Entropy Analysis of Heart Rate Variability in Different Sleep Stages

How the complexity or irregularity of heart rate variability (HRV) changes across different sleep stages and the importance of these features in sleep staging are not fully understood. This study aimed to investigate the complexity or irregularity of the RR interval time series in different sleep stages and explore their values in sleep staging. We performed approximate entropy (ApEn), sample entropy (SampEn), fuzzy entropy (FuzzyEn), distribution entropy (DistEn), conditional entropy (CE), and permutation entropy (PermEn) analyses on RR interval time series extracted from epochs that were constructed based on two methods: (1) 270-s epoch length and (2) 300-s epoch length. To test whether adding the entropy measures can improve the accuracy of sleep staging using linear HRV indices, XGBoost was used to examine the abilities to differentiate among: (i) 5 classes [Wake (W), non-rapid-eye-movement (NREM), which can be divide into 3 sub-stages: stage N1, stage N2, and stage N3, and rapid-eye-movement (REM)]; (ii) 4 classes [W, light sleep (combined N1 and N2), deep sleep (N3), and REM]; and (iii) 3 classes: (W, NREM, and REM). SampEn, FuzzyEn, and CE significantly increased from W to N3 and decreased in REM. DistEn increased from W to N1, decreased in N2, and further decreased in N3; it increased in REM. The average accuracy of the three tasks using linear and entropy features were 42.1%, 59.1%, and 60.8%, respectively, based on 270-s epoch length; all were significantly lower than the performance based on 300-s epoch length (i.e., 54.3%, 63.1%, and 67.5%, respectively). Adding entropy measures to the XGBoost model of linear parameters did not significantly improve the classification performance. However, entropy measures, especially PermEn, DistEn, and FuzzyEn, demonstrated greater importance than most of the linear parameters in the XGBoost model.300-s270-s.

Large-Grain Spanning Monolayer Cu2 ZnSnSe4 Thin-Film Solar Cells Grown from Metal Precursor

The persistent double layer structure whereby two layers with different properties form at the front and rear of absorbers is a critical challenge in the field of kesterite thin-film solar cells, which imposes additional nonradiative recombination in the quasi-neutral region and potential limitation to the transport of hole carriers. Herein, an effective model for growing monolayer CZTSe thin-films based on metal precursors with large grains spanning the whole film is developed. Voids and fine grain layer are avoided successfully by suppressing the formation of a Sn-rich liquid metal phase near Mo back contact during alloying, while grain coarsening is greatly promoted by enhancing mass transfer during grain growth. The desired morphology exhibits several encouraging features, including significantly reduced recombination in the quasi-neutral region that contributes to the large increase of short-circuit current, and a quasi-Ohmic back contact which is a prerequisite for high fill factor. Though this growth mode may introduce more interfacial defects which require further modification, the strategies demonstrated remove a primary obstacle toward higher efficiency kesterite solar cells, and can be applicable to morphology control with other emerging chalcogenide thin films.

Correction: Antimicrobial peptide modification enhances the gene delivery and bactericidal efficiency of gold nanoparticles for accelerating diabetic wound healing

Correction for 'Antimicrobial peptide modification enhances the gene delivery and bactericidal efficiency of gold nanoparticles for accelerating diabetic wound healing' by Song Wang et al., Biomater. Sci., 2018, 6, 2757-2772, DOI: 10.1039/C8BM00807H.

Proteomic profiling of Arachis hypogaea in response to drought stress and overexpression of AhLEA2 improves drought tolerance

Drought is the main factor restricting peanut growth, but the molecular mechanism underlying peanut drought tolerance remains unclear. Herein, the seedling stage of drought-resistant peanut cultivar J11 was subjected to drought stress, and its proteomic profile was systematically analysed by isobaric tags for relative and absolute quantification (iTRAQ), the results of which were further complemented with our previous transcriptome results. A total of 4,018 proteins were identified by proteomic analysis, which revealed that the expression levels of 69 proteins were altered under drought stress. Among the differentially expressed proteins (DEPs), 50 were upregulated, and 19 were downregulated. The most enriched metabolic pathways for these DEPs were those involving phenylpropanoid biosynthesis, flavonoid biosynthesis, and plant hormone signal transduction. The proteomic data and previous transcriptome results revealed 44 groups of genes/proteins with the same expression trend, including a LEA (Late embryogenesis abundant) gene, AhLEA2. Our present study showed that overexpression of the AhLEA2 gene enhanced the drought resistance of transgenic Arabidopsis plants, and the activities of related antioxidant enzymes in the transgenic plants significantly changed. The AhLEA2 gene was found to be located in the cytoplasm and cell membrane by subcellular localization experiments. This work systematically analysed the differentially expressed proteins in peanut in response to drought stress, providing important candidates for further functional analysis of the stress response of peanut. Our results also indicated that AhLEA2 plays an important role in the peanut response to drought stress.

A Nomogram Based on Circulating CD4+ T Lymphocytes and Lactate Dehydrogenase to Predict Distant Metastasis in Patients with Nasopharyngeal Carcinoma

Purpose

Distant metastasis is the main pattern of treatment failure in nasopharyngeal carcinoma (NPC) in the era of intensity-modulated radiotherapy (IMRT). We aimed to establish and validate a prognostic nomogram to identify patients with a high risk of distant metastasis.

Patients and Methods

A total of 503 patients with nonmetastatic NPC were included in this retrospective study. We established a prognostic nomogram for distant metastasis-free survival (DMFS) based on the Cox proportional hazards model. The predictive discriminative ability and accuracy of the nomogram were assessed with the concordance index (C-index), receiver operating characteristic (ROC) curve, and calibration curve. The nomogram’s clinical utility was also evaluated using decision curve analysis (DCA) and Kaplan–Meier method. The predictive ability of the nomogram was validated in an independent cohort.

Results

The multivariate analysis showed that circulating CD4⁺ T lymphocytes, lactate dehydrogenase (LDH), serum ferritin (SF), and N stage were independent prognostic factors for DMFS. Then, we constructed the nomogram based on these factors. The C-indexes of the nomogram for distant metastasis were 0.763 (95% CI: 0.685–0.841) and 0.760 (95% CI: 0.643–0.877) in the training cohort and validation cohort, respectively, which was higher than the 8th TNM staging system (0.672 and 0.677). The calibration curve showed that the prediction results of the nomogram were in high agreement with the actual observation. The ROC curve indicated that the nomogram had a better predictive ability than TNM staging. The DCA also demonstrated that the nomogram was clinically beneficial. In addition, the patients were classified into two different risk groups (high-risk, low-risk) by the nomogram.

Conclusion

As a supplement to TNM staging, our nomogram could provide a more effective and accurate prognostic prediction of distant metastasis in NPC patients. It has the potential to guide the individualized treatment of patients to improve their survival.

Prognostic Significance of Circulating Lymphocyte Subsets Before Treatment in Patients with Nasopharyngeal Carcinoma

Purpose

We set out to explore the prognostic value of circulating lymphocyte subsets in patients with nasopharyngeal carcinoma (NPC) before treatment and to investigate changes in lymphocyte subsets resulting from chemoradiotherapy.

Patients and Methods

This retrospective study included 677 patients with non-metastatic NPC. The cutoff value of lymphocyte subsets was determined by the receiver operating characteristic curve (ROC), and the prognostic significance of lymphocyte subsets was evaluated by the Log rank test and Cox proportional hazards model. The endpoints were overall survival (OS), progression-free survival (PFS), locoregional relapse-free survival (LRFS) and distant metastasis-free survival (DMFS). Differences in lymphocyte subsets before and after chemoradiotherapy were analyzed by Wilcoxon signed rank test.

Results

NPC patients with high levels of CD19⁺ B cells (>9.55%) had better 5-year OS (90.4% VS 76.8%, P < 0.001), 5-year PFS (85.3% VS 71.6%, P < 0.001) and 5-year DMFS (94% VS 86.8%, P = 0.002) than patients with low levels of CD19⁺ B cells. Patients with high levels of CD4⁺ T cells (> 37.05%) had better 5-year PFS (83% VS 74.2%, P = 0.015) and better 5-year DMFS (95.8% VS 86.7%, P < 0.001) than those with low levels of CD4⁺ T cells. Multivariate analyses indicated that CD19⁺ B cell was an independent prognostic factor for OS, PFS and DMFS in NPC. And CD4⁺ T cell was an independent prognostic factor for PFS and DMFS. Within 1 month after chemoradiotherapy, the percentages of CD4⁺ T cells, CD19⁺ B cells, and the CD4/CD8 ratio decreased significantly, while the percentages of CD8⁺ T cells increased significantly.

Conclusion

NPC patients with low levels of CD19⁺ B cells or CD4⁺ T cells before treatment have a poor prognosis. In addition, chemoradiotherapy may reduce the body’s immune function in NPC patients.

Immunity cells in the small intestinal mucosa of newborn yaks

BACKGROUND

This study aimed to characterize and evaluate the main markers of T lymphocytes, B lymphocytes, immunoglobulin (Ig) A and IgG plasmocytes, macrophages, and dendritic cells of the intestinal mucosa of newborn yaks.

MATERIALS AND METHODS

Ten newborn yaks (2-4 weeks old) were choosed. Immunohistochemistry and real-time quantitative polymerase chain reaction were used to analyze the immune cell distribution and specific markers at the mRNA expression level in the duodenum, jejunum, and ileum.

RESULTS

The results showed in the epithelium, CD3-positive T lymphocyte levels were higher than other immune cell levels (P<0.05). Additionally, in the lamina propria, the number of cells positive for CD3, CD68, and signal inhibitory regulatory protein alpha (SIRPα) were higher in the villi, while CD79α, IgA, and IgG cells were more common at the base of the crypt. Moreover, both in the epithelium and lamina propria, the number of CD3, CD68 and SIRPα were decreased from the duodenum to the ileum (P<0.05), additionally the number of CD79α, IgA and IgG positive cells were increased from the duodenum to the ileum of newborn yaks (P<0.05). Furthermore, the mRNA expression levels of CD3ε, CD68, and SIRPα increased from the duodenum to the ileum (P<0.05), while the mRNA expression levels of CD79α, IgA, and IgG decreased from the duodenum to the ileum.

CONCLUSIONS

Immunohistochemical characterization and expression levels of immune factors in the small intestinal mucosa of newborn yaks suggest that the intestinal mucosa is an important part of the natural barrier and provides useful references for immunity functions of newborn yak intestinal mucosa.

BGL3 inhibits papillary thyroid carcinoma progression via regulating PTEN stability

PURPOSE

BGL3, a novel long non-coding RNA (lncRNA) that plays a crucial role in several human malignancies. However, the clinical significance and biological function of BGL3 in papillary thyroid carcinoma (PTC) have not been explored. Herein, we aimed to investigate the role of BGL3 in human PTC.

METHODS

A total of 85 pairs of PTC and normal tissues were collected for clinicopathological analysis. Expression of BGL3 was determined by quantitative real-time polymerase chain reaction (qRT-PCR). The effects of BGL3 on PTC cells ware determined by CCK-8, colony formation, EdU and wound healing assays. The molecular mechanism underlying BGL3 was tested by ChIP, Co-IP, RNA pull-down and luciferase reporter assays. In vivo experiments were conducted using xenografts in nude mice.

RESULTS

BGL3 was significantly decreased in PTC tissues compared to adjacent normal thyroid tissues, and it was transcriptionally repressed by oncogene Myc. Low BGL3 is positively related to larger tumor size, lymph node metastasis, later TNM stage and poor prognosis. Overexpression of BGL3 inhibited PTC cell proliferation and migration in vitro, and reduced tumor size and lung metastasis nodules in vivo. BGL3 was mainly located in the cytoplasm, in which interacted with PTEN and recruited OTUD3, enhancing the de-ubiquitination effect of OTUD3 on PTEN, resulting in increasing PTEN protein stability and inactivating carcinogenic PI3K/AKT signaling.

CONCLUSIONS

Our data underscore the critical tumor-inhibiting role of BGL3 in PTC via post-translational regulation of PTEN protein stability, which may serve as a novel therapeutic target and prognostic biomarker in human PTC.

Macrophage M1/M2 ratio as a predictor of pleural thickening in patients with tuberculous pleurisy

We evaluated the association between macrophage polarization and the development of pleural thickening in patients with tuberculous pleurisy. Patients with tuberculous pleurisy admitted to our hospital between October 2018 and March 2019 were prospectively recruited. Pleural fluid samples were obtained before treatment for detection of adenosine deaminase (ADA) and macrophage phenotype (M1: CD14+ CD86+; M2: CD14+ CD163+). Peripheral blood samples were subjected to interferon gamma release assay (IGRA). All subjects were administered standard anti-tuberculosis regimen (2HREZ/4HR); high-resolution CT was performed to determine pleural thickening (thickness>2mm) after completion of treatment. Pleural effusion in patients with thickened pleura had significantly more M1 but fewer M2 macrophages, and higher ADA level, as compared to those with normal pleura (P<0.05). No significant between-group difference was observed with respect to IGRA. In receiver operating characteristic (ROC) curve analysis, the optimal cut-off level of M1/M2 ratio for predicting pleural thickening was 1.149 (area under the curve: 0.842; sensitivity: 88.6%; specificity: 69.2%; positive predictive value: 86.3%; negative predictive value: 81.7%). M1/M2 ratio in the pleural fluid is a promising marker for predicting the development of pleural thickening in patients with tuberculous pleurisy. Macrophage-mediated immune response may play an important role in the pathogenesis of tuberculous pleurisy.

CT-Based Radiomics Nomogram for Prediction of Progression-Free Survival in Locoregionally Advanced Nasopharyngeal Carcinoma

Purpose

We aimed to construct of a nomogram to predict progression-free survival (PFS) in locoregionally advanced nasopharyngeal carcinoma (LA-NPC) with risk stratification using computed tomography (CT) radiomics features and clinical factors.

Patients and Methods

A total of 311 patients diagnosed with LA-NPC (stage III–IVa) at our hospital between 2010 and 2014 were included. The region of interest (ROI) of the primary nasopharyngeal mass was manually outlined. Independent sample t-test and LASSO-logistic regression were used for selecting the most predictive radiomics features of PFS, and to generate a radiomics signature. A nomogram was built with clinical factors and radiomics features, and the risk stratification model was tested accordingly.

Results

In total, 20 radiomics features most associated with prognosis were selected. The radiomics nomogram, which integrated the radiomics signature and significant clinical factors, showed excellent performance in predicting PFS, with C-index of 0.873 (95% CI: 0.803~0.943), which was better than that of the clinical nomogram (C-index, 0.729, 95% CI: 0.620~0.838) as well as of the TNM staging system (C-index, 0.689, 95% CI: 0.592–0.787) in validation cohort. The calibration curves and the decision curve analysis (DCA) plot obtained suggested satisfying accuracy and clinical utility of the model. The risk stratification tool was able to predict differences in prognosis of patients in different risk categories (p<0.001).

Conclusion

CT-based radiomics features, an in particular, radiomics nomograms, have the potential to become an accurate and reliable tool for assisting with prognosis prediction of LA-NPC.

[Effects of Microplastics Addition on Soil Organic Carbon Mineralization in Citrus Orchard]

To investigate the effects of microplastics on soil organic carbon mineralization and the changes in soil enzyme activities, an incubation experiment was conducted whereby single applications of either microplastics or straw, and combined application of both, were added to Dangyang citrus orchard soil. The results showed that the combined application of straw and microplastics significantly affected organic carbon mineralization in the soil, but the single addition of microplastics had no significant effect. Compared with straw alone, the application of a small combined amount of microplastics and straw significantly increased soil organic carbon mineralization by 8.20%, while medium and high amounts of the combined application significantly inhibited soil organic carbon mineralization. The lowest amount of organic carbon mineralization occurred with the highest amount of combined microplastics and straw, 10.13% lower than with straw alone. The addition of microplastics significantly reduced the activity of β-glucosidase. In particular, a high amount of microplastics significantly decreased the activity of β-glucosidase, compared with the control, by 20.52%, 43.93%, and 17.79% on the day 1, 6, and 35, respectively. However, straw application alleviated the inhibition effect of microplastic application on soil β-glucosidase activity. The soil organic carbon mineralization rate was significantly positively correlated with DOC, MBC and β-glucosidase activity.

The Structure Biology of Tau and Clue for Aggregation Inhibitor Design

Tau is a microtubule-associated protein that is mainly expressed in central and peripheral nerve systems. Tau binds to tubulin and regulates assembly and stabilization of microtubule, thus playing a critical role in neuron morphology, axon development and navigation. Tau is highly stable under normal conditions; however, there are several factors that can induce or promote aggregation of tau, forming neurofibrillary tangles. Neurofibrillary tangles are toxic to neurons, which may be related to a series of neurodegenerative diseases including Alzheimer's disease. Thus, tau is widely accepted as an important therapeutic target for neurodegenerative diseases. While the monomeric structure of tau is highly disordered, the aggregate structure of tau is formed by closed packing of β-stands. Studies on the structure of tau and the structural transition mechanism provide valuable information on the occurrence, development, and therapy of tauopathies. In this review, we summarize recent progress on the structural investigation of tau and based on which we discuss aggregation inhibitor design.

[rCsHscB derived from Clonorchis sinensis has therapeutic effect on dextran sodium sulfate-induced chronic ulcerative colitis in mice]

OBJECTIVE

To investigate the therapeutic effect of rCsHscB derived from Clonorchis sinensis on dextran sodium sulfate (DSS)-induced chronic ulcerative colitis in mice.

OBJECTIVE

C57BL/6 mice were randomized into negative control (NC) group (n= 10), rCsHscB group (n=10), DSS group (n=15), and DSS+rCsHscB group (n=15), and in the latter two groups, chronic ulcerative colitis was induced in the mice using 2% DSS. In rCsHscB and DSS+ rCsHscB groups, the mice received intraperitoneal injections of 125 μg/mL rCsHscB on the 4th and 7th day following DSS administration, and PBS was injected in the other two groups. The mice were euthanized on the 84th day, and pathological changes of the colon were evaluated by HE and Masson staining. The levels of CD4⁺ and CD8⁺ T cells in the peripheral blood and lamina propria gastric lymphocytes (LPL) were analyzed by flow cytometer; the levels of IL-6, MCP-1 and IL-10 in colon homogenate were determined using ELISA, and the phosphorylation of ERK1/2, JNK and P38 was detected with Western blotting.

OBJECTIVE

Compared with those in NC group, the mice in rCsHscB group exhibited no adverse responses to the treatment. The mice in DSS group had severe pathologies in the colon with significantly increased ratios of CD4⁺ and CD4⁺/CD8⁺ T cells in peripheral blood and LPL, increased levels of IL-6 and MCP-1 but no obvious changes in IL-10 in colon homogenate, and significantly augmented phosphorylation levels of ERK1/2, JNK and P38. Compared with those in DSS group, the mice in DSS+ rCsHscB group showed ameliorated colon pathologies with decreased CD4⁺T/CD8⁺T cell ratio in the peripheral blood and LPL, significantly decreased IL-6 and MCP-1 levels and increased IL-10 in colon homogenate, and lowered phosphorylation levels of ERK1/2, JNK and P38.

OBJECTIVE

rCsHscB can produce therapeutic effect on DSS-induced chronic ulcerative colitis in mice possibly by inhibiting the production of pro-inflammatory factors and regulating the balance of CD4⁺/CD8⁺T cells through the MAPK pathway.

Kesterite Solar Cells: Insights into Current Strategies and Challenges

Earth-abundant and environmentally benign kesterite Cu2ZnSn(S,Se)4 (CZTSSe) is a promising alternative to its cousin chalcopyrite Cu(In,Ga)(S,Se)2 (CIGS) for photovoltaic applications. However, the power conversion efficiency of CZTSSe solar cells has been stagnant at 12.6% for years, still far lower than that of CIGS (23.35%). In this report, insights into the latest cutting-edge strategies for further advance in the performance of kesterite solar cells is provided, particularly focusing on the postdeposition thermal treatment (for bare absorber, heterojunction, and completed device), alkali doping, and bandgap grading by engineering graded cation and/or anion alloying. These strategies, which have led to the step-change improvements in the power conversion efficiency of the counterpart CIGS solar cells, are also the most promising ones to achieve further efficiency breakthroughs for kesterite solar cells. Herein, the recent advances in kesterite solar cells along these pathways are reviewed, and more importantly, a comprehensive understanding of the underlying mechanisms is provided, and promising directions for the ongoing development of kesterite solar cells are proposed.

Short-Term Effect of Percutaneous Coronary Intervention on Heart Rate Variability in Patients with Coronary Artery Disease

Myocardial ischemia in patients with coronary artery disease (CAD) leads to imbalanced autonomic control that increases the risk of morbidity and mortality. To systematically examine how autonomic function responds to percutaneous coronary intervention (PCI) treatment, we analyzed data of 27 CAD patients who had admitted for PCI in this pilot study. For each patient, five-minute resting electrocardiogram (ECG) signals were collected before and after the PCI procedure. The time intervals between ECG collection and PCI were both within 24 h. To assess autonomic function, normal sinus RR intervals were extracted and were analyzed quantitatively using traditional linear time- and frequency-domain measures [i.e., standard deviation of the normal-normal intervals (SDNN), the root mean square of successive differences (RMSSD), powers of low frequency (LF) and high frequency (HF) components, LF/HF] and nonlinear entropy measures [i.e., sample entropy (SampEn), distribution entropy (DistEn), and conditional entropy (CE)], as well as graphical metrics derived from Poincaré plot [i.e., Porta’s index (PI), Guzik’s index (GI), slope index (SI) and area index (AI)]. Results showed that after PCI, AI and PI decreased significantly (p < 0.002 and 0.015, respectively) with effect sizes of 0.88 and 0.70 as measured by Cohen’s d static. These changes were independent of sex. The results suggest that graphical AI and PI metrics derived from Poincaré plot of short-term ECG may be potential for sensing the beneficial effect of PCI on cardiovascular autonomic control. Further studies with bigger sample sizes are warranted to verify these observations.

New scheme for the preparation and use of artificial cerebrospinal fluid

This study aimed to explore a set of simplified schemes for the preparation and application of artificial cerebrospinal fluid (ACSF) to improve the experiment efficiency and neurosafety of ACSF. We prepared ACSF into parts A and B, according to the cerebrospinal fluid (CSF) data in rabbits. They were mixed in equal volumes to form ACSF, continous foaming with mixture gas (95% O₂ and 5% CO₂). Sampling inspection showed the chemical stability of ACSF in the three months after preparation. However, it needed to be kept continous foaming, as pH is correlated to the solubility of CO₂. We further improved the application scheme by sealing the foamed ACSF in infusion bags filled with mixture gas, which could keep the pH stable for 24 hours. It was helpful in promoting the progress of clinical and experimental research relating to ACSF.

PERK activation by CCT020312 chemosensitizes colorectal cancer through inducing apoptosis regulated by ER stress

Endoplasmic reticulum (ER) stress is a significant mechanism for chemoresistance to colorectal cancer (CRC) treatment. The RNA-like endoplasmic reticulum kinase (PERK) is critical for ER stress induction. In the present study, we attempted to explore whether PERK activator CCT020312 (CCT) could be effective for CRC treatment, and reveal the underlying mechanisms. We first found that CCT dose- and time-dependently reduced CRC cell proliferation. Importantly, it markedly improved the chemosensitivity of CRC cells that were drug-sensitive or -resistant to taxol treatment, as evidenced by the significantly decreased cell viability. Moreover, CCT at the non-toxic concentration exhibited obviously synergistic effects with taxol to induce apoptosis and cell cycle arrest in G2/M phase in vitro. In addition, we showed that CCT alone considerably induced ER stress in CRC cells through a dose- and time-dependent fashion. Meanwhile, CCT combined with taxol caused significant ER stress through improving phosphorylated PERK, eukaryotic translation initiation factor 2α (eIF2ɑ), C/EBP homologous protein (CHOP) and glucose-regulated protein 78 (GRP78). More studies showed that the interaction between PERK and GRP78 was a potential target for CCT to perform its regulatory events. Intriguingly, PERK knockdown markedly abolished the regulatory role of CCT and taxol cotreatments in cell proliferation suppression and apoptosis induction, indicating the importance of PERK for CCT to perform its anti-cancer bioactivity. Our in vivo experiments confirmed that CCT plus taxol dramatically reduced tumor growth in CRC xenografts. Together, all these results suggested that promoting PERK activation by CCT may be an effective therapeutic strategy to improve CRC to taxol treatment.

Uncovering the Role of Hole Traps in Promoting Hole Transfer from Multiexcitonic Quantum Dots to Molecular Acceptors

Understanding electronic dynamics in multiexcitonic quantum dots (QDs) is important for designing efficient systems useful in high power scenarios, such as solar concentrators and multielectron charge transfer. The multiple charge carriers within a QD can undergo undesired Auger recombination events, which rapidly annihilate carriers on picosecond time scales and generate heat from absorbed photons instead of useful work. Compared to the transfer of multiple electrons, the transfer of multiple holes has proven to be more difficult due to slower hole transfer rates. To probe the competition between Auger recombination and hole transfer in CdSe, CdS, and CdSe/CdS QDs of varying sizes, we synthesized a phenothiazine derivative with optimized functionalities for binding to QDs as a hole accepting ligand and for spectroscopic observation of hole transfer. Transient absorption spectroscopy was used to monitor the photoinduced absorption features from both trapped holes and oxidized ligands under excitation fluences where the averaged initial number of excitons in a QD ranged from ∼1 to 19. We observed fluence-dependent hole transfer kinetics that last around 100 ps longer than the predicted Auger recombination lifetimes, and the transfer of up to 3 holes per QD. Theoretical modeling of the kinetics suggests that binding of hole acceptors introduces trapping states significantly different from those in native QDs passivated with oleate ligands. Holes in these modified trap states have prolonged lifetimes, which promotes the hole transfer efficiency. These results highlight the beneficial role of hole-trapping states in devising hole transfer pathways in QD-based systems under multiexcitonic conditions.

Precise Colloidal Plasmonic Photocatalysts Constructed by Multistep Photodepositions

Natural photosynthesis relies on a sophisticated charge transfer pathway among multiple components with precise spatial, energetic, and temporal organizations in the aqueous environment. It continues to inspire and challenge the design and fabrication of artificial multicomponent colloidal nanostructures for solar-to-fuel conversion. Herein, we introduce a plasmonic photocatalyst synthesized with colloidal methods with five integrated components including cocatalysts installed in orthogonal locations. The precise deposition of individual inorganic components on an Au/TiO₂ nanodumbell nanostructure is enabled by photoreduction and photo-oxidation, which selectively occurs at the TiO₂ tip sites and Au lateral sites, respectively. Under visible-light irradiation, the photocatalyst exhibited activity of oxygen evolution from water without scavengers. We demonstrate that each component is essential for improving the photocatalytic performance. In addition, mechanistic studies suggest that the photocatalytic reaction requires combining the hot charge carriers derived from exciting both the d-sp interband transition and the localized surface plasmon resonance of Au.

Transfemoral-venous transcatheter access to left ventricle through the created communication of inter-ventricular septum with the assistance of arterio-venous circuit

Background

During transcatheter aortic/mitral valve replacement (TA/MVR), current available routes are limited due to unfavorable entry-angle, vessel-anatomy or mini-thoracotomy. Through created communication of inter-ventricular septum (C-IVS), transfemoral venous transcatheter access to left ventricle becomes feasible with the assistance of arterio-venous circuit.

Purpose

The study was conducted to investigate the feasibility and safety of transfemoral-venous transcatheter access to left ventricle through the created C-IVS in a swine model.

Methods

Via femoral artery, transcatheter puncture of mid-IVS was performed with the custom-made nickel-titanium needle (0.038-inch, needle-tip bent 60 degrees automatically associated with increased hardness when temperature was above 30°C) and 6F-sheath in 20 healthy Chinese mini-swine. Then femoral arterio-venous circuit was established through created C-IVS with hydrophilic guidewire in all swine, and femoral veno-venous circuit was further created through C-IVS and atrial septum in 4 swine. After pre-dilation of C-IVS, a 20F-sheath was introduced into left ventricle transvenously over the guidewire. Furthermore, transfemoral-venous TAVR was attempted with this approach in one swine. C-IVS was evaluated postoperatively and was further confirmed pathologically 2 months later.

Results

All transcatheter puncture of IVS was performed successfully in left ventricle and the thickness of mid-IVS was 7.67±0.98 mm. During the puncture, ventricular fibrillation occurred in one swine (successfully defibrillation) and only isolated ventricular premature beats/non-sustained ventricular tachycardia were observed in other swine. In all swine, femoral arterio-venous/veno-venous circuit was established via C-IVS, and the 20F-sheath was introduced into left ventricle safely through femoral vein and C-IVS. With the aid of vessel circuit, the 20F-sheath was further advanced into aorta in 16 swine (the entry-angle was 145.3±12.2 degrees) and into left atrium in 4 swine. After the procedure, there was one swine with moderate tricuspid regurgitation and 5 swine with mild residual shunt (2.6±0.7 mm). In addition, epicardial coronary arteries were normal in all swine. Two months later, residual shunt was still detected in 3 swine and the communication was confirmed pathologically. In other swine, there was no defect of IVS and mild replacement-scar was identified along C-IVS. In the swine underwent transfemoral-venous TAVR, prosthetic valve was deployed successfully with good function.

Conclusions

With the aid of vessel circuit, transfemoral-venous transcatheter access to left ventricle is feasible and safe via C-IVS, and transfemoral-venous TAVR was achieved successfully using this novel approach with favorable entry-angle.

Figure 1

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): National Natural Science Foundation of China

Indirect evaluation of device-endothelialization with cardiac-CT after transcatheter closure of atrial septal defect: how long should antiplatelet therapy last postoperatively?

Background

After transcatheter closure of atrial septal defect (ASD), it is still unclear about the in-vivo process of device-endothelialization in humans, which determines the duration of antiplatelet therapy. Based on contrast-uptake within device, cardiac-CT might have the potential to assess device-endothelialization indirectly.

Purpose

The study was conducted to investigate the status of device-endothelialization with cardiac-CT after transcatheter closure of ASD.

Methods

After more than 6 months of transcatheter ASD closure, cardiac-CT was performed in 119 patients (48M/71F; age: 46.7±14.4 years). According to contrast-uptake within device, complete or incomplete device-endothelialization was determined. In the latter, it was further divided into partial-endothelialization (with filling-defect) and no-endothelialization (without filling-defect). Multivariate logistic regression was used to determine the risk factors of incomplete device-endothelialization. In addition, device-endothelialization was analyzed grossly and histopathologically in 7 patients.

Results

During the implantation-period of 2.57±2.59 years, incomplete device-endothelialization was identified in 43.7% of patients (partial-endothelialization in 36 patients and no-endothelialization in 16 patients). Complete device-endothelialization occurred in 14.3% of patients during 0.5–1 year and 73.8% after one year. After 6-month antiplatelet therapy, migraine restarted in 15 patients with incomplete device-endothelialization and 3 patients with complete device-endothelialization. After one-year antiplatelet therapy, migraine was still detected in 4 of 15 patients with incomplete device-endothelialization. There was a significant association between high in-vivo device-thickness and incomplete device-endothelialization (P&lt;0.001) after adjusted for confounding factors. Pathological findings from 7 patients corresponded well with cardiac-CT.

Conclusions

Cardiac-CT had the potential to evaluate the status of device-endothelialization after transcatheter closure of ASD and there was a good clinico-pathological correlation. Incomplete device-endothelialization was common postoperatively in humans and was associated with device-oversizing. Further research is required to determine the appropriate duration of antiplatelet therapy after device implantation.

Figure 1

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): National Natural Science Foundation of China