We investigated the impact of defect states on the measured forward current-voltage (<inline-formula> <tex-math notation="LaTeX">{I} </tex-math></inline-formula>-<inline-formula> <tex-math ...notation="LaTeX">{V} </tex-math></inline-formula>) curves of ion-implanted planar 4H-SiC p-i-n diodes of a different anode dimension by means of a fine-tuned numerical model. Cross sections and activation energies of defects related to the carbon vacancy (EH 6/7 and Z 1/2 ) and Titanium (Ti) impurity used in our model were experimentally identified in the diodes of the same batch. We analyzed the effect of each individual defect on the I-V curves and estimated the unknown hole capture cross sections by ensuring the optimal match between simulated and measured currents. Small discrepancies between measured and simulated forward current-voltage curves of diodes of equal shape but a different perimeter-to-area ratio has been accounted for by considering, in the simulations, the presence of a fixed positive charge at the diode surface. By using this procedure, diodes of every dimension have been simulated without the use of adjustment parameters. These results are valuable in understanding the role of defects in the I-V curves of the ion-implanted SiC diode.
In this study we perform an extensive campaign of numerical simulations of thin-film solar cell structures aimed at investigating how the conduction band offsets at buffer/window (ΔBW) and ...buffer/absorber (ΔAB) heterojunctions and the thickness and doping of the buffer layer combine to affect the performance parameters (Jsc, Voc, FF and η). For the two scenarios of ideal (i.e., without traps) and non-ideal (with traps) buffer/absorber interface, we vary ΔAB and ΔBW in the range −0.5eV to 0.5eV, and analyze, for each combination, the physical mechanisms limiting the cell performance and the way to optimize it by choosing optimal buffer doping and thickness. We show that assuming ΔAB as the main indicator for the potential performance of a cell can be misleading because ΔBW can heavily influence performance, even when ΔAB is positive (conduction band higher in the buffer than in the absorber) and near to its theoretical optimal value (0.3eV). However, we also show that ΔAB<0 (conduction band lower in the buffer than in the absorber) is usually coupled with an efficiency loss that is even worse if ΔBW>0. We verify our findings by simulating several examples of CIGS-based solar cells with different buffer layers (CdS, Zn1−xMgxO, In2S3, Zn(O,S)) taken from the literature; these comparisons confirm the validity of our results and suggest that the combination of ΔAB and ΔBW is the predominant factor in the design of high-efficiency solar cells. We finally propose simple quantitative guidelines for thin-film solar cell design and optimization.
•We simulate thin-film solar cells with a window/buffer/absorber structure.•We study the effect of conduction band offsets (CBOs) on performance.•The buffer/absorber CBO is not the sole parameter impacting on performance.•The window/buffer CBO is shown to play a major role.•When applied to published experimental data our model shows a good match.
Despite many years of research efforts, lung cancer still remains the leading cause of cancer deaths worldwide. Objective of this study was to set up a platform of non-small cell lung cancer patient ...derived xenografts (PDXs) faithfully representing primary tumour characteristics and offering a unique tool for studying effectiveness of therapies at a preclinical level. We established 38 PDXs with a successful take rate of 39.2%. All models closely mirrored parental tumour characteristics although a selective pressure for solid patterns, vimentin expression and EMT was observed in several models. An increased grafting rate for tumours derived from patients with worse outcome (p = 0.006), higher stage (p = 0.038) and higher CD133
/CXCR4
/EpCAM
stem cell content (p = 0.019) was observed whereas a trend towards an association with SUV
higher than 8 (p = 0.084) was detected. Kaplan Meier analyses showed a significantly worse (p = 0.0008) overall survival at 5 years in patients with grafted vs not grafted PDXs also after adjusting for tumour stage. Moreover, for 63.2% models, grafting was reached before clinical recurrence occurred. Our findings strengthen the relevance of PDXs as useful preclinical models closely reflecting parental patients tumours and highlight PDXs establishment as a functional testing of lung cancer aggressiveness and personalized therapies.
The identification of lung tumor-initiating cells and associated markers may be useful for optimization of therapeutic approaches and for predictive and prognostic information in lung cancer ...patients. CD133, a surface glycoprotein linked to organ-specific stem cells, was described as a marker of cancer-initiating cells in different tumor types. Here, we report that a CD133⁺, epithelial-specific antigen-positive (CD133⁺ESA⁺) population is increased in primary nonsmall cell lung cancer (NSCLC) compared with normal lung tissue and has higher tumorigenic potential in SCID mice and expression of genes involved in stemness, adhesion, motility, and drug efflux than the CD133⁻ counterpart. Cisplatin treatment of lung cancer cells in vitro resulted in enrichment of CD133⁺ fraction both after acute cytotoxic exposure and in cells with stable cisplatin-resistant phenotype. Subpopulations of CD133⁺ABCG2⁺ and CD133⁺CXCR4⁺ cells were spared by in vivo cisplatin treatment of lung tumor xenografts established from primary tumors. A tendency toward shorter progression-free survival was observed in CD133⁺ NSCLC patients treated with platinum-containing regimens. Our results indicate that chemoresistant populations with highly tumorigenic and stem-like features are present in lung tumors. The molecular features of these cells may provide the rationale for more specific therapeutic targeting and the definition of predictive factors in clinical management of this lethal disease.
Using numerical simulations, we investigate the effect of a deep donor known to exist at E V + 1.33 eV, as a contribution to explain the large V OC deficit of Ga-rich absorbers.. We find that uniform ...GGI absorbers with GGI > 0.5 suffer for the presence of this deep donor, with the V OC deficit linearly increasing with GGI. On the other hand, simulations indicate that this deep donor is unlikely to be a significant performance limiter in double-graded cells.
We carry out numerical 3D simulations of CIGS cells with back-side Al 2 O 3 passivation and point contact openings in the presence of grain boundaries in the absorber. We consider CIGS cells with ...different absorber thickness, from 0.35 to 3\ \mu \mathrm{m} . For thinner absorbers ( 1\ \mu \mathrm{m} or less) we observe that GBs terminating on the Al 2 O 3 are completely or almost completely passivated, while the effectiveness of the passivation decreases for thicker absorbers. GBs terminating on the point contact, instead, significantly lower the efficiency, regardless of absorber thickness. The presence of grain boundaries and the dimension of grains should therefore be taken into consideration when optimizing the back-side point contact array geometry.
Background
Sentinel lymph node (SLN) biopsy is considered the standard of care in early-stage endometrial cancer (EC). For SLN failure, a side-specific lymphadenectomy is recommended. Nevertheless, ...most hemipelvises show no nodal involvement. The authors previously published a predictive score of lymphovascular involvement in EC. In case of a negative score (value 3–4), the risk of nodal metastases was extremely low. This multicenter study aimed to analyze a predictive score of nodal involvement in EC patients.
Methods
The study enrolled patients with EC who had received comprehensive surgical staging with nodal assessment. A preoperative predictive score of nodal involvement was calculated for all the patients before surgery. The score included myometrial infiltration, tumor grading (G), tumor diameter, and Ca125 assessment. The STARD (standards for Reporting Diagnostic accuracy studies) guidelines were followed for score accuracy.
Results
The study analyzed 1038 patients and detected 155 (14.9%) nodal metastases. The score was negative (3 or 4) for 475 patients and positive (5–7) for 563 of these patients. The score had a sensitivity of 83.2%, a specificity of 50.8%, a negative predictive value of 94.5%, and a diagnostic value of 55.7%. The area under the curve was 0.75. The logistic regression showed a significant correlation between a negative score and absence of nodal metastasis (odds ration OR, 5.133, 95% confidence interval CI, 3.30–7.98;
p
< 0.001).
Conclusion
The proposed predictive score is a useful test to identify patients at low risk of nodal involvement. In case of SLN failure, the application of the current score in the SLN algorithm could allow avoidance of unnecessary lymphadenectomies.
Optical fiber-based biosensors are an emerging field of research with an extremely broad area of possible applications and a disruptive potential to turn the paradigm known as lab-on-fiber into ...reality. In the past few years, a variety of system choices has been explored, ranging from the type of sensing fiber, to the optical transducing element, to possible sensing amplification strategies. We revise some of the possible approaches to the design of a biosensor, highlighting their advantages and disadvantages, based on previous literature and on the experience of our research groups. The discussion is focused onto DNA sensing systems, especially in a label-free format, where the hybridization and recognition of the sought DNA sequence is translated directly into a modification of the optical fiber properties.
Zn(II) coordination polymers are being increasingly studied for their stability and properties. Similarly, there is a growing interest in imidazo1,5-
pyridine derivatives, which show great potential ...in luminescence and pharmaceutical applications. In this work, we successfully synthesized and crystallized three new coordination polymers, using Zn(II) as the metallic node, dicarboxylic acids of different length and nature as linkers, and a linear ditopic imidazo1,5-
pyridine derivative, to explore the role of this molecule as a propagator of the dimensionality of the structure or as an ancillary ligand. Our work demonstrates the structural capability of imidazo1,5-
pyridines in an unexplored domain for this family of ligands. Notably, we observed a pronounced ability of this heterocyclic scaffold to establish π···π interactions in the solid state. The supramolecular π-stacked assemblies were theoretically analyzed using DFT calculations based on model structures.
Colorectal cancer (CRC) screening programs help diagnose cancer precursors and early cancers and help reduce CRC mortality. However, currently recommended tests, the fecal immunochemical test (FIT) ...and colonoscopy, have low uptake. There is therefore a pressing need for screening strategies that are minimally invasive and consequently more acceptable to patients, most likely blood based, to increase early CRC identification. MicroRNAs (miRNAs) released from cancer cells are detectable in plasma in a remarkably stable form, making them ideal cancer biomarkers. Using plasma samples from FIT‐positive (FIT+) subjects in an Italian CRC screening program, we aimed to identify plasma circulating miRNAs that detect early CRC. miRNAs were initially investigated by quantitative real‐time PCR in plasma from 60 FIT+ subjects undergoing colonoscopy at Fondazione IRCCS Istituto Nazionale dei Tumori, then tested on an internal validation cohort (IVC, 201 cases) and finally in a large multicenter prospective series (external validation cohort EVC, 1121 cases). For each endoscopic lesion (low‐grade adenoma LgA, high‐grade adenoma HgA, cancer lesion CL), specific signatures were identified in the IVC and confirmed on the EVC. A two‐miRNA‐based signature for CL and six‐miRNA signatures for LgA and HgA were selected. In a multivariate analysis including sex and age at blood collection, the areas under the receiver operating characteristic curve (95% confidence interval) of the signatures were 0.644 (0.607–0.682), 0.670 (0.626–0.714) and 0.682 (0.580–0.785) for LgA, HgA and CL, respectively. A miRNA‐based test could be introduced into the FIT+ workflow of CRC screening programs so as to schedule colonoscopies only for subjects likely to benefit most.
What's new?
Colon cancer screening currently focusses on stool samples, but precancerous adenomas are not reliably recognized by occult blood‐based or immunochemical tests. Here the authors identify three plasma circulating miRNA‐based signatures that can detect among the individuals positive for the fecal immunochemical test those with precancerous and cancerous lesions. They propose that a blood test based on these signatures could be an additional analysis in individuals with positive fecal test to limit the number of colonoscopies to those likely to benefit most.
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