Gastric gastrointestinal stromal tumors: therapeutic strategies and long-term prognosis.

OBJECTIVES: This study aimed to evaluate the clinical and prognostic characteristics of primary gastric gastrointestinal stromal tumors (GIST). METHODS: Patients who underwent resection for primary gastric GIST between January 2002 and December 2017 were included. Recurrence-free survival (RFS) was calculated by Kaplan-Meier analysis, and Cox proportional hazards model was used to identify independent prognostic factors. RESULTS: Altogether, 653 patients were enrolled. The median patient age was 59 years (range 15-86 years). Open, laparoscopic, and endoscopic resections were performed in 394 (60.3%), 105 (16.1%), and 154 (23.6%) patients, respectively. According to the modified NIH consensus classification, 132 (20.2%), 245 (37.5%), 166 (25.4%), and 88 (13.5%) patients were categorized into very low-, low-, intermediate-, and high-risk, respectively. A total of 136 (20.8%) patients received adjuvant imatinib treatment. The median follow-up time was 78 months (range 4-219 months), and the estimated 5-year RFS rate was 93.0%. In all patients, tumor size and rupture, mitotic counts, and adjuvant imatinib treatment were independent prognostic factors. The prognosis of gastric GIST treated with endoscopic resection was not significantly different from that of laparoscopic or open resection after adjusting for covariates using propensity score matching (log-rank p = .558). Adjuvant imatinib treatment (HR = 0.151, 95%CI 0.055-0.417, p < .001) was a favorable prognostic factor for high-risk patients, but was not associated with prognosis in intermediate-risk patients. CONCLUSION: Patients with small gastric GISTs who successfully underwent endoscopic resection may have a favorable prognosis. Adjuvant imatinib treatment improve the prognosis of high-risk gastric GISTs, however, its use in intermediate-risk patients remains controversial.

The prognostic role of gastrointestinal bleeding in patients with a primary gastrointestinal stromal tumor: a long-term follow-up study.

Background: Gastrointestinal (GI) bleeding is one of the common symptoms of GI stromal tumor (GIST). Although several studies have highlighted its prognostic role, conclusions have been inconsistent. This study aimed to investigate the prognosis of GIST patients with GI bleeding. Methods: Primary GIST patients who underwent complete resection and did not receive adjuvant imatinib therapy from January 2003 to December 2008 were reviewed. The Kaplan-Meier method was used to estimate recurrence-free survival (RFS), and multivariate analysis was performed using the Cox proportional hazard model. Propensity score matching (PSM) was conducted to reduce confounders. A systematic review of the published articles in the PubMed, Embase, Cochrane Collaboration, and Medline databases was also conducted, and the inclusion criteria were determined using PICOS (patients, intervention, comparison, outcomes, and study design) principles. Results: In total, 84 patients presenting with GI bleeding and 90 patients without GI bleeding were enrolled in this study. The median time of follow-up was 140 months (range, 10-196 months), and 38 patients developed tumor recurrence/metastasis. For all patients, the multivariate analysis indicated that tumor location [hazard ratio (HR) =3.48, 95% confidence interval (CI): 1.78-6.82, P<0.001], tumor size (HR =1.91, 95% CI: 1.05-3.47, P=0.035), mitotic index (MI; HR =5.69, 95% CI: 2.77-11.67, P<0.001), and age (HR =2.68, 95% CI: 1.49-4.82, P=0.001) were the independent prognostic factors for poor RFS. However, GI bleeding was not associated with RFS (HR =1.21, 95% CI: 0.68-2.14, P=0.518). After PSM, 45 patients from each group were included, and it was found that GI bleeding was still not the independent prognostic factor (HR =1.23, 95% CI: 0.51-2.97, P=0.642). Moreover, the pooled results of our study and six previously reported studies showed that GI bleeding was not the independent prognostic factor (HR =1.45, 95% CI: 0.73-2.86, P=0.287). Conclusions: In this study, tumor location, tumor size, MI, and age were independent prognostic factors in primary GIST patients who underwent radical resection. However, GI bleeding was not associated with worse RFS.

CT features combined with RECIST 1.1 criteria improve progression assessments of sunitinib-treated gastrointestinal stromal tumors.

OBJECTIVES: To explore the auxiliary value of combining CT features with existing response evaluation criteria in the prediction of progressive disease (PD) in gastrointestinal stromal tumors (GIST) patients treated with sunitinib. MATERIAL AND METHODS: Eighty-one patients with GISTs who received sunitinib were included in this retrospective multicenter study and divided into training and external validation cohorts. Progression at six months was determined as a reference standard. The predictive performance of the RECIST 1.1 and Choi criteria was compared. CT features at baseline and the first follow-up were analyzed. Logistic regression analyses were used to determine the most significant predictors and develop modified criteria. RESULTS: A total of 216 lesions showed a good response and 107 showed a poor response in 81 patients. The RECIST 1.1 criteria performed better than the Choi criteria in predicting progression (AUC, 0.75 vs. 0.69, p = 0.04). The expanded/intensified high-enhancement area, blurred tumor-tissue interface, and progressive enlarged vessels feeding or draining the mass (EVFDM) differed significantly between lesions with good and poor responses in the training cohort (p = 0.001, 0.003, and 0.000, respectively). Multivariate analysis revealed that the expanded/intensified high-enhancement area (p = 0.001), progressive EVFDM (p = 0.000), and RECIST PD (p = 0.000) were independent predictive factors. Modified RECIST (mRECIST) criteria were developed and showed significantly higher AUCs in the training and external validation cohorts than the RECIST 1.1 criteria (training: 0.81 vs. 0.73, p = 0.002; validation: 0.82 vs. 0.77, p = 0.04). CONCLUSION: The mRECIST criteria, combining CT features with the RECIST 1.1 criteria, demonstrated superior performance in the prediction of early progression in GIST patients receiving sunitinib. CLINICAL RELEVANCE STATEMENT: The mRECIST criteria, which combine CT features with the RECIST 1.1 criteria, may facilitate the early detection of progressive disease in GIST patients treated with sunitinib, thereby potentially guiding the timely switch to late-line medications or combination with surgical excision. KEY POINTS: • The RECIST 1.1 criteria outperformed the Choi criteria in identifying progression of GISTs in patients treated with sunitinib. • GISTs displayed different morphologic features on CT depending on how they responded to sunitinib. • Combining CT morphologic features with the RECIST 1.1 criteria allowed for the prompt and accurate identification of progressing GIST lesions.

Anti-reflection effect of high refractive index polyurethane with different light trapping structures on solar cells.

The textured surfaces to reduce light reflectivity by using acid-alkali chemical etching and SiNx films are generally necessary for commercial crystalline silicon solar cells. However, this etching process requires a large amount of environmentally harmful acid-alkali solution and has limited options for texture and size. To overcome these disadvantages, a new anti-reflection strategy is proposed in this study, which is using soft nanoimprint lithography to prepare the textured structures on the outside of the SiNx films. The polyurethane with a high refractive index of 1.64 is selected as the texture material, and different templates are selected to prepare it into different light trapping structures, including positive-inverted pyramids, inverted lace cones, and positive-inverted moth-eye nanostructures allowing for easy customization of the textured structures. The finite element simulation and experiments demonstrate that these light trapping structures have a wide spectrum anti-reflection performance in visible and near-infrared bands. With the back surface of the commercial passivated emitter rear contact (PERC) bi-facial solar cells as the imprint substrates, some light trapping structures can reduce the surface weighted average light reflectivity (Rw) at the band of 300-1200 nm from 18.31% to less than 10% and the optimal structures can reduce Rw to 8.71%. This anti-reflection strategy can also be applied to thin-film solar cells and crystalline silicon solar cells of other structures, such as HIT, Topcon, Perovskite/c-Si tandem, and so forth, which shows great development potential.

Efficacy and safety of ripretinib in Chinese patients with advanced gastrointestinal stromal tumors: a real-world, multicenter, observational study.

Introduction: Mutations in KIT proto-oncogene, receptor tyrosine kinase (KIT) and platelet-derived growth factor receptor-α (PDGFRA) render the available tyrosine kinase inhibitors (TKI) ineffective in treating advanced gastrointestinal stromal tumors (GIST). Ripretinib, a broad-spectrum switch-control kinase inhibitor, has shown increased efficacy and manageable safety, but real-world evidence remains scarce. This study evaluates the efficacy and safety of ripretinib among Chinese patients in a real-world setting. Methods: Advanced GIST patients (N=23) receiving ripretinib following progression on previous lines of TKI treatment were enrolled to determine the efficacy [progression-free survival (PFS) and overall survival (OS)]. Safety was assessed by the incidence and severity of adverse events (AEs). All statistical analyses were performed using SPSS version 20.0 and a p-value of <0.05 was considered significant. Results: The median PFS (mPFS) of efficacy analysis set (EAS) (N=21) was 7.1 months. mPFS of patients receiving ripretinib following ≤2 lines of previous TKI treatment and ≥3 prior lines of therapy were 7.1 and 9.2 months, respectively. The median OS (mOS) was 12.0 months and shorter interval between the end of the latest TKI and ripretinib therapy was correlated with longer median PFS and OS (p=0.054 and p=0.046), respectively. Alopecia and asthenia were the most common AEs observed. Conclusion: Compared to previous lines of TKI in advanced GIST patients, ripretinib showed superior efficacy with clinically manageable AEs. Real-world results are comparable to that of phase III INVICTUS study and its Chinese bridging study. Hence, ripretinib can be used for the clinical management of advanced GIST patients.

Advances in the diagnosis of non-occlusive mesenteric ischemia and challenges in intra-abdominal sepsis patients: a narrative review.

Non-occlusive mesenteric ischemia (NOMI) is a type of acute mesenteric ischemia (AMI) with a high mortality rate mainly because of a delayed or misdiagnosis. Intra-abdominal sepsis is one of the risk factors for developing NOMI, and its presence makes early diagnosis much more difficult. An increase in routine abdominal surgeries carries a corresponding risk of abdominal infection, which is a complication that should not be overlooked. It is critical that physicians are aware of the possibility for intestinal necrosis in abdominal sepsis patients due to the poor survival rate of NOMI. This review aims to summarize advances in the diagnosis of NOMI, and focuses on the diagnostic challenges of mesenteric ischemia in patients with intra-abdominal sepsis.

Surface Reconstruction for Efficient and Stable Monolithic Perovskite/Silicon Tandem Solar Cells with Greatly Suppressed Residual Strain.

Despite the swift rise in power conversion efficiency (PCE) to more than 32%, the instability of perovskite/silicon tandem solar cells is still one of the key obstacles to practical application and is closely related to the residual strain of perovskite films. Herein, a simple surface reconstruction strategy is developed to achieve a global incorporation of butylammonium cations at both surface and bulk grain boundaries by post-treating perovskite films with a mixture of N,N-dimethylformamide and n-butylammonium iodide in isopropanol solvent, enabling strain-free perovskite films with simultaneously reduced defect density, suppressed ion migration, and improved energy level alignment. As a result, the corresponding single-junction perovskite solar cells yield a champion PCE of 21.8%, while maintaining 100% and 81% of their initial PCEs without encapsulation after storage for over 2500 h in N2 and 1800 h in air, respectively. Remarkably, a certified stabilized PCE of 29.0% for the monolithic perovskite/silicon tandems based on tunnel oxide passivated contacts is further demonstrated. The unencapsulated tandem device retains 86.6% of its initial performance after 306 h at maximum power point (MPP) tracking under continuous xenon-lamp illumination without filtering ultraviolet light (in air, 20-35 °C, 25-75%RH, most often ≈60%RH).

Reassessment of the recurrence risk of primary gastrointestinal stromal tumour after complete resection.

OBJECTIVES: The modified National Institutes of Health (NIH) risk criteria for gastrointestinal stromal tumours (GISTs) have some limitations and need to be improved. METHODS: Patients who underwent radical resection of primary GIST were retrospectively reviewed. Peripheral blood indices including the neutrophil-to-lymphocyte ratio (NLR) and prognostic nutritional index (PNI) were analysed. Recurrence-free survival (RFS) was calculated and compared. Multivariate analysis was conducted. Area under the receiver operating characteristic curve (ROC) was calculated. RESULTS: A total of 492 patients were enrolled. Tumour size, mitotic index (MI), tumour location and PNI were independent prognostic factors. The modified NIH criteria could not distinguish among very low-, low- and intermediate-risk patients, and PNI was the only independent prognostic factors for them. The five-year RFS rate in the high risk (HR) group was significantly lower. A further modification to the NIH risk criteria was proposed (the 'NIH-PNI stratification'). Non-high risk (NHR) patients were divided into the NHR-PNI-H group (PNI > 48.05) and the NHR-PNI-L group (PNI ≤ 48.05), respectively. HR patients were divided according to tumour size and MI: the HR1, HR2 and HR3 groups. The five-year RFS rates of the NHR-PNI-H, NHR-PNI-L, HR1, HR2 and HR3 groups were 97.3%, 93.5%, 74.1%, 61.7% and 24.4%, respectively (p < .001). The area under the curve (AUC) for the NIH-PNI stratification, modified NIH criteria, NIH criteria (2002), AFIP criteria and nomogram were 0.857, 0.807, 0.817, 0.843 and 0.831, respectively. CONCLUSION: The proposed NIH-PNI stratification was able to distinguish among five groups in terms of risk of recurrence.

A further modification to the NIH risk criteria for GISTs was proposed ('NIH-PNI stratification'). Non-high risk (NHR) patients were divided into NHR-PNI-H and NHR-PNI-L groups. High risk (HR) patients were divided to HR1, HR2 and HR3 groups. The five-year RFS rates were 97.3%, 93.5%, 74.1%, 61.7% and 24.4%, respectively (p < .001). The AUC for the NIH-PNI stratification, modified NIH criteria, NIH criteria (2002), AFIP criteria and nomogram were 0.857, 0.807, 0.817, 0.843 and 0.831.

Additive Engineering of the CuSCN Hole Transport Layer for High-Performance Perovskite Semitransparent Solar Cells.

CuSCN has been widely considered a promising candidate for low-cost and high-stable hole transport material in perovskite semitransparent solar cells (STSCs). However, the low conductivity of the solution-processed CuSCN hole transport layer (HTL) hinders the hole extraction and transport in devices, which makes it hard to achieve devices with high performance. Herein, we report a facile additive engineering approach to optimize the p conductivity of CuSCN HTLs in perovskite STSCs. The n-butylammonium iodide additive facilitates the formation of Cu2+ and generates more Cu vacancies in the CuSCN HTL. This realizes a significant enhancement of the hole concentration and p conductivity of the film. Moreover, the additive improves the solubility of the CuSCN precursor solution and results in a uniform coverage on the perovskite active layer. Therefore, the perovskite STSC with a high power conversion efficiency (PCE) of 19.24% has been achieved, which is higher than that of the spiro-OMeTAD (18.83%) and CuSCN (17.45%) counterparts. In addition, the unencapsulated CuSCN-based device retains 87.5% of the initial PCE after 20 days in the ambient atmosphere.

Precursor engineering for efficient and stable perovskite solar cells.

The perovskite film prepared by the two-step spin coating method is widely used in photovoltaic devices due to its good film morphology and great reproducibility. However, there usually exists excessive lead iodide (PbI2) in the perovskite film for this method, which is believed to passivate the grain boundaries (GBs) to increase the efficiency of the perovskite solar cells. Nevertheless, the excessive PbI2at the GBs of perovskite is believed to induce the decomposition of the perovskite film and undermine the long-term stability of devices. In this study, we utilize precursor engineering to realize the preparation of perovskite solar cells with high efficiency and stability. The concentration of organic salts (AX: A = MA+, FA+; X = I-, Cl-) in the precursor solution for the second step of the two-step spin coating method is adjusted to optimize the perovskite light-absorbing layer so that the excessive PbI2is converted into perovskite to obtain a smooth and pinhole-free perovskite film with high performance. Our results indicate that by adjusting the concentration of AX in the precursor solution, PbI2in the film could be completely converted into perovskite without excessive AX residue. Both the efficiency and stability of the perovskite solar cells without excessive PbI2have been significantly improved. A planar perovskite solar cell with the highest power conversion efficiency (PCE) of 21.26% was achieved, maintaining about 90% of the initial PCE after 300 h of storage in a dry air environment and in the dark, about 76% of the initial PCE after 300 h of continuous illumination of 1 Sun.

Validation of the DNA Methylation Landscape of TFF1/TFF2 in Gastric Cancer.

As one of the most frequently occurring tumor types, the increasing incidence of gastric cancer (GC) has been observed in the past decades. The recent studies have illustrated that epigenetic modifications mediated by DNA methyltransferases (DNMTs) are the major epigenetic hallmark in GC progression. Nowadays, DNA methylation was considered to be necessary for inducing the silence of tumor suppressor genes (TSGs). As an important group of peptides, the TFF family has been confirmed to function as a TSG in various kinds of cancers. However, whether TFFs could be modified by DNA methylation in gastric cancer remains unknown. Here, we initially screened out two transcriptional sequencing profiles about GC from Gene Expression Omnibus (GEO) database. The lower expression levels of TFF1 and TFF2 were observed in GC tumor tissues as compared to those in normal tissues. Additionally, utilizing the Kaplan-Meier analysis, the expressions of TFF1 and TFF2 were identified to be associated with the prognosis of GC patients. Subsequently, the integrative analysis was performed to estimate the DNA methylation level of each site in TFF1/TFF2 CpG islands. Importantly, our findings indicated that hyper-methylation of cg01886855 and cg26403416 were separately responsible for the downregulation of TFF1 and TFF2 in GC samples. In addition, utilizing the experiments in vitro, we demonstrated that TFF1/TFF2 could suppress the proliferation of GC cells. Based on these results, we suspected that TFF1/TFF2 could potentially act as the putative tumor suppressor in GC, and these two TFFs were of great value for predicting the overall survival (OS) status in the gastric cancer cohort. Totally, our findings revealed a potential therapeutic method for targeting the TFFs for the treatment of GC.

Luminescence-guided and visibly transparent solar concentrators based on silicon quantum dots.

In this work, we demonstrate a new tapered prism-shaped luminescent solar concentrator (LSC), which guides most of the luminescence toward one edge instead of four, for the solar window application. Only one Si photovoltaic (PV) strip attached to the light-emitting sidewall is needed to collect the luminescence, which further reduces PV material cost and avoids electrical mismatch. To achieve high visible transmission and mitigate reabsorption, colloidal silicon quantum dots (SiQDs) with ultraviolet-selective absorption and large Stokes shift are used as the fluorophores. With the SiQD concentration equal to 8 mg mL-1, the SiQD-LSC as a solar window can attain a power conversion efficiency (PCE) equal to 0.27%, while ensuring high average visible transmission (AVT = 86%) and high color rendering index (CRI = 94 with AM1.5G as the incident spectrum). When adjusted to front-facing, the Si PV strip can harvest not only the direct sunlight but also the concentrated SiQD fluorescence guided from the LSC. As a result, the overall solar window PCE can be increased to 1.18%, and the PCE of the front-facing Si PV strip alone can be increased by 7% due to the luminescence guided from the SiQD-LSC.

Elevated preoperative controlling nutritional status (CONUT) scores as a predictor of postoperative recurrence in gastrointestinal stromal tumors.

BACKGROUND: The controlling nutritional status (CONUT) score is associated with the postoperative outcomes in various types of tumors, and its prognostic role in gastrointestinal stromal tumors (GISTs) needs to be clarified. METHODS: Patients with completely resected primary GISTs in the absence of imatinib adjuvant therapy were included. Recurrence-free survival (RFS) was estimated with the Kaplan-Meier method and compared using log-rank test. Prognostic factors were compared using Cox proportional hazards model. RESULTS: A total of 455 patients were included. The median follow-up time was 132.0 months (range: 7.0-253.0). Recurrence/metastasis developed in 92 (20.2%) patients. Patients were assigned to three groups: 219 (48.1%) were in normal nutrition group (CONUT = 0-1), 196 (43.1%) were in mild malnutrition group (CONUT = 2-4) and 40 (8.8%) were in moderate-severe malnutrition group (CONUT ≥ 5). Nongastric primary tumor site, large tumor size, high mitotic index, tumor rupture and high CONUT score were independent prognostic factors for shorter RFS using multivariate analysis (p < 0.05). CONCLUSIONS: Elevated preoperative CONUT score was a predictor of recurrence for patients with resected GIST. The clinical application of the CONUT score is simple and feasible, and might contribute to the individualized treatment of GIST patients.

Effect of S-1 Plus Oxaliplatin Compared With Fluorouracil, Leucovorin Plus Oxaliplatin as Perioperative Chemotherapy for Locally Advanced, Resectable Gastric Cancer: A Randomized Clinical Trial.

IMPORTANCE: Perioperative chemotherapy is a potential treatment for locally advanced gastric cancer. However, the optimal chemotherapy regimen remains unknown. OBJECTIVE: To investigate the safety and efficacy of S-1 plus oxaliplatin (SOX) vs fluorouracil, leucovorin, and oxaliplatin (FOLFOX) as a perioperative chemotherapy regimen for patients with locally advanced gastric cancer. DESIGN, SETTING, AND PARTICIPANTS: In this phase 3, open-label, multicenter, randomized clinical trial, patients from 12 Chinese hospitals were enrolled between June 2011 and August 2016, with a last follow-up date of September 2019. The primary tumor was evaluated as either invading the serosa or the adjacent structures with or without metastatic lymph nodes, and with no evidence of distant metastases. Data were analyzed from December 2019 to June 2020. INTERVENTIONS: Patients were randomly assigned (1:1) to receive either 6 perioperative (2-4 preoperative and 2-4 postoperative) 3-week cycles of 130 mg/m2 oxaliplatin on day 1 and 80 to 120 mg/d S-1 orally daily for 2 weeks (SOX) or 130 mg/m2 oxaliplatin, 400 mg/m2 fluorouracil, 400 mg/m2 leucovorin, and 2400 mg/m2 fluorouracil as 46-hour infusion on day 1 (FOLFOX). MAIN OUTCOMES AND MEASURES: The primary end point was 3-year overall survival (OS). An absolute noninferiority margin of -8% was chosen. RESULTS: A total of 583 patients were enrolled; 293 were randomized to the SOX group and 290 were randomized to the FOLFOX group. Twelve patients (2.1%) refused preoperative chemotherapy (5 patients in the SOX group and 7 patients in the FOLFOX group), leaving a total of 288 patients in the SOX group (median [range] age, 61 [24 to 78] years; 197 men [68.4%]) and 283 patients in the FOLFOX group (median [range] age, 62 [24 to 80] years; 209 men [73.9%]) who received preoperative chemotherapy. The 3-year OS rate was 75.2% (95% CI, 70.3% to 80.5%) in the SOX group and 67.8% (95% CI, 62.5% to 73.5%) in the FOLFOX group. The absolute difference of 3-year OS rate between the 2 groups was 7.4% (95% CI, -0.1% to 14.9%), which was greater than the prespecified noninferiority margin (-8%) and showed the noninferiority of perioperative chemotherapy with SOX compared with FOLFOX. CONCLUSIONS AND RELEVANCE: In this randomized clinical trial, SOX was noninferior to FOLFOX as perioperative chemotherapy for patients with locally advanced gastric cancer and could be recommended as an alternative treatment for these patients in Asia. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01364376.

Visibly Transparent Solar Windows Based on Colloidal Silicon Quantum Dots and Front-Facing Silicon Photovoltaic Cells.

We demonstrate luminescent solar concentrators (LSCs) based on colloidal silicon quantum dots (SiQDs) as UV-selective fluorophores and coupled with front-facing silicon photovoltaic cells for the solar window application. The visibly transparent LSC composed of a thin layer of liquid SiQD suspension sandwiched between two thin glass slabs constitutes the windowpane, while strips of silicon photovoltaic cells with their front surfaces adhering to the LSC rear surface form the window frame. Furthermore, the LSC perimeter is surrounded by reflecting mirrors for preventing the fluorescence from leaking out through the edges. The SiQDs dispersed in 1-octadecene selectively absorb UV light and re-emit red fluorescence with quantum efficiency about 40%. Owing to the negligible overlap between the absorbance and photoluminescence spectra, the reabsorption effect is insignificant. The front-facing silicon photovoltaic strips located at the window frame can produce electricity by harvesting not only solar radiation but also the SiQD-generated fluorescence propagating from the windowpane. For the SiQD-LSC with the total light absorbing area equal to 12 cm × 12 cm and the reflecting mirrors tilted 45°, an overall power conversion efficiency of 2.47% under simulated sunlight can be obtained of which about 6% is contributed by the SiQD fluorescence. Meanwhile, the SiQD-LSC retains high spectral quality with average visible transmission and color rendering index through the windowpane equal to 86% and 94, respectively.

CsPbI2Br Perovskite Solar Cells Based on Carbon Black-Containing Counter Electrodes.

CsPbI2Br perovskite solar cells (PSCs) based on carbon electrodes (CEs) are considered to be low-cost and thermally stable devices. Nevertheless, the insufficient contact and energy level mismatch between the CsPbI2Br layer and CE hinder the further enhancement of the cell efficiency. Herein, a carbon black (CB) interlayer was introduced between the perovskite layer and CE. The hole extraction was facilitated due to the larger contact area and suitable energy band alignment in the CsPbI2Br/CB interface. Further investigation indicated the diffusion of CB nanoparticles from the CE or CB layer to the CsPbI2Br film after a certain period of time. We disclosed the formation of a CB-CsPbI2Br bulk heterojunction structure due to the carbon diffusion, which resulted in an efficiency enhancement. As a result, a record efficiency of 13.13% is achieved for carbon-based inorganic PSCs. This work also reveals that the diffusion of CB nanoparticles in CB-containing PSCs is universal and inevitable, although this kind of diffusion results in the enhancement of cell efficiency.

The Correlation Between Computed Tomography Volumetry and Prognosis of Advanced Gastric Cancer Treated with Neoadjuvant Chemotherapy.

PURPOSE: To investigate the feasibility and utility of computer tomography (CT) volumetry in evaluating the tumor response to neoadjuvant chemotherapy (NAC) in advanced gastric cancer (AGC) patients. PATIENTS AND METHODS: One hundred and seventeen Patients with AGC who received NAC followed by R0 resection between January 2006 and December 2012 were included. Tumor volumes were quantified using OsiriX software. The volume reduction rate (VRR) was calculated as follows: VRR = [(pre-chemotherapy total volume) - (post-chemotherapy total volume)]/(pre-chemotherapy total volume) × 100%. The optimal cut-off VRR for differentiating favorable from unfavorable prognosis was determined by receiver operating characteristic (ROC) analysis. Overall survival was calculated using Kaplan-Meier analysis and values were compared using the Log-rank test. Multivariate analysis was determined by the Cox proportional regression model. RESULTS: The optimal cut-off VRR was 31.95% according to ROC analysis, with a sensitivity of 70.4% and a specificity of 71.7%. Based on the cut-off VRR, patients were divided into the VRR-High (VRR ≥ 31.95%, n = 63) and VRR-Low (VRR < 31.95%, n = 54) groups. The VRR-Low group exhibited a worse prognosis than that of the VRR-High group (HR, 2.85; 95% CI, 1.69-4.82, P < 0.001), with 3-year survival rates of 40.7% and 79.4%, and 5-year survival rates of 31.5% and 63.5%, respectively. CONCLUSION: CT volumetry is a feasible and reliable method for assessing the tumor response to NAC in patients with AGC.

ypT0 gastric carcinoma after preoperative chemotherapy: a unique status according to AJCC 8th edition cancer staging system.

BACKGROUND: American Joint Committee on Cancer (AJCC) recently had published 8th edition staging system, in which a separate staging system was proposed for gastric cancers those received preoperative therapy (ypStage), however ypT0 was not included. The aim of this study was to propose the inclusion of ypT0 into the new staging classification. METHODS: We collected data of gastric cancer patients who underwent gastrectomy after preoperative chemotherapy in the First Affiliated Hospital of Zhejiang University (2004-2015). Kaplan-Meier survival estimations and log-rank tests were performed to compare survival. RESULTS: 314 patients were enrolled in this study according to inclusion and exclusion criteria. The 5-year overall survival (OS) rate of all patients was 53.5% and the survival estimation was well discriminated by ypstage (P<0.001). Twenty-five patients were identified achieving pathological complete regression in primary lesion (ypT0), in which there were 16 pCR patients and 9 ypT0N+ patients. The 5-year OS of pCR patients was 93.8%, which was not better than ypstage I with 5-year OS of 97.5% (P=0.507). Meanwhile, ypT0N+ patients' 5-year OS was 66.7%, which was significantly shorter than those with ypstage I (P=0.002), but no statistical difference from ypstage II with 5-year OS of 71.6% (P=0.583). CONCLUSIONS: Complete pathological regression of primary lesion (ypT0) was a predictor for long-term outcomes. pCR and ypT0N+ patients might be considered for inclusion in the ypstage I and ypstage II group respectively.

Design and simulation of perovskite solar cells with Gaussian structured gradient-index optics.

To unlock the full potential of the perovskite solar cell (PSC) photocurrent density and power conversion efficiency, the topic of optical management and design optimization is of absolute importance. Here, we propose a gradient-index optical design of the PSC based on a Gaussian-type front-side glass structure. Numerical simulations clarify a broadband light-harvesting response of the new design, showing that a maximal photocurrent density of 23.35 mA/cm2 may be expected, which is an increase by 1.21 mA/cm2 compared with that of the traditional flat-glass counterpart (22.14 mA/cm2). Comprehensive analysis of the electric field distributions elucidates the light-trapping mechanism. Furthermore, PSCs having the Gaussian index profile display superior optical properties and performance compared to those of the uniform index counterpart under varying conditions of perovskite layer thicknesses and incident angles. The simulation results in this study provide an effective design scheme to promote optical absorption in PSCs.

Phosphate-Passivated SnO2 Electron Transport Layer for High-Performance Perovskite Solar Cells.

Tin oxide (SnO2) is widely used in perovskite solar cells (PSCs) as an electron transport layer (ETL) material. However, its high surface trap density has already become a strong factor limiting PSC development. In this work, phosphoric acid is adopted to eliminate the SnO2 surface dangling bonds to increase electron collection efficiency. The phosphorus mainly exists at the boundaries in the form of chained phosphate groups, bonding with which more than 47.9% of Sn dangling bonds are eliminated. The reduction of surface trap states depresses the electron transport barriers, thus the electron mobility increases about 3 times when the concentration of phosphoric acid is optimized with 7.4 atom % in the SnO2 precursor. Furthermore, the stability of the perovskite layer deposited on the phosphate-passivated SnO2 (P-SnO2) ETL is gradually improved with an increase of the concentration. Due to the higher electron collection efficiency, the P-SnO2 ETLs can dramatically promote the power conversion efficiency (PCE) of the PSCs. As a result, the champion PSC has a PCE of 21.02%. Therefore, it has been proved that this simple method is efficient to improve the quality of ETL for high-performance PSCs.