction of surface primary amine groups. ANCC showed promising bactericidal activities, against Gram-negative species due to their thinner and penetrable cell wall.

Dimensionally reduced nonlinear solids with general loads and constitutive laws: Theory and finite element formulation for rod-like bodies

Dimensionally reduced solids are formulated by linking the kinematics of a slender, rod-like body and a true, geometrically exact, rod. This link is enforced in such a way that the solid, where volumetric and surface loads can be applied, becomes slave of the rod, where the mechanical equilibrium is enforced. The model poses no limitations on the size of the deformations and displacements in either body and it can be used for quasistatic or dynamic analyses. A general finite-element approximation of the ensemble is described in detail, and shown to require only modifications at the assembly level for its implementation, resulting in large computational savings. These dimensionally reduced models are especially useful for problems such as fluid/solid interaction and contact where the surface forces among neighboring bodies need to be calculated accurately. By accounting for the internal energy in the slave solid instead of the rod, the proposed formulation allows also to model — without any additional ingredients — the mechanics of rods with complex material constitutive laws. Numerical examples illustrate the use of the new models in situations with complex loading and constitutive behavior.

Continuous models for peristaltic locomotion with application to worms and soft robots.

A continuous model for the peristaltic locomotion of compressible and incompressible rod-like bodies is presented. Using Green and Naghdi's theory of a directed rod, incompressibility is enforced as an internal constraint. A discussion on muscle actuation models for a single continuum is included. The resulting theory is demonstrated in a simulation of a soft-robotic device. In addition, a calibration of parameters is performed and the incompressible rod is validated against a biomimetic model of earthworm locomotion.

Blood and Merogonic Stages of Haemogregarina Species Naturally Infecting The Nile Monitor Varanus niloticus, Egypt

Haemogregarines are haemoparasites (Apicomplexa: Adeleiorina) of all class of vertebrates nearly, worldwide. The present study was aimed to establish and describe the developmental stages of a Haemogregarina species infecting Nile monitor (Varanus niloticus). The captured Nile monitors were three animals with 80-100 cm in length, they captured from Qena province, Southern Egypt, and thin blood films were prepared and microscopically examined. Also, small pieces of the liver and the lungs of the infected animals were separated and prepared for sectioning, which stained and examined. The recovered parasites have rod-like bodies, infecting the erythrocytes only, with a single stage, in a parasitophorous vacuole and have no karyolitic effect. The parasitaemia level was found up to 5010,000 counted erythrocytes. Only gamonts have been recognized in blood smears, and they were found in two forms; the first form is short, thick (called short gamont) and measured 11.02 × 2.65 µm. The second form was found long and thin (called long gamont), with a subterminal nucleus, measured 14.18 × 2.45 µm. Both forms cause either slightly or strong displacement of the host cell nucleus. The infected erythrocytes had either slightly or markedly hypertrophied in presence of short and long gamonts. The infected erythrocyte measured 18.05 × 8.87 µm, but the uninfected erythrocyte was 16.52 × 8.77 µm in length and width, respectively. Schizogony phase was observed in the lungs only of the infected Nile monitor, where the meronts were formed within parasitophorous vacuoles. The parasite nucleus divided many times, and the produced nuclei are peripherally arranged in the meront, forming merozoites. After separation of the merozoites, residual bodies formed. The merogonic stages were differentiated into two forms, micromeront that measured 15.57×14.29 µm, and produces a few numbers of macromerozoites, meanwhile the macromeront measured 19×15.9 µm and produces up to six micromerozoites.

Poisonous setae on a Baltic amber caterpillar

The knobbed setae on a small caterpillar in 45–55 million years old [Eocene] Baltic amber were studied and characterized as urticating, with evidence of liquid release implying the production of poisons. It is presumed that the caterpillar had been disturbed just prior to falling into the resin, as some of its setae showed defensive responses. The swollen tips of the setae are equipped with “trip hairs” and when disturbed, the tips release liquid deposits, some of which contain rod-like bodies. These setal responses to a disturbance are the first report of poisonous setal defense mechanisms in a fossil insect.

Hairy cationic nanocrystalline cellulose as a novel flocculant of clay

HypothesisThe present paper investigates, for the first time, the potential of cationic hairy cellulose nanocrystals (CNCC) to induce the flocculation of a model suspension of kaolinite. CNCC belong to a brand new family of nanocelluloses characterized for presenting a crystalline rod-like body and functionalized amorphous chains at both ends. Given that these chains can be easily tuned, these nanocelluloses present a high potential as fit-to-purpose flocculants. ExperimentsCNCC were produced through periodate oxidation, cationization and thermal treatment of cellulose. Flocculation was monitored by both photometric dispersion analysis and laser reflectance. Flocs were characterized by the determination of zeta potential, supernatant turbidity removal and optical microscopy. A recently developed machine learning random forest regression model was used to estimate fractal dimension (Df) from chord length distribution data. FindingsAlthough a high efficiency was achieved for CNCC dosages between 7.5 and 75 mg/g, the maximum floc size and the fastest flocculation were found near the isoelectric point (10–30 mg/g). Thus, CNCC acted through charge neutralization mechanism. The model used to estimate flocs Df was found very successful to describe the flocculation process. The clay/CNCC flocs Df values suggest a relation between floc conformation and CNCC dosage, presenting an opener structure when closer to the isoelectric point.

Biallelic Mutations in MYPN, Encoding Myopalladin, Are Associated with Childhood-Onset, Slowly Progressive Nemaline Myopathy

Nemaline myopathy (NM) is a common form of congenital nondystrophic skeletal muscle disease characterized by muscular weakness of proximal dominance, hypotonia, and respiratory insufficiency but typically not cardiac dysfunction. Wide variation in severity has been reported. Intranuclear rod myopathy is a subtype of NM in which rod-like bodies are seen in the nucleus, and it often manifests as a severe phenotype. Although ten mutant genes are currently known to be associated with NM, only ACTA1 is associated with intranuclear rod myopathy. In addition, the genetic cause remains unclear in approximately 25%-30% of individuals with NM. We performed whole-exome sequencing on individuals with histologically confirmed but genetically unsolved NM. Our study included individuals with milder, later-onset NM and identified biallelic loss-of-function mutations in myopalladin (MYPN) in four families. Encoded MYPN is a sarcomeric protein exclusively localized in striated muscle in humans. Individuals with identified MYPN mutations in all four of these families have relatively mild, childhood- to adult-onset NM with slowly progressive muscle weakness. Walking difficulties were recognized around their forties. Decreased respiratory function, cardiac involvement, and intranuclear rods in biopsied muscle were observed in two individuals. MYPN was localized at the Z-line in control skeletal muscles but was absent from affected individuals. Homozygous knockin mice with a nonsense mutation in Mypn showed Z-streaming and nemaline-like bodies adjacent to a disorganized Z-line on electron microscopy, recapitulating the disease. Our results suggest that MYPN screening should be considered in individuals with mild NM, especially when cardiac problems or intranuclear rods are present.

Suspected myofibrillar myopathy in Arabian horses with a history of exertional rhabdomyolysis.

Although exertional rhabdomyolysis (ER) is common in Arabian horses, there are no dedicated studies describing histopathological characteristics of muscle from Arabian horses with ER. To prospectively identify distinctive histopathological features of muscle from Arabian endurance horses with a history of ER (pro-ER) and to retrospectively determine their prevalence in archived samples from Arabian horses with exertional myopathies (retro-ER). Prospective and retrospective histopathological description. Middle gluteal muscle biopsies obtained from Arabian controls (n=14), pro-ER (n=13) as well as archived retro-ER (n=25) muscle samples previously classified with type 2 polysaccharide storage myopathy (15/25), recurrent exertional rhabdomyolysis (7/25) and no pathology (3/25) were scored for histopathology and immunohistochemical staining of cytoskeletal proteins. Glutaraldehyde-fixed samples (2 pro-ER, one control) were processed for electron microscopy. Pro-ER and retro-ER groups were compared with controls using Mann-Whitney U and Fisher's exact tests. Centrally located myonuclei in mature myofibres were found in significantly more (P<0.05) pro-ER (12/13) and retro-ER (21/25) horses than controls (4/14). Degenerating myofibres were not evident in any biopsies. Retro-ER horses had amylase-resistant polysaccharide (6/25, P<0.05) and higher scores for cytoplasmic glycogen, rimmed vacuoles and rod-like bodies. A few control horses (3/14) and significantly (P<0.05) more pro-ER (12/13) and retro-ER (18/25) horses had disrupted myofibrillar alignment and large desmin and αβ-crystallin positive cytoplasmic aggregates. Prominent Z-disc degeneration and focal myofibrillar disruption with regional accumulation of β-glycogen particles were identified on electron microscopy of the 2 pro-ER samples. In a subset of Arabian horses with intermittent episodes of exertional rhabdomyolysis, ectopic accumulation of cytoskeletal proteins and Z-disc degeneration bear a strong resemblance to a myofibrillar myopathy. While many of these horses were previously diagnosed with type 2 polysaccharide storage myopathy, pools of glycogen forming within disrupted myofibrils appeared to give the false appearance of a glycogen storage disorder.

Zebrafish models for nemaline myopathy reveal a spectrum of nemaline bodies contributing to reduced muscle function.

Nemaline myopathy is characterized by muscle weakness and the presence of rod-like (nemaline) bodies. The genetic etiology of nemaline myopathy is becoming increasingly understood with mutations in ten genes now known to cause the disease. Despite this, the mechanism by which skeletal muscle weakness occurs remains elusive, with previous studies showing no correlation between the frequency of nemaline bodies and disease severity. To investigate the formation of nemaline bodies and their role in pathogenesis, we generated overexpression and loss-of-function zebrafish models for skeletal muscle α-actin (ACTA1) and nebulin (NEB). We identify three distinct types of nemaline bodies and visualize their formation in vivo, demonstrating these nemaline bodies not only exhibit different subcellular origins, but also have distinct pathological consequences within the skeletal muscle. One subtype is highly dynamic and upon breakdown leads to the accumulation of cytoplasmic actin contributing to muscle weakness. Examination of a Neb-deficient model suggests this mechanism may be common in nemaline myopathy. Another subtype results from a reduction of actin and forms a more stable cytoplasmic body. In contrast, the final type originates at the Z-disk and is associated with myofibrillar disorganization. Analysis of zebrafish and muscle biopsies from ACTA1 nemaline myopathy patients demonstrates that nemaline bodies also possess a different protein signature. In addition, we show that the ACTA1D286G mutation causes impaired actin incorporation and localization in the sarcomere. Together these data provide a novel examination of nemaline body origins and dynamics in vivo and identifies pathological changes that correlate with muscle weakness.Electronic supplementary materialThe online version of this article (doi:10.1007/s00401-015-1430-3) contains supplementary material, which is available to authorized users.

One-dimensional quasistatic model of biodegradable elastic curved rods

In this paper, we derive and analyze a one-dimensional model of biodegradable elastic curved rods. The model is given for displacement and degradation as unknown functions and is nonlinear. It is obtained from the three-dimensional equations of the biodegradable elastic rod-like bodies using formal asymptotic expansion techniques with respect to the small thickness of the rod. Existence and uniqueness of the solution of the one-dimensional model are proved. Some qualitative properties of the model are also obtained from the numerical approximation of the model.

Intrinsic viscosity of suspensions of electrosterically stabilized nanocrystals of cellulose

Electrosterically stabilized nanocrystals of cellulose (ENCCs) have emerged recently as new cellulose nanoparticles among common nanocrystals of cellulose (NCCs) and cellulose nanofibers. ENCC has a special structure being composed of a crystal with protruded amorphous chains at each endcaps bearing carboxyl groups. Here, we studied the intrinsic viscosity of aqueous suspensions of ENCCs as a function of pH and ionic strength. Low pH or high ionic strength reduced the ENCCs to rigid rod-like particles while a polyelectrolyte-like behavior was observed for suspensions of ENCCs around pH 7 and at low ionic strength. The pH had a great effect on charges due to both deprotonation of carboxyl groups and counter-ion effect, while the ionic strength only affected the surface charges of the particles. The zeta potential of ENCC suspensions was measured as a function of pH and ionic strength to establish a link between particle charges and the intrinsic viscosity. Finally, the Fedors model was used to compare our data in the case of rigid rod-like body behavior with literature data on NCC suspensions and the model was shown to be unsuitable.

1P1-R04 細菌の集団運動の時空間構造計測と数値シミュレーション

Bacteria exhibit collective motion when the freely-swimming cells are cultivated and become tightly packed. This collective motion has some spatio-temporal patterns that are not found for the freely-swimming cells. In this study, we conducted the observation and numerical simulation to find some characteristics in the collective motion. In the microscopic observation, the overall flow velocity of the bacterial swarming is analyzed by the particle image velocimetry. The correlation between two velocity vectors is calculated. With the increase in the number density of cells, the correlation length becomes larger, up to 10 micrometers. In the numerical simulation, the effect of alignment of cells due to their interaction is considered, where the close cells have only repulsion like a collision of the rigid rodlike bodies. With increase in number density of the model cells, the correlation length of the velocity correlation becomes larger, which agrees with the observed result.

Ultrastructure of head organs (anterior adhesive apparatus) and posterior secretory systems of Caballeria liewi Lim, 1995 (Monogenea, Ancyrocephalidae).

Caballeria liewi Lim, 1995, uses adhesive secretions from the head organs and posterior secretory systems to assist in locomotion and attachment. Ultrastructural investigations show that the head organs of C. liewi consist of three pairs of antero-lateral pit-like openings bearing microvilli and ducts leading from two types of uninucleated gland cells (located lateral to the pharynx), one type producing rod-like (S1) bodies with an electron-dense matrix containing less electron-dense vesicles and the second type producing oval (S2) bodies with a homogeneous electron-dense matrix. Interlinking band-like structures are observed between S1 bodies and between S2 bodies. S1 body is synthesised in the granular endoplasmic reticulum, transported to a Golgi complex to be packaged into vesicles and routed into ducts for exudation. The synthesis of the S2 body is unresolved. Haptoral secretions manifested externally as net-like structures are derived from dual electron-dense (DED) secretory body produced in the peduncular gland cells. The DED body consists of a less electron-dense oval core in a homogeneous electron-dense matrix. On exocytosis into the pyriform haptoral reservoir, DED bodies are transformed into a secretion with two types of inclusions (less electron-dense oval and electron-dense spherical inclusions) in an electron-dense matrix. The secretions are further transformed (as small, oval, electron-dense bodies) when transported to the superficial anchor grooves, and on exudation into the gill tissues, the secretions become an electron-dense matrix. Secretory bodies associated with uniciliated structures, anchor sleeves and marginal hooks are also observed.

On the Cosserat model for thin rods made of thermoelastic materials with voids

In this paper we employ a Cosserat model for rod-like bodies and study the governing equations of thin thermoelastic porous rods. We apply the counterpart of Korn's inequality in the three-dimensional elasticity theory to prove existence and uniqueness results concerning the solutions to boundary value problems for thermoelastic porous rods, both in the dynamical theory and in the equilibrium case.

Universality in the point discretization method for calculating Casimir interactions with classical Gaussian fields

We study how universality arises when computing Casimir interactions between arbitrary bodies by discretizing their boundaries into pointlike constraints viewed as pointlike inclusions. Introducing ad hoc cutoff and regularization for the field's correlation function, we find that universality arises when i) the separation δ between the pointlike inclusions is less than the cutoff Λ−1, and ii) the bodies are much larger than the cutoff. A sharp transition from discrete to continuous boundaries occurs at δ = π/Λ in the thermodynamic limit for rods at large separation. We illustrate our findings in two dimensions with rodlike bodies and more complex bodies shaped as moons.

A model for alignment between microscopic rods and vorticity

Numerical simulations show that microscopic rod-like bodies suspended in a turbulent flow tend to align with the vorticity vector, rather than with the dominant eigenvector of the strain-rate tensor. This paper investigates an analytically solvable limit of a model for alignment in a random velocity field with isotropic statistics. The vorticity varies very slowly and the isotropic random flow is equivalent to a pure strain with statistics which are axisymmetric about the direction of the vorticity. We analyse the alignment in a weakly fluctuating uniaxial strain field, as a function of the product of the strain relaxation time τs and the angular velocity ω about the vorticity axis. We find that when ωτs ≫ 1, the rods are predominantly either perpendicular or parallel to the vorticity.

Shear zones between rock units with no relative movement

Shear zones are normally viewed as relatively narrow deformation zones that accommodate relative displacement between two “blocks” that have moved past each other in opposite directions. This study reports localized zones of shear between adjacent blocks that have not moved past each other. Such deformation zones, which we call wakes, form due to the movement of exotic blocks within a viscous medium (denser blocks sinking within a salt structure, (the paths) between separated boudins), melt in partially molten surroundings (melt movement during migmatisation), or solid blocks sinking through a partially molten magma body (stoping). From the fluid dynamics perspective these shear zones can be regarded as low Reynolds number deformation zones within the wake of a body moving through a viscous medium. While compact moving bodies (aspect ratio 1:1:1) generate axial symmetric (cone like) shear zones or wakes, elongated bodies (vertical plates or horizontal rod-like bodies) produce tabular shear zones or wakes. Unlike conventional shear zones across which shear indicators usually display consistent symmetries, shear indicators on either side of the shear zone or wake reported here show reverse kinematics. Thus profiles exhibit shear zones with opposed senses of movement across their center-lines or -planes.We have used field observations and results from analytical and numerical models to suggest that examples of wakes are the transit paths that develop where denser blocks sink within salt structures, bodies of melt rise through migmatites, between boudins separated by progressive extension and (perhaps) where slabs of subducted oceanic lithosphere delaminate from the continental crust and sink into the asthenosphere. We also argue that such shear zones may be more common than they have been given credit for and may be responsible for some reverse kinematics reported in shear zones.

Derivation of the nonlinear bending–torsion model for a junction of elastic rods

We derive the one-dimensional bending–torsion equilibrium model for the junction of straight rods. The starting point is a three-dimensional nonlinear elasticity equilibrium problem written as a minimization problem for a union of thin, rod-like bodies. By taking the limit as the thickness of the three-dimensional rods tends to zero, and by using ideas from the theory of Γ-convergence, we find that the resulting model consists of the union of the usual one-dimensional nonlinear bending–torsion rod models which satisfy the following transmission conditions at the junction point: continuity of displacement and rotation of the cross-sections; balance of contact forces and contact couples.

On a thermodynamic theory of rods with two temperature fields

This paper presents a thermodynamic theory for elastic rods using the model of directed curves. In this model, the thin rod-like bodies are described as deformable curves with a triad of rigidly rotating vectors attached to each point. To account for the thermal effects in rods, we introduce two independent temperature fields: the absolute temperature field and the temperature deviation field. We present a complete derivation of the non-linear equations of thermoelastic rods, starting from the principles of thermodynamics. Finally, we prove the uniqueness of solution to the linearized equations of thermoelastodynamics for rods.