Part Of Sheath Research Articles

Research on the influence of heat release from cement hydration on the mechanical properties of casing

In order to study the influence of cement hydration heat release on the mechanical properties of casing, this paper calculates the wellbore temperature and pressure field based on the mathematical model of steady-state heat conduction of casing-cement ring-formation rock, establishes a mathematical model for the mechanical evaluation of cement hydration heat release and casing interaction, and performs finite element calculation and experimental simulation of the effect of cement hydration heat release on casing loss, and the results show that the results show: Along the axial direction of the wellbore, the maximum stress on the entire cement ring occurs in the lower position of the cement ring, and the maximum deformation on the casing occurs in the middle position. The axial stress variation range of the middle part of the casing is 50MPa, and the strain is 0.12%; The axial stress variation range of the outer ring is 235MPa, and the strain is 0.09%; The circumferential stress of the middle part varies from 500MPa to 0.255%. It is found that the stress and strain in the middle part of cement sheath are large, and yield is prone to occur. Under the action of cement hydration heat release, the long-axis elliptical deformation of (7.15∼31.8) mm occurs in the casing, that is, a large ovality is produced, which weakens the collapse strength of the casing. Two repeated tests showed that under the cement hydration heat release condition at the casing loss position, the temperature change of 60°C caused the increase of axial force of casing column and the increase of annular air pressure, which caused the non-uniform deformation of casing under the composite load of external extrusion and compression axial force.

A Study of Brachial Plexus Sheath and Dye Spread Through the Sheath in Single- and Multi-Directional Injections in Cadaver

Background: The in-depth understanding of the anatomy of brachial plexus (BP) sheath is very important for the successful application of BP block. The flow dynamics of injectable anesthetic might vary depending on the site and mode of injection. The objectives of this study were to explore and document the detailed anatomy of BP sheath and to compare the dye spread by injections given in single direction and multi-directional approaches in formalin-fixed cadavers. Materials and Methods: This study is a descriptive, observational, and cross-sectional study based on findings on cadaver dissection and injecting dye in cadavers. Twenty-four sides of 12 well-embalmed cadavers were utilized for injecting dye solution into the intact brachial sheath by single-direction and multi-direction injection approaches at the axillary level. All the cadavers were dissected to compare the spread of dye in two approaches. In addition, one more cadaver was utilized for a detailed dissection of the infraclavicular part of BP sheath and its contents without injecting dye. Microsoft Excel software was used for statistical analysis. Results: We observed BP sheath was a fibrous connective tissue sheath-containing multiple neurovascular structures, all of which had individual delicate connective tissue wrapping around them. More uniform dye spread was observed in multi-direction approaches and the musculocutaneous nerve was stained more frequently in multi-direction approach. Conclusions: The presence of delicate porous connective tissue wrapping gives a tunnel-like appearance of the infraclavicular part of BP sheath. Multi-directional injections resulted in dye staining of the larger area involving more structures than single-direction injections.

Tissue-specific expression analysis of Na+ and Cl\u2212 transporter genes associated with salt removal ability in rice leaf sheath

BackgroundA significant mechanism of salt-tolerance in rice is the ability to remove Na+ and Cl− in the leaf sheath, which limits the entry of these toxic ions into the leaf blade. The leaf sheath removes Na+ mainly in the basal parts, and Cl− mainly in the apical parts. These ions are unloaded from the xylem vessels in the peripheral part and sequestered into the fundamental parenchyma cells at the central part of the leaf sheath.ResultsThis study aimed to identify associated Na+ and Cl− transporter genes with this salt removal ability in the leaf sheath of rice variety FL 478. From 21 known candidate Na+ and Cl− transporter rice genes, we determined the salt responsiveness of the expression of these genes in the basal and apical parts, where Na+ or Cl− ions were highly accumulated under salinity. We also compared the expression levels of these transporter genes between the peripheral and central parts of leaf sheaths. The expression of 8 Na+ transporter genes and 3 Cl− transporter genes was up-regulated in the basal and apical parts of leaf sheaths under salinity. Within these genes, OsHKT1;5 and OsSLAH1 were expressed highly in the peripheral part, indicating the involvement of these genes in Na+ and Cl− unloading from xylem vessels. OsNHX2, OsNHX3, OsNPF2.4 were expressed highly in the central part, which suggests that these genes may function in sequestration of Na+ and Cl− in fundamental parenchyma cells in the central part of leaf sheaths under salinity. Furthermore, high expression levels of 4 candidate genes under salinity were associated with the genotypic variation of salt removal ability in the leaf sheath.ConclusionsThese results indicate that the salt removal ability in rice leaf sheath may be regulated by expressing various Na+ or Cl− transporter genes tissue-specifically in peripheral and central parts. Moreover, some genes were identified as candidates whose expression levels were associated with the genotypic variation of salt removal ability in the leaf sheath. These findings will enhance the understanding of the molecular mechanism of salt removal ability in rice leaf sheath, which is useful for breeding salt-tolerant rice varieties.

Rice dwarf and low tillering 10 (OsDLT10) regulates tiller number by monitoring auxin homeostasis

Tiller number is a crucial agronomic trait that directly affects the number of effective panicles and yield formation in rice. Here, we report a semi-dwarf and low tillering mutant Osdlt10 (dwarf and low tillering 10) that exhibited reduced tiller number, semi-dwarfism, increased grain width, low seed-setting rate, curled leaf tip and a series of abnormalities of agronomic traits. Phenotypic observations showed that Osdlt10 mutants had defects in tiller bud formation and grew slowly at the tillering stage. Map-based cloning revealed that LOC_Os10g41310 was the responsible gene for OsDLT10, which was subsequently demonstrated using the CRISPR/Cas9 system and a complementary experiment. Expression pattern analysis indicated that OsDLT10 was primarily expressed in the stem node, the basic part of axillary bud and leaf sheath, pulvinus. The hormone treatment investigation indicated that extremely high of exogenous auxin concentrations can inhibit the expression of OsDLT10. Endogenous auxin content decreased significantly at the base of stem node and axillary bud in Osdlt10 mutants. The results showed that OsDLT10 was related to auxin. qPCR analysis results further showed that the expression levels of auxin transport genes (PINs) and early response genes (IAAs) were significantly increased. The expression levels of WUS-like and FON1 were substantially decreased in the Osdlt10 mutants. These results revealed that OsDLT10 played a critical role in influencing tiller number, likely in association with hormone signals and the WUS-CLV pathway, to regulate axillary bud development in rice.

PEG‐PLA‐PCL based electrospun yarns with curcumin control release property as suture

AbstractThis work presents an interesting method using an electrospinning process to fabricate suture yarns loaded with curcumin to achieve reasonable mechanical properties as well as tunable drug release behavior. Different structures including different yarn counts and twists as well as core‐sheath structures were used to adjust drug release properties along with improving the yarn's mechanical properties. The core parts were made of polycaprolactone and the sheath parts were made of polyethylene glycol, polylactic acid, and polycaprolactone. Drugs can be incorporated in both parts based on the required condition and application. Electrospun yarns were compared using both structural properties and their drug release profiles as metrics. The results of comparing drug release profiles of six electrospun yarns with different yarn counts and twists showed that yarns with finer fiber diameters in the core part have more drug release as well as more initial release. Overall evaluations showed that core‐sheath drugloaded yarn with appropriate physical and mechanical properties can be a useful material as a drug delivery system to the site of damaged tissue. It can also be concluded that the amount and duration of drug release can be controlled using the structural parameters of electrospun yarns as an engineering tool for designing suture yarns with required properties.

Physiological Mechanism of Internode Bending Growth After the Excision of Shoot Sheath in Fargesia yunnanensis and Its Implications for Understanding the Rapid Growth of Bamboos.

The physiological function of bamboo shoot sheaths is still unclear. In the present study, we investigated the anatomical and physiological influences of bamboo shoot sheaths on internode elongation by longitudinally striping parts of sheaths. The internodes would bend toward the bare sides during night. The results showed that amounts of water leaked at the cut of shoot sheaths during night, which impeded the increase of water, water pressure and assimilate transport rates, and decreased starch and soluble sugar catabolism in the bare side of the internodes. A higher level of water pressure and sugar metabolism increased the vacuole expansion and promoted the cell expansion in the outer sides as compared to the bare sides. The bending growth of internodes was mainly due to the significant differences in cell expansion, which was led by the difference in water pressure and sugar hydrolysis levels between the inner and outer sides. Bamboo internode elongation mainly relied on the increase of water pressure and soluble sugar concentration. Shoot sheaths played an important role in the rapid growth of bamboo shoots as a controller in water and assimilate transportation. This study gave a new insight into understanding the rapid growth mechanism of bamboo plants.

Programmable Release of Berberine Chloride Hydrate from Shape Memory Fibers Prepared from Core-Sheath Wet-Spinning Technology.

Smart wet-spun fibers for highly programmable release of therapeutic drug have been rarely reported. Herein, thermalresponsive composite fibers were successfully prepared by core-sheath wet-spinning technology in present study. They consisted of a model drug of natural antibacterial berberine chloride hydrate (BCH) and a drug carrier of temperature responsive shape memory polyurethane (SMPU). The obtained composite fibers featured with well-controlled microscopic morphologies, exhibiting significantly enhanced thermal stability and superb mechanical properties. In vitro drug release test and corresponding release kinetics study were performed for investigation of BCH's release behavior. Results demonstrated that the release behaviors of BCH from the core-sheath fibers were pH-dependent, influenced by both diffusion from pore channels and the solubility of BCH in the release mediums, and BCH imbedded only in core part showed a longer release period compared with that in both core and sheath parts of the composite fibers. More importantly, the release rate of BCH can be simply controlled by changing the initial shapes of fibers through stretching and fixation of the stretched deformations. Furthermore, the antibacterial durability of the smart composites fibers was demonstrated and tracked according to the growth inhibition against both negative E. coli and positive S. aureus bacteria strains. All these results suggest that the developed composite fibers can be promising candidates as smart drug delivery vehicles for highly adjustable doses of target drugs towards practical applications.

Salivary Sheaths of the Asian Citrus Psyllid Show Signs of Degradation 3-4 Weeks Following Their Deposition into Citrus Leaves by the Feeding Psyllids.

Background:Salivary sheaths, also known as stylet sheaths or stylet tracks, are essential features of the piercing-sucking feeding mechanism of plant-feeding hemipteran insects, many of which are vectors of economically important plant viral and bacterial pathogens. Although knowledge of their structure and function is incomplete, these salivary sheaths are frequently used by researchers to study hemipteran's feeding behavior, host preference, or host resistance, because these sheaths remain in the plant tissues after the insect withdraws its stylets following its feeding or probing on these tissues. However, in most cases, it is not known how long these salivary sheaths may last in plant tissues after their deposition by the feeding insects. An earlier report suggested that the salivary sheaths of the Asian citrus psyllid, Diaphorina citri (Hemiptera, Liviidae), vector of the devastating huanglongbing (citrus greening) disease bacterium, start to dissipate 1 week after their deposition in citrus leaves.Methods and Results:Here, using epifluorescence microscopy of cross sections in citron leaves, we found that D. citri salivary sheaths show signs of degradation in 3–4 weeks and become mostly degraded by 5–6 weeks, following their deposition by the psyllids into citrus tissues. Degradation of the salivary sheath starts at or near the “flange” area close to the leaf surface and continues gradually inward through the intercellular part of the sheath, within the mesophyll tissue, but apparently does not extend to the deeper or intracellular parts of the sheath in or near the phloem. Staining citron leaf sections with the fluorescent stain calcofluor white, which stains fungi, or propidium iodide (DNA/RNA stain) suggested that the degraded parts of the older salivary sheaths are not associated with fungi or bacterial accumulations.Conclusion:We speculate that degradation of the salivary sheaths may be due to enzymatic activities in the host plant, especially in the extracellular matrix of the mesophyll tissue.

Thermal insulating particle boards reinforced with coconut leaf sheaths

This paper studies the potential use of coconut husk particles bonded by castor oil-based polyurethane resin to manufacture low-density thermal insulating particle boards, reinforced on their external surfaces by coconut leaf sheaths naturally available in tropical regions as a textile. Panels with a nominal density of 300 kg/m3 were manufactured, and a resin/particle ratio of 0·2 (by weight) was adopted to ensure the necessary adhesion of the particles. The panels under consideration were: plain coir particle boards without tissue reinforcement; one external side reinforced by one layer of the upper parts of leaf sheaths; both external sides reinforced by one layer of the leaf sheath‘s upper parts (UP2S); and both external sides reinforced by one layer of the leaf sheath‘s bottom parts. The thermal, physical and mechanical properties of the boards were evaluated and the thermal-physical-mechanical results indicated that coconut husk particle boards reinforced on both external sides by the upper part of the coconut textiles (UP2S) can be considered for thermal insulation.

Colony sheath formation is accompanied by shell formation and release in the green alga Botryococcus braunii (race B)

Botryococcus braunii race B is a promising candidate for renewable biofuel production. Its colony organization is unique. Cells are connected by extracellular biopolymers containing hydrocarbons at their basolateral regions, enclosed by a retaining wall, and form a sphere inside a colony sheath composed of polysaccharide fibrils. This unique colony structure is a key for the hydrocarbon production and storage, but how the colony forms remains unknown. We studied ultrastructure of colony sheath and its formation process by rapid freezing and freeze-substitution electron microscopy. Fibrils of colony sheath extend from the retaining wall and are branched, and repel India ink. The sheath formation starts in mitosis and completes during the following daughter cell maturation. In this process, the older retaining wall and thin layers at the cell apex are released as shells and new fibrils formed on the new retaining wall extend into and merge with the pre-existing colony sheath. Its formation also accompanied by the hydrocarbon secretion and accumulation at the basolateral region. The fibrils of colony sheath that extend from a cell wall are replaced by new fibrils after each cell division, while fibrils in the extracellular biopolymers accumulate to form the remaining part of sheath, without replacement.

Three new species of the subfamily Microgastrinae (Hymenoptera: Braconidae) from Vietnam

Three new species of the subfamily Microgastrinae (Hymenoptera: Braconidae) from Vietnam

Coherence analysis on thermal effect for power cables under different environmental conditions

There are 2 important aspects of this research; these are the experimental study and the data analysis, which are based on coherence analysis. In this study, a low-voltage power cable is tested under 2 different environments, air and water, and the variations in temperature are measured for the conductor, the sheath parts of the cable, and the environment. The recorded test data are analyzed using such as coherence analysis. This in turn provides the means to determine the relationship among the sheath, conductor, and the environment. In conclusion, high correlated peaks in the frequency domain are used to determine the temperature effect.

English

INTRODUCTION: Giant cell tumours of the tendon sheath are the second commonest tumours of the hand after ganglion cysts. Usually they involve volar aspect of the proximal interphalangeal joint of fingers. Here is a case where dorsal aspect of the distal interphalangeal joint of the middle finger is involved which is a rare presentation. CASE DETAILS: 47 yrs male patient came with swelling in the middle finger of left hand since two years, examination of it reveals 2.5x2 cm firm lobulated swelling adherent to underlying tissues, skin over it is free from the swelling. X- ray examination reveals rounded soft tissue shadow with erosion of the dorsal surface and radial border of the distal phalanx. It was treated with marginal excision of the tumour and a part of tendon sheath. Histopathological examination confirms the diagnosis of giant cell tumour of the tendon sheath. CONCLUSION: Giant cell tumour of tendon sheath involving the dorsal aspect of the distal interphalangeal joint of the fingers is rare. Radiologically it produces bone erosion. Involving the dorsal aspect, distal interphalangeal joint and erosion of bone in X-ray are the factors for the high recurrence rate. Surgical marginal excision is the treatment of choice.

Implant Failure of Bryan Cervical Disc due to Broken Polyurethane Sheath

A case report. A rare case of Bryan disc implantation failure due to broken polyurethane sheath was reported. The bone ingrowth at implant-bone interface and wear debris leaking from broken Bryan disc were also observed. The Bryan disc is one of the most commonly used cervical prostheses and has shown satisfactory results compared with anterior cervical discectomy and fusion in short- and long-term follow-up. The complications, including neurological worsening, heterotopic ossification, kyphosis, and so forth, still occur, although infrequently. The broken polyurethane sheath is an extremely rare complication that has seldom been reported before. A 55-year-old female patient experienced progressive neck pain after 8 years of Bryan disc implantation because of cervical spondylotic myelopathy at C5-C6 level. The subsequent magnetic resonance imaging scan demonstrated a cystic mass in front of Bryan disc, with high-signal intensity on T2-weighted images. The Bryan disc was removed and segment (C5-C6) was fused with cage and plate. The bone ingrowth and wear debris of retrieved Bryan disc were studied. RESULTS.: In revision surgery, a cyst with thick pseudocapsule connecting the anterior part of Bryan disc was excised. A transverse crack (5 mm) was identified in the anterior part of polyurethane sheath. The bacteria test of fluid from the cyst showed a negative result. Micro-computed tomography and histological study both indicated abundant bone ingrowth at implant-bone interface. The metal wear debris could be observed around titanium alloy shells. This case demonstrates the unique incident of broken Bryan disc after 8 years of implantation. Follow-up imaging shortly after the procedure should be mandatory to monitor such potential complication.

The Multiple Contributions of Phytochromes to the Control of Internode Elongation in Rice

Although phyAphyBphyC phytochrome-null mutants in rice (Oryza sativa) have morphological changes and exhibit internode elongation, even as seedlings, it is unknown how phytochromes contribute to the control of internode elongation. A gene for 1-aminocyclopropane-1-carboxylate oxidase (ACO1), which is an ethylene biosynthesis gene contributing to internode elongation, was up-regulated in phyAphyBphyC seedlings. ACO1 expression was controlled mainly by phyA and phyB, and a histochemical analysis showed that ACO1 expression was localized to the basal parts of leaf sheaths of phyAphyBphyC seedlings, similar to mature wild-type plants at the heading stage, when internode elongation was greatly promoted. In addition, the transcription levels of several ethylene- or gibberellin (GA)-related genes were changed in phyAphyBphyC mutants, and measurement of the plant hormone levels indicated low ethylene production and bioactive GA levels in the phyAphyBphyC mutants. We demonstrate that ethylene induced internode elongation and ACO1 expression in phyAphyBphyC seedlings but not in the wild type and that the presence of bioactive GAs was necessary for these effects. These findings indicate that phytochromes contribute to multiple steps in the control of internode elongation, such as the expression of the GA biosynthesis gene OsGA3ox2, ACO1 expression, and the onset of internode elongation.

Postnatal development of microcyst in the anteroventral cochlear nucleus of the Mongolian gerbil: a light- and electron microscopic study

We investigated the postnatal formation and origin of the microcyst, which are not fully elucidated at present, in the cochlear nucleus of gerbils. Sixty-six Mongolian gerbils were investigated at the light microscope level, and 35 of them were observed at the electron microscopic level. Foamy structures were evidently found at 2 days of age and remained unchanged through 4-8 days. The first small vacuole, presumably the former microcyst, appeared at 8 days. Myelin sheath bundles first appeared at 13 days. Electron-dense bodies were frequently found in the junction of the superficial layer and the deep layer at 2 days. The medium-sized vacuole was found in close association with the spherical bushy cells in the anteroventral cochlear nucleus (AVCN) as early as 5 weeks. Various large and small vacuoles were presumably coalesced to form a large vacuole at 3 and 6 months. Membranous structures and red blood cells were in the budding-like vacuoles at 6 months. In addition to membranous structures, the microcyst contained distorted mitochondria and parts of myelin sheaths. The vacuole was interposed between spherical bushy cells at age of 10 months. Small vacuoles were mainly located in the flame-shaped neurons at 14 months. An internal detachment and an external protrusion of the myelin sheath into the adjacent microcyst were found. Thus, this study suggests the first appearance of microcysts at 8 days. Also, the microcyst and the blood vessel may exchange their contents through a leakage in the anteroventral cochlear nucleus.

Structural evaluation of elastic core-spun yarns and fabrics under tensile fatigue loading

Nowadays the application of elastic core-spun yarns in fabric manufacturing and the clothing industry has increased tremendously. These yarns undergo tensile fatigue loading, a common phenomenon which occurs on some part of apparel such as the knee during wearing and use. In this research, cotton covered spandex filament core-spun yarns with 5 different draw ratios on the core part were subjected to 500, 1000 and 1500 tensile fatigue cyclic loads using a purpose-built instrument for fatigue behavior assessment. Also, the woven fabrics of these yarns were produced and underwent the same cyclic loadings. Tensile properties of fatigued yarns were measured by a tensile tester. The yarn deformation and displacement of core and sheath parts was traced via a microtomy technique and scanning electron microscopy (SEM) studies. Finally, the surface of the fatigued fabrics was studied by image processing to see any surface roughness and pilling due to straining. The results revealed the pronounced effect of draw ratio on the breaking strength and breaking elongation after cyclic loading. The obtained results showed that the samples produced by a 2.9 and 3.9 draw ratio of the core part had the highest and lowest level of breaking strength after 1500 tensile cyclic loading, respectively. The samples produced by a 2.9 draw ratio showed the highest decrease of breaking elongation after 1500 tensile cyclic loading. The likely mechanism of buckling behavior of core-spun yarns after experiencing strain energy is proposed. The results showed that after 1000 cyclic loads, the highest number of pills was countable on the fabric surface.

ACO1, a gene for aminocyclopropane‐1‐carboxylate oxidase: effects on internode elongation at the heading stage in rice

Although reports on a gene for 1-amino-cyclopropane-1-carboxylate (ACC) oxidase (ACO1) in rice (Oryza sativa L.) suggest that high levels of its transcript are associated with internode elongation of deep-water rice during submergence, the role of ACO1 in rice development is largely unknown. The tissue-specificity of ACO1 expression indicated that its transcript significantly accumulated in lower parts of elongating internodes at the heading stage. Histochemical analysis and in situ hybridization showed that the ACO1 expression was localized in the basal parts of leaf sheaths immediately above nodes or the lower parts of elongating internodes. To further examine the role of ACO1, ACO1-deficient (aco1) and overexpressing (ACO1-OX) mutants were characterized. The total length of the elongated internodes of aco1 mutants was slightly shorter than that of wild-type plants and that of ACO1-OX mutants was longer. Interestingly, expression of the ACC synthase gene ACS1 and ethylene signalling gene OsEIN2 was up-regulated in the aco1 mutants. This study suggests that the ACO1 has a little effect on internode elongation at the heading stage, and that up-regulation of the ACS1 and OsEIN2 expression may attenuate inhibition of internode elongation.

ACO1, a gene for aminocyclopropane-1-carboxylate oxidase: effects on internode elongation at the heading stage in rice

Although reports on a gene for 1-amino-cyclopropane-1-carboxylate (ACC) oxidase (ACO1) in rice (Oryza sativa L.) suggest that high levels of its transcript are associated with internode elongation of deep-water rice during submergence, the role of ACO1 in rice development is largely unknown. The tissue-specificity of ACO1 expression indicated that its transcript significantly accumulated in lower parts of elongating internodes at the heading stage. Histochemical analysis and in situ hybridization showed that the ACO1 expression was localized in the basal parts of leaf sheaths immediately above nodes or the lower parts of elongating internodes. To further examine the role of ACO1, ACO1-deficient (aco1) and overexpressing (ACO1-OX) mutants were characterized. The total length of the elongated internodes of aco1 mutants was slightly shorter than that of wild-type plants and that of ACO1-OX mutants was longer. Interestingly, expression of the ACC synthase gene ACS1 and ethylene signalling gene OsEIN2 was up-regulated in the aco1 mutants. This study suggests that the ACO1 has a little effect on internode elongation at the heading stage, and that up-regulation of the ACS1 and OsEIN2 expression may attenuate inhibition of internode elongation.

Microstructural analysis of neutron-irradiation induced changes in polyester fibre studied using EPMA

Electron microscopy is an important characterization technique for the study of textile fibre as it gives more information on fabric wear, nature of fibre fracture, chemical degradation, abrasion, fatigue and many others. Electron Probe Micro Analyzer (EPMA) micrographs of virgin and some neutron-irradiated samples (graphite coated) are discussed. The filament diameter, D, of virgin PET fibre obtained from EPMA study was 12.5 μn. The surface topography of single filament distinctly reveals the core and sheath parts of the filament. The core diameter of the virgin fibre was estimated to be 1.43 μm. The fibre irradiated at fluence 1 × 1012 n/cm2 shows radiation induced sphere like polymer balls or spherulites of diameter 2.27 μm in the expanded core region. Due to irradiation, the sheath area crosslinks with expanded core region, which may be responsible for increase of strength and hardness of the polymer materials. Moreover, the micrograph at 3000 X magnifications clearly shows that there is no preferred orientation of the polymer in any direction confirming the isotropic nature of the sample.