Sheath Type Research Articles

Detailed Pharmacognostical Standardisation and Phytochemical Analysis of Whole Plant of <i>Tephrosia barber</i> — An Endemic Novel Medicinal Plant

Background: Tephrosia barberi J. R. Drumm. is a perennial herb belonging to the Fabaceae family. Aim: The present research work is focused on carrying out the pharmacognostic standardisation and primary phytochemical analysis of the whole plant of T. barberi. Methods: The morphology, microscopy, powder microscopy, quantitative analysis of leaf constants, fluorescence analysis and physio-chemical parameters were included in the pharmacognostical work for the whole plant followed WHO prescribed quality control methods. The primary phytochemical analysis is carried out for powder with different solvent extracts using standard procedure. Results: The study reveals that the microscopical character of the whole plant of T. barberi includes the presence of cork, phloem fibres, xylem vessels, starch grains, tracheids, unicellular warty trichomes, anamocytic type of stomata and prismatic type calcium oxalate crystal sheath. The total ash, acid insoluble ash, water soluble ash value, sulphated ash, and loss on drying were quantified as physiochemical parameters, which were observed by 3%, 1%, 2%, 5% and 8%, respectively, using T. barberi dry powder. Under daylight, long and short UV, extracts of the whole plant and with various reagents were seen as various fluorescent reflection shades, which showed satisfactory results. Additionally, the primary phytochemical analysis of different extracts of T. barberi showed the presence of alkaloids, flavonoids, steroidal glycosides, polyphenols and terpenoids. Conclusion: All these findings ensured that the whole plant profile for T. barberi could be accomplished, which may provide proper identification and probable to minimise the adulteration of other plant species. Furthermore, the primary phytochemical screening study would be useful to carry out the isolation of phytoconstituents and their therapeutic potency in future.

Metabolomics of related C3 and C4 Flaveria species indicate differences in the operation of photorespiration under fluctuating light.

C3 photosynthesis can be complemented with a C4 carbon concentrating mechanism (CCM) to minimize photorespiratory losses. C4 photosynthesis is often more efficient than C3 under steady-state conditions. However, the C4 CCM depends on inter-cellular metabolite concentration gradients, which must increase following increases in light intensity and could decrease rates of C4 photosynthesis under fluctuating light. Additionally, incomplete flux through photorespiration could prove beneficial to C4 assimilation during light induction of the CCM. Here, we compare metabolic profiles in the closely related C3 Flaveria robusta and C4 Flaveria bidentis during a light transient from low to high light to determine if these non-steady state accumulation patterns provide insight to the induction of the metabolite gradients needed to drive C4 intermediate transport and if there is incomplete cycling of photorespiratory intermediates. In these C3 and C4 species, metabolite steady-state pool sizes suggest that C4 transport acids maintain concentration gradients across the bundle sheath and mesophyll cell types under these light fluctuations. However, there was incomplete flux through photorespiration in the C4 F. bidentis, which could reduce photorespiratory CO2 loss via glycine decarboxylation and help maintain higher rates of assimilation during following induction periods.

Intrarenal pressure detection during flexible ureteroscopy with fiber optic pressure sensor system in porcine model

To validate the feasibility of a fiber-optic pressure sensor-based pressure measurement device for monitoring intrarenal pressure and to analyze the effects of ureteral acess sheath (UAS) type, surgical location, perfusion flow rate, and measurement location on intrarenal pressure (IRP). The measurement deviations and response times to transient pressure changes were compared between a fiber-optic pressure sensing device and a urodynamic device IRP in an in vitro porcine kidney and in a water tank. Finally, pressure measurements were performed in anesthetized female pigs using fiber-optic pressure sensing device with different UAS, different perfusion flow rates, and different surgical positions at different renal calyces and ureteropelvic junctions (UPJ). According to our operation, the result is fiber optic pressure sensing devices are highly accurate and sensitive. Under the same conditions, IRP varied among different renal calyces and UPJ (P < 0.05). IRP was lowest at 50 ml/min and highest at 150 ml/min (P < 0.05). Surgical position had a significant effect on IRP (P < 0.05). 12/14 Fr UAS had a lower IRP than 11/13 Fr UAS. Therefore fiber optic pressure sensing devices are more advantageous for IRP measurements. In ureteroscopy, the type of ureteral sheath, the surgical position, the perfusion flow rate, and the location of the measurement all affect the intrarenal pressure value.

The bug-killer fly Gymnosoma rotundatum (L.) (Diptera: Tachinidae) forms the respiratory funnel independently of the host's immune response.

In internal parasitism, the respiration strategy within the host's body is as essential as evading attack from the host's immune system. Tachinid flies are parasitoids of terrestrial arthropods, mostly insects, during their larval stage. To obtain oxygen while living in the host body, they build a cylindrical structure known as the respiratory funnel at the aperture opened by the tachinid larva on the host integument or trachea. These funnels can be divided morphologically into sheath and cone types. Previous research on sheath-type funnels revealed that they are derived from the encapsulating substance produced by the host's immune system. In contrast, the cone-type funnels cover part of the body of the larval tachinid and may be constructed independently from the host immune system. To determine the mechanisms of cone-type funnel formation, histological observations were carried out on Gymnosoma rotundatum (L.) (Diptera: Tachinidae), which possesses this type of funnel. The respiratory funnel of G. rotundatum was found to be derived from the tube-shaped faeces wrapped with the peritrophic membrane and excreted by the fly larva, not from host tissue or haemocytes. Additionally, secretory glands putatively involved in the funnel formation were discovered around the larval anal plate of G. rotundatum. A comparison of funnel types within Tachinidae revealed that Phasiinae and Dexiinae have cone-type funnels, which may be created by the same mechanism as in G. rotundatum. These new findings suggest that funnel formation that does not use the host immune system is relevant to tachinid phylogeny.

Proof of Concept: A New Solution for Low-Profile Transcatheter Implantation of Optimus-L Stents in Small Children

BackgroundThere is no stent designed or approved for use in infants. We sought to obtain in vitro and in vivo data on a new concept conceived to implant Optimus-L stents at infant vessel diameters and offer a potential long term stent solution. MethodsNineteen Optimus-L stents were mounted on 8 types of angioplasty balloons with diameters 6, 8, and 10 mm with the use of an injection-moulded hand crimper. We evaluated balloon-stent unit (BSU) stability before insertion and advancement through short Terumo introducers with incremental French size and possibility of side-arm contrast injections. Three types of long sheaths were tested. Stents were inflated to balloon nominal diameters and re-expanded to 18 and 23 mm. Stent recoil, foreshortening, and fracture were evaluated. In vivo implantations were performed afterward. ResultsIn vitro: Medtronic Evercross balloons and modified Terumo Destination sheaths were the best combination: BSUs were inserted in 6 F sheaths with possible injections (for 6 and 8 mm balloons), and 7 F sheaths without injections (for the 10 mm balloon). Retrieving BSUs inside the sheath required 1 additional F-size. Boston Scientific Sterling and Balton Lovix balloons, as well as APT Braidin L guiding sheaths showed unsatisfactory performance. Dilation up to 23 mm was possible, and stent shortening was < 24% at 18 mm and < 37% at 23 mm. Recoil was limited, and no stent fractured. In vivo: Optimus-L stents were used to treat 2 infants with aortic coarctation and 2 children with pulmonary artery stenosis with the use of 8 mm balloons and low-profile access. ConclusionsOptimus-L stents can be implanted safely in small patients with a low-profile approach. These stents have the potential to achieve adult size while maintaining structural integrity.

Clinical effectiveness and efficiency of a new steerable sheath technology for radiofrequency ablation in Chinese patients with atrial fibrillation: a retrospective comparative cohort study.

The clinical effectiveness and efficiency of a steerable sheath for radiofrequency catheter ablation (RFCA) in Chinese patients with atrial fibrillation (AF) needs to be compared with a fixed curve sheath to optimize RFCA procedure. This retrospective study included adult AF patients with their first RFCA that was conducted by the same electrophysiologist using a steerable sheath (VIZIGO, Biosense Webster, Inc.) or a fixed curve sheath (NaviEase, Synaptic Medical) in a Chinese tertiary care hospital from January to November 2021. The medical records kept at the hospital were the source of study data that included patient baseline characteristics and outcome measures for the clinical effectiveness and efficiency of RFCA procedure. Multivariate generalized linear regression analyses were performed to explore the impact of sheath type on clinical effectiveness and efficiency after adjustment. Fourteen patients using steerable sheath and 34 patients using fixed curve sheath for RFCA were included in the data analysis. Most of patient baseline characteristics associated with the two study groups were comparable except that the steerable sheath group had significantly higher left atrium diameter (41.9±6.5 vs. 38.1±3.9 mm, P=0.017) and larger left atrium volume (150.4±29.5 vs. 126.8±27.5 mL, P=0.017) than the fixed curve sheath group. Using steerable sheath was associated with significantly shorter total pulmonary vein isolation (PVI) fluoroscopy time and post-surgery hospital length of stay (LOS) than using fixed curve sheath in both unadjusted comparisons (PVI fluoroscopy time: 1.3±1.5 vs. 4.0±3.9 min, P=0.004; post-surgery LOS: 2.1±0.7 vs. 2.9±1.5 days, P=0.034) and multivariate generalized regression analyses (PVI fluoroscopy time: coefficient =-0.859, P=0.014; post-surgery LOS: coefficient =-0.303, P=0.018). Compared to fixed curve sheath, steerable sheath used for RFAC could have the potential to shorten the PVI fluoroscopy time and reduce post-surgery LOS in a Chinese real-world hospital setting. Future real-world studies with large sample size are needed to confirm our study findings.

A Feasibility Study on Clinical Utility, Efficacy and Limitations of 2 Types of Flexible and Navigable Suction Ureteral Access Sheaths in Retrograde Intrarenal Surgery for Renal Stones

To evaluate stone-free rate, device maneuverability, and complications after retrograde intrarenal surgery (RIRS) using 2 different sizes of flexible and navigable suction ureteral access sheaths (FANS). A retrospective analysis was performed for patients who underwent RIRS for renal stones of any size, number, and location between November 2021 and October 2022. Group 1 had FANS of 12 French. Group 2 had FANS of 10 French. Both sheaths have a Y-shaped suction channel. Tip of 10 French FANS has 20% more flexibility. Lithotripsy was achieved using either thulium fiber or high-power holmium lasers. A 5-point Likert scale was used to assess the performance of each sheath. There were 16 patients in Group 1 and 15 patients in Group 2. Baseline demographics and stone parameters were similar. Four patients in Group 2 had the same session bilateral RIRS. Sheath insertion was successful in all renal units but one. Ten French FANS had a higher percentage of excellent scores for ease of use, manipulation, and visibility. Neither of the sheaths had an average or difficult rating for all evaluation scales. A fornix rupture requiring prolonged stenting occurred in group 2. All patients were discharged within 24hours of surgery. One patient in each group visited the emergency department (analgesic treatment). There were no infectious complications. At 3 months, a computed tomography scan showed that the absence of residual fragments >2mm was significantly higher in Group 2 (94.7% vs 68.8%, P=0.01). The 10 Fr FANS showed a higher stone-free rate. There was no infectious complication using both sheaths.

Quantification of outflow resistance for ureteral drainage devices used during ureteroscopy.

Since renal pelvis pressure is directly related to irrigation flowrate and outflow resistance, knowledge of outflow resistance associated with commonly used drainage devices could help guide the selection of the type and size of ureteral access sheath or catheter for individual ureteroscopic cases. This study aims to quantitatively measure outflow resistance for different drainage devices utilized during ureteroscopy. With measured irrigation flowrate and renal pelvis pressure, outflow resistance was calculated using a hydrodynamic formula. After placement of a drainage device into a silicone kidney-ureter model, a disposable ureteroscope with a 9.5-Fr outer diameter was inserted with its tip positioned at the renal pelvis. Irrigation was delivered through the ureteroscope from varying heights above the renal pelvis. Renal pelvis pressure was measured directly from the port of the kidney model using a pressure sensor (Opsens, Canada). Outflow resistance was determined by plotting flowrate versus renal pelvis pressure. All trials were performed in triplicate for each drainage device inserted. Flowrate was linearly dependent on renal pelvis pressure for all drainage devices tested. Outflow resistance values were 0.2, 1.1, 1.4, 3.9, and 6.5 cmH2O/[ml/min] for UAS 13/15 Fr, UAS 11/13 Fr, UAC 6 Fr, UAC 4.8 Fr, and UAC 4.0 Fr, respectively, across the range of commonly used irrigation flowrates. In this study, outflow resistance of different ureteral drainage devices was quantitatively measured. This knowledge can be useful when selecting which type and size of drainage device to insert to maintain safe renal pelvis pressure during ureteroscopy.

Analysis Behavior of Openings on Full-Size Cross-Laminated Timber (CLT) Frame Shear Walls Tested Monotonically

Walls, as components of the lateral-force-resisting system of a building, are defined as shear walls. This study aims to determine the behavior of shear wall panel cross-laminated-timber-based mangium wood (Acacia mangium Willd) (CLT-mangium) in earthquake-resistant prefabricated houses. The earthquake performance of CLT mangium frame shear walls panels has been studied using monotonic tests. The shear walls were constructed using CLT-mangium measuring 2400 mm × 1200 mm × 68 mm with various design patterns (straight sheathing, diagonal sheathing/45°, windowed shear wall with diagonal pattern and a door shear wall with a diagonal pattern). Shear wall testing was carried out using a racking test, and seismic force calculations were obtained using static equivalent earthquake analysis. CLT-mangium sheathing installed horizontally (straight sheathing) is relatively weak compared to the diagonal sheathing, but it is easier and more flexible to manufacture. The diagonal sheathing type is stronger and stiffer because it has triangulation properties, such as truss properties, but is more complicated to manufacture (less flexible). The type A design is suitable for low-intensity zones (2), and types B, D, E1 and E2 are suitable for moderate-intensity zones (3, 4), and type C is suitable for severe-intensity zones (5).

Sealing failure of a cement sheath under temperature variation

The sealing failure of cement sheaths caused by temperature variations in wellbores seriously threatens the safe production of oil and gas wells. The finite element method (FEM) is usually employed to analyze this complex engineering problem. However, the current FEM models solved this problem are based on the constant temperature change value assumption, which ignore the damage of cement sheaths during the evolution of temperature field and the temperature change rate. This work established a FEM model based on the transient heat conduction theory and concrete damage plastic (CDP) model. The proposed numerical model is implemented in the commercial finite element software Abaqus and its accuracy has been verified through experiments. The damage states of the cement sheath during temperature changes were analyzed. The results indicate the variety of failure types of the cement sheath caused by temperature variation in the wellbore. An increase in temperature by 70 °C in the wellbore leads to both compression and tensile damages of the cement sheath, while a decrease in temperature by more than 46 °C will lead to the interface failure between casing and cement sheath. The variation rate of temperature in the wellbore has a significant influence on the sealing integrity of the cement sheath, and damage to the cement sheath increases with the temperature change rate increasing. Therefore, the cement sheath will be protected to reduce its damage by lowering the variation rate of temperature, such as by controlling the production rate of oil and gas wells. These research results provide theoretical supports for production allocation measures in oil and gas exploitation.

Dry shrinkage of Moso bamboo in relation to vascular bundle structure

Abstract Bamboo is susceptible to moisture-induced dimensional instability and cracking. Combining traditional methods with vascular bundle detection, the coordinates and fiber sheath area of each vascular bundle was determined accurately. Based on data fitting, the change in the shape of cross-section was quantified and analyzed based on parameters such as radius, radian, and arc length. The changes in the total area and the areas of different types of fiber sheath, as well as the changes in the arrangement of vascular bundles were studied. The results showed that when the moisture content was reduced from 64% to 0%, the radius of the cross section was increased by 21%, while the radian and arc length decreased by 22% and 6%, respectively. The fibers shrunk by 15%, which was greater than that of the other tissues except bamboo fibers (9%). The gradient distribution of the fiber volume fraction contributed to its asynchronous dry shrinkage. Significant radial and tangential displacements were found in vascular bundles. This work further elucidated the dry shrinkage mechanism of bamboo, and was of great significance for the quantitative analysis of changes in bamboo structure from a combination of micro and macro perspectives.

Transvenous Lead Extraction Procedure-Indications, Methods, and Complications.

Transvenous lead extraction (TLE) is a complex and technically challenging procedure useful in the management strategy for many complications related to the presence of cardiac implantable electronic devices (CIEDs). The decision to perform lead extraction should take into consideration the clinical indication for the procedure, risks versus benefits, extractor and team experience, and also patient preference for the procedure. A variety of techniques can be used when performing TLE procedures, such as simple traction, traction devices, and various types of sheaths or snares. TLE is a procedure with a potentially high risk of complications that can be divided into major complications, which require rapid intervention, and minor complications, which are more frequent but are not life-threatening. The present review aims to highlight the indications, contraindications, methods, and complications of transvenous lead extraction procedures.

Selection of Sheath Voltage Limiter for Mixed Overhead-Underground Cable in 220 kV Transmission Lines

This paper presents the most common methods of sheath bonding of transmission cables and the calculation of parameters, including rated voltage and energy absorption, of sheath voltage limiters for a mixed overhead-underground 220 kV transmission lines. The dependence of sheath voltage limiters parameters on the sheath types, system parameters such as the short-circuit capacity, the cable length, lightning current amplitudes, grounding resistance and cable installation are calculated in details. In this research, several methods in selecting sheath bonding types as well as sheath voltage limiters for a given set of conditions in mixed overhead-cable 220 kV transmission lines are proposed. The cross bonding permits to choose SVLs with the lowest rating voltage. However, the grounding resistance value of the tower at the junction between overhead lines and cables must be maintained at or below 3 Ω. The surrounding environment of cables changes, the required parameters of SVL to be selected must be recalculated to take the cable installation into account.

Review of the NRC Canada Studies on Fire Resistance of Walls: Results, Research Gaps and Design Guidelines

The National research council Canada conducted three major fire resistance studies on the interior party walls, interior fire separation walls and exterior walls. The fire resistance results of these studies were published over the past three decades and the publications were short in suggesting design guidelines for practioners’ use and gaps for future research. This paper summaries the fire resistance results of 35 full-scale wall tests, suggests design guidelines and identifies future research gaps for interior party walls, interior fire separation walls and exterior walls. The result summary includes the effect of different design parameters on the fire resistance performance of wall assemblies such as the stud type and spacing, number of stud rows, number of gypsum board layers and thickness, mid-height blocking, resilient channels installation and spacing, screws spacing for attaching gypsum board to either wall faming or resilient channels, insulation type and exterior wall sheathing type on the fire resistance of loadbearing and non-loadbearing wall assemblies. The summary results was used as the basis for suggesting design guidelines for practioners’ use and identifying gaps for future research to improve the fire resistance performance of wall assemblies. For example, the use of a reduced screw spacing from 406 mm o.c. to 203 mm o.c. in the gypsum board field and from 406 mm o.c. to 150 mm o.c. at the board joints was suggested for future research to keep the protective gypsum board layer attached to studs or resilient channels longer for a better fire resistance performance of wall assemblies. Also, fire resistance design guidelines are suggested, for examples, the use of rock fibre insulation for non-load bearing interior party walls to achieve 1.5-h fire resistance, the use of cellulose fibre insulation for loadbearing fire separation walls to achieve 2-h fire resistance rating and the use of reduced screw spacing in attaching the gypsum board to wall framing from 406 mm o.c. to 203 mm o.c. for loadbearing exterior wall assembly with gypsum board glass mat sheathing to expand the fire resistance rating from non-useful 30-min to a useful code compliance 45-min fire resistance rating assembly. Additional suggested examples for future research gaps and design guidelines are also provided.

Aggregative movement of mesophyll chloroplasts occurs in a wide variety of C4 plant species

• Redistributions of chloroplasts in 36 C 4 monocots and eudicots were examined. • Mesophyll chloroplasts in 35 C 4 plants aggregated towards the bundle sheath. • This chloroplast movement would be a general physiological response in C 4 plants. • Mesophyll chloroplasts in monocots aggregated more strongly than in eudicots. • Degrees of movement in NADP-ME were lower than in PCK species. C 4 plants have two types of photosynthetic cells, mesophyll (M) and bundle sheath (BS) cells with different subcellular structures. In C 4 plants, maize and finger millet, the chloroplasts of M cells are normally distributed toward the periphery but redistribute toward the BS cell side in response to environmental stresses. This directional movement of M chloroplasts is called aggregative movement, of which physiological significance remains unknown. Furthermore, few C 4 plant species have been examined for aggregative movement, and it has not been established whether this is a common phenomenon in C 4 plants. Hence, this study aims to investigate whether the aggregative movement is widely observed and diverse in C 4 plants. Thirty-six monocotyledonous and dicotyledonous C 4 plant species (Poaceae, Amaranthaceae, Asteraceae, and Portulaceae) including all three C 4 subtypes were examined. Leaf segments were infiltrated with the abscisic acid solution and irradiated with blue light to induce aggregative movement of M chloroplasts. Aggregative movement of M chloroplasts was observed in 35 C 4 species across 11 evolutionary lineages. The degree of aggregative movement was significantly greater in monocots than that in eudicots; phospho enol pyruvate carboxykinase subtype C 4 plants showed significantly greater aggregative movement than NADP-ME type C 4 plants. The aggregative movements would be broadly shared stress responses in C 4 plants. The differences in the degree of aggregative movement could be related to morphological and physiological differences between monocots and eudicots, and among C 4 subtypes.

Mechanical property design method of cement sheath in a horizontal shale oil well under fracturing conditions

Based on the elastoplastic model of cement sheath considering the influence of three-dimensional principal stress and the stress field model of interface crack, a mechanical performance design method of cement sheath is established to meet the wellbore sealing requirements during fracturing. This method takes the failure types of the cement sheath, such as tensile failure, plastic yield, interface crack propagation along interface and zigzag propagation into account. Meanwhile, the elasticity modulus and Poisson's ratio quantitative design charts of cement sheath are constructed based on this method, and the safety and risk areas of wellbores are defined, which quantify the yield strength and tensile strength indexes of cement sheath. The results show that decreasing elasticity modulus, increasing yield strength and Poisson's ratio of cement sheath can avoid plastic deformation of cement sheath; increasing the tensile strength of cement sheath can prevent its tensile failure; increasing elasticity modulus and Poisson's ratio of cement sheath is good for shortening the length of the interface crack, but will increase the risk of interface cracks zigzagging into cement sheath. The model calculation and case verification has proved that the method in this paper can give accurate calculation results and is convenient for field application.

Light and scanning electron microscopic imaging of leaf transverse sections of indigenous fodder grasses of central Punjab, Pakistan.

The significance of grasses as fodder is enormous. However, it has been observed that different fodder grasses are identified locally with the similar vernacular names. Even same species recognized with different names. This happened due to their reduced and overlapped morphological characters. Hence comprehensive taxonomic keys were required to provide authentic identification of this grass flora. Current study established microscopic identification tools on the basis of leaf transverse anatomical features. Results demonstrated a great diversity in ribs and furrows arrangement among all studied grass members. Lolium temulentum, Phalaris minor, Poa annua, Arundo donax, Aristida adscensionis, Desmostachya bipinnata, Cenchrus biflorus and Digitaria ciliaris possessed ribs and furrows only at adaxial surfaces whereas all other species possessed this feature abaxially. Generally all the species contain three types of vascular bundles i.e. small, medium and large. Therefore, this qualitative feature is valuable only at family level, however, it found insignificant in taxa identification. Diversity was observed in bundle sheath type which could be taxonomically significant. Generally bundle sheath was found complete in most of species but in Bromus japonicus Thunb., Dactylis glomerata L., Acrachne racemosa (Heyne ex Roth) Ohwi, Chrysopogon aucheri (Boiss.) Stapf, Dichanthium annulatum (Forssk.) Stapf, Heteropogon contortus (L.) P Beauv. Ex. Roem & Schult. Eragrostis minor Host. and in Agrostis gigantea Roth. had incomplete type of sheath. Results reported great diversity in characters which could be taxonomically viable. RESEARCH HIGHLIGHTS: This research highlighted the significance of microscopic examination of leaf transverse anatomical features in field of taxonomy. Established anatomical tools would be of great importance for the identification of studied species.

Computed tomography measurement for left atrial appendage closure.

Percutaneous left atrial appendage closure (LAAC) has been reported many therapeutic effects with regard to its safety and efficacy, and the number of patients with non-valvular atrial fibrillation undergoing LAAC is increasing worldwide. Although it is a highly safe procedure, further improvements are expected and preoperative planning is extremely important. For this purpose, transesophageal echocardiography has been mainly performed so far, however, nowadays, it is recommended to determine a more optimal treatment strategy combined with computed tomography. Preoperative CT predicts not only the risk of the intervention based on anatomical features of the left atrial appendage (LAA) but also the device type and size, sheath type, optimal location for septal puncture and pre-procedurally clarifies the left atrium and LAA dimensions. Furthermore, postoperative CT can evaluate device-related thrombus and peri-device leak, making it possible to observe the postoperative course using less invasive methods. This study reviews the practical utility of CT in pre- and post-LAAC.

A Novel Continuum Robot With Stiffness Variation Capability Using Layer Jamming: Design, Modeling, and Validation

This paper presents a novel continuum robot ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OctRobot-I</i> ) that has controllable stiffness variation capability in both the transverse and axial directions. Robot design, stiffness variation analysis and experimental testing are discussed in detail. Stiffness models based on the Euler-Bernoulli beam theory are developed, and then four static deflection cases are analysed. Experiments are conducted with two types of layer jamming sheaths (overlap numbers <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</i> = 3, 5) and four different vacuum pressures (0kPa, 25kPa, 50kPa, 75kPa) at three different bending angles (0°, 90°, 180°). The results demonstrate that the stiffness changing tendency is in compliance with the derived models and show that the robot has a good stiffness variable capability. With the jamming sheath of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</i> = 3, the stiffness ranges (ratios) are 36.4 to 241.7 N/m (6.6) and 92.9 to 19.3×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> N/m (207.8) in the transverse and axial directions, respectively. With the jamming sheath of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</i> = 5, the stiffness ranges (ratios) are 65.7 to 398.3 N/m (6.1) and 106.7 to 20.8×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> N/m (194.9) in the transverse and axial directions, respectively. Additionally, the actuating and gripping experiments demonstrate that this robot has good performance in real-world applications.

Lead extractions: dissecting adhesions up to the lead‐tip of the right ventricle: safety and success‐rates

AbstractAimsGoal of Transvenous Lead Extraction (TLE) is complete removal of all targeted leads, without complications. Despite counter traction manoeuvres, efficacy rates are often hampered by broken right ventricle lead (RV‐lead) tips. Mechanically powered lead extraction (Evolution sheath) is effective, however safety of dissection up to the lead tip is unclear. Therefore, we examined the feasibility and safety of RV‐lead extraction requiring dissection up to the myocardium.Methods and resultsFrom 2009 to 2018, all TLE in the Isala Heart Centre (Zwolle, The Netherlands) requiring the hand‐powered mechanical Evolution system to extract RV‐leads (n = 185) were examined from a prospective registry. We assessed 4 groups: TLE with the first generation Evolution (n = 43) with (A1,n = 18) and without (A2,n = 25) adhesions up to the myocardium and TLE with the Novel R/L type (n = 142) of sheath with (B1, n = 59) and without (B2, n = 83) adhesions up to the myocardium. Complete success rate in Group B was significantly higher than group A (96.5 vs 76.7%, p = 0.0354). When comparing the patients with adhesions up to the myocardium, total complete success is higher in the R/L group (61.1% vs 90.5%, p = 0.0067). There were no deaths. Overall major complication rates were low (2/185; 1.1%) and there was no statistically significant difference in major and minor complications between the two groups.ConclusionExtraction strategy with the bidirectional Evolution R/L sheath for right ventricular leads with adhesions up to the myocardium is safe and feasible.