Thickness-modulated optical nonlinearity of colloidal CdSe-CdS core-shell nanoplatelets: large two-photon absorption and self-focusing effects.

As a one-dimensional quantum confined material, colloidal semiconductor nanoplatelets have been widely studied as potential nonlinear materials due to their strong exciton effect and large two-photon absorption cross-section similar to that of two-dimensional materials. In this work, CdSe-CdS core-shell nanoplatelets were synthesized and third-order nonlinear optical properties related to shell thickness were measured using the Z-scan method. Measurement revealed a monotonic increase in the imaginary part of the third-order nonlinear susceptibility (Imχ(3)) of CdSe-CdS nanoplatelets, ranging from 0.62 × 10-13 esu to 2.43 × 10-13 esu, with the growth of shell thickness. The real part of the third-order nonlinear susceptibility (Reχ(3)) shows a non-monotonic change between 4.28 × 10-13 esu and 1.99 × 10-13 esu. The trends were further elucidated by analyzing the optical properties of the nanoplatelets, such as absorption, photoluminescence, and quantum yield, and understanding the variations in defect distribution, exciton binding energy, and quantum confinement effects. The results indicated that the appropriate passivation of the CdS shell effectively enhanced the luminescent performance and third-order nonlinearity of the nanoplatelets, while the induced defects and weakened quantum confinement effects due to the continued shell growth resulted in the opposite effect.

Study of the mechanisms of the phonon bottleneck effect in CdSe/CdS core/shell quantum dots and nanoplatelets and their application in hot carrier multi-junction solar cells.

The hot carrier multi-junction solar cell (HCMJSC) is one of the promising advanced conceptual solar cells with theoretical efficiency greater than 65%, consisting of a thin top junction with a wide bandgap and a thicker junction at the bottom with a medium bandgap for absorption of high and low energy photons. The wide bandgap CdSe/CdS low-dimensional systems (e.g. quantum dots, QDs and nanoplatelets, NPLs) widely used in optoelectrical devices are expected to be an appropriate candidate for the top junction. However, the mechanisms underlying the carrier relaxation rate reduction (or phonon bottleneck effect, PBE) for HCMJSC in these material systems are not well understood so far. In this work, the carrier relaxation mechanisms in CdSe/CdS core/shell QDs and NPLs are quantitatively analyzed by calculating the thermalization coefficient (Qth) through steady state photoluminescence (SSPL) and picosecond-time resolved photoluminescence (ps-TRPL). A significantly extended carrier relaxation time of more than 20 ns was observed in the TRPL of QDs. This could be attributed to both the Auger reheating (AR) at the initial fast decay stage and acoustic phonon folding at the slow decay stage. For SSPL, the Qth value of QDs is much lower due to a 1 order of magnitude higher AR rate. A strong coupling may exist between AR and Qth with a high probability of PBE, where a lower Qth gives a higher AR rate. The AR may dominate carrier thermalization if the PBE level is high. Meanwhile, other mechanisms like acoustic phonon folding will also affect the carrier relaxation if the PBE is at a much lower level.

Optimal treatment strategy and prognostic analysis for hypopharyngeal squamous-cell carcinoma patients with T3-T4 or node-positive: A population-based study.

PURPOSE: To explore the optimal treatment strategy and relevant prognostic analysis for hypopharyngeal squamous-cell carcinoma patients (HSCC) with T3-T4 or node-positive. METHODS AND MATERIALS: From 2004 to 2018, data for 2574 patients from the Surveillance, Epidemiology, and End Results database (SEER) and 66 patients treated at our center from 2013 to 2022 with T3-T4 or N + HSCC were collected. Patients in the SEER cohort were randomly assigned to the training set or validation set at a 7:3 ratio. Variables with statistically significant (P < 0.05) in univariate COX regression analysis or clinical significance were included in the multivariate COX regression model and subsequently used to construct the nomogram. RESULTS: The 3-year OS (52.9%vs44.4%, P < 0.01) and 3-year CSS rate (58.7%vs51.5%, P < 0.01) rates in the surgery combined with postoperative adjuvant therapy (S + ADT) group were superior to the radiotherapy combined with chemotherapy (CRT) group. The multivariate Cox regression analysis of the training group showed that age, race, marital status, primary site, T stage, N stage, and treatment modalities were correlated with OS and CSS. Based on those variables, we constructed nomograms for OS and CSS. Both the internal and external validation showed high prediction accuracy of the nomogram. CONCLUSION: Among patients with T3-T4 or node-positive, S + ADT was associated with superior OS and CSS compared to those treated with primary CRT, while the survival rate in the CRT group was comparable to S + ADT group in T2-T3 disease. The internal and external verification shows that the prognostic model has good discrimination ability and accuracy.

MT1X is an oncogene and indicates prognosis in ccRCC.

The metallothionein 1 (MT1) family was previously shown to be involved in metal ion homeostasis, DNA damage, oxidative stress, and carcinogenesis. Our team's previous study showed that MT1X is most closely associated with ccRCC. However, its role in clear cell RCC (ccRCC) remains unclear. The present study aimed to demonstrate MT1X's prognostic value, potential biologic function, impact on the immune system, and influence on cell growth, the cell cycle, apoptosis, and migration in the setting of ccRCC. The relationship between clinical pathologic features and MT1X was analyzed using bioinformatics. We knocked down MT1X in the ccRCC cell line 786O with si-MT1X to verify the results of the bioinformatic analysis at the cytological level. Apoptosis assay, cell cycle assay, wound-healing assay, colony formation assay, and RT-qPCR were performed. MT1X is correlated with the stage (T and M) and grade and is able to be an independent prognostic factor for ccRCC. The TISIDB database analysis showed a significant correlation between MT1X and tumor-infiltrating lymphocytes such as central memory CD8+ T cells and γΔT cells. MT1X was also positively related to immunomodulators such as TGFB1 and CXCR4. We also found that MT1X knockdown inhibits cell growth, induces apoptosis, arrests cells in the S cell cycle, and inhibits the wound healing proportion in ccRCC. Gene set enrichment analysis and quantitative PCR (q-PCR) analysis found that down-regulation of MT1X reduced the accumulation of hypoxia-associated factors. Bioinformatic analysis associated increased MT1X expression with a worse prognosis. Laboratory experiments confirmed bioinformatic findings. MT1X was also found to be an independent prognostic biomarker for ccRCC and is involved in immune system regulation.

Survival Comparisons between Breast Conservation Surgery and Mastectomy Followed by Postoperative Radiotherapy in Stage I-III Breast Cancer Patients: Analysis of the Surveillance, Epidemiology, and End Results (Seer) Program Database.

Background: This study aims to evaluate the overall and breast cancer-specific survival (BCSS) after breast-conserving surgery (BCS) plus radiotherapy (RT) compared with mastectomy plus RT in resectable breast cancer. Moreover, the aim is to also identify the subgroups who benefit from BCS plus RT and establish a predictive nomogram for stage II patients. Methods: Stage I−III breast cancer patients were identified from the Surveillance, Epidemiology, and End Results (SEER) database between 1990 and 2016. Patients with available clinical information were split into two groups: BCS plus RT and mastectomy plus RT. Kaplan−Meier survival analysis, univariate and multivariate regression analysis, and propensity score matching were used in the study. Hazard ratio (HR) was calculated based on stratified Cox univariate regression analyses. A prognostic nomogram by multivariable Cox regression model was developed for stage II patients, and consistency index (C-index) and calibration curve were used to evaluate the accuracy of the nomogram in the training and validation set. Results: A total of 24,590 eligible patients were enrolled. The difference in overall survival (OS) and BCSS remained significant in stage II patients both before and after PSM (after PSM: OS: HR = 0.8536, p = 0.0115; BCSS: HR = 0.7803, p = 0.0013). In stage II patients, the survival advantage effect of BCS plus RT on OS and BCSS was observed in the following subgroups: any age, smaller tumor size (<1 cm), stage IIA (T2N0, T0−1N1), ER (+), and any PR status. Secondly, the C-indexes for BCSS prediction was 0.714 (95% CI 0.694−0.734). The calibration curves showed perfect agreement in both the training and validation sets. Conclusions: BCS plus RT significantly improved the survival rates for patients of stage IIA (T2N0, T0−1N1), ER (+). For stage II patients, the nomogram was a good predictor of 5-, 10-, and 15-year BCSS. Our study may help guide treatment decisions and prolong the survival of stage II breast cancer patients.

A Large Solitary Fibrous Tumor of the Nasal Cavity and Paranasal Sinuses Involving the Anterior Frontal Fossa: A Case Report and Review of the Literature.

The Solitary Fibrous Tumor (SFT) is a rare mesenchymal neoplasm that arises mainly from the pleura. The sinonasal tract is generally not affected by SFT, and less than 100 cases have been reported in the English literature to date. We report an extremely rare SFT of the nasal cavity and paranasal sinuses extending into the anterior frontal fossa through the floor of the anterior skull base. To our knowledge, this case is the fourth SFT of the sinonasal tract involving the anterior frontal fossa in the world. Meanwhile, the tumor, measuring 13 × 6 cm in images, is the largest SFT of the sinonasal tract compared to previously reported cases. Three surgical procedures, including a transcranial one, were performed for the patient to achieve complete removal of the tumor. The diagnosis of SFT was established primarily by immunohistochemical positivity for CD34, STAT6, and negativity for S-100 protein. We emphasize the possibility of recurrence in SFT, and close follow-up is necessary with the help of nasal endoscopy and imaging approaches.

Ultralow Threshold Room Temperature Polariton Condensation in Colloidal CdSe/CdS Core/Shell Nanoplatelets.

Room-temperature exciton-polariton Bose-Einstein condensation (BEC), a phase transition to single quantum state with strong nonlinearity, provides a new strategy for coherent light sources and ultralow threshold optic switches. In this work, colloidal CdSe/CdS 2D nanoplatelets are embedded into a microcavity, and exciton-polariton BEC is realized with an ultralow threshold of 0.5 µJ cm-2 at room temperature. The superlinear power-dependent emission, macroscopic occupation of the ground state, strong blueshift and broadening of the emission peak, and long-range coherence strongly confirm the realization of the polariton laser. This work suggests considerable prospects for colloidal nanoplatelets in low-cost, high-performance polariton devices, and coherent light sources.

Observation of high-density multi-excitons in medium-size CdSe/CdZnS/ZnS colloidal quantum dots through transient spectroscopy and their optical gain properties.

Semiconductor quantum dots have extremely significant advantages in terms of optoelectronic devices. However, it is unfeasible to avoid the generation of charged exciton states during operation. Such states can change the radiation recombination rate and bring additional non-radiative Auger recombination channels. Herein, we synthesize high photoluminescence quantum yield medium-size CdSe/CdZnS/ZnS core/alloy shell/shell QDs. Their multiexciton spectra and dynamics were systematically studied by pump-power-dependent fluorescence blinking and time-correlated spectroscopy. The lifetimes of positively/negatively charged trions and biexcitons are estimated to be 0.74/6.1 and 0.16 ns, respectively. It demonstrated that the band-edge biexciton is influenced by the Coulomb interaction and Stark effect. The amplified spontaneous emission threshold is only 81 µJ cm-2 and can retain a long operation lifetime under continuous pumping. A vertical microcavity surface-emitting laser device is fabricated using these QDs. The coupling factor between the spontaneous emission and cavity mode is 0.81, which benefits the low stimulated emission threshold. This work provides a new perspective of the charged states in the multiexciton AR process in the QDs, implying a promising application prospect of such QDs as optical gain materials in "zero-threshold" laser fabrication.

Overexpressed pseudogene MT1L associated with tumor immune infiltrates and indicates a worse prognosis in BLCA.

BACKGROUND: BLCA is a common cancer worldwide, and it is both aggressive and fatal. Immunotherapy (ICT) has achieved an excellent curative effect in BLCA; however, only some BLCA patients can benefit from ICT. MT1L is a pseudogene, and a previous study suggested that MT1L can be used as an indicator of prognosis in colorectal cancer. However, the role of MT1L in BLCA has not yet been determined. METHODS: Data were collected from TCGA, and logistic regression, Kaplan-Meier plotter, and multivariate Cox analysis were performed to demonstrate the correlation between the pseudogene MT1L and the prognosis of BLCA. To identify the association of MT1L with tumor-infiltrating immune cells, TIMER and TISIDB were utilized. Additionally, GSEA was performed to elucidate the potential biological function. RESULTS: The expression of MT1L was decreased in BLCA. Additionally, MT1L was positively correlated with immune cells, such as Tregs (ρ = 0.708) and MDSCs (ρ = 0.664). We also confirmed that MT1L is related to typical markers of immune cells, such as PD-1 and CTLA-4. In addition, a high MT1L expression level was associated with the advanced T and N and high grade in BLCA. Increased expression of MT1L was significantly associated with shorter OS times of BLCA patients (p < 0.05). Multivariate Cox analysis revealed that MT1L expression could be an independent prognostic factor in BLCA. CONCLUSION: Collectively, our findings demonstrated that the pseudogene MT1L regulates the immune microenvironment, correlates with poor survival, and is an independent prognostic biomarker in BLCA.

"Giant" quantum dots encapsulated inside a freeform lens.

A freeform lens containing giant red and green quantum dots (QDs) was designed to be used for a direct-illumination-type LED backlight wide-color-gamut display. Encapsulating the QDs with the freeform lens enabled us to not only expand the illumination area, where the uniform lighting area was about 2 cm in radius on the plane 1.5 cm above the LED, but to also avoid QDs coming into direct contact with the LED chip, which reduced the QDs' surrounding temperature from 94°C to 61°C. Moreover, this encapsulation and the thick shell of the QDs significantly improved the device's lifetime up to more than 100 h due to the reduced temperature. A color gamut of ∼130% of the National Television Systems Committee standard was obtained with the freeform lens.