Salvage of an Incomplete Sandwich With a Covered Celiac Trunk and a "Floating" Superior Mesenteric Artery Stent in a Thoracoabdominal Aortic Aneurysm

PURPOSE

To report a case of a patient with a large thoracoabdominal aortic aneurysm (TAAA) extent V treated with a custom-made fenestrated and branched endovascular repair (F/B-EVAR) after a failed and incomplete attempt of a Sandwich repair technique.

REPORT

An 83-year-old patient was referred to our department after a failed attempt at endovascular repair of type V TAAA with a sandwich technique. The celiac trunk was inadvertently covered with the first endograft and a covered long superior mesenteric artery stent was placed and left facing upward inside the aorta. We performed a staged repair, by first catheterizing and stenting the celiac trunk and bringing it under and inside the main aortic endograft. In interval, a F/B-EVAR was performed using a bimodular custom-made device (CMD) with a proximal 2 branch module for the celiac trunk and superior mesenteric artery and distal module with fenestrations for both renal arteries. The intervention was successful, and the follow-up was uneventful at 6 months.

CONCLUSIONS

Re-intervention after failed endovascular attempts of TAAA repair are technically challenging and require advanced endovascular techniques. The ability to construct CMDs allowed to extend repair to our patient which had severe anatomical constraints for other techniques.

Sustainable Pultruded Sandwich Profiles with Mycelium Core

This research focuses on exploring the potential of mycelium as a sustainable alternative to wood or solid foam in pultruded glass fiber-reinforced plastic (GFRP) sandwich profiles. The study evaluates the performance and the environmental sustainability potential of this composite by mechanical tests and life cycle assessment (LCA). Analysis and comparison of pultruded sandwich profiles with mycelium, polyurethane (PUR) foam and chipboard demonstrate that mycelium is competitive in terms of its performance and environmental impact. The LCA indicates that 88% of greenhouse gas emissions are attributed to mycelium production, with the heat pressing (laboratory scale) being the main culprit. When pultruded profiles with mycelium cores of densities 350 and 550 kg/m³ are produced using an oil-heated lab press, a global warming potential (GWP) of 5.74 and 9.10 kg CO2-eq. per functional unit was calculated, respectively. When using an electrically heated press, the GWP decreases to 1.50 and 1.78 kg CO2-eq. Compared to PUR foam, a reduction of 23% in GWP is possible. In order to leverage this potential, the material performance and the reproducibility of the properties must be further increased. Additionally, an adjustment of the manufacturing process with in situ mycelium deactivation during pultrusion could further reduce the energy consumption.

Rapid 3D absolute B1 + mapping using a sandwiched train presaturated TurboFLASH sequence at 7 T for the brain and heart

PURPOSE

To shorten the acquisition time of magnetization-prepared absolute transmit field (B₁ ⁺ ) mapping known as presaturation TurboFLASH, or satTFL, to enable single breath-hold whole-heart 3D B₁ ⁺ mapping.

METHODS

SatTFL is modified to remove the delay between the reference and prepared images (typically 5 T₁ ), with matching transmit configurations for excitation and preparation RF pulses. The new method, called Sandwich, is evaluated as a 3D sequence, measuring whole-brain and gated whole-heart B₁ ⁺ maps in a single breath-hold. We evaluate the sensitivity to B₁ ⁺ and T₁ using numerical Bloch, extended phase graph, and Monte Carlo simulations. Phantom and in vivo images were acquired in both the brain and heart using an 8-channel transmit 7 Tesla MRI system to support the simulations. A segmented satTFL with a short readout train was used as a reference.

RESULTS

The method significantly reduces acquisition times of 3D measurements from 360 s to 20 s, in the brain, while simultaneously reducing bias in the measured B₁ ⁺ due to T₁ and magnetization history. The mean coefficient of variation was reduced by 81% for T₁ s of 0.5-3 s compared to conventional satTFL. In vivo, the reproducibility coefficient for flip angles in the range 0-130° was 4.5° for satTFL and 4.7° for our scheme, significantly smaller than for a short TR satTFL sequence, which was 12°. The 3D sequence measured B₁ ⁺ maps of the whole thorax in 26 heartbeats.

CONCLUSION

Our adaptations enable faster B₁ ⁺ mapping, with minimal T₁ sensitivity and lower sensitivity to magnetization history, enabling single breath-hold whole-heart absolute B₁ ⁺ mapping.

A Monoclonal Antibody-Based Immunochromatographic Test Strip and Its Application in the Rapid Detection of Cucumber Green Mottle Mosaic Virus

Two specific monoclonal antibodies (mAbs) were screened, and an immunochromatographic strip (ICS) test for rapid and specific detection of cucumber green mottle mosaic virus (CGMMV) was developed. The coat protein of CGMMV was heterologously expressed as an immunogen, and specific capture mAb 2C9 and the detection mAb 4D4 were screened by an uncompetitive immunoassay. The test and control lines on the nitrocellulose membrane were coated with the purified 2C9 and a goat anti-mouse IgG, respectively, and a nanogold probe combined with 4D4 was applied to the conjugate pad. Using these mAbs, a rapid and sensitive ICS was developed. Within the sandwich mode of 2C9-CGMMV-4D4, the test line showed a corresponding positive relationship with CGMMV in infected samples. The ICS test had a detection limit of 1:5000 (w/v) for CGMMV in samples and was specific for CGMMV, with no observed cross-reaction with TMV or CMV.

Reprocessed Materials Used in Rotationally Moulded Sandwich Structures for Enhancing Environmental Sustainability: Low-Velocity Impact and Flexure-after-Impact Responses

In the rotational moulding industry, non-used, scrap, and waste purge materials have tremendous potential to be reprocessed and applied in skin-foam-skin sandwich structures to replace and reduce the use of virgin polymers. This approach not only encourages the re-use of these waste materials but also significantly contributes to reduce environmental impacts associated with the use of virgin polymers in this sector. The demand of rotationally moulded sandwich structures is rapidly increasing in automotive, marine, and storage tanks, where investigating their impact and after-impact responses are crucial. Hence, this study investigated the low-velocity impact (LVI) and flexure-after-impact (FAI) responses of rotationally moulded sandwich structures manufactured using reprocessed materials. Results obtained from LVI induced damage at two different incident energy levels (15 J, 30 J), and the residual flexural strength of impacted structures evaluated by three-points bending tests were compared with non-reprocessed sandwich structures (virgin materials). The impact damage progression mechanism was characterized using the X-ray micro-computer-tomography technique. Reprocessed sandwiches demonstrated 91% and 66% post-impact residual strength at 15 J and 30 J respectively, while for non-reprocessed sandwiches, these values were calculated as 93% and 88%. Although reprocessed sandwich structures showed a lower performance over non-reprocessed sandwiches, they have a strong potential to be used in sandwich structures for various applications.

Sandwich osteotomy with interpositional grafts for vertical augmentation of the mandible: A meta-analysis

Sandwich osteotomy is a technique for vertical augmentation based on the principle of a graft being placed between two pedicled native bones. The inherent vascularization helps in graft consolidation. The aim is to review the bone height gained, implant survival and pitfalls with sandwich osteotomy. The PICO model was used to identify the suitable studies for the review. Oxford level of evidence, Newcastle Ottawa Scale and Cochrane's tool for Systematic Reviews of Interventions was applied for identifying study quality. Meta-analysis was performed with the help of RevMan. Funnel plot was used to evaluate publication bias and bias during article selection. Difference in means was used as principal summary measure. Fixed effects model with inverse variance statistics was used. I2test statistics was applied to identify study heterogeneity. Forest plots were produced for the outcome variables with 95% confidence interval (CI) and overall treatment effects and subgroup effects at a significance level of 0.05. The overall implant survival rate ranged from 90%-100% and prosthetic survival rate from 87%-95%. An overall 6-10mm of bone can be gained in the anterior mandible and 4-8mm in the posterior mandible. A total of 1030 implants were placed of which 988 implants survived after the mean follow up periods (odds ratio: 0.77, 95% CI: 0.49-1.21). Implant survival is independent of the graft being used. Vertical augmentation in the posterior mandible is limited compared to anterior owing to the presence of inferior alveolar nerve and the keratinized tissue deficiency.

Research Note: Development of a sandwich ELISA for determining plasma growth hormone concentrations in goose

Growth hormone (GH) is required for normal postnatal development in poultry; however, no immunoassay exists to assess its levels in geese plasma, hindering the study of endocrine regulation in this species. We developed a sandwich ELISA to determine the GH concentrations in the plasma of geese. Recombinant goose GH was produced using a eukaryotic expression system and purified for use as the reference standard in ELISA and the antigen for producing the polyclonal antibodies in rabbits. Rabbit anti-goose GH polyclonal antibody was used to coat the wells of the ELISA plate, and its biotinylated form served as the detection antibody. An avidin-conjugated horseradish peroxidase was used to bind the detection antibody and catalyze the chromogenic reaction of 3,3,5,5-tetramethylbenzidine and H₂O₂. A sigmoidal curve was fitted to the optical density and the log of the standard GH concentration using the four-parameter logistic model. The sensitivity of the assay was less than 0.156 ng/mL. The intra- and interassay coefficients of variation were less than 9 and 13%, respectively. The response curve of the serially diluted plasma samples from geese exhibited a good parallel relationship with that observed for the reference standards. The assay effectively detected differences in GH concentrations in plasma samples from geese at various physiological stages; thus, it will be useful for future study of their growth and metabolism.

Design, Development, and Characterization of Advanced Textile Structural Hollow Composites

The research is focused on the design and development of woven textile-based structural hollow composites. E-Glass and high tenacity polyester multifilament yarns were used to produce various woven constructions. Yarn produced from cotton shoddy (fibers extracted from waste textiles) was used to develop hybrid preforms. In this study, unidirectional (UD), two-dimensional (2D), and three-dimensional (3D) fabric preforms were designed and developed. Further, 3D woven spacer fabric preforms with single-layer woven cross-links having four different geometrical shapes were produced. The performance of the woven cross-linked spacer structure was compared with the sandwich structure connected with the core pile yarns (SPY). Furthermore, three different types of cotton shoddy yarn-based fabric structures were developed. The first is unidirectional (UD), the second is 2D all-waste cotton fabric, and the third is a 2D hybrid fabric with waste cotton yarn in the warp and glass multifilament yarn in the weft. The UD, 2D, and 3D woven fabric-reinforced composites were produced using the vacuum-assisted resin infusion technique. The spacer woven structures were converted to composites by inserting wooden blocks with an appropriate size and wrapped with a Teflon sheet into the hollow space before resin application. A vacuum-assisted resin infusion technique was used to produce spacer woven composites. While changing the reinforcement from chopped fibers to 3D fabric, its modulus and ductility increase substantially. It was established that the number of crossover points in the weave structures offered excellent association with the impact energy absorption and formability behavior, which are important for many applications including automobiles, wind energy, marine and aerospace. Mechanical characterization of honeycomb composites with different cell sizes, opening angles and wall lengths revealed that the specific compression energy is higher for regular honeycomb structures with smaller cell sizes and a higher number of layers, keeping constant thickness.

Green and Scalable Fabrication of Sandwich-like NG/SiOx/NG Homogenous Hybrids for Superior Lithium-Ion Batteries

SiOx is considered as a promising anode for next-generation Li-ions batteries (LIBs) due to its high theoretical capacity; however, mechanical damage originated from volumetric variation during cycles, low intrinsic conductivity, and the complicated or toxic fabrication approaches critically hampered its practical application. Herein, a green, inexpensive, and scalable strategy was employed to fabricate NG/SiOx/NG (N-doped reduced graphene oxide) homogenous hybrids via a freeze-drying combined thermal decomposition method. The stable sandwich structure provided open channels for ion diffusion and relieved the mechanical stress originated from volumetric variation. The homogenous hybrids guaranteed the uniform and agglomeration-free distribution of SiOx into conductive substrate, which efficiently improved the electric conductivity of the electrodes, favoring the fast electrochemical kinetics and further relieving the volumetric variation during lithiation/delithiation. N doping modulated the disproportionation reaction of SiOx into Si and created more defects for ion storage, resulting in a high specific capacity. Deservedly, the prepared electrode exhibited a high specific capacity of 545 mAh g-1 at 2 A g-1, a high areal capacity of 2.06 mAh cm-2 after 450 cycles at 1.5 mA cm-2 in half-cell and tolerable lithium storage performance in full-cell. The green, scalable synthesis strategy and prominent electrochemical performance made the NG/SiOx/NG electrode one of the most promising practicable anodes for LIBs.

Effect of Core Architecture on Charpy Impact and Compression Properties of Tufted Sandwich Structural Composites

This study presents a novel sandwich structure that replaces the polypropylene (PP) foam core with a carbon fiber non-woven material in the tufting process and the liquid resin infusion (LRI) process. An experimental investigation was conducted into the flatwise compression properties and Charpy impact resistance of sandwich composites. The obtained results validate an enhancement to the mechanical properties due to the non-woven core and tufting yarns. Compared to samples with a pure foam core and samples without tufting threads, the compressive strength increased by 45% and 86%, respectively. The sample with a non-woven layer and tufting yarns had the highest Charpy absorbed energy (23.85 Kj/m2), which is approximately 66% higher than the samples without a non-woven layer and 90% higher than the samples without tufting yarns. Due to the buckling of the resin cylinders in the Z-direction that occurred in all of the different sandwich samples during the compression test, the classical buckling theory was adopted to analyze the differences between the results. The specific properties of the weight gains are discussed in this paper. The results show that the core layers have a negative effect on impact resistance. Nevertheless, the addition of tufting yarns presents an obvious benefit to all of the specific properties.

Endovascular Repair of a Ruptured Thoracoabdominal Aortic Aneurysm With the Sandwich Technique: A Case Report

INTRODUCTION

aortic aneurysms involving the renal and visceral arteries are endovascular challenges, especially for emergencies. We report a case of ruptured thoracoabdominal aortic aneurysm (TAAA) in a morbidly obese 71-year-old man. The patient was admitted with a stable hemodynamic state. A computed tomography angiogram (CTA) revealed a contained ruptured TAAA with an occluded celiac trunk and left renal artery due to previous nephrectomy. Due to the emergency and his comorbidities, we performed an endovascular aortic repair with the sandwich technique and 2 chimneys. Two bridging stents (chimneys) were deployed between the aorta and the target vessels (superior mesenteric and right renal arteries) in a space created in-between 2 aortic straight endografts. Ten days postoperative, acute renal failure appeared and right renal stent occlusion was diagnosed on CTA. Unfortunately, no adequate kidney revascularization could be obtained, requiring permanent hemodialysis. At a 3-month follow-up visit, the patient did well with stable aneurysm dimensions.

CONCLUSIONS

encouraging outcomes of chimney-EVAR techniques, comparable to those in published reports of fenestrated-EVAR and branched-EVAR, support this procedure as a valid off-the-shelf available alternative in emergency situations. Nevertheless, only few midterm results achieved are actually available and long-term outcomes are actually unknown.

Lightweight Highly Tunable Jamming-Based Composites

Tunable-impedance mechanisms can improve the adaptivity, robustness, and efficiency of a vast array of engineering systems and soft robots. In this study, we introduce a tunable-stiffness mechanism called a "sandwich jamming structure," which fuses the exceptional stiffness range of state-of-the-art laminar jamming structures (also known as layer jamming structures) with the high stiffness-to-mass ratios of classical sandwich composites. We experimentally develop sandwich jamming structures with performance-to-mass ratios that are far greater than laminar jamming structures (e.g., a 550-fold increase in stiffness-to-mass ratio), while simultaneously achieving tunable behavior that standard sandwich composites inherently cannot achieve (e.g., a rapid and reversible 1800-fold increase in stiffness). Through theoretical and computational models, we then show that these ratios can be augmented by several orders of magnitude further, and we provide an optimization routine that allows designers to build the best possible sandwich jamming structures given arbitrary mass, volume, and material constraints. Finally, we demonstrate the utility of sandwich jamming structures by integrating them into a wearable soft robot (i.e., a tunable-stiffness wrist orthosis) that has negligible impact on the user in the off state, but can reduce muscle activation by an average of 41% in the on state. Through these theoretical and experimental investigations, we show that sandwich jamming structures are a lightweight highly tunable mechanism that can markedly extend the performance limits of existing structures and devices.

Synthesis of Monolayer Gold Nanorings Sandwich Film and Its Higher Surface-Enhanced Raman Scattering Intensity

Most previous studies relating to surface-enhanced Raman spectroscopy (SERS) signal enhancement were focused on the interaction between the light and the substrate in the x-y axis. 3D SERS substrates reported in the most of previous papers could contribute partial SERS enhancement via z axis, but the increases of the surface area were the main target for those reports. However, the z axis is also useful in achieving improved SERS intensity. In this work, hot spots along the z axis were specifically created in a sandwich nanofilm. Sandwich nanofilms were prepared with self-assembly and Langmuir-Blodgett techniques, and comprised of monolayer Au nanorings sandwiched between bottom Ag mirror and top Ag cover films. Monolayer Au nanorings were formed by self-assembly at the interface of water and hexane, followed by Langmuir-Blodgett transfer to a substrate with sputtered Ag mirror film. Their hollow property allows the light transmitted through a cover film. The use of a Ag cover layer of tens nanometers in thickness was critical, which allowed light access to the middle Au nanorings and the bottom Ag mirror, resulting in more plasmonic resonance and coupling along perpendicular interfaces (z-axis). The as-designed sandwich nanofilms could achieve an overall ~8 times SERS signals amplification compared to only the Au nanorings layer, which was principally attributed to enhanced electromagnetic fields along the created z-axis. Theoretical simulations based on finite-difference time-domain (FDTD) method showed consistent results with the experimental ones. This study points out a new direction to enhance the SERS intensity by involving more hot spots in z-axis in a designer nanostructure for high-performance molecular recognition and detection.

Surgical treatment of unilateral severe overeruption and opposing alveolar atrophy

Overeruption with simultaneous alveolar deficiency is not uncommon but very difficult to treat. In mild cases of overeruption without opposing alveolar deficiency, selective removal of enamel from the overerupted teeth may be an option, yet not advocated. Extraction of the overerupted teeth should be avoided if the teeth are intact with sufficient bone support. The Schuchardt operation is a good option for cases limited to the overeruption. In cases of overeruption with simultaneous opposed alveolar deficiency, it is suggested to perform simultaneous maxillary and mandibular surgical procedures: alveolar segmental operation, followed by a sandwich osteotomy on the opposing arch. This article presents a posterior segmental osteotomy in the maxilla and a simultaneous sandwich procedure in the mandible utilizing the bone graft removed from the maxilla. The results showed good functional and esthetic outcomes. This method preserves the native teeth. It also utilizes an autogenous bone graft that is harvested regardless of the interpositional graft and spares a second surgical site. In addition, it allows for a one-stage procedure which enables for both treatment of the overeruption and augmentation of the opposing arch.

Buckyball sandwiches

Two-dimensional (2D) materials have considerably expanded the field of materials science in the past decade. Even more recently, various 2D materials have been assembled into vertical van der Waals heterostacks, and it has been proposed to combine them with other low-dimensional structures to create new materials with hybridized properties. We demonstrate the first direct images of a suspended 0D/2D heterostructure that incorporates C₆₀ molecules between two graphene layers in a buckyball sandwich structure. We find clean and ordered C₆₀ islands with thicknesses down to one molecule, shielded by the graphene layers from the microscope vacuum and partially protected from radiation damage during scanning transmission electron microscopy imaging. The sandwich structure serves as a 2D nanoscale reaction chamber, allowing the analysis of the structure of the molecules and their dynamics at atomic resolution.

Isolation and cultivation of adult primary bovine hepatocytes from abattoir derived liver

The aim was to establish a cell culture of adult primary bovine hepatocytes obtained from liver following slaughter and to cultivate the cells in a sandwich culture. Cells and medium samples were taken after separation of cells (day 0), during monolayer (days 1, 2 and 3) and during sandwich culture (days 1, 2, 3, 4, 7, 10 and 14). The mRNA expression of BAX, BCL2L, FAS, IGF-1 and GHR1A was measured as well as urea and LDH. Hepatocytes were obtained by using a two-step collagenase perfusion and were purified thereafter by density gradient centrifugation. The viability was 68.2 ± 9.5 %. In sandwich culture, cells have a typical polygonal hepatocyte-like shape, build cell-cell contacts, and show irregularity of cell borders suggesting bile canaliculi generation. The BAX mRNA expression increased on day 1 as well but decreased steadily until day 3 and remained constant for 14 days. Urea- and LDH-concentrations increased from day 4 to day 7. In conclusion, we found that it is possible to gather viable primary hepatocytes from adult bovine liver after slaughter, and that cells gathered this way show typical morphologies, urea-production and low LDH-leakage especially at day 4 in a sandwich system.

A Flexible and Thin Graphene/Silver Nanowires/Polymer Hybrid Transparent Electrode for Optoelectronic Devices

A typical thin and fully flexible hybrid electrode was developed by integrating the encapsulation of silver nanowires (AgNWs) network between a monolayer graphene and polymer film as a sandwich structure. Compared with the reported flexible electrodes based on PET or PEN substrate, this unique electrode exhibits the superior optoelectronic characteristics (sheet resistance of 8.06 Ω/□ at 88.3% light transmittance). Meanwhile, the specific up-to-bottom fabrication process could achieve the superflat surface (RMS = 2.58 nm), superthin thickness (∼8 μm thickness), high mechanical robustness, and lightweight. In addition, the strong corrosion resistance and stability for the hybrid electrode were proved. With these advantages, we employ this electrode to fabricate the simple flexible organic light-emitting device (OLED) and perovskite solar cell device (PSC), which exhibit the considerable performance (best PCE of OLED = 2.11 cd/A²; best PCE of PSC = 10.419%). All the characteristics of the unique hybrid electrode demonstrate its potential as a high-performance transparent electrode candidate for flexible optoelectronics.

High-Performance Li-O2 Batteries with Controlled Li2O2 Growth in Graphene/Au-Nanoparticles/Au-Nanosheets Sandwich

The working of nonaqueous Li-O2 batteries relies on the reversible formation/decomposition of Li2O2 which is electrically insulating and reactive with carbon and electrolyte. Realizing controlled growth of Li2O2 is a prerequisite for high performance of Li-O2 batteries. In this work, a sandwich-structured catalytic cathode is designed: graphene/Au-nanoparticles/Au-nanosheets (G/Au-NP/Au-NS) that enables controlled growth of Li2O2 spatially and structurally. It is found that thin-layer Li2O2 (below 10 nm) can grow conformally on the surface of Au NPs confined in between graphene and Au NSs. This unique crystalline behavior of Li2O2 effectively relieves or defers the electrode deactivation with Li2O2 accumulation and largely reduces the contact of Li2O2 with graphene and electrolyte. As a result, Li-O2 batteries with the G/Au-NP/Au-NS cathode exhibit superior electrochemical performance. A stable cycling of battery can last 300 times at 400 mA g-1 when the capacity is limited at 500 mAh g-1. This work provides a practical design of catalytic cathodes capable of controlling Li2O2 growth.

Polarisation and functional characterisation of hepatocytes derived from human embryonic and mesenchymal stem cells

Adult hepatocytes are polarised with their apical and basolateral membranes separated from neighbouring cells by tight junction proteins. Although efficient differentiation of pluripotent stem cells to hepatocytes has been achieved, the formation of proper polarisation in these cells has not been thoroughly investigated. In the present study, human embryonic stem cells (hESCs) and human mesenchymal stem cells (hMSCs) were differentiated to hepatocyte-like cells and the derived hepatocytes were characterised for mature hepatocyte markers. The secretion of hepatic proteins, expression of hepatic genes and the functional hepatic polarisation of stem cell-derived hepatocytes, foetal hepatocytes and the HepG2 hepatic cell line were evaluated and the different lines were compared. The results indicate that hESC-derived hepatocytes are phenotypically more robust and functionally more efficient compared with the hMSC-derived hepatocytes, suggesting their suitability for toxicity studies.

Off-pump repair of a post myocardial infarction ventricular septal defect

Refractory cardiogenic shock meant that traditional patch repairs requiring cardiopulmonary bypass would be poorly tolerated and external sandwich closure of post myocardial ventricular septal defect (VSD) appears to be simple and effective after initial myocardial infarction (MI). The three cases presented with a VSD after of acute MI with or without thrombolysed with streptokinase during patient admission. The general condition of the three patients was poor with pulmonary edema, low cardiac output and renal failure. The heart was approached through a median sternotomy. Off-pump coronary artery bypass grafting of the coronary artery lesion was done first using octopus and beating heart surgery method and latero - lateral septal plication was performed using sandwich technique. Low cardiac output managed with intra-aortic balloon pump in these patients accompanied with inotropic drugs. Post-operative transesophageal echocardiography revealed that VSD was closed completely in one patient and in two patients small residual VSD remained. More experience is required to ascertain whether this technique will become an accepted alternative to patch repairs.