Molecular-Level Insight into Impact of Additives on Film Formation and Molecular Packing in Y6-based Organic Solar Cells.

Additive engineering is widely utilized to optimize film morphology in active layers of organic solar cells (OSCs). However, the role of additive in film formation and adjustment of film morphology remains unclear at the molecular level. Here, taking high-efficiency Y6-based OSC films as an example, this work thus employs all-atom molecular-dynamics simulations to investigate how introduction of additives with different π-conjugation degree thermodynamically and dynamically impacts nanoscale molecular packings. These results demonstrate that the van der Waals (vdW) interactions of the Y6 end groups with the studied additives are strongest. The larger the π-conjugation degree of the additive molecules, the stronger the vdW interactions between additive and Y6 molecules. Due to such vdW interactions, the π-conjugated additive molecules insert into the neighboring Y6 molecules, thus opening more space for relaxation of Y6 molecules to trigger more ordered packing. Increasing the interactions between the Y6 end groups and the additive molecules not only accelerates formation of the Y6 ordered packing, but also induces shorter Y6-intermolecular distances. This work reveals the fundamental molecular-level mechanism behind film formation and adjustment of film morphology via additive engineering, providing an insight into molecular design of additives toward optimizing morphologies of organic semiconductor films.

Manipulation of the Self-Assembly Morphology by Side-Chain Engineering of Quinoxaline-Substituted Organic Photothermal Molecules for Highly Efficient Solar-Thermal Conversion and Applications.

Organic photothermal materials have attracted increasing attention because of their structural diversity, flexibility, and compatibility. However, their energy conversion efficiency is limited owing to the narrow absorption spectrum, strong reflection/transmittance, and insufficient nonradiative decay. In this study, two quinoxaline-based D-A-D-A-D-type molecules with ethyl (BQE) or carboxylate (BQC) substituents were synthesized. Strong intramolecular charge transfer provided both molecules with a broad absorption range of 350-1000 nm. In addition, the high reorganization energy and weak molecular packing of BQE resulted in efficient nonradiative decay. More importantly, the self-assembly of BQE leads to a textured surface and enhances the light-trapping efficiency with significantly reduced light reflection/transmittance. Consequently, BQE achieved an impressive solar-thermal conversion efficiency of 18.16 % under 1.0 kW m-2 irradiation with good photobleaching resistance. Based on this knowledge, the water evaporation rate of 1.2 kg m-2 h-1 was attained for the BQE-based interfacial evaporation device with an efficiency of 83 % under 1.0 kW m-2 simulated sunlight. Finally, the synergetic integration of solar-steam and thermoelectric co-generation devices based on BQE was realized without significantly sacrificing solar-steam efficiency. This underscores the practical applications of BQE-based technology in effectively harnessing photothermal energy. This study provides new insights into the molecular design for enhancing light-trapping management by molecular self-assembly, paving the way for photothermal-driven applications of organic photothermal materials.

Reconstruction of upper mediastinal pleura reduces postoperative complications in enhanced recovery surgery system after esophagectomy: A propensity score matching study.

OBJECTIVES: This study aimed to explore the effect of suturing upper mediastinum pleura on postoperative complications, surgery-related mortality, and hospital stay. METHODS: Four hundred and thirty-eight patients with esophageal cancer who underwent esophagectomy were identified. Patients were divided into two groups: those in the test group who received reconstruction of upper mediastinal pleura, those in the conventional group who did not. The incidence of postoperative complications, surgery-related mortality, and hospital stay were compared. To reduce the impact of confounding factors, a propensity score matching (PSM) method was performed. RESULTS: A total of 273 patients were treated with suturing upper mediastinal pleura and 165 were not. After PSM, compared with the conventional group, the incidence of atelectasis (7.2% vs. 1.4%, p = 0.035), anastomotic leakage (5.8% vs. 0.7%, p = 0.036), and delayed gastric emptying (10.8% vs. 3.6%, p = 0.034) were significantly lower in the test group. And suturing the upper mediastinal pleura could reduce the severity of leakage (p = 0.045), consistent with the results before PSM. Moreover, there were no significant differences in the incidence of other complications, postoperative hospital stay, and 30-day mortality (all p > 0.05). CONCLUSIONS: In this study, suturing the upper mediastinal pleura can reduce the incidence of atelectasis, anastomotic leakage, and delayed gastric emptying, and the severity of leakage, without increasing the incidence of other complications, surgery-related death, and postoperative hospital stay.

Critical role of intermediate electronic states for spin-flip processes in charge-transfer-type organic molecules with multiple donors and acceptors.

Spin-flip in purely organic molecular systems is often described as a forbidden process; however, it is commonly observed and utilized to harvest triplet excitons in a wide variety of organic material-based applications. Although the initial and final electronic states of spin-flip between the lowest singlet and lowest triplet excited state are self-evident, the exact process and the role of intermediate states through which spin-flip occurs are still far from being comprehensively determined. Here, via experimental photo-physical investigations in solution combined with first-principles quantum-mechanical calculations, we show that efficient spin-flip in multiple donor-acceptor charge-transfer-type organic molecular systems involves the critical role of an intermediate triplet excited state that corresponds to a partial molecular structure of the system. Our proposed mechanism unifies the understanding of the intersystem crossing mechanism in a wide variety of charge-transfer-type molecular systems, opening the way to greater control over spin-flip rates.

High stability and luminescence efficiency in donor-acceptor neutral radicals not following the Aufbau principle.

With their unusual electronic structures, organic radical molecules display luminescence properties potentially relevant to lighting applications; yet, their luminescence quantum yield and stability lag behind those of other organic emitters. Here, we designed donor-acceptor neutral radicals based on an electron-poor perchlorotriphenylmethyl or tris(2,4,6-trichlorophenyl)methyl radical moiety combined with different electron-rich groups. Experimental and quantum-chemical studies demonstrate that the molecules do not follow the Aufbau principle: the singly occupied molecular orbital is found to lie below the highest (doubly) occupied molecular orbital. These donor-acceptor radicals have a strong emission yield (up to 54%) and high photostability, with estimated half-lives reaching up to several months under pulsed ultraviolet laser irradiation. Organic light-emitting diodes based on such a radical emitter show deep-red/near-infrared emission with a maximal external quantum efficiency of 5.3%. Our results provide a simple molecular-design strategy for stable, highly luminescent radicals with non-Aufbau electronic structures.

Sarcopenia and Short-Term Outcomes After Esophagectomy: A Meta-analysis.

BACKGROUND: This meta-analysis aimed to investigate the value of preoperative sarcopenia in predicting complications after esophagectomy. Clinicopathologic characteristics of sarcopenia patients, which may support sarcopenia management, also were studied. METHODS: This study searched for articles describing an association between sarcopenia and short-term outcomes after esophagectomy using PubMed, EMBASE, and the Cochrane Library. Mantel-Haenszel and inverse variance models were used for the meta-analyses of end points. RESULTS: The meta-analysis included 14 studies comprising a total of 2387 patients. Sarcopenia was significantly associated with advanced age (weighted mean difference [WMD], 3.48; 95% confidence interval [CI], 2.22-4.74), lower body mass index (WMD - 2.22; 95% CI - 2.65 to - 1.79), squamous cell carcinoma (odds ratio [OR], 2.78; 95% CI 1.72-4.47), advanced clinical tumor stage (OR 1.65; 95% CI 1.28-2.15), and neoadjuvant therapy (OR 1.87; 95% CI 1.38-2.53). The sarcopenia patients showed lower preoperative albumin levels (WMD - 0.11; 95% CI - 0.19 to - 0.04) than the nonsarcopenia patients. Sarcopenia was significantly predictive of pneumonia (OR 2.58; 95% CI 1.75-3.81) and overall complications (OR 1.52; 95% CI 1.07-2.15) after esophagectomy. The sarcopenia patients also showed nonsignificant increases in the risks of anastomotic leakage (OR 1.29; 95% CI 0.99-1.67), vocal cord palsy (OR 2.03; 95% CI 0.89-4.64), and major complications (≥ Clavien-Dindo grade III; OR 1.30; 95% CI 0.95-1.79) but not increased operation time, blood loss, or mortality. CONCLUSIONS: Preoperative sarcopenia assessment showed considerable potential for predicting postoperative complications for esophageal cancer patients. To realize this potential, more effective diagnostic criteria and severity classifications for sarcopenia are warranted.

An Observational Study: Is N-Acetylcysteine Helpful in Performance Improvement of Mycoplasma IST2 Testing through Sample Homogenization?

BACKGROUND: Culture is still the gold standard for the detection of genital mycoplasma which could cause urogenital infections in humans. Mycoplasma IST2 is a commercial kit widely used for the detection of M. hominis and Ureaplasma species. Its accuracy was partially impaired because clinical specimens are usually mixed with purulent or transparent mucus. We aimed to solve this problem through sample homogenization by N-acetylcysteine (NAC) treatment. METHODS: Twenty-two endocervical swab samples were collected from 22 female patients with suspected mycoplasma infection, while 11 of these specimens were with purulent or transparent mucus. Mycoplasma IST2 testing kit was used for mycoplasma culture and AST for the control group and NAC-treated group. RESULTS: Genital mycoplasma was detected in 15 of 22 samples for both groups. The colony number in 6 out of 11 purulent specimens (54.5%) was more than 104 CFU/ml of genital mycoplasma for the NAC-treated group, while only one of 11 (9.1%) for the control group. For the nonpurulent specimens, no significant difference had been found in colony counting of genital mycoplasma between the control group and NAC-treated group (P > 0.05). The results of antimicrobial susceptibility testing for the NAC-treated group were highly similar to those for the control group. CONCLUSIONS: Our results demonstrate that NAC is helpful in sample homogenization and NAC treatment can improve the detection efficiency of mycoplasma with Mycoplasma IST2 testing.

Thermally Activated Delayed Fluorescence (TADF) Path toward Efficient Electroluminescence in Purely Organic Materials: Molecular Level Insight.

Since the seminal work of Tang and Vanslyke in 1987 on small-molecule emitters and that of Friend and co-workers in 1990 on conjugated-polymer emitters, organic light-emitting diodes (OLEDs) have attracted much attention from academia as well as industry, as the OLED market is estimated to reach the $30 billion mark by the end of 2018. In these first-generation organic emitters, on the basis of simple spin statistics, electrical excitation resulted in the formation of ∼25% singlet excitons and ∼75% triplet excitons. Radiative decay of the singlet excitons to the singlet ground state leads to a prompt fluorescence emission, while the triplet excitons only lead to weak phosphorescence due to the very small spin-orbit couplings present in purely organic molecules. The consequence is a ca. 75% energy loss, which triggered wide-ranging efforts to try and harvest as many of the triplet excitons as possible. In 1998, Thompson, Forrest, and their co-workers reported second-generation OLED emitters based on coordination complexes with heavy transition metals (e.g., iridium or platinum). Here, the triplet excitons stimulate efficient and fast phosphorescence due to the strong spin-orbit couplings enabled by the heavy-metal atoms. Internal quantum efficiencies (IQE) up to 100% have been reported, which means that for every electron injected into the device, a photon is emitted. While these second-generation emitters are those mainly exploited in current OLED applications, there is strong impetus from both cost and environmental standpoints to find new ways of exploiting purely organic emitters, which in addition can offer greater flexibility to fine-tune the electronic and optical properties by exploiting the synthetic organic chemistry toolbox. In 2012, Adachi and co-workers introduced a promising strategy, based on thermally activated delayed fluorescence (TADF), to harvest the triplet excitons in purely organic molecular materials. These materials now represent the third generation of OLED emitters. Impressive photophysical properties and device performances have been reported, with internal quantum efficiencies also reaching nearly 100%. Our objectives in this Account are threefold: (i) to lay out a comprehensive description, at the molecular level, of the fundamental photophysical processes behind TADF emitters; (ii) to discuss some of the challenges facing the design of TADF emitters, such as the need to balance the efficiency of thermal activation of triplet excitons into the singlet manifold with the efficiency of radiative transition to the ground state; and (iii) to highlight briefly some of the recent molecular-design strategies that pave the way to new classes of TADF materials.

Theoretical Study on Charge Transport Properties of Intra- and Extra-Ring Substituted Pentacene Derivatives.

A series of pentacene derivatives, halogen-substituted and thiophene- and pyridine-substituted, have been studied with a focus on the electronic properties and charge transport properties using density functional theory and classical Marcus charge-transfer theory. The transport properties of holes and electrons have been studied to get insight into the effect of halogenation and heteroatom substitution on transport and injection of charge carriers. The calculation results revealed that fluorination and chlorination can effectively lower the lowest unoccupied molecular orbital (LUMO) level, modulate the hole and electron reorganization energy, improve the stacking mode of the crystal structure, and enhance the ambipolar characteristic. Chlorination gives a better ambipolar characteristic. On the basis of halogen substitution, the substitution of terminal benzene ring of triisopropyl-silylethynyl-pentacene (TIPS-PEN) by a thiophene or pyridine will greatly lower the LUMO level and improve the stacking mode, leading to more suitable ambipolar materials. Hence, both intra- and extra-ring substitution are favorable to enhance the ambipolar transport property of TIPS-PEN.

Stable pure-green organic light-emitting diodes toward Rec.2020 standard.

Manipulating dynamic behaviours of charge carriers and excitons in organic light-emitting diodes (OLEDs) is essential to simultaneously achieve high colour purity and superior operational lifetime. In this work, a comprehensive transient electroluminescence investigation reveals that incorporating a thermally activated delayed fluorescence assistant molecule with a deep lowest unoccupied molecular orbital into a bipolar host matrix effectively traps the injected electrons. Meanwhile, the behaviours of hole injection and transport are still dominantly governed by host molecules. Thus, the recombination zone notably shifts toward the interface between the emissive layer (EML) and the electron-transporting layer (ETL). To mitigate the interfacial carrier accumulation and exciton quenching, this bipolar host matrix could serve as a non-barrier functional spacer between EML/ETL, enabling the distribution of recombination zone away from this interface. Consequently, the optimized OLED exhibits a low driving voltage, promising device stability (95% of the initial luminance of 1000 cd m-2, LT95 > 430 h), and a high Commission Internationale de L'Éclairage y coordinate of 0.69. This indicates that managing the excitons through rational energy level alignment holds the potential for simultaneously satisfying Rec.2020 standard and achieving commercial-level stability.

Neoadjuvant chemotherapy combined with immunotherapy versus neoadjuvant chemoradiotherapy in patients with locally advanced esophageal squamous cell carcinoma.

BACKGROUND: To date, few studies have compared effectiveness and survival rates of neoadjuvant chemotherapy combined with immunotherapy (NACI) and conventional neoadjuvant chemoradiotherapy (NCRT) in patients with locally advanced esophageal squamous cell carcinoma (ESCC). The present study was conducted to compare therapeutic response and survival between NACI and NCRT. METHODS: The study cohort comprised patients with locally advanced ESCC treated with either NACI or NCRT followed by surgery between June 2018 and March 2021. The 2 groups were compared for treatment response, 3-year overall survival (OS), and disease-free survival (DFS). Survival curves were created using the Kaplan-Meier method, differences were compared using the log-rank test, and potential imbalances were corrected for using the inverse probability of treatment weighting (IPTW) method. RESULTS: Among 202 patients with locally advanced ESCC, 81 received NACI and 121 received conventional NCRT. After IPTW adjustment, the R0 resection rate (85.2% vs 92.3%; P = .227) and the pathologic complete response (pCR) rate (27.5% vs 36.4%; P = .239) were comparable between the 2 groups. Nevertheless, patients who received NACI exhibited both a better 3-year OS rate (91.7% vs 79.8%; P = .032) and a better 3-year DFS rate (87.4% vs 72.8%; P = .039) compared with NCRT recipients. CONCLUSIONS: NACI has R0 resection and pCR rates comparable to those of NCRT and seems to be correlated with better prognosis than NCRT. NACI followed by surgery may be an effective treatment strategy for locally advanced ESCC.

Efficient, narrow-band, and stable electroluminescence from organoboron-nitrogen-carbonyl emitter.

Organic light-emitting diodes (OLEDs) exploiting simple binary emissive layers (EMLs) blending only emitters and hosts have natural advantages in low-cost commercialization. However, previously reported OLEDs based on binary EMLs hardly simultaneously achieved desired comprehensive performances, e.g., high efficiency, low efficiency roll-off, narrow emission bands, and high operation stability. Here, we report a molecular-design strategy. Such a strategy leads to a fast reverse intersystem crossing rate in our designed emitter h-BNCO-1 of 1.79×105 s-1. An OLED exploiting a binary EML with h-BNCO-1 achieves ultrapure emission, a maximum external quantum efficiency of over 40% and a mild roll-off of 14% at 1000 cd·m-2. Moreover, h-BNCO-1 also exhibits promising operational stability in an alternative OLED exploiting a compact binary EML (the lifetime reaching 95% of the initial luminance at 1000 cd m-2 is ~ 137 h). Here, our work has thus provided a molecular-design strategy for OLEDs with promising comprehensive performance.

On the role of asymmetric molecular geometry in high-performance organic solar cells.

Although asymmetric molecular design has been widely demonstrated effective for organic photovoltaics (OPVs), the correlation between asymmetric molecular geometry and their optoelectronic properties is still unclear. To access this issue, we have designed and synthesized several symmetric-asymmetric non-fullerene acceptors (NFAs) pairs with identical physical and optoelectronic properties. Interestingly, we found that the asymmetric NFAs universally exhibited increased open-circuit voltage compared to their symmetric counterparts, due to the reduced non-radiative charge recombination. From our molecular-dynamic simulations, the asymmetric NFA naturally exhibits more diverse molecular interaction patterns at the donor (D):acceptor (A) interface as compared to the symmetric ones, as well as higher D:A interfacial charge-transfer state energy. Moreover, it is observed that the asymmetric structure can effectively suppress triplet state formation. These advantages enable a best efficiency of 18.80%, which is one of the champion results among binary OPVs. Therefore, this work unambiguously demonstrates the unique advantage of asymmetric molecular geometry, unveils the underlying mechanism, and highlights the manipulation of D:A interface as an important consideration for future molecular design.

Charge injection engineering at organic/inorganic heterointerfaces for high-efficiency and fast-response perovskite light-emitting diodes.

The development of advanced perovskite emitters has considerably improved the performance of perovskite light-emitting diodes (LEDs). However, the further development of perovskite LEDs requires ideal device electrical properties, which strongly depend on its interfaces. In perovskite LEDs with conventional p-i-n structures, hole injection is generally less efficient than electron injection, causing charge imbalance. Furthermore, the popular hole injection structure of NiOx/poly(9-vinylcarbazole) suffers from several issues, such as weak interfacial adhesion, high interfacial trap density and mismatched energy levels. In this work, we insert a self-assembled monolayer of [2-(9H-carbazol-9-yl)ethyl]phosphonic acid between the NiOx and poly(9-vinylcarbazole) layers to overcome these challenges at the organic/inorganic heterointerfaces by establishing a robust interface, passivating interfacial trap states and aligning the energy levels. We successfully demonstrate blue (emission at 493 nm) and green (emission at 515 nm) devices with external quantum efficiencies of 14.5% and 26.0%, respectively. More importantly, the self-assembled monolayer also gives rise to devices with much faster response speeds by reducing interfacial capacitance and resistance. Our results pave the way for developing more efficient and brighter perovskite LEDs with quick response, widening their potential application scope.

De Novo Designed Self-Assembling Rhodamine Probe for Real-Time, Long-Term and Quantitative Live-Cell Nanoscopy.

Super-resolution imaging provides a powerful approach to image dynamic biomolecule events at nanoscale resolution. An ingenious method involving tuning intramolecular spirocyclization in rhodamine offers an appealing strategy to design cell-permeable fluorogenic probes for super-resolution imaging. Nevertheless, precise control of rhodamine spirocyclization presents a significant challenge. Through detailed study of the structure-activity relationship, we identified that multiple key factors control rhodamime spirocyclization. The findings provide opportunities to create fluorogenic probes with tailored properties. On the basis of our findings, we constructed self-assembling rhodamine probes for no-wash live-cell confocal and super-resolution imaging. The designed self-assembling probe Rho-2CF3 specifically labeled its target proteins and displayed high ring-opening ability, fast labeling kinetics (<1 min), and large turn-on fold (>80 folds), which is very difficult to be realized by the existing methods. Using the probe, we achieved high-contrast super-resolution imaging of nuclei and mitochondria with a spatial resolution of up to 42 nm. The probe also showed excellent photostability and proved ideal for real-time and long-term tracking of mitochondrial fission and fusion events with high spatiotemporal resolution. Furthermore, Rho-2CF3 could resolve the ultrastructure of mitochondrial cristae and quantify their morphological changes under drug treatment at nanoscale. Our strategy thus demonstrates its usefulness in designing self-assembling probes for super-resolution imaging.

Treatment and Prognosis of Resectable Cervical Esophageal Cancer: A Population-Based Study.

BACKGROUND: The optimal treatment strategy for resectable cervical esophageal cancer remains controversial. This study aimed to explore prognostic factors and optimal treatment strategies in the context of staging. METHODS: In this population-based study, 1371 patients with resectable cervical esophageal cancer were identified in the Surveillance, Epidemiology, and End Results database. Univariate analysis and multivariable Cox regression model were performed to evaluate factors related to overall survival (OS). Subgroup analysis based on staging was performed to assess the effect of treatments on survival and propensity score matching was conducted to adjust confounding factors. RESULTS: Univariate and multivariable analyses revealed that age, sex, year of diagnosis, histological type, tumor size, cN stage, surgery, radiotherapy, and chemotherapy are independent prognostic factors. After propensity score matching, patients with local disease (cT1-2N0M0) who received surgery alone had a higher 10-year OS rate than those received chemoradiotherapy (CRT) (20.7% vs 11.4%, P = .023). Compared with CRT, surgery-based multimodal therapy did not increase the OS rate of patients (14.8% vs 11.1%, P = .084). For regional disease (cT3-4aN0M0/cT1-4aN1-3M0), although surgery alone did not improve the OS rate of patients compared with CRT (7.3% vs 8.2%, P = .18), we observed a significant difference in 10-year OS among patients who underwent surgery-based multimodal therapy vs those who underwent CRT (20.4% vs 9.0%, P = .031). CONCLUSIONS: Compared with CRT, surgery alone improves the long-term survival of patients with localized disease, and surgery-based multimodal therapy increases the survival rate of patients with regional disease. Further studies are required to confirm our findings.

99m Tc bone scintigraphy does not affect preoperative workup for patients with potentially resectable esophageal squamous cell carcinoma.

BACKGROUND: 99m Tc bone scintigraphy (BS) is the mainstay and most widely used technique in evaluation of bone metastasis (BM) in China. This study aimed to investigate the value of 99m Tc BS in preoperative workup for patients with potentially resectable (cT1-4a N0-3 ) esophageal squamous cell carcinoma (ESCC). METHODS: This prospective cross-section clinical trial (ChiCTR1800020304) enrolled a total of 385 patients with ESCC diagnosed at thoracic surgery clinic from October 2018 to September 2020. All patients were diagnosed with stage cT1-4a N0-3 and were potential candidates for surgical resection. BS was performed preoperatively and the treatment strategy was changed after confirmation of BM. The primary endpoint was the rate of change of the treatment regimen because of BM, while the secondary endpoint was the rate of positive BS findings. RESULTS: Out of the 385 patients, only two (0.5%) changed their treatment regimen because of BM. The rate of positive BS findings was 1%, while two patients (0.5%) had false-positive or false-negative results. The BS diagnostic performance for BM was sensitivity 50%, specificity 99.5%, positive predictive value 50%, negative predictive value 99.5%, and accuracy 99.0%. There was no significant difference in BM in relation to age, sex, tumor location or clinical stage. CONCLUSION: Our data demonstrated that 99m Tc bone scintigraphy does not significantly affect the preoperative workup in patients with potentially resectable ESCC, especially in early clinical stage patients.

Clinical significance of left tracheobronchial lymph node dissection in thoracic esophageal squamous cell carcinoma.

OBJECTIVE: The left tracheobronchial lymph nodes are considered as regional lymph nodes for esophageal squamous cell carcinoma, but routine prophylactic left tracheobronchial lymph node dissection for all resectable esophageal squamous cell carcinoma has been controversial. This study aimed to evaluate the prognostic impact of left tracheobronchial lymph node dissection and left tracheobronchial lymph node metastases in thoracic esophageal squamous cell carcinoma and to analyze the risk factors of left tracheobronchial lymph node metastases. METHODS: A total of 3522 patients with esophageal squamous cell carcinoma undergoing esophagectomy were included. Overall survival was calculated by a Kaplan-Meier method and compared using the log-rank test. Propensity score matching was conducted to adjust confounding factors. Univariable and multivariable logistic regression analyses were used to identify independent risk factors of left tracheobronchial lymph node metastases. RESULTS: In this study, 608 patients underwent left tracheobronchial lymph node dissection and 45 patients had left tracheobronchial lymph node metastases (7.4%). After propensity score matching, the 5-year overall survival in patients receiving left tracheobronchial lymph node dissection was better than in patients who did not (68.2% vs 64.6%, P = .012). In patients receiving left tracheobronchial lymph node dissection, patients with left tracheobronchial lymph node metastases had a significantly poorer survival than patients without (5-year overall survival: 40.5% vs 62.2%, P = .029). Multivariable logistic analyses showed that clinical T stage and tumor differentiation were independent risk factors for left tracheobronchial lymph node metastases. CONCLUSIONS: In thoracic esophageal squamous cell carcinoma, station left tracheobronchial lymph node metastases indicate a poor prognosis and left tracheobronchial lymph nodes dissection seems to be associated with a more favorable prognosis. Clinical T stage and tumor differentiation were independent risk factors for left tracheobronchial lymph node metastases. For patients with high risk, routine prophylactic left tracheobronchial lymph node dissection should be performed.

Multiple resonance type thermally activated delayed fluorescence by dibenzo [1,4] azaborine derivatives.

We studied the photophysical and electroluminescent (EL) characteristics of a series of azaborine derivatives having a pair of boron and nitrogen aimed at the multi-resonance (MR) effect. The computational study with the STEOM-DLPNO-CCSD method clarified that the combination of a BN ring-fusion and a terminal carbazole enhanced the MR effect and spin-orbit coupling matrix element (SOCME), simultaneously. Also, we clarified that the second triplet excited state (T2) plays an important role in efficient MR-based thermally activated delayed fluorescence (TADF). Furthermore, we obtained a blue-violet OLED with an external EL quantum efficiency (EQE) of 9.1%, implying the presence of a pronounced nonradiative decay path from the lowest triplet excited state (T1).

Development and validation of a nomogram model for the prediction of 4L lymph node metastasis in thoracic esophageal squamous cell carcinoma.

Objectives: The left tracheobronchial (4L) lymph nodes (LNs) are considered as regional LNs for esophageal squamous cell carcinoma (ESCC), but there is a controversy about routine prophylactic 4L LN dissection for all resectable ESCCs. This study aimed to develop a nomogram for preoperative prediction of station 4L lymph node metastases (LNMs). Methods: A total of 522 EC patients in the training cohort and 370 in the external validation cohort were included. The prognostic impact of station 4L LNM was evaluated, and multivariable logistic regression analyses were performed to identify independent risk factors of station 4L LNM. A nomogram model was developed based on multivariable logistic regression analysis. Model performance was evaluated in both cohorts in terms of calibration, discrimination, and clinical usefulness. Results: The incidence of station 4L LNM was 7.9% (41/522) in the training cohort. Patients with station 4L LNM exhibited a poorer 5-year overall survival rate than those without (43.2% vs. 71.6%, p < 0.001). In multivariate logistic regression analyses, six variables were confirmed as independent 4L LNM risk factors: sex (p = 0.039), depth of invasion (p = 0.002), tumor differentiation (p = 0.016), short axis of the largest 4L LNs (p = 0.001), 4L conglomeration (p = 0.006), and 4L necrosis (p = 0.002). A nomogram model, containing six independent risk factors, demonstrated a good performance, with the area under the curve (AUC) of 0.921 (95% CI: 0.878-0.964) in the training cohort and 0.892 (95% CI: 0.830-0.954) in the validation cohort. The calibration curve showed a good agreement on the presence of station 4L LNM between the risk estimation according to the model and histopathologic results on surgical specimens. The Hosmer-Lemeshow test demonstrated a non-significant statistic (p = 0.691 and 0.897) in the training and validation cohorts, which indicated no departure from the perfect fit. Decision curve analysis indicated that the model had better diagnostic power for 4L LNM than the traditional LN size criteria. Conclusions: This model integrated the available clinical and radiological risk factors, facilitating in the precise prediction of 4L LNM in patients with ESCC and aiding in personalized therapeutic decision-making regarding the need for routine prophylactic 4L lymphadenectomy.