Size-Dependent Penetration of Nanoparticles in Tumor Spheroids: A Multidimensional and Quantitative Study of Transcellular and Paracellular Pathways.

Tumor penetration of nanoparticles is crucial in nanomedicine, but the mechanisms of tumor penetration are poorly understood. This work presents a multidimensional, quantitative approach to investigate the tissue penetration behavior of nanoparticles, with focuses on the particle size effect on penetration pathways, in an MDA-MB-231 tumor spheroid model using a combination of spectrometry, microscopy, and synchrotron beamline techniques. Quasi-spherical gold nanoparticles of different sizes are synthesized and incubated with 2D and 3D MDA-MB-231 cells and spheroids with or without an energy-dependent cell uptake inhibitor. The distribution and penetration pathways of nanoparticles in spheroids are visualized and quantified by inductively coupled plasma mass spectrometry, two-photon microscopy, and synchrotron X-ray fluorescence microscopy. The results reveal that 15 nm nanoparticles penetrate spheroids mainly through an energy-independent transcellular pathway, while 60 nm nanoparticles penetrate primarily through an energy-dependent transcellular pathway. Meanwhile, 22 nm nanoparticles penetrate through both transcellular and paracellular pathways and they demonstrate the greatest penetration ability in comparison to other two sizes. The multidimensional analytical methodology developed through this work offers a generalizable approach to quantitatively study the tissue penetration of nanoparticles, and the results provide important insights into the designs of nanoparticles with high accumulation at a target site.

Dual-Doped Nickel Sulfide for Electro-Upgrading Polyethylene Terephthalate into Valuable Chemicals and Hydrogen Fuel.

Electro-upcycling of plastic waste into value-added chemicals/fuels is an attractive and sustainable way for plastic waste management. Recently, electrocatalytically converting polyethylene terephthalate (PET) into formate and hydrogen has aroused great interest, while developing low-cost catalysts with high efficiency and selectivity for the central ethylene glycol (PET monomer) oxidation reaction (EGOR) remains a challenge. Herein, a high-performance nickel sulfide catalyst for plastic waste electro-upcycling is designed by a cobalt and chloride co-doping strategy. Benefiting from the interconnected ultrathin nanosheet architecture, dual dopants induced up-shifting d band centre and facilitated in situ structural reconstruction, the Co and Cl co-doped Ni3S2 (Co, Cl-NiS) outperforms the single-doped and undoped analogues for EGOR. The self-evolved sulfide@oxyhydroxide heterostructure catalyzes EG-to-formate conversion with high Faradic efficiency (> 92%) and selectivity (> 91%) at high current densities (> 400 mA cm-2). Besides producing formate, the bifunctional Co, Cl-NiS-assisted PET hydrolysate electrolyzer can achieve a high hydrogen production rate of 50.26 mmol h-1 in 2 M KOH, at 1.7 V. This study not only demonstrates a dual-doping strategy to engineer cost-effective bifunctional catalysts for electrochemical conversion processes, but also provides a green and sustainable way for plastic waste upcycling and simultaneous energy-saving hydrogen production.

Microscale fluid and particle dynamics in filtration processes in water treatment: A review.

The complex filtration processes in water treatment, granular filtration and membrane filtration, often suffer from filter fouling, and the fundamental understanding of microscale fluid and particle dynamics is a key to improving filtration efficiency and stability. In this review, we identify and review several key topics in filtration processes: drag force, fluid velocity profile, intrinsic permeability and hydraulic tortuosity in microscale fluid dynamics, and particle straining, absorption, and accumulation in microscale particle dynamics. The paper also reviews several key experimental and computational techniques for investigating filtration processes at microscale considering their applicability and capability. Then, major findings in previous studies on these key topics are comprehensively reviewed in terms of microscale fluid and particle dynamics. Last, future research is discussed in terms of techniques, scopes and links. The review provides a comprehensive overview of microscale fluid and particle dynamics in filtration processes for water treatment and particle technology communities.

Self-Propelled Initiative Collision at Microelectrodes with Vertically Mobile Micromotors.

Impact experiments enable single particle analysis for many applications. However, the effect of the trajectory of a particle to an electrode on impact signals still requires further exploration. Here, we investigate the particle impact measurements versus motion using micromotors with controllable vertical motion. With biocatalytic cascade reactions, the micromotor system utilizes buoyancy as the driving force, thus enabling more regulated interactions with the electrode. With the aid of numerical simulations, the dynamic interactions between the electrode and micromotors are categorized into four representative patterns: approaching, departing, approaching-and-departing, and departing-and-reapproaching, which correspond well with the experimentally observed impact signals. This study offers a possibility of exploring the dynamic interactions between the electrode and particles, shedding light on the design of new electrochemical sensors.

Particle-scale modelling of fluid velocity distribution near the particles surface in sand filtration.

Sand filtration is widely used in drinking water treatment processes, yet the hydraulic fundamentals at particle-scale are not well defined, especially the fluid velocity profile near the sand particles surface. In this study, a numerical model is developed by combining the Lattice Boltzmann (LBM) and the Discrete Element Method (DEM), used to describe the fluid flow over the sand particles surface and the micro-structure details of the sand packed bed respectively. The model is validated by comparing the simulation results with the experimental measurements using two systems, showing that the model can describe the fluid velocity distribution around the particles surface. Critical flow velocity is introduced as the balance between hydrodynamic and adhesive torques acting on sand particle surface. Furthermore, a new concept - effective filter surface (EFS), is defined as the area where the velocity near sand particles surface is less than the critical flow velocity, aiming for indirectly evaluating the performance of sand filtration. It is quantitatively demonstrated that increasing the sand particle size or feed flow velocity results in the decrease of both critical flow velocity and EFS under the given tested conditions. The LBM-DEM model provides a useful tool for understanding the fundamentals of liquid flow distribution and also estimating sand filtration performance under different operation conditions.

Effects of Surgical Ventricular Restoration on Left Ventricular Shape, Size, and Function for Left Ventricular Anterior Aneurysm.

BACKGROUND: Surgical ventricular restoration (SVR) has been performed to treat left ventricular (LV) aneurysm. However, there is limited analysis of changes in LV shape. This study aimed to evaluate the changes in LV shape induced by SVR and the effects of SVR on LV size and function for LV aneurysm. METHODS: Between April 2006 and March 2015, 18 patients with dyskinetic (dyskinetic group) and 12 patients with akinetic (akinetic group) postinfarction LV anterior aneurysm receiving SVR with the Dor procedure at Chinese People's Liberation Army General Hospital were enrolled in this study. A retrospective analysis was carried out using data from the echocardiography database. LV shape was analyzed by calculating the apical conicity index (ACI). LV end-diastolic volume index, end-systolic volume index, and ejection fraction (EF) were measured. One-way analysis of variance was used to compare means at different time points within each group. RESULTS: Within one week after SVR, LV shape became more conical in the two groups (ACI decreased from 0.84 ± 0.13 to 0.69 ± 0.11 [t = 5.155, P = 0.000] in dyskinetic group and from 0.73 ± 0.07 to 0.60 ± 0.11 [t = 2.701, P = 0.026] in akinetic group; LV volumes were decreased significantly and became closer to normal values and EF was improved significantly in the two groups). On follow-up at least one year, LV shape remained unchanged in dyskinetic group (ACI increased from 0.69 ± 0.11 to 0.74 ± 0.12, t = -1.109, P = 0.294), but became more spherical in akinetic group (ACI significantly increased from 0.60 ± 0.11 to 0.75 ± 0.11, t = -1.880, P = 0.047); LV volumes remained unchanged in dyskinetic group, but increased significantly in akinetic group and EF remained unchanged in the two groups. CONCLUSIONS: SVR could reshape LV to a more conical shape and a more normal size and improve LV function significantly early after the procedure in patients with dyskinetic or akinetic postinfarction LV anterior aneurysm. However, LV tends to be more spherical and enlarged in the akinetic group on at least 1-year follow-up.

Echocardiographic Follow-up of Robotic Mitral Valve Repair for Mitral Regurgitation due to Degenerative Disease.

BACKGROUND: Mitral valve (MV) repair can now be carried out through small incisions with the use of robotic assistance. Previous reports have demonstrated the excellent clinical result of robotic MV repair for degenerative mitral regurgitation (MR). However, there has been limited information regarding the echocardiographic follow-up of these patients. The present study was therefore to evaluate the echocardiographic follow-up outcomes after robotic MV repair in patients with MR due to degenerative disease of the MV. METHODS: A retrospective analysis was undertaken using data from the echocardiographic database of our department. Between March 2007 and February 2015, 84 patients with degenerative MR underwent robotic MV repair. The repair techniques included leaflet resection in 67 patients (79.8%), artificial chordae in 20 (23.8%), and ring annuloplasty in 79 (94.1%). Eighty-one (96.4%) of the 84 patients were eligible for echocardiographic follow-up assessment, and no patients were lost to follow-up. RESULTS: At a median echocardiographic follow-up of 36.0 months (interquartile range 14.3-59.4 months), four patients (4.9%) developed recurrent mild MR, and no patients had more than mild MR. Mean MR grade, left atrial diameter (LAD), left ventricular end-diastolic diameter (LVEDD), and left ventricular ejection fraction (LVEF) were significantly decreased when compared with preoperative values. Mean MR grade decreased from 3.96 ± 0.13 to 0.17 ± 0.49 (Z = -8.456, P < 0.001), LAD from 43.8 ± 5.9 to 35.5 ± 3.8 mm (t = 15.131, P < 0.001), LVEDD from 51.0 ± 5.0 to 43.3 ± 2.2 mm (t = 14.481,P< 0.001), and LVEF from 67.3 ± 7.0% to 63.9 ± 5.1% (t = 4.585, P < 0.001). CONCLUSION: Robotic MV repair for MR due to degenerative disease is associated with a low rate of recurrent MR, and a significant improvement in MR grade, LAD, and LVEDD, but a significant decrease in LVEF at echocardiographic follow-up.

[Role of intraoperative transesophageal echocardiography in patients undergoing robotic atrial myxoma excision].

OBJECTIVE: To evaluate the role of intraoperative transesophageal echocardiography (TEE) during robotic atrial myxoma excision. METHODS: Thirty-eight consecutive patients undergoing robotic atrial myxoma excision from September 2007 to August 2012 were enrolled in the study. During the procedure, TEE was performed to document the myxoma position, its attachment, and hemodynamic information before cardiopulmonary bypass (CPB). During establishment of peripheral CPB, TEE was used to guide placement of the cannulae in the inferior vena cava (IVC), superior vena cava (SVC), and ascending aorta (AAO). After weaning from CPB, TEE was performed to evaluate the effect of the procedure. RESULTS: The accuracy of TEE for the position or its attachment of the myxoma was 100%. All the cannulae in the SVC, IVC and AAO were located in correct position. In all patients, TEE confirmed successful excision. CONCLUSION: Intraoperative TEE is a valuable adjunct in patients undergoing robotic atrial myxoma excision.

[Intraoperative transesophageal echocardiography in robotic perimembranous ventricular septal defect repair].

OBJECTIVE: To explore the role of intraoperative transesophageal echocardiography (TEE) in robotic perimembranous ventricular septal defect (VSD) repair. METHODS: A retrospective analysis was conducted with intraoperative TEE data of 18 consecutive patients who underwent robotic perimembranous VSD repair from January 2009 to August 2012. (1) Before cardiopulmonary bypass (CPB), TEE was performed to document the anatomic types, numbers, and the size of VSD. The procedures were predetermined by the surgeon according to TEE information. (2) During the establishment of peripheral CPB, TEE was used to guide the placement of cannulae in inferior vena cava (IVC), superior vena cava (SVC), and ascending aorta (AAO). (3) After weaning from CPB, TEE was conducted to evaluate the effect of the procedure. RESULTS: (1) Accuracy of TEE was 100% for diagnosing the anatomic types of VSD. All the surgical procedures were performed based on the predetermined information. (2) Under TEE guidance, all the cannulae in the SVC, IVC and AAO were located in correct positions. (3) In all patients, TEE confirmed successful VSD repair. CONCLUSION: TEE is a useful tool in the assessment of robotic perimembranous VSD repair.

[Heterogeneity of mitochondrial DNA in black and white hair of patients with type 2 diabetes].

OBJECTIVE: To detect the heterogeneity of mitochondrial DNA (mtDNA) in black and white hair of patients with type 2 diabetes. METHODS: MtDNA was extracted from the hair shaft of the patients to amplify two target DNA fragment from mtDNA coding region and control region using PCR. The differences in the heterogeneity in the target DNA fragment was analyzed between diabetic patients and the control group with denaturing high-performance liquid chromatography (DHPLC). RESULTS: In the control subjects and diabetic patients, the mtDNA heterogeneity in the black hair was 3% and 10% in 20-45 year-old groups and 9% and 17% in 45-70 year-old groups, as compared to 9%, 20%, 21%, and 40% in the white hair, respectively. The mtDNA heterogeneity in the black and white hair was both higher in the diabetic patients than in the control subjects of the same age group, and was also higher in older age subgroups in both control and diabetic groups (P<0.05). The white hair mtDNA showed a significantly higher heterogeneity than the black hair mtDNA in the two age groups of diabetic patients and in 45-70 year-old control group (P<0.05). CONCLUSION: The mtDNA heterogeneity in the hair increases in type 2 diabetic patients and show an association with aging.

[Intraoperative transesophageal echocardiography in patients undergoing robotic mitral valve replacement].

OBJECTIVE: To retrospectively assess the value of intraoperative transesophageal echocardiography (TEE) during robotic mitral valve (MV) replacement. METHODS: Intraoperative TEE was performed in 21 patients undergoing robotic MV replacement for severe rheumatic mitral stenosis between November 2008 and December 2010. During the procedure, TEE was performed to document the mechanism of rheumatic mitral stenosis (leaflet thickening and calcification, commissural fusion or chordal fusion) before cardiopulmonary bypass (CPB). During the establishment of peripheral CPB, TEE was used to guide the placement of the cannulae in the inferior vena cava (IVC), superior vena cava (SVC), and ascending aorta (AAO). After weaning from CPB, TEE was performed to evaluate the effect of the procedure. RESULTS: Accuracy of TEE was 100% for rheumatic mitral stenosis. All the cannuli in the SVC, IVC and AAO were located in the correct position. In all patients, TEE confirmed successful procedure. CONCLUSION: TEE is useful in the assessment of robotic MV replacement.

[Live three-dimensional and two-dimensional transesophageal echocardiography for evaluating functional anatomy of mitral regurgitation: a comparative study].

OBJECTIVE: To compare the accuracy of live three-dimensional (Live-3D-TEE) and two-dimensional transesophageal echocardiography (2D-TEE) in the evaluation of functional anatomy of mitral regurgitation. METHDOS: Thirty-eight consecutive patients with severe mitral regurgitation were enrolled prospectively. The accuracy of Live-3D-TEE and 2D-TEE for functional assessment of mitral regurgitation was evaluated against surgical findings. RESULTS: The accuracy in etiological assessment of mitral regurgitation was 94.7% with Live-3D-TEE and 89.5% with 2D-TEE (P=0.09). For assessment of lesions of the mitral valve, Live-3D-TEE showed an overall accuracy of 93.2%, significantly higher than that of 2D-TEE (88.6%, P=0.001). Live-3D-TEE also showed a significantly higher accuracy than 2D-TEE in localization of mitral valve lesions (93.3% vs 86.7%, P=0.000). CONCLUSION: Both Live-3D-TEE and 2D-TEE allow accurate assessment of the etiology of mitral regurgitation, but Live-3D-TEE can be more accurate in the evaluation of the lesions of the mitral valve and their localization.