Presence Of Collar Research Articles

Soybean Bradyrhizobium spp. Spontaneously Produce Abundant and Diverse Temperate Phages in Culture

Soybean bradyrhizobia (Bradyrhizobium spp.) are symbiotic root-nodulating bacteria that fix atmospheric nitrogen for the host plant. The University of Delaware Bradyrhizobium Culture Collection (UDBCC; 353 accessions) was created to study the diversity and ecology of soybean bradyrhizobia. Some UDBCC accessions produce temperate (lysogenic) bacteriophages spontaneously under routine culture conditions without chemical or other apparent inducing agents. Spontaneous phage production may promote horizontal gene transfer and shape bacterial genomes and associated phenotypes. A diverse subset (n = 98) of the UDBCC was examined for spontaneously produced virus-like particles (VLPs) using epifluorescent microscopy, with a majority (69%) producing detectable VLPs (>1 × 107 mL−1) in laboratory culture. Phages from the higher-producing accessions (>2.0 × 108 VLP mL−1; n = 44) were examined using transmission electron microscopy. Diverse morphologies were observed, including various tail types and lengths, capsid sizes and shapes, and the presence of collars or baseplates. In many instances, putative extracellular vesicles of a size similar to virions were also observed. Three of the four species examined (B. japonicum, B. elkanii, and B. diazoefficiens) produced apparently tailless phages. All species except B. ottawaense also produced siphovirus-like phages, while all but B. diazoefficiens additionally produced podovirus-like phages. Myovirus-like phages were restricted to B. japonicum and B. elkanii. At least three strains were polylysogens, producing up to three distinct morphotypes. These observations suggest spontaneously produced phages may play a significant role in the ecology and evolution of soybean bradyrhizobia.

A species of ceratopogonidae, Genus Bezzia from Manipur

No-see-ums are biting midges of small size and difficult to spot belongs to the family Ceratogononodae. Their main feed comprised of blood of humans and animals. But the species of four genera attacked mammals. Both medically and veterinary these insects are very important of many diseases like Oropouche fever, manonellosis or Leishmaniasis. The records of over 4000 species from 78 genera of this family are cosmopolitan. There are over 4, 000 species in 78 genera worldwide for this family. The literature survey from Manipur on this family is not found. A survey of the insect was performed during 2019-2020 from different parts of the aquatic habitats like lake, pond and river. The larvae of the insect were captured and reared to obtain the full life cycle. The distinguishing morphological features of the larvae in the present study were presence of collar, epipharynx and anal bristles and they move quickly between the wet plant parts in their habitats with serpent like quick movement. The pupae were having prominent terminal processes in both the sexes. Adults were small with distinct black patches on the wings. The tentative identification of the species is Bezzia galesa. Their identities, diversity and control measures will be useful in preventing the diseases from such common insect for general population as well as the academic point.

Phenotypic characterization of aromatic rice (Oryza sativa L.) landraces of Odisha, India

A total of 127 accessions of aromatic short grain rice were collected with detailed passport informationfrom 30 districts of Odisha, India. The agro-morphological characters of all the landraces wererecordedaccording to Distinctiveness, Uniformity and Stability (DUS) guidelines with 21 qualitative and 16quantitative characters and statistically analysed. Out of the different qualitative traits studied, ligule colour,panicle type, secondary branching, panicle axis and awning were found to be dimorphic; blade colour,blade pubescence, basal leaf sheath colour, collar colour, auricle colour, internode colour, culm strength,panicle exsertion, sterile lemma colour and stigma colour were trimorphic; leaf angle, culm angle, flag leafangle, apiculus colour and lemma palea colour were tetramorphic. Variations were observed for all thequalitative traits except the presence of collar, auricles, and split shaped ligule among the accessions. Thehighest frequency was observed for panicle architecture; the presence of secondary branching (96%) anddrooping type of panicle axis (95.3%).The weight of 1000 grain wt. which is a key character for selectinghigh yield variety, varied from 11.86g (Ranimasuri) to 23.09g (Kalkati). Similarly, panicle weight variedfrom 1.42g (Siresa) to 3.7g (Tulasiphool). The days to 50% flowering varied from 85.5 (Basumati) to 131(Basauoga) with a mean of 111.17 days indicating that they are mostly medium to late flowering landraces.High grain yield landraces are Basapatri2, Basumati, Kalkatia, Tulasibas. These landraces may be popularizedamong the farmers and the same may be used in hybridization programmes for varietal development.

Reduction of scour around circular piers using collars

AbstractRiver dynamics and sediment transport play an important role in river bed morphology. Building a bridge pier along the river alters the cross‐section of the river and causes the change in flow processes. These changes are mainly responsible for pier scour. In this paper, the usage of collars to reduce scour around circular piers has been investigated. The collars with different diameters and depth positions have been studied using previous data and additional data collected in the present study to assess their effectiveness in reducing scour. Using a wide range of measured data, an empirical equation to compute the maximum scour depth around the circular piers in the presence of collars has been proposed. The proposed equation has been validated and proven to be applicable to a wide range of pier layouts. It has been found that the maximum efficiency can be achieved by fixing the collar at bed level and adopting a collar diameter 1.5–2.5 times of pier diameter.

The effect of collar width ratio on the flow pattern around an oblong pier in a bend

Abstract In this paper, the effect of collar width ratio on the flow pattern around an oblong pier in a 180-degree channel bend was experimentally studied. This channel has a rectangular cross section. It is 1 m in width and 0.7 m in height. The upstream and downstream paths are respectively 6.5 and 5 m long. The ratio of the bend's central curvature radius to the channel width is 2; hence, it qualifies as a sharp bend. Experiments were carried out under clear water approach flow conditions. The results showed that the presence of collars around an oblong pier creates vortices in the opposite direction of the longitudinal flow, causes the distortion and disturbance of the streamlines toward the pier downstream, and decreases downflow strength in front of the pier nose. Furthermore, doubling the collar width results in 0.93 and 0.68 times the vorticity and the power of the secondary flow on the pier upstream, respectively. It also reduced the maximum values of the Reynolds stresses perpendicular to the y-plane in x direction and perpendicular to the z-plane in y direction by respectively 45 and 60%, and increased the Reynolds stress perpendicular to the z-plane in x direction by 25%.

THE EFFECT OF COMPLETE AND PARTIAL CONTOUR ZIRCONIA COPINGS ON THE FRACTURE RESISTANCE OF ALL CERAMIC RESTORATIONS

INTRODUCTION Veneer chipping is a common failure of zirconia based restorations, especially in the presence of high occlusal loads. Modifying zirconia design may influence veneer chipping. OBJECTIVES: Purpose of this study was to evaluate fracture resistance of complete and partial contour zirconia crowns. MATERIALS AND METHODS: Twenty standardized epoxy resin dies, prepared to receive zirconia based crowns, were divided into 4 groups, 5 specimens each. Zirconia framework designs were: (a) Full contour zirconia crown (FC), (b) Partial contour zirconia coping with buccal veneering (PC), (c) Anatomically reduced zirconia coping with palatal and proximal collar (ARD) and (d) half mm zirconia coping without collar (CON) (control group). Dual scanning technique was done for the test groups to fabricate zirconia copings with the use of standardized resin patterns, while normal scanning was made for the control group. After milling and sintering of zirconia specimens, veneering was done for all desired surfaces. All crowns were adhesively luted to their corresponding dies, and subjected to thermal cycling and mechanical loading corresponding to one year clinical service. Single load to fracture was applied to all the specimens. Type of failure was recorded for each specimen, investigated visually then by using Stereomicroscope and SEM. RESULTS: Complete and partial contour zirconia restorations showed high resistance to fracture. The presence of collar was insignificant for increasing fracture resistance, but had an influence on the fracture extension toward the proximal surface of the veneered restorations.

The Effect of Collar on the Size of Proper Riprap Cover around the Cylindrical Bridge Piers in the Rivers Bend

Riprap of bridge piers is placed to eliminate local scour and to secure the pier from failure. However, riprap surfaces frequently rupture to protect bridges pier during deluges despite arrangement of riprap particles around its foundations. Improper design of proper extent for riprap cover greatly reduces the riprap efficiency in local scour control. Therefore, in this research in order to determine the proper size of riprap cover at the angle of 60° of river bend, some experiments were carried out under clean water conditions in a flume of 180°. The effect of collar presence around the pier and also different size of collar on proper size of riprap were examined in different experiments. The results showed that the presence of collar around the cylindrical bridge pier decreased the proper size of riprap as 26% compared to the pier without collar. Moreover, as the collar diameter increased, the size of riprap cover decreased which is economically affordable.

The Effect of Collar on the Size of Proper Riprap Cover around the Cylindrical Bridge Piers in the Rivers Bend

Riprap of bridge piers is placed to eliminate local scour and to secure the pier from failure. However, riprap surfaces frequently rupture to protect bridges pier during deluges despite arrangement of riprap particles around its foundations. Improper design of proper extent for riprap cover greatly reduces the riprap efficiency in local scour control. Therefore, in this research in order to determine the proper size of riprap cover at the angle of 60° of river bend, some experiments were carried out under clean water conditions in a flume of 180°. The effect of collar presence around the pier and also different size of collar on proper size of riprap were examined in different experiments. The results showed that the presence of collar around the cylindrical bridge pier decreased the proper size of riprap as 26% compared to the pier without collar. Moreover, as the collar diameter increased, the size of riprap cover decreased which is economically affordable. Keywords: Bend, Bridge, Collar, Pier, Riprap, Scour

The Influence of Collar on Surge Pressure Caused by the Drill String Inertia Force Under Closed Pipe Condition

The study of surge pressure is of significant importance for the safety of drilling process. However, the existing surge pressure models rarely take the impact of the collar into consideration and thus will inevitably affect the precision of the surge pressure calculation. In this paper, based on closed pipe condition, a steady-state calculation model for surge pressure caused by drill string inertia force is developed considering the presence of collar. In the end a case study is presented to demonstrate the importance of collar during the calculation of surge pressure.

The Influence of Collar on Surge Pressure Caused by the Drilling Fluid Viscous Force under Pumping Condition

The study of surge pressure is of significant importance for the safety of drilling process because field practice shows that the surge pressure caused by fluid viscous force can cause a great damage to the drilling operation. The accurate calculation of surge pressure is directly related to the safety of the drilling process. However, the existing surge pressure models rarely take the impact of the collar into consideration and thus will inevitably affect the precision of the surge pressure calculation. In this study, based on the pumping condition, a steady-state calculation model for surge pressure caused by drilling fluid viscous force is developed considering the presence of collar. In the end a case study is presented to demonstrate the importance of collar during the calculation of surge pressure.

Exceptional Soft-Tissue Preservation in Boring Ctenostome Bryozoans and Associated “Fungal” Borings from the Early Devonian of Podolia, Ukraine

Colonies of boring ctenostome bryozoans and microborings of “fungi” that occur in the Early Devonian (Lochkovian, ∼416 Ma) of Podolia, western Ukraine, have soft-tissue preserved by phosphatization. These comprise exceptional three-dimensional body walls of feeding zooids with probable parietal muscles inserted on the cystid wall, and setigerous collars twisted within the vestibulum. The presence of collars in this Early Devonian ctenostomes proves the existence of this feature for more than 416 Ma of ctenostome evolution. Phosphatized remains of the zooid walls are interpreted as relicts of the originally chitinous cystid walls. This is the first record of soft-tissue fossilization in a boring bryozoan. The presence of cavities (specialized heterozooids), empty or filled with laminated calcium phosphate, is also documented in bryozoans for the first time. These cavities are interpreted as “store-rooms” in which the bryozoans accumulated nutrients. The new taxon, Podoliaporu doroshevi gen. et sp. nov. is ...

Vladimariales ordo nov. (Gymnospermae) from the Middle Jurassic deposits of the Mikhailovskii rudnik locality (Kursk Region, European Russia)

Composite seed-bearing capsules (formed by fusion of eight radially arranged elementary capsules), assigned to a new monotypic order Vladimariales ordo nov., were found in the Upper Bathonian deposits of the Mikhailovskii rudnik locality (Zheleznogorsk town, Kursk Region). In its morphology, the new order demonstrates valuable, phylogenetically conditioned similarity to Peltaspermales and Umkomasiales, but it is evolutionarily more advanced than these latter. A base of the composite capsule is supported by a collar on a stalk, which in external appearance is not different from collar of Ginkgo L., but has stalk, vascularized in a different way (its conducting tissue consisted of eight radially arranged collateral vascular bundles; each vascular bundle correspond to one of eight fused elementary capsules, each of which contain a solitary seed). Capsules and seeds are inverted relative to the collar; as a result, collar protects micropilar tips of seeds. The presence of collar and whole aspect of the new plant composite capsules give them the significant superficial similarity with seed-bearing organs of modern Ginkgo. Mature composite capsule in Vladimariales ordo nov. dehisced along the lines of fusion of elementary capsules, forming the composite capsule, and scattered seeds; opened composite capsule detached from axis. The significance of the new order for gymnosperm phylogeny is discussed.

Review of the genus Megalomma (Polychaeta: Sabellidae) in Australia with description of three new species, new records and notes on certain features with phylogenetic implications

The aim of this paper is to document the presence, diversity and distribution of Megalomma in Australia. This could be considered the first valid record of the genus in this continent as the only species previously recorded was transferred to another genus (Knight-Jones, 1997). The species diversity found during this study indicates that the occurrence of Megalomma in Australia has been overlooked, as the genus is well represented with at least seven species, living in a range of habitats and depths, and three of which are herein described as new, M. phyllisae n.sp, M. inflata n.sp. and M. interrupta n.sp. Cladistic analyses have been performed after the generation of a matrix of morphological features including those of some well documented species, in order to find informative characters for grouping species and to test the validity of previous artificial classifications. According to the phylogenetic hypothesis presented herein, the fusion of dorsal collar margins to the faecal groove and the presence of collar "pockets" characterizes the apomorphic clade of Megalomma species but the number of radiolar eyes is a homoplastic character, varying substantially in the Megalomma radiation, meaning that the traditional groups should be reviewed. A dichotomous key is provided to facilitate Australian species identification.

Design of intramedullary prostheses to prevent bone loss: predictions based on damage-stimulated remodelling

The adaptation of bone around intramedullary fixated prostheses, such as the femoral component of the hip joint or the radial component of the elbow joint, is well documented in follow-up studies. Bone adaptation takes the form of proximal bone atrophy accompanied, in some cases, by distal bone hypertrophy. A mechanistic model has been formulated to predict bone adaptation based on the concept that the continuous processes of damage and repair regulate bone adaptation. We apply the model to investigate the significance of two features of intramedullary prosthesis design on bone adaptation: prosthesis Young's modulus and the presence of a prosthesis collar. Results, as well as indicating some characteristics of accumulative-damage stimulated bone adaptation, predict that a low Young's modulus stem will very much reduce the extent of bone loss whereas the presence of a collar will have no significant effect. The results predict that a collarless low stiffness prosthesis is one possible approach for improving the secondary stability of intramedullary-fixated orthopaedic implants.

Ultrastructural Observations on the Dikaryotic Haustorium ofCronartium Flaccidum(Alb. & Schw.) Wint. inVincetoxicum HirundinariaMedicus

SUMMARYThe haustorium of the uredial stage of Cronartium flaccidum in Vincetoxicum hirundinaria was studied with TEM. The observations concern the haustorial mother cell and its relation to the host cell wall, the penetration peg, the shape and the cytoplasm of the haustorium and some host cell organelles in relation to the haustorium. The presence of collars was noted. These features are similar to those described for host-dikaryotic haustorium relationship in other rusts. The extrahaustorial matrix however shows a unusual development. In fact, it wraps the whole length of haustorial neck although it is separated from the haustorial neck wall by the extrahaustorial membrane doubled in this region. The probable significance of this host-parasite interface, perhaps limited to the genus Cronartium, is discussed.