Feasibility Study of a Novel Transapical Chordal Implantation System in a Porcine Model.

Transapical beating-heart mitral repair with chordal implantation system has been considered as an alternative treatment for degenerative mitral regurgitation. This study aimed to assess the feasibility and safety of the E-Chord system (Med-Zenith Medical, Beijing, China) for transapical beating-heart mitral valve repair in a porcine model. Artificial chordae were transapically implanted on the mitral valves of 12 anesthetized pigs under epicardial echocardiographic guidance and secured outside the left ventricular apex. The study endpoints included procedural success, device durability, and tissue response to the device. The procedural success rate was 100% (12/12). All animals were implanted with E-Chord in the anterior and posterior leaflets, respectively, and survived uneventfully until euthanized as planned. During the 180-day follow-up, no animal had significant mitral valve dysfunction. The gross observation showed no evidence of anchor detachment and chordal rupture, and there was no obvious damage or changes to mitral leaflets. Microscopic evaluation revealed that the endothelialization of anchor and chordae was completed 90 days after implantation and there was no evidence of chordal rupture, thrombosis, or infection during the 180-day follow-up. The E-Chord system was found to be feasible and safe for heart-beating mitral chordal implantation in a porcine model. The findings of this study suggest that the E-Chord system may be a potential alternative for the treatment of degenerative mitral regurgitation in humans.

Formate-Mediated Electroenzymatic Synthesis via Biological Cofactor NADH.

Synthetic biohybrid systems by coupling artificial system with nature's machinery may offer a disruptive solution to address the global energy crisis. We developed a versatile electroenzymatic pathway for the continuous synthesis of valuable chemicals, facilitated by formate-driven NADH regeneration. Utilizing a bismuth electrocatalyst, we achieved stable CO2 reduction to formate with approximately 90 % Faraday efficiency at a current density of 150 mA cm-2. The generated formate acts as a mediator to regenerate NADH, which is then coupled with immobilized redox enzymes-alcohol dehydrogenase (ADH), L-lactate dehydrogenase (LDH), and L-glutamate dehydrogenase (GDH)-to produce targeted chemicals at significant rates and exceptionally high turnover numbers (1.8×106 to 3.1×106). These achievements not only underscore the efficiency of the system but also its practical applicability in industrial settings. By leveraging in situ generated formate, this innovative approach demonstrates the potential of integrating electrocatalysis with enzymatic reactions for sustainable and efficient chemical production on a practical scale.

Bioinspired Hydrophobicity for Enhancing Electrochemical CO2 Reduction.

Electrochemical carbon dioxide reduction (CO2 R) is a promising pathway for converting greenhouse gasses into valuable fuels and chemicals using intermittent renewable energy. Enormous efforts have been invested in developing and designing CO2 R electrocatalysts suitable for industrial applications at accelerated reaction rates. The microenvironment, specifically the local CO2 concentration (local [CO2 ]) as well as the water and ion transport at the CO2 -electrolyte-catalyst interface, also significantly impacts the current density, Faradaic efficiency (FE), and operation stability. In nature, hydrophobic surfaces of aquatic arachnids trap appreciable amounts of gases due to the "plastron effect", which could inspire the reliable design of CO2 R catalysts and devices to enrich gaseous CO2 . In this review, starting from the wettability modulation, we summarize CO2 enrichment strategies to enhance CO2 R. To begin, superwettability systems in nature and their inspiration for concentrating CO2 in CO2 R are described and discussed. Moreover, other CO2 enrichment strategies, compatible with the hydrophobicity modulation, are explored from the perspectives of catalysts, electrolytes, and electrolyzers, respectively. Finally, a perspective on the future development of CO2 enrichment strategies is provided. We envision that this review could provide new guidance for further developments of CO2 R toward practical applications.

Comparison of Balloon-Expandable Valve and Self-Expandable Valve in Transcatheter Aortic Valve Replacement: A Patient-Specific Numerical Study.

Transcatheter aortic valve replacement (TAVR) is a minimally invasive strategy for the treatment of aortic stenosis. The complex postoperative complications of TAVR were related to the type of implanted prosthetic valve, and the deep mechanism of this relationship may guide the clinical pre-operative planning. This technical brief developed a numerical method of TAVR to compare the outcome difference between balloon-expandable valve and self-expandable valve and predict the postoperative results. A complete patient-specific aortic model was reconstructed. Two prosthetic valves (balloon-expandable valve and self-expandable valve) were introduced to simulate the implantation procedure, and postprocedural function was studied with fluid-structure interaction method, respectively. Results showed similar stress distribution for two valves, but higher peak stress for balloon-expandable valve model. The balloon-expandable valve was associated with a better circular cross section and smaller paravalvular gaps area. Hemodynamic parameters like cardiac output, mean transvalvular pressure difference, and effective orifice area (EOA) of the balloon-expandable valve model were better than those of the self-expandable valve model. Significant outcome difference was found for two prosthetic valves. Balloon-expandable valve may effectively decrease the risk and degree of postoperative paravalvular leak, while self-expandable valve was conducive to lower stroke risk due to lower aortic stress. The numerical TAVR simulation process may become an assistant tool for prosthesis selection in pre-operative planning and postoperative prediction.

Two MicroRNAs, miR-34a and miR-125a, Are Implicated in Bicuspid Aortopathy by Modulating Metalloproteinase 2.

It has been recognized that wall shear stress plays an important role in the development of Bicuspid Aortopathy (BA), but the intrinsic mechanism is not well elucidated. This study aims to explore the underlying relationship between hemodynamical forces and pathological phenomenon. Total RNA was prepared from aortic wall tissues collected from 20 BA patients. RNA sequencing, bioinformatic analysis and quantitative reverse-transcription PCR validation identified nine miRNAs that were up-regulated in the aortic part exposed to high wall shear stress compared to the low wall shear stress control, and six miRNAs that were down-regulated. Among these candidates, miR-34a and miR-125a, both down-regulated in the high wall shear stress parts, were shown to be potential inhibitors of the metalloproteinase 2 gene. Luciferase reporter assays confirmed that both miRNAs could inhibit the expression of metalloproteinase 2 mRNA in CRL1999 by complementing with its 3' untranslated region. Conversely, immunofluorescence assays showed that inhibition of miR-34a or miR-125a could lead to increased metalloproteinase 2 protein level. On the other hand, both miR-34a and miR-125a were shown to alleviate stretch-induced stimulation of metalloproteinase 2 expression in CRL1999 cells. The results suggested that miR-34a and miR-125a might be implicated in wall shear stress induced aortic pathogenesis due to their apparent regulatory roles in metalloproteinase 2 expression and extracellular matrix remodeling, which are key events in the weakening of aortic walls among BA patients.

Home Environment Augmented Reality System Based on 3D Reconstruction of a Single Furniture Picture.

With the popularization of the concept of "metaverse", Augmented Reality (AR) technology is slowly being applied to people's daily life as its underlying technology support. In recent years, rapid 3D reconstruction of interior furniture to meet AR shopping needs has become a new method. In this paper, a virtual home environment system is designed and the related core technologies in the system are studied. Background removal and instance segmentation are performed for furniture images containing complex backgrounds, and a Bayesian Classifier and GrabCut (BCGC) algorithm is proposed to improve on the traditional foreground background separation technique. The reconstruction part takes the classical occupancy network reconstruction algorithm as the network basis and proposes a precise occupancy network (PONet) algorithm, which can reconstruct the structural details of furniture images, and the model accuracy is improved. Because the traditional 3D registration model is prone to the problems of model position shift and inaccurate matching with the scene, the AKAZE-based tracking registration algorithm is improved, and a Multiple Filtering-AKAZE (MF-AKAZE) based on AKAZE is proposed to remove the matching points. The matching accuracy is increased by improving the RANSAC filtering mis-matching algorithm based on further screening of the matching results. Finally, the system is verified to realize the function of the AR visualization furniture model, which can better complete the reconstruction as well as registration effect.

Short-Term Outcomes After Transcatheter Aortic Valve Replacement in Predominant Aortic Regurgitation with Left Ventricular Dysfunction.

Patients with aortic stenosis and low left ventricular ejection fraction (LVEF) would benefit from transcatheter aortic valve replacement. However, the safety and efficacy of transcatheter aortic valve replacement in patients with aortic regurgitation and left ventricular dysfunction remains unknown.We defined LVEF < 50% as left ventricular dysfunction. A total of 27 symptomatic patients with aortic regurgitation and ejection fraction < 50% underwent transcatheter aortic valve replacement using the J-Valve™ system (JieCheng Medical Technology Co, Ltd, Suzhou, China) in Zhongshan Hospital, Fudan University, from May 2014 to June 2019. Procedural and postoperative clinical outcomes were analyzed according to Valve Academic Research Consortium-2 (VARC-2) criteria.All patients (eight females; 70.6 ± 7.1 years) were considered to be at least intermediate surgical risk and/or severe comorbidity precluding for surgical aortic valve replacement (logistic European System for Cardiac Operative Risk Evaluation, 16.8 ± 9.5%, range 4.6% to 37.9%) by a multidisciplinary heart team. Transapical implantations were successful in 26 (96.3%) patients. All-cause mortality was 3.7% in the latest follow-up (25-590 days, median 369 days). Significant improvements in LVEF, left ventricular end-diastolic, and systolic dimensions were observed after procedure (from 40.3 ± 6.7% to 50.8 ± 10.5%, P < 0.001; from 65.1 ± 8.9 mm to 56.0 ± 9.6 mm, P = 0.002; from 52.2 ± 9.8 mm to 35.9 ± 13.4 mm, P < 0.001, respectively). No patient had aortic stenosis and paravalvular leak more than moderate and heart function improvement was obtained in the majority of patients at 1-year follow-up.Transcatheter aortic valve replacement using the J-Valve™ system is a reasonable alternative for patients with aortic regurgitation and left ventricular dysfunction regarding promising short-term outcomes.

Suppression of microRNA-155 exerts an anti-inflammatory effect on CD4+ T cell-mediated inflammatory response in the pathogenesis of atherosclerosis.

In the current study, we aimed to investigate the effects of miR-155 on CD4+ T cell-mediated immune response in the pathogenesis of atherosclerosis. CD34+ hematopoietic stem cells, CD4+ T lymphocytes, endothelial cells (ECs), and vascular smooth muscle cells (VSMCs) were harvested from the same donor. Knockdown of miR-155 in the CD4+ T cells was achieved by lentiviral transfection, whereas control RNA-transfected or untransfected lymphocytes were used as controls. The transfected CD4+ T cells were activated by incubating with oxidized low-density lipoprotein-treated dendritic cells. The proliferative capacities, phenotype distribution, and cytokine secretion profiles of the activated CD4+ T cells from different groups were evaluated. The activated lymphocytes were used to treat ECs co-cultivated with VSMCs. The ability of the CD4+ T cells to induce the apoptosis of the ECs and to promote the proliferation of the VSMCs was investigated. Inhibition of miR-155 was found to significantly reduce the proliferation rate of the transfected CD4+ T cells. CD4+ T lymphocytes transfected with the miR-155 inhibitor showed increased populations of T helper type 2 and regulatory T cells, as well as more production of anti-inflammatory cytokines. MiR-155 knockdown was also shown to significantly hamper the ability to CD4+ T cells to induce EC apoptosis and to promote the growth of VSMCs. Our data suggested that inhibition of miR-155 in CD4+ T cells could slow down the formation of atherosclerotic plaques. These results lay the groundwork for future research on the therapeutic potential of miR-155 against atherosclerosis-associated cardiovascular diseases.

Donor heart preservation with a novel long-term and slow-releasing hydrogen sulfide system.

Cardiac transplantation has been limited by the inability to long preserve donor hearts safely. Hydrogen sulfide (H2S) has been recognized as an important gasotransmitter exerting potent cardioprotection from ischemia/reperfusion injury (I/R). Herein we investigated the cardioprotective effects of a novel long-term and slow-releasing H2S system, namely DATS-MSN, in heart preservation solution using a heart transplantation models. The release of H2S from DATS-MSN was slow and continuous in the University of Wisconsin solution (UW), correspondingly, DATS-MSN application demonstrated superior cardioprotective effects over the control and traditional H2S donors after 6 h heart preservation and 1 h reperfusion, associated with greater allograft performance including left ventricular developed pressure (LVDP) and dP/dt max, reduced plasmic CK-MB and troponin I levels, inhibited myocardial inflammation, increased antioxidant enzyme activities, preserved mitochondria structure and function, and decreased cardiomyocyte apoptosis index. Also, DATS-MSN application presented significant superiority in long-term allografts survival and function after 8 weeks of transplantation. In the in vitro experiments, cardiomyocytes injury from hypoxia was found to be relived with the treatment of DATS-MSN by anti-inflammatory effects via TLR4/NLRP3 pathway. The present work provides a long-term releasing H2S donor compatibly applied in the donor heart preservation, and preliminary explores its underlying mechanisms.

Photoswitched Cell Adhesion on Azobenzene-Containing Self-Assembled Films.

Stimuli-responsive surfaces that can regulate and control cell adhesion have attracted much attention for their great potential in diverse biomedical applications. Unlike for pH- and temperature-responsive surfaces, the process of photoswitching requires no additional input of chemicals or thermal energy. In this work, two different photoresponsive azobenzene films are synthesized by chemisorption and electrostatic layer-by-layer (LbL) assembly techniques. The LbL film exhibits a relatively loose packing of azobenzene chromophores compared with the chemisorbed film. The changes in trans/cis isomer ratio of the azobenzene moiety and the corresponding wettability of the LbL films are larger than those of the chemisorbed films under UV light irradiation. The tendency for cell adhesion on the LbL films decreases markedly after UV light irradiation, whereas adhesion on the chemisorbed films decreases only slightly, because the azobenzene chromophores stay densely packed. Interestingly, the tendency for cell adhesion can be considerably increased on rough substrates, the roughness being introduced by use of photolithography and inductively coupled plasma deep etching techniques. For the chemisorbed films on rough substrates, the amount of cells that adhere also changes slightly after UV light irradiation, whereas, the amount of cells that adhere to LbL films on rough substrates decreases significantly.

Photobleaching and stabilization of carbon nanodots produced by solvothermal synthesis.

In this work we performed a detailed investigation of the photostability of bottom-up produced carbon nanodots (CDs) prepared from citric acid and urea by solvothermal synthesis. Analytical ultracentrifugation (AUC) reveals that the CDs have a hydrodynamic diameter of <1 nm and a very narrow size distribution. In the community it is widely assumed that CDs are photo-stable. In contrast, we found that CDs exposed to UV-irradiation exhibit noteworthy fluorescence degeneration compared to freshly prepared CDs or CDs stored in the dark, indicating that fluorescence bleaching is caused by a photochemical process. We found that fluorescence intensity decay due to exposure to UV-irradiation is accelerated in the presence of oxygen and identified the surface status of CDs as the decisive factor of fluorescence bleaching of CDs. Based on a discussion on the underlying mechanisms we show how to avoid photobleaching of CDs.

Branched artificial nanofinger arrays by mesoporous interfacial atomic rearrangement.

The direct production of branched semiconductor arrays with highly ordered orientation has proven to be a considerable challenge over the last two decades. Here we report a mesoporous interfacial atomic rearrangement (MIAR) method to directly produce highly crystalline, finger-like branched iron oxide nanoarrays from the mesoporous nanopyramids. This method has excellent versatility and flexibility for heteroatom doping of metallic elements, including Sn, Bi, Mn, Fe, Co, Ni, Cu, Zn, and W, in which the mesoporous nanopyramids first absorb guest-doping molecules into the mesoporous channels and then convert the mesoporous pyramids into branching artificial nanofingers. The crystalline structure can provide more optoelectronic active sites of the nanofingers by interfacial atomic rearrangements of doping molecules and mesopore channels at the porous solid-solid interface. As a proof-of-concept, the Sn-doped Fe2O3 artificial nanofingers (ANFs) exhibit a high photocurrent density of ∼1.26 mA/cm(2), ∼5.25-fold of the pristine mesoporous Fe2O3 nanopyramid arrays. Furthermore, with surface chemical functionalization, the Sn-doped ANF biointerfaces allow nanomolar level recognition of metabolism-related biomolecules (∼5 nm for glutathione). This MIAR method suggests a new growth means of branched mesostructures, with enhanced optoelectronic applications.

Off-pump Skeletonized Versus Pedicled Left Internal Mammary Artery Grafting: Mid-term Results.

BACKGROUND: Skeletonization of the internal mammary artery for single left internal mammary artery (LIMA) use remains controversial. We sought to elucidate the effect of different harvesting techniques applied in single LIMA grafting. METHOD: Between January 2006 and January 2012, 982 patients undergoing off-pump coronary artery bypass with pedicled LIMA conduits (P Group) and 928 patients undergoing the same operation with skeletonized LIMA conduits (S Group) were enrolled. The length and blood flow of the conduits, and in-hospital and mid-term outcomes with one-year postoperative graft angiographic results were analyzed and compared between groups. RESULTS: Twenty-five (2.7%) patients in the S group died in hospital, compared with 26 (2.6%) in the P group, with similar rates of sternal wound infection, chest wall pain, and low-output syndrome. Although the length and blood flow of conduits were increased in the S Group, postoperative conduit patency was similar between groups (p = 0.470). During a median follow-up of 32.2 months, the groups showed similar total survival (88.3 ± 3.2%, S Group; 85.5 ± 2.0%, P Group; p = 0.118) and cardiac event-free survival (82.7 ± 3.3%, S Group; 80.3 ± 2.0%; P Group; p = 0.129), with similar postoperative complications. CONCLUSIONS: Skeletonization of single LIMA has no extra benefit in early or mid-term outcomes, suggesting no advantage over the pedicled technique.

Optical identification of MoS2/graphene heterostructure on SiO2/Si substrate.

Chemical vapor deposition (CVD) method is considered to be an efficient way to prepare Van der Waals heterostructure. However, accurately and hurtlessly identifying the layers number of MoS(2) in the heterostructure is still a challenge. Here, we calculated the expected contrast between MoS(2)/graphene heterostructure and underlying SiO(2)/Si substrate by using a Fresnel law based model. And we indicated that contrast at blue and green incident light is ideal for visibility and layer number detecting. Our measured value showed good agreement with calculated ones. And Raman spectrum helped to confirm our speculation.

Suppressor of cytokine signaling 3 is a negative regulator for neointimal hyperplasia of vein graft stenosis.

Coronary artery bypass graft (CABG) surgery is one of the most effective treatments for coronary artery disease. However, neointimal hyperplasia and ultimate luminal occlusion that is caused by vascular smooth muscle cell (VSMC) migration, proliferation and inflammatory response impede the long-term prognosis. The SOCS3 protein is involved in modulating various autoimmune and inflammatory diseases. However, the role of SOCS3 in vein graft disease is still unclear. We found that the mRNA and protein expression levels of IL-1ß, IL-6, MCP-1, ICAM-1, TNF-α, STAT3, P-STAT3 and SOCS3 were significantly higher in the graft samples compared to normal veins. After transfecting the recombinant adenovirus carrying the rat SOCS3 gene into cultured rat VSMCs or grafting veins in rat, SOCS3 overexpression was found to significantly inhibit VSMC migration and proliferation in vitro and neointimal hyperplasia in vivo, respectively. Furthermore, SOCS3 overexpression inhibited VSMC migration and growth in vitro and alleviated VSMC inflammation in vitro by inhibiting STAT3 activation and phosphorylation. In conclusion, SOCS3 is a crucial physiological negative regulator for vein graft failure and provides a novel target for vein graft stenosis therapy after CABG.

A simple colorimetric DNA detection by target-induced hybridization chain reaction for isothermal signal amplification.

A novel DNA detection method is presented based on a gold nanoparticle (AuNP) colorimetric assay and hybridization chain reaction (HCR). In this method, target DNA hybridized with probe DNA modified on AuNP, and triggered HCR. The resulting HCR products with a large number of negative charges significantly enhanced the stability of AuNPs, inhibiting aggregation of AuNPs at an elevated salt concentration. The approach was highly sensitive and selective. Using this enzyme-free and isothermal signal amplification method, we were able to detect target DNA at concentrations as low as 0.5 nM with the naked eye. Our method also has great potential for detecting other analytes, such as metal ions, proteins, and small molecules, if the target analytes could make HCR products attach to AuNPs.

Modulated photoluminescence of graphene quantum dots in the vicinity of an individual silver nano-octahedron.

We propose an effective strategy to enhance and modulate the photoluminescence (PL) of graphene quantum dots (GQDs) in the vicinity of a single silver nano-octahedron (SNO) utilizing three-dimensional finite-difference time-domain calculations. The SNO is designed to act as a multifrequency plasmonic antenna with multiple plasmon resonance modes covering multiple emission peaks of GQDs. The spectral modifications of spontaneous emission are investigated with the variations of the GQD's position and dipole moment orientation relative to the SNO. The PL colour of the GQD can be precisely adjusted between blue and green through the strong interaction with the designed antenna. The multicolour features of GQDs will also facilitate their potential applications as eco-friendly and multifunctional optical probes. The study contributes to a deeper understanding of the PL properties of GQDs near the metallic nanoparticles.

Spectroscopic detection of clenbuterol applying gold nanoparticles encapsulated with melamine.

In this paper, a simple, rapid and highly sensitive method for detecting trace amount of clenbuterol based on gold nanoparticles (GNPs) encapsulated with melamine was investigated. Morphological characterization using SEM and AFM revealed that the size of obtained GNPs was about 15 nm. The hydrogen-bonding interaction existed between clenbuterol and melamine, which caused the aggregation of GNPs, was demonstrated by FT-IR and EELS spectrum. Consequently, the concentration of clenbuterol can be measured by the change of GNPs' color and optical absorption band with naked eye or absorption spectrum, respectively. A relationship existed between the intensity of the absorption band and concentration of clenbuterol. The possible impurities in practical applications such as alanine, MgCl2, tryptophan, NaCI, did not interfere in the detection of clenbuterol. The proposed protocol showed promising applications in the clinical and industrial detection of clenbuterol in food safety area.

Synthesis of gold nanoparticles with graphene oxide.

Single sheets of functionalized graphene oxide are derived through chemical exfoliation of natural flake graphite. We present an effective synthetic method of graphene-gold nanoparticles hybrid nanocomposites. AFM (Atomic Force Microscope) was used to measure the thickness of the individual GO nanosheet. FTIR (Fourier transform infrared) spectroscopy was used to verify the attachment of oxygen functionalities on the surface of graphene oxide. TEM (Transmission Electron Microscope) data revealed the average diameters of the gold colloids and characterized the composite particles situation. Absorption spectroscopy showed that before and after synthesis the gold particle size did not change. Our studies indicate that the hybrid is potential substrates for catalysts and biosensors.

Soft-tissue sound-speed-aware ultrasound-CT registration method for computer-assisted orthopedic surgery.

Ultrasound (US) has been introduced to computer-assisted orthopedic surgery for bone registration owing to its advantages of nonionizing radiation, low cost, and noninvasiveness. However, the registration accuracy is limited by US image distortion caused by variations in the acoustic properties of soft tissues. This paper proposes a soft-tissue sound-speed-aware registration method to overcome the above challenge. First, the feature enhancement strategy of multi-channel overlay is proposed for U2-net to improve bone segmentation performance. Secondly, the sound speed of soft tissue is estimated by simulating the bone surface distance map for the update of US-derived points. Finally, an iterative registration strategy is adopted to optimize the registration result. A phantom experiment was conducted using different registration methods for the femur and tibia/fibula. The fiducial registration error (femur, 0.98 ± 0.08 mm (mean ± SD); tibia/fibula, 1.29 ± 0.19 mm) and the target registration error (less than 2.11 mm) showed the high accuracy of the proposed method. The experimental results suggest that the proposed method can be integrated into navigation systems that provide surgeons with accurate 3D navigation information.