106 research outputs found
The Ford Foundation and the National Committee on United States-China Relations: How They Assisted Chinese Economic Reforms during the 1980s
This research report summarizes my research experience at the Rockefeller Archive Center (RAC) in July 2017. I went to RAC to collect records related to the activities organized by the National Committee on United States-China Relations (NCUSCR) and the Ford Foundation to support the People's Republic of China's (PRC) post-1978 economic reforms. I incorporated a significant amount of materials from these records into my PhD dissertation, which analyzes how different American institutions, including non-governmental organizations (NGOs), assisted and encouraged China's economic transition during the 1980s.The documents I found were extremely helpful in my effort to reconstruct and analyze the activities and the exchanges the NCUSCR and the Ford Foundation undertook with China during the 1980s. Furthermore, the records also clarified the motivations behind this assistance, revealing not only a genuine desire on the part of the two organizations to learn more about the PRC's economic outlook but also driven by an interest to disseminate ideas that these NGOs believed were necessary to strengthen a world in which liberalism and democracy would dominate.
A Systematic Review of Few-Shot Learning in Medical Imaging
The lack of annotated medical images limits the performance of deep learning
models, which usually need large-scale labelled datasets. Few-shot learning
techniques can reduce data scarcity issues and enhance medical image analysis,
especially with meta-learning. This systematic review gives a comprehensive
overview of few-shot learning in medical imaging. We searched the literature
systematically and selected 80 relevant articles published from 2018 to 2023.
We clustered the articles based on medical outcomes, such as tumour
segmentation, disease classification, and image registration; anatomical
structure investigated (i.e. heart, lung, etc.); and the meta-learning method
used. For each cluster, we examined the papers' distributions and the results
provided by the state-of-the-art. In addition, we identified a generic pipeline
shared among all the studies. The review shows that few-shot learning can
overcome data scarcity in most outcomes and that meta-learning is a popular
choice to perform few-shot learning because it can adapt to new tasks with few
labelled samples. In addition, following meta-learning, supervised learning and
semi-supervised learning stand out as the predominant techniques employed to
tackle few-shot learning challenges in medical imaging and also best
performing. Lastly, we observed that the primary application areas
predominantly encompass cardiac, pulmonary, and abdominal domains. This
systematic review aims to inspire further research to improve medical image
analysis and patient care.Comment: 48 pages, 29 figures, 10 tables, submitted to Elsevier on 19 Sep 202
Causality-Driven One-Shot Learning for Prostate Cancer Grading from MRI
In this paper, we present a novel method to automatically classify medical
images that learns and leverages weak causal signals in the image. Our
framework consists of a convolutional neural network backbone and a
causality-extractor module that extracts cause-effect relationships between
feature maps that can inform the model on the appearance of a feature in one
place of the image, given the presence of another feature within some other
place of the image. To evaluate the effectiveness of our approach in low-data
scenarios, we train our causality-driven architecture in a One-shot learning
scheme, where we propose a new meta-learning procedure entailing meta-training
and meta-testing tasks that are designed using related classes but at different
levels of granularity. We conduct binary and multi-class classification
experiments on a publicly available dataset of prostate MRI images. To validate
the effectiveness of the proposed causality-driven module, we perform an
ablation study and conduct qualitative assessments using class activation maps
to highlight regions strongly influencing the network's decision-making
process. Our findings show that causal relationships among features play a
crucial role in enhancing the model's ability to discern relevant information
and yielding more reliable and interpretable predictions. This would make it a
promising approach for medical image classification tasks.Comment: 9 pages, 2 figures, accepted on Aug 07 2023 for ICCV-CVAMD 2023 and
to be published in the proceeding
analisi dei processi di interscambio idrico su letti in macroscabrezza
la tesi tratta del processo di filtrazione e della dissipazione energetica che avviene lungo le rampe in pietram
Cine cardiac MRI reconstruction using a convolutional recurrent network with refinement
Cine Magnetic Resonance Imaging (MRI) allows for understanding of the heart's
function and condition in a non-invasive manner. Undersampling of the -space
is employed to reduce the scan duration, thus increasing patient comfort and
reducing the risk of motion artefacts, at the cost of reduced image quality. In
this challenge paper, we investigate the use of a convolutional recurrent
neural network (CRNN) architecture to exploit temporal correlations in
supervised cine cardiac MRI reconstruction. This is combined with a
single-image super-resolution refinement module to improve single coil
reconstruction by 4.4\% in structural similarity and 3.9\% in normalised mean
square error compared to a plain CRNN implementation. We deploy a high-pass
filter to our loss to allow greater emphasis on high-frequency details
which are missing in the original data. The proposed model demonstrates
considerable enhancements compared to the baseline case and holds promising
potential for further improving cardiac MRI reconstruction.Comment: MICCAI STACOM workshop 202
Investigation of genomic DNA methylation by ultraviolet resonant Raman spectroscopy
Cytosine plays a preeminent role in DNA methylation, an epigenetic mechanism that regulates gene expression, the misregulation of which can lead to severe diseases. Several methods are nowadays employed for assessing the global DNA methylation levels, but none of them combines simplicity, high sensitivity, and low operating costs to be translated into clinical applications. Ultraviolet (UV) resonant Raman measurements at excitation wavelengths of 272 nm, 260 nm, 250 nm, and 228 nm have been carried out on isolated deoxynucleoside triphosphates (dNTPs), on a dNTP mixture as well as on genomic DNA (gDNA) samples, commercial from salmon sperm and non-commercial from B16 murine melanoma cell line. The 228 nm excitation wavelength was identified as the most suitable energy for enhancing cytosine signals over the other DNA bases. The UV Raman measurements performed at this excitation wavelength on hyper-methylated and hypo-methylated DNA from Jurkat leukemic T-cell line have revealed significant spectral differences with respect to gDNA isolated from salmon sperm and mouse melanoma B16 cells. This demonstrates how the proper choice of the excitation wavelength, combined with optimized extraction protocols, makes UV Raman spectroscopy a suitable technique for highlighting the chemical modifications undergone by cytosine nucleotides in gDNA upon hyper- and hypo-methylation events
Shedding Plasma Membrane Vesicles Induced by Graphene Oxide Nanoflakes in Brain Cultured Astrocytes
Microvesicles (MVs) generated and released by astrocytes, the brain prevalent cells, crucially contribute to intercellular communication, representing key vectorized systems able to spread and actively transfer signaling molecules from astrocytes to neurons, ultimately modulating target cell functions. The increasing clinical relevance of these signaling systems requires a deeper understanding of MV features, currently limited by both their nanoscale dimensions and the low rate of their constituent release. Hence, to investigate the features of such glial signals, nanotechnology-based approaches and the applications of unconventional, cost-effective tools in generating MVs are needed. Here, small graphene oxide (s-GO) nanoflakes are used to boost MVs shedding from astrocytes in cultures and s-GO generated MVs are compared with those generated by a natural stimulant, namely ATP, by atomic force microscopy, light scattering, attenuated total reflection\u2013fourier transform infra-red and ultraviolet resonance Raman spectroscopy. We also report the ability of both types of MVs, upon acute and transient exposure of patch clamped cultured neurons, to modulate basal synaptic transmission, inducing a stable increase in synaptic activity accompanied by changes in neuronal plasma membrane elastic features
Detention and mapping of iron and toxic environmental elements in human ovarian endometriosis: A suggested combined role
Background: Endometriosis is a disease affecting 10-15 % of women worldwide, consisting in the ectopic growth of endometrial cells outside the uterine cavity. Whist the pathogenetic mechanisms of endometriosis remain elusive and contemplating even environmental causes, iron deposits are common in endometrial lesions, indicating an altered iron metabolism at this level. This study was undertaken to reveal a possible relationship between iron dysmetabolism and accumulation of environmental metals. Methods: By combining histological and histochemical analysis (H&E and Perl's staining) with ÎĽ- and nano- synchrotron-based (SR-based) X-ray Fluorescence (XRF) microscopy, we investigated the distribution of iron and other elements in the ovarian endometriomas of 12 endometriosis patients and in 7 healthy endometrium samples. Results: XRF microscopy expanded the findings obtained by Perl's staining, revealing with an exceptional sensitivity intracellular features of iron accumulation in the epithelial endometrium, stroma and macrophages of the endometriotic lesions. XRF evidenced that iron was specifically accumulated in multiple micro aggregates, reaching concentrations up to 10-20 % p/p. Moreover, by XRF analysis we revealed for the first time the retention of a number of exogenous and potentially toxic metals such as Pb, Br, Ti, Al Cr, Si and Rb partially or totally co-localizing with iron. Conclusion: ÎĽXRF reveals accumulation and colocalization of iron and environmental metals in human ovarian endometriosis, suggesting a role in the pathogenesis of endometriosis
Clinical validation of full HR-HPV genotyping HPV Selfy assay according to the international guidelines for HPV test requirements for cervical cancer screening on clinician-collected and self-collected samples
Background According to international guidelines, Human Papillomavirus (HPV) DNA tests represent a valid alternative to Pap Test for primary cervical cancer screening, provided that they guarantee balanced clinical sensitivity and specificity for cervical intraepithelial neoplasia grade 2 or more (CIN2+) lesions. The study aimed to assess whether HPV Selfy (Ulisse BioMed - Trieste, Italy), a full-genotyping HPV DNA test that detects and differentiates 14 high-risk HPV (HR-HPV) types, meets the criteria for primary cervical cancer screening described in the international guidelines, on clinician-collected as well as on self-collected samples. Methods For each participant woman, consecutively referring to Azienda Sanitaria Universitaria Giuliano Isontina (Trieste, Italy) and CRO-National Cancer Institute (Aviano, Italy) for the cervical cancer screening program, the following samples were tested: (a) a clinician-collected cervical specimen, analyzed with the reference test (Hybrid Capture (R) 2 test, HC2) and HPV Selfy; and (b) a self-collected vaginal sample, analyzed with HPV Selfy. Enrolled women were also asked to fulfill a questionnaire about self-sampling acceptability. As required by guidelines, a non-inferiority test was conducted to compare the clinical performance of the test under evaluation with its reference test. Results HPV Selfy clinical sensitivity and specificity resulted non-inferior to those of HC2. By analysis of a total of 889 cervical liquid-based cytology samples from a screening population, of which 98 were from women with CIN2+, HPV Selfy showed relative sensitivity and specificity for CIN2+ of 0.98 and 1.00 respectively (non-inferiority score test: P = 0.01747 and P = 0.00414, respectively); the test reached adequate intra- and inter-laboratory reproducibility. Moreover, we demonstrated that the performance of HPV Selfy on self-collected vaginal samples was non-inferior to the performance obtained on clinician-collected cervical specimen (0.92 relative sensitivity and 0.97 relative specificity). Finally, through HPV Selfy genotyping, we were able to describe HPV types prevalence in the study population. Conclusions HPV Selfy fulfills all the requirements of the international Meijer's guidelines and has been clinically validated for primary cervical cancer screening purposes. Moreover, HPV Selfy has also been validated for self-sampling according to VALHUDES guidelines. Therefore, at date, HPV Selfy is the only full-genotyping test validated both for screening purposes and for self-sampling. Trial registration ASUGI Trieste n. 16008/2018; CRO Aviano n.17149/201
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