839 research outputs found
Enhanced light harvesting in bulk heterojunction photovoltaic devices with shape-controlled Ag nanomaterials: Ag nanoparticles versus Ag nanoplates
Enhanced power conversion efficiency (PCE(%)) with improved optical path length from two types of shape controlled silver (Ag) materials (Ag nanoplates versus Ag nanoparticles (NPs)) was studied in poly(3-hexylthiophene) (P3HT)/[6,6]-phenyl C 71 butyric acid methyl-ester (PC 71BM) or poly[N-9′′-hepta-decanyl-2,7-carbazole-alt-5,5-(4′, 7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT)/[6,6]-phenyl C 71 butyric acid methyl-ester (PC 71BM) bulk heterojunction (BHJ) devices. The Ag nanoplates and Ag NPs can be synthesized by simple solution polyol chemistry with well defined size and shape. A BHJ with a 0.5 wt% optimized blend ratio of Ag nanoplates shows improved cell performance and photo-current density than a BHJ with Ag NPs owing to the enhanced light absorption with the results of an excitation of localized surface plasmon and efficient light scattering by the Ag nanoplates embedded BHJ film. When the BHJ is combined with the Ag nanoplates at an optimized ratio of 0.5 wt%, the PCE (%) increases from 3.2% to 4.4% in P3HT/PC 71BM, and from 5.9% to 6.6% in PCDTBT/PC 71BM BHJ devices. © 2012 The Royal Society of Chemistry.1
An efficient method for detection of key objects in video shots with camera motions
The most fundamental task in video processing is to partition long video sequences into a number of shots and find a key frame of each shot for indexing and browsing.keywords: Video object segmentacion, shot boundary detection, color quantization, MPEG-4/MPEG-7
Maxillary Sinus Retention Cysts Protruding Into the Inferior Meatus
Although most of the maxillary sinus retention cysts are asymptomatic, a few of them increase in size and cause symptoms. However, they rarely erode bony walls nor protrude into the inferior meatus. I present 2 cases with maxillary sinus retention cysts protruding into the inferior meatus by making a large defect on the medial wall of the maxillary sinus
A Neural Pre-Conditioning Active Learning Algorithm to Reduce Label Complexity
Deep learning (DL) algorithms rely on massive amounts of labeled data.
Semi-supervised learning (SSL) and active learning (AL) aim to reduce this
label complexity by leveraging unlabeled data or carefully acquiring labels,
respectively. In this work, we primarily focus on designing an AL algorithm but
first argue for a change in how AL algorithms should be evaluated. Although
unlabeled data is readily available in pool-based AL, AL algorithms are usually
evaluated by measuring the increase in supervised learning (SL) performance at
consecutive acquisition steps. Because this measures performance gains from
both newly acquired instances and newly acquired labels, we propose to instead
evaluate the label efficiency of AL algorithms by measuring the increase in SSL
performance at consecutive acquisition steps. After surveying tools that can be
used to this end, we propose our neural pre-conditioning (NPC) algorithm
inspired by a Neural Tangent Kernel (NTK) analysis. Our algorithm incorporates
the classifier's uncertainty on unlabeled data and penalizes redundant samples
within candidate batches to efficiently acquire a diverse set of informative
labels. Furthermore, we prove that NPC improves downstream training in the
large-width regime in a manner previously observed to correlate with
generalization. Comparisons with other AL algorithms show that a
state-of-the-art SSL algorithm coupled with NPC can achieve high performance
using very few labeled data.Comment: NeurIPS 202
Correlation of hypoxia inducible transcription factor in breast cancer and SUVmax of F-18 FDG PET/CT
BACKGROUND: Tumor hypoxia induces the expression of several genes via the hypoxia-inducible transcription factor-1 alpha (HIF-1a). It is associated with the prognosis of several cancers. We studied the immunohistochemical expression of HIF-1a in patients with invasive ductal cancer (IDC) of the breast and the possible correlation with the maximum standardized uptake value of the primary tumor (pSUVmax) as well as other biological parameters. Prognostic significance of pSUVmax and expression of HIF-1a for the prediction of progression-free survival (PFS) was also assessed.
MATERIAL AND METHODS: Two-hundred seven female patients with IDC who underwent pretreatment fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) were enrolled. The pSUVmax was compared with clinicopathological parameters including estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), axillary lymph node (LN) metastasis, stage and HIF-1a expression. The prognostic value of pSUVmax for PFS was assessed using the Kaplan-Meier method.
RESULTS: pSUVmax was significantly higher in patients with HIF-1a expression ≥ 2 compared to patients with HIF-1a expression < 2 (5.2 ± 4.5 vs. 3.7 ± 3.1, p = 0.008). pSUVmax was also significantly higher in higher stage (p < 0.000001), ER-negative tumors (p < 0.0001), PR-negative tumors (p = 0.0011) and positive LN metastasis (p = 0.0013). pSUVmax was significantly higher in patients with progression compared to patients who were disease-free (6.8 ± 4.4 vs. 4.1 ± 3.7, p = 0.0005). A receiver-operating characteristic curve demonstrated a pSUVmax of 6.51 to be the optimal cutoff for predicting PFS (sensitivity: 53.6%, specificity: 86.0%). Patients with high pSUVmax (> 6.5) had significantly shorter PFS compared to patients with low pSUVmax (p < 0.0001).
CONCLUSIONS: pSUVmax on pretreatment F-18 FDG PET/ CT reflect expression of HIF-1a and can be used as a good surrogate marker for the prediction of progression in patients with IDC. The amount of FDG uptake is determined by the presence of glucose metabolism and hypoxia in breast cancer cell
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