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1 |
Compensating over- and underexposure in optical target pose determination
Compensating over- and underexposure in optical target pose determination-2021 Optical coded targets allow to determine the relative pose of a camera, on a metric scale, from one image only. Furthermore, they are easily and efficiently detected, opening to a wide range of applications in robotics and computer vision. In this work we describe the effect of pixel saturation and non-ideal lens Point Spread Function, causing the apparent position of the corners and the edges of the target to change as a function of the camera exposure time. This effect, which we call exposure bias, is frequent in over- or underexposed images and introduces a systematic error in the estimated camera pose. We propose an algorithm that is able to estimate and correct for the exposure bias exploiting specific geometric features of a common target design based on concentric circles. Through rigorous laboratory experiments carried out in a highly controlled environment, we demonstrate that the proposed algorithm is seven times more precise and three times more accurate in the target distance estimation than the algorithms available in the literature.© 2021 Elsevier Ltd. All rights reserved. Keywords: Optical target | Target orientation | Image processing algorithm | Geometry | Ellipse fitting | Computer vision | Overexposure | Exposure compensation | Resection |
مقاله انگلیسی |
2 |
Pathological high frequency oscillations associate with increased GABA synaptic activity in pediatric epilepsy surgery patients
نوسانات فرکانس پاتولوژیک با افزایش فعالیت سیناپسی GABA در بیماران جراحی صرع کودکان ارتباط دارد-2020 Pathological high-frequency oscillations (HFOs), specifically fast ripples (FRs,>250 Hz), are pathognomonic of
an active epileptogenic zone. However, the origin of FRs remains unknown. Here we explored the correlation
between FRs recorded with intraoperative pre-resection electrocorticography (ECoG) and spontaneous synaptic
activity recorded ex vivo from cortical tissue samples resected for the treatment of pharmacoresistant epilepsy.
The cohort included 47 children (ages 0.22–9.99 yr) with focal cortical dysplasias (CD types I and II), tuberous
sclerosis complex (TSC) and non-CD pathologies. Whole-cell patch clamp recordings were obtained from pyramidal
neurons and interneurons in cortical regions that were positive or negative for pathological HFOs, defined
as FR band oscillations (250–500 Hz) at ECoG. The frequency of spontaneous excitatory and inhibitory
postsynaptic currents (sEPSCs and IPSCs, respectively) was compared between HFO+ and HFO- regions.
Regardless of pathological substrate, regions positive for FRs displayed significantly increased frequencies of
sIPSCs compared with regions negative for FRs. In contrast, the frequency of sEPSCs was similar in both regions.
In about one third of cases (n=17), pacemaker GABA synaptic activity (PGA) was observed. In the vast majority
(n=15), PGA occurred in HFO+ areas. Further, fast-spiking interneurons displayed signs of hyperexcitability
exclusively in HFO+ areas. These results indicate that, in pediatric epilepsy patients, increased GABA synaptic
activity is associated with interictal FRs in the epileptogenic zone and suggest an active role of GABAergic
interneurons in the generation of pathological HFOs. Increased GABA synaptic activity could serve to dampen
excessive excitability of cortical pyramidal neurons in the epileptogenic zone, but it could also promote neuronal
network synchrony. Keywords: Fast ripples | Cortical dysplasia | GABA | Electrophysiology | Slice | Synaptic activity |
مقاله انگلیسی |
3 |
Automatic voice based disease detection method using one dimensional local binary pattern feature extraction network
روش تشخیص بیماری مبتنی بر صدا به صورت خودکار با استفاده از یک ویژگی شبکه استخراج الگوی باینری محلی یک بعدی -2019 Voices have been widely used for disease detection in the literature but these methods are non-invasive.
In this article a 1D local binary pattern (LBP) based feature extraction network (1D-LBPNet) is proposed to
extract stable features from voices. The proposed 1D-LBPNet is inspired by convolutional neural networks
(CNN) for instance AlexNet, GoogleNet, ResNet. Then, a voice based disease recognition method is presented
in this paper. The presented voice based disease recognition method consists of feature extraction
using 1D-LBPNet, feature concatenation, feature reduction using neighborhood component analysis
(NCA) and classification phases. In the feature extraction phase, 1D-LBPNet extracts 256 8 = 2048 features
because it has 7 layers. The extracted features are concatenated in the feature concatenation phase.
To reduce the concatenated features, a NCA based feature reduction method is used. 1 nearest neighbor
(1NN) classifier is utilized as classifier to demonstrate distinctive of the extracted features. To test performance
of the proposed method, Saarbruecken Voice Database (SVD) is used in this article. /a/ vowels of
the Cordectomy and frontolateral resection diseases are chosen to test the proposed 1D-LBPNet based
recognition method. 10 cases are defined using single and concatenated voices for each disease. The
results and comparisons clearly shown that the proposed 1D-LBPNet achieved high success rates and
these results clearly proved success of the proposed method. Keywords: 1D local binary pattern based network | Neighborhood component analysis | Pathological voice detection | Pattern recognition |
مقاله انگلیسی |
4 |
STING Restricts oHSV Replication and Spread in Resistant MPNSTs but Is Dispensable for Basal IFN-Stimulated Gene Upregulation
STING Restricts oHSV Replication and Spread in Resistant MPNSTs but Is Dispensable for Basal IFN-Stimulated Gene Upregulation-2019 Malignant peripheral nerve sheath tumors (MPNSTs) are an
aggressive soft-tissue sarcoma amenable only to surgical resection.
Oncolytic herpes simplex viruses (oHSVs) are a promising
experimental therapy. We previously showed that basal interferon
(IFN) and nuclear factor kB (NFkB) signaling upregulate
IFN-stimulated gene (ISG) expression and restrict efficient viral
infection and cell-to-cell spread in 50% of tested MPNSTs.
Stimulator of Interferon Genes (STING) integratesDNAsensor
activity and mediates downstream IFN signaling in infected
cells. We sought to identify STING’s role in oHSV resistance
and contribution to basal ISG upregulation in MPNSTs. We
show that the level of STINGactivity in humanMPNST cell lines
is predictive of oHSV sensitivity and that resistant cell lines have
intact mechanisms for detection of cytosolic double-stranded
DNA (dsDNA). Furthermore, we show that STING downregulation
renders MPNSTs more permissive to oHSV infection
and cell-to-cell spread. While next-generation viruses can
exploit this loss of STING activity, first-generation viruses
remain restricted. Finally, STING is not integral to the previously-
observed basal ISG upregulation, indicating that other
pathways contribute to basal IFN signaling in resistant
MPNSTs. These data broaden our understanding of the intrinsic
pathways in MPNSTs and their role in oHSV resistance and
offer potential targets to potentiate oncolytic virus activity |
مقاله انگلیسی |
5 |
Comparison of machine learning classifiers for differentiation of grade 1 from higher gradings in meningioma: A multicenter radiomics study
مقایسه طبقه بندی کننده های یادگیری ماشین برای تمایز درجه 1 از درجه های بالاتر در مننژیوما: یک مطالعه رادیومتری چند متری-2019 Background and purpose: Advanced imaging analysis for the prediction of tumor biology and modelling of
clinically relevant parameters using computed imaging features is part of the emerging field of radiomics research.
Here we test the hypothesis that a machine learning approach can distinguish grade 1 from higher
gradings in meningioma patients using radiomics features derived from a heterogenous multicenter dataset of
multi-paramedic MRI.
Methods: A total of 138 patients from 5 international centers that underwent MRI prior to surgical resection of
intracranial meningiomas were included. Segmentation was performed manually on co-registered multi-parametric
MR images using apparent diffusion coefficient (ADC) maps, T1-weighted (T1), post-contrast T1-weighted
(T1c), subtraction maps (Sub, T1c – T1), T2-weighted fluid-attenuated inversion recovery (FLAIR) and T2-
weighted (T2) images. Feature selection was performed and using cross-validation to separate training from
testing data, four machine learning classifiers were scored on combinations of MRI modalities: random forest
(RF), extreme gradient boosting (XGBoost), support vector machine (SVM) and multilayer perceptron (MLP).
Results: The best AUC of 0.97 (1.0 and 0.97 for sensitivity and specificity) was observed for the combination of
ADC, ADC of the peritumoral edema, T1, T1c, Sub and FLAIR-derived features using only 16 of the 10,914
possible features and XGBoost.
Conclusions: Machine learning using radiomics features derived from multi-parametric MRI is capable of high
AUC scores with high sensitivity and specificity in classifying meningiomas between low and higher gradings
despite heterogeneous protocols across different centers. Feature selection can be performed effectively even
when extracting a large amount of data for radiomics fingerprinting Keywords: Random forest | Support vector machine | Multilayer perceptron | XGBoost | Machine learning | Meningioma | Grading | Feature selection |
مقاله انگلیسی |
6 |
Toll-like receptor 3 downregulation is an escape mechanism from apoptosis during hepatocarcinogenesis
Toll-like receptor 3 downregulation is an escape mechanism from apoptosis during hepatocarcinogenesis-2019 Background & Aims: Low levels of toll-like receptor 3 (TLR3) in
patients with hepatocellular carcinoma (HCC) are associated
with poor prognosis, primarily owing to the loss of inflammatory
signaling and subsequent lack of immune cell recruitment
to the liver. Herein, we explore the role of TLR3-triggered apoptosis
in HCC cells.
Methods: Quantitative reverse transcription PCR, western blotting,
immunohistochemistry and comparative genomic
hybridization were used to analyze human and mouse HCC cell
lines, as well as surgically resected primary human HCCs, and to
study the impact of TLR3 expression on patient outcomes. Functional
analyses were performed in HCC cells, following the
restoration of TLR3 by lentiviral transduction. The role of
TLR3-triggered apoptosis in HCC was analyzed in vivo in a transgenic
mouse model of HCC.
Results: Lower expression of TLR3 in tumor compared to nontumor
matched tissue was observed at both mRNA and protein
levels in primary HCC, and was predictive of shorter recurrencefree
survival after surgical resection in both univariate (hazard
ratio [HR] 1.79; 95% CI 1.04–3.06; p = 0.03) and multivariate
analyses (HR 1.73; CI 1.01–2.97; p = 0.04). Immunohistochemistry
confirmed frequent downregulation of TLR3 in human
and mouse primary HCC cells. None of the 6 human HCC cell
lines analyzed expressed TLR3, and ectopic expression of TLR3
following lentiviral transduction not only restored the inflammatory
response but also sensitized cells to TLR3-triggered
apoptosis. Lastly, in the transgenic mouse model of HCC,
absence of TLR3 expression was accompanied by a lower rate
of preneoplastic hepatocyte apoptosis and accelerated hepatocarcinogenesis
without altering the tumor immune infiltrate.
Conclusion: Downregulation of TLR3 protects transforming
hepatocytes from direct TLR3-triggered apoptosis, thereby contributing
to hepatocarcinogenesis and poor patient outcome.
Lay summary: Hepatocellular carcinoma (HCC) is a heterogeneous
disease associated with a poor prognosis. In patients with
HCC, TLR3 downregulation is associated with reduced survival.
Herein, we show that the absence of TLR3 is associated with a
lower rate of apoptosis, and subsequently more rapid hepatocarcinogenesis,
without any change to the immune infiltrate
in the liver. Therefore, the poor prognosis associated with low
TLR3 expression in HCC is likely linked to tumors ability to
escape apoptosis. TLR3 may become a promising therapeutic
target in TLR3-positive HCC. |
مقاله انگلیسی |
7 |
Retro-peritoneal paraganglioma, diagnosis and management
paraganglioma یکپارچه صفاقی، تشخیص و مدیریت-2018 Introduction. — Paragangliomas, defined as extra-adrenal chromaffin-cells tumors, are rarely
located in the retro-peritoneum. Clinical presentation is similar to pheochromocytoma, and
mainly depends on the producing character of the tumor. Positive diagnosis requires plasmatic
and urinary hormonal assays. Radiological and isotopic explorations are essential before surgery.
The only curative therapeutic strategy is surgical, associated to peri-operative prevention and
monitoring of the frequently reported hemodynamic and cardiovascular disorders. Outcome
depends of the metastatic character of the tumor, the presence of tumor remnant after surgi
cal resection. Genetic study is recommended; the risk of recurrence and association to other
neoplasm is more described in genetic forms.
Material and methods. — Authors report 5 cases of retro-peritoneal paraganglioma, operated
in the department of urology of Hospital, between 2013 and 2017. Observations are about
2 men and 3 women. Clinical presentation is not always specific and paraganglioma may be
discovered fortuitously. Two patients have been operated by coelioscopic approach, midline
incision was performed in two other cases, and dorsal lumbotomy associated to a Rutherford
Morrison incision in a patient.
KEYWORDS : Paraganglioma ; Retroperitoneal neoplasms ; Anesthesia ; Surgery |
مقاله انگلیسی |
8 |
Using the National Cancer Database to Create a Scoring System that Identifies Patients with Early-Stage Esophageal Cancer at Risk for Nodal Metastases
استفاده از پایگاه داده های ملی سرطان برای ایجاد یک سیستم امتیاز دهی شناسایی بیماران مبتلا به مراحل اولیه سرطان مری در معرض خطر گره متاستاز-2017 Objectives
Endoscopic resection is gaining popularity as a treatment for early-stage esophageal adenocarcinoma, particularly for T1a tumors. The goal of this study was to create a scoring system to reflect the risk of nodal metastases in early-stage esophageal adenocarcinoma to be used after endoscopic resection to better individualize treatment. Methods The National Cancer Database was queried for patients with T1a or T1b esophageal adenocarcinoma who underwent esophagectomy. We identified variables affecting nodal metastases using multivariable logistic regression, which we then used to create a scoring system. We stratified the model for T1a or T1b tumors, tested model discrimination, and validated the models by refitting in 1000 bootstrap samples. C-statistics greater than 0.7 were considered relevant. Results We identified 1283 patients with T1a or T1b tumors; 146 had nodal metastases (11.4%). Tumor category (pT1a vs pT1b), grade, and size and the presence of angiolymphatic invasion significantly affected the risk of nodal metastases. We assigned points to each variable and added them to get a risk score. In patients with T1a tumors, less than 3% of patients with a risk score of 3 or less had nodal metastases, whereas 16.1% of patients with a risk score of 5 or greater had nodal metastases. In patients with T1b tumors, less than 5% of patients with a risk score of 2 or less had nodal metastases, whereas 41% of patients with a score of 6 or greater had nodal metastases (c-statistic = 0.805). Conclusions The proposed scoring system seems to be useful in discriminating risk of nodal metastases in patients with T1a or T1b esophageal adenocarcinoma and may be useful in directing patients who received endoscopic resection to esophagectomy or careful follow-up. KeyWords: esophageal cancer | early stage | esophagectomy | endoscopic therapy | nodal metastases |
مقاله انگلیسی |
9 |
Improved survival with postoperative radiotherapy in thymic carcinoma: A propensity-matched analysis of Surveillance, Epidemiology, and End Results (SEER) database
بقای بهبود یافته با رادیوتراپی پس از عمل در کارسینوم ایممی: یک تجزیه و تحلیل وابسته به تماسی از پایگاه داده های نظارت، اپیدمیولوژی و پایان (SEER)-2017 Objectives: Thymic carcinoma is a rare and aggressive malignancy with poor prognosis. Although post
operative radiotherapy (PORT) is used for obtaining better locoregional tumor control, its association
with survival has not been established. This study evaluated the prognostic impact of PORT in thymic
carcinoma.
Materials and methods: We identified patients diagnosed with thymic carcinoma between 2004 and 2013
using the Surveillance, Epidemiology, and End Results (SEER) database. Propensity score matching with
Kaplan-Meier and Cox-regression analyses were used to assess prognosis.
Results: In the unmatched population (n = 312), 184 (59%) patients underwent PORT. The 5-year overall
survival rates were better with receipt of PORT, both before and after matching (P = 0.012 and 0.007,
respectively). After adjusting for related covariates (n = 256), age ≥63 years (P = 0.023), Masaoka stage
III (P = 0.028) and IV (P < 0.001), debulking surgery (P = 0.021), and no receipt of PORT (P = 0.013) were
independently poor prognostic factors. In subgroup analyses, favorable survival impacts of PORT were
observed for Masaoka stage III tumors (hazard ratio [HR] 0.31, 95% confidence interval [CI] 0.15–0.66),
tumors sized >6.0 cm (HR 0.48, 95% CI 0.26–0.89), node-negative status (HR 0.58, 95% CI 0.33–1.00), and
surgical extent of local excision or partial removal (HR 0.44, 95% CI 0.22–0.86).
Conclusion: On SEER analysis, survival benefits of PORT in thymic carcinoma were demonstrated. With
strong prognostic associations of Masaoka stage and types of surgery, PORT should be considered for
non-metastatic locally advanced tumors with limited surgical resection.
Keywords: Thymiccarcinoma | SEER program | Propensity score matching | Postoperative radiotherapy | Overall survival |
مقاله انگلیسی |
10 |
Management of glioblastoma in elderly patients
مدیریت گلیوبلاستوما در بیماران مسن-2017 Glioblastoma (GBM) is the most common primary malignant brain tumor in adults over
55 years of age. The median age of diagnosis for patients with GBM is 64 years old, with
the incidence of patients between 75 and 85 increasing. The optimal treatment paradigm
for elderly GBM patients continues to evolve due to the higher frequency of age-related
and/or medical co-morbidities. Geriatric GBM patients have historically been excluded
from larger, controlled clinical trials due to their presumed decreased likelihood of a
sustained treatment response and/or a prolonged good outcome. Here, we highlight
current treatment considerations of elderly GBM patients with respect to surgical,
radiological and systemic modalities, with considerations for improving future clinical
outcomes for this patient population.
Keywords: Glioblastoma | High-grade glioma | Elderly | Surgical resection | Chemotherapy | Radiation therapy |
مقاله انگلیسی |