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1.
Chem Commun (Camb) ; 60(35): 4707-4710, 2024 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-38596875

RESUMEN

Bulk degradation processes are examined in the LiNiO2 cathode using high resolution solid-state NMR, combined with magnetometry and X-ray diffraction. Capacity decay is correlated with bulk heterogeneity, whereby multiple structural domains coexist in the charged state, and the Li content and electrochemical activity of these domains is unraveled for the first time.

2.
ESMO Open ; 9(2): 102243, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38394984

RESUMEN

BACKGROUND: Following the development of gender medicine in the past 20 years, more recently in the field of oncology an increasing amount of evidence suggests gender differences in the epidemiology of cancers, as well as in the response and toxicity associated with therapies. In a gender approach, critical issues related to sexual and gender minority (SGM) populations must also be considered. MATERIALS AND METHODS: A working group of opinion leaders approved by the Italian Association of Medical Oncology (AIOM) has been set up with the aim of drafting a shared document on gender oncology. Through the 'consensus conference' method of the RAND/University of California Los Angeles (UCLA) variant, the members of the group evaluated statements partly from the scientific literature and partly produced by the experts themselves [good practice points (GPPs)], on the following topics: (i) Healthcare organisation, (ii) Therapy, (iii) Host factors, (iv) Cancer biology, and (v) Communication and social interventions. Finally, in support of each specific topic, they considered it appropriate to present some successful case studies. RESULTS: A total of 42 articles met the inclusion criteria, from which 50 recommendations were extracted. Panel participants were given the opportunity to propose additional evidence from studies not included in the research results, from which 32 statements were extracted, and to make recommendations not derived from literature such as GPPs, four of which have been developed. After an evaluation of relevance by the panel, it was found that 81 recommendations scored >7, while 3 scored between 4 and 6.9, and 2 scored below 4. CONCLUSIONS: This consensus and the document compiled thereafter represent an attempt to evaluate the available scientific evidence on the theme of gender oncology and to suggest standard criteria both for scientific research and for the care of patients in clinical practice that should take gender into account.


Asunto(s)
Oncología Médica , Neoplasias , Humanos , Neoplasias/epidemiología , Neoplasias/terapia , Italia/epidemiología
3.
Clin Ter ; 174(3): 245-248, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37199358

RESUMEN

Background: Osteoarthritis (OA) is a common disease in the elderly people, inducing pain and functional limitations. Clodronate (CLO) a first generation non-nitrogen containing bisphosphonate has been purposed as a treatment of OA, being effective on pain, inflammation, bone marrow oedema, osteophytosis and cartilage regeneration. Intra-muscular routes of CLO showed efficacy in the treatment of Knee OA (KOA) and erosive OA of the hand. In KOA intraarticular CLO at low doses (0.5-2 mg) showed efficacy as well as hyaluronic acid (HA), being able to improve the effectiveness if associated to HA. Methods: Nine Consecutive patients (4 female, 5 male, mean age 78,22) with KOA at 2nd or 3rd degree following Kellgren-Lawrance scale, non responder to HA and unintended to surgery. They were treated with intraarticular CLO at the weekly dose of 20 mg, plus lidocaine 1% in 5 cc of saline solution for a route of 5 weekly infil-trations, followed by a second route of 5 intraarticular infiltrations 3 months after the first course. Visual analog score (VAS) pain and Tegner-Lysholm Score (TLS) were used to assess changes following CLO treatment. Results: Baseline pain was 6,77/10, reduced to 1,09 at day 150 (after second course) and to 2,3/10 at day 240. TLS at baseline was 56,7/100, improved to 96,7 at day 150 and to 84,1 at day 240. At day 240 only 2 out of 9 patients had a negative judgement of the treatment and decided to stop it, while 7 were satisfied and available to a further course. There was no increase of consumption of anti-inflammatory or analgesic drugs. A short time lasting pain after the injections was registered in all patients. Conclusions: In a small cohort of patients affected by KOA, non responders to intraarticular HA a higher dose of intraarticular CLO in KOA showed good compliance, amelioration of pain and functionality.


Asunto(s)
Osteoartritis de la Rodilla , Humanos , Masculino , Femenino , Anciano , Osteoartritis de la Rodilla/complicaciones , Osteoartritis de la Rodilla/tratamiento farmacológico , Ácido Hialurónico/uso terapéutico , Ácido Hialurónico/efectos adversos , Ácido Clodrónico/uso terapéutico , Estudios de Seguimiento , Resultado del Tratamiento , Dolor/inducido químicamente , Dolor/tratamiento farmacológico
4.
G Chir ; 33(11-12): 387-91, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-23140922

RESUMEN

Fine needle aspiration cytology (FNAC) is the more accurate diagnostic method for cervical lymph node (CLN) metastasis from differentiated thyroid cancers (DTC). However, FNAC diagnosis of cystic CLN is, in most cases, uninformative due to inadequate cellularity. Recently, thyroglobulin (Tg) detection in FNAC needle washout fluid has been shown to improve the diagnostic accuracy of FNAC, and its routine association with cytology is recommended. We here describe the case of a 20 yr old girl complaining of the recent appearance of palpable non-painful laterocervical nodes in the neck. Ultrasound examination revealed the presence of 3 cystic CLNs and 2 mixed thyroid nodules, with the larger one showing irregular margins. On the latter, and on 2 larger CLNs, FNAC was performed, and both Tg protein and mRNA were determined in the needle washout. The cytological analysis was not diagnostic for the two CLNs, while that of the thyroid nodule reported the presence of colloid and groups of thyrocytes with normal morphology. Both CLNs showed, however, high levels of Tg protein and were positive for Tg mRNA, suggestive of metastatic DTC. Based on these findings, the FNAC analysis was performed on the second smaller thyroid nodule suggesting (Tir4) the presence of PTC. The patient was then subjected to total thyroidectomy with lymph nodes resection of the central and homolateral compartments. The histological diagnosis confirmed the presence of a PTC in the small nodule and metastatic lymph nodes. In conclusion, this case confirms that the cytological diagnosis of cystic lymph nodes is challenging, and that the measurement of Tg protein and/or mRNA in the needle washout may overcome this limitation.


Asunto(s)
Biopsia con Aguja Fina , Carcinoma Papilar/química , Carcinoma Papilar/diagnóstico , Cuello/patología , Tiroglobulina/análisis , Neoplasias de la Tiroides/química , Neoplasias de la Tiroides/diagnóstico , Adulto , Biomarcadores/análisis , Carcinoma Papilar/secundario , Carcinoma Papilar/cirugía , Femenino , Estudios de Seguimiento , Humanos , Escisión del Ganglio Linfático , Cuello/cirugía , Estadificación de Neoplasias , Valor Predictivo de las Pruebas , Sensibilidad y Especificidad , Neoplasias de la Tiroides/secundario , Neoplasias de la Tiroides/cirugía , Tiroidectomía , Resultado del Tratamiento , Ultrasonografía Intervencional
5.
Breast Cancer Res Treat ; 130(2): 465-75, 2011 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-21308409

RESUMEN

Triple negative breast cancer (TNBC) patients are not likely to benefit from anti-estrogen or anti-HER2 therapy and this phenotype is associated with a more aggressive clinical course and worse clinical outcome. Taking into account the limited treatment possibilities in TNBC, the aim of the present work was to study a potential therapy based on Cetuximab-mediated immune activity by natural killer (NK) cells. We performed in vitro studies on human breast cancer (BC) cell lines, IIB-BR-G, and the in vivo metastatic variant IIB-BR-G MT. The immunohistochemical analysis showed a TNBC phenotype with high but different levels of EGFR expression on each cell line, measured by flow cytometry. DNA sequencing showed that both cell lines have a mutated K-RAS status, 38 G > A at codon 13. Consequently, Cetuximab did not inhibit cellular proliferation or induce apoptosis. We investigated if Cetuximab could trigger immune mechanisms, and we determined that both cell lines treated with 1 µg/ml Cetuximab were susceptible to antibody dependent cellular cytotoxicity (ADCC), mediated by peripheral blood mononuclear cells (PBMC). At 50:1 effector:target ratio, lytic activity was 34 ± 2% against IIB-BR-G and 27 ± 6% against IIB-BR-G MT cells. PBMC pretreatment with IL-2 allowed reaching 65 ± 3% of Cetuximab-mediated ADCC against IIB-BR-G and 63 ± 6.5% against IIB-BR-G MT. Furthermore, IL-15 pretreatment increased the ADCC up to 71 ± 3% in IIB-BR-G and 79 ± 3.5% in IIB-BR-G MT. We suggest that NK cells are the effectors present in PBMC since they were able to induce ADCC at lower effector:target ratios. Besides, IL-2- and mainly IL-15-induced upregulation of NK activating receptors CD16 and NKG2D and enhanced IFN-γ production. EGFR-expressing TNBC could be killed by Cetuximab-mediated ADCC at clinically achievable concentrations. IL-15 could advantageously replace IL-2 in most of its immunologic activities, stimulating the ability to produce IFN-γ, and paralleling the up-regulation of activating receptors.


Asunto(s)
Anticuerpos Monoclonales/farmacología , Antineoplásicos/farmacología , Receptores ErbB/metabolismo , Interleucina-15/farmacología , Interleucina-2/farmacología , Anticuerpos Monoclonales Humanizados , Apoptosis/efectos de los fármacos , Secuencia de Bases , Neoplasias de la Mama , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Cetuximab , Técnicas de Cocultivo , Análisis Mutacional de ADN , Femenino , Proteínas Ligadas a GPI/genética , Proteínas Ligadas a GPI/metabolismo , Humanos , Interferón gamma/metabolismo , Interleucina-15/fisiología , Interleucina-2/fisiología , Células Asesinas Naturales/efectos de los fármacos , Células Asesinas Naturales/metabolismo , Subfamilia K de Receptores Similares a Lectina de Células NK/genética , Subfamilia K de Receptores Similares a Lectina de Células NK/metabolismo , Mutación Puntual , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas p21(ras) , Receptor ErbB-2/metabolismo , Receptores de Estrógenos/metabolismo , Receptores de IgG/genética , Receptores de IgG/metabolismo , Receptores de Progesterona/metabolismo , Regulación hacia Arriba/efectos de los fármacos , Proteínas ras/genética
6.
Cytogenet Genome Res ; 132(4): 304-8, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21212648

RESUMEN

Chronic myeloid leukemia (CML) is a clonal malignant disorder of a pluripotent hematopoietic stem cell characterized by the presence of a Philadelphia (Ph) chromosome. Less than 10% of patients present variant Ph chromosomes involving 1 or more additional chromosomes, other than chromosomes 9 and 22, with uncertain prognosis. There are mainly 1- or 2-step mechanisms proposed to explain the genesis of variant Ph chromosomes depending on whether the involved chromosomes are simultaneously broken and rejoined or if a standard t(9;22) occurs first. By combined standard cytogenetic and FISH analysis we detected a novel variant Ph translocation among chromosomes 9, 11 and 22 in a patient with CML without progression to an accelerated phase of the disease after 7 years, with the derivative chromosome 9 also having an acquired pericentric inversion. This novel case illustrates the use of FISH in metaphase to confirm a new rearrangement not previously described in variant Ph formation and that the present karyotype could have originated by a 1-step mechanism with 4 simultaneous breakages without deletion of ABL1.


Asunto(s)
Inversión Cromosómica/genética , Cromosomas Humanos Par 11/genética , Cromosomas Humanos Par 22/genética , Cromosomas Humanos Par 9/genética , Leucemia Mielógena Crónica BCR-ABL Positiva/genética , Translocación Genética/genética , Anciano , Antineoplásicos/uso terapéutico , Benzamidas , Bandeo Cromosómico , Dasatinib , Femenino , Humanos , Hidroxiurea/uso terapéutico , Mesilato de Imatinib , Hibridación Fluorescente in Situ , Interferón gamma/uso terapéutico , Cariotipificación , Leucemia Mielógena Crónica BCR-ABL Positiva/tratamiento farmacológico , Metafase , Cromosoma Filadelfia , Piperazinas/uso terapéutico , Pirimidinas/uso terapéutico , Tiazoles/uso terapéutico
7.
Int J Immunopathol Pharmacol ; 24(3): 639-49, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21978696

RESUMEN

Cross-Reacting Material 197 (CRM197) is a diphtheria toxin non-toxic mutant that has shown antitumor activity in mice and humans. It is still unclear whether this anti-tumorigenic effect depends on its strong inflammatory-immunological property, its ability to inhibit heparin-binding epidermal growth factor (HB-EGF), or even its possible weak toxicity. CRM197 is utilized as a specific inhibitor of HB-EGF that competes for the epidermal growth factor receptor (EGFR), overexpressed in colorectal cancer and implicated in its progression. In this study we evaluate the effects of CRM197 on HT-29 human colon cancer cell line behaviour and, for CRM197 recognized ability to inhibit HB-EGF, its possible influence on EGFR activation. In particular, while HT-29 does not show any reduction of viability after CRM197 treatment (MTT modified assay), or changes in cell cycle distribution (flow cytometry), in EGFR localization, phospho-EGFR detected signals (immunohistochemistry) or in morphology (scanning electron microscopy, SEM) they show a change in the gene expression profile by microarray analysis (cDNA microarray SS-H19k8). The overexpression of genes like protein phosphatase 2, catalytic subunit, alpha isozyme (PPP2CA), guanine nucleotide-binding protein G subunit alpha-1(GNAI1) and butyrophilin, subfamily 2, member A1 (BTN2A1) has been confirmed with real-time-qPCR. This is the first study where the CRM197 treatment on HT-29 shows a possible scarce implication of endogenous HB-EGF on EGFR expression and cancer cell development. At the same time, our results show the alteration of a specific and selected number of genes.


Asunto(s)
Proteínas Bacterianas/farmacología , Neoplasias del Colon/genética , Perfilación de la Expresión Génica/métodos , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Ciclo Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Colorantes , ADN Complementario/biosíntesis , ADN Complementario/genética , Enterocitos/efectos de los fármacos , Enterocitos/metabolismo , Receptores ErbB/biosíntesis , Receptores ErbB/genética , Citometría de Flujo , Células HT29 , Factor de Crecimiento Similar a EGF de Unión a Heparina , Humanos , Inmunohistoquímica , Hibridación in Situ , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Análisis por Micromatrices , Microscopía Electrónica de Rastreo , ARN Neoplásico/biosíntesis , ARN Neoplásico/genética , Receptor ErbB-4 , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Azul de Tripano
8.
J Bioinform Comput Biol ; 18(5): 2050028, 2020 10.
Artículo en Inglés | MEDLINE | ID: mdl-32757808

RESUMEN

The secondary and tertiary structure of a protein has a primary role in determining its function. Even though many folding prediction algorithms have been developed in the past decades - mainly based on the assumption that folding instructions are encoded within the protein sequence - experimental techniques remain the most reliable to establish protein structures. In this paper, we searched for signals related to the formation of [Formula: see text]-helices. We carried out a statistical analysis on a large dataset of experimentally characterized secondary structure elements to find over- or under-occurrences of specific amino acids defining the boundaries of helical moieties. To validate our hypothesis, we trained various Machine Learning models, each equipped with an attention mechanism, to predict the occurrence of [Formula: see text]-helices. The attention mechanism allows to interpret the model's decision, weighing the importance the predictor gives to each part of the input. The experimental results show that different models focus on the same subsequences, which can be seen as codes driving the secondary structure formation.


Asunto(s)
Aminoácidos/química , Aprendizaje Automático , Modelos Moleculares , Conformación Proteica en Hélice alfa , Bases de Datos de Proteínas , Estructura Secundaria de Proteína , Programas Informáticos
9.
Aust Dent J ; 64(3): 237-245, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-30958567

RESUMEN

BACKGROUND: The aim of this study was to compare different surgical therapies to treat peri-implantitis. METHODS: Twenty-three patients presenting one implant affected by peri-implantitis were divided into three groups: (i) open flap debridement (OFD) and citric acid decontamination (CAD); (ii) OFD, CAD and subepithelial connective tissue graft (SCTG); (iii) OFD, CAD and implantoplasty. Modified plaque index (MPI), gingival bleeding index (GBI), keratinized mucosa (KM) width, probing depth (PD), bleeding or suppuration on probing (B/SOP), and radiographic crestal bone level were registered 1(T1), 2(T2) and 3(T3) years after treatment. RESULTS: In Group 1 there was a significant improvement in MPI from baseline to T1, and a significant reduction in PD over time. In Group 2, none of the assessed clinical parameters showed any statistically significant variation over time. In Group 3, there was a significant decrease in PD and B/SOP over time. When comparing the 3 Groups, KM was significanlty greater in Group 2 vs. Group 1 and Group 3 at T1 and T2, and in Group 2 vs. Group 3 at T3. CONCLUSION: All therapies were successful in the management of peri-implantitis; however, SCTG maintained the greatest KM width. Surgical therapies combined with mechanical and chemical decontamination contributed to peri-implant tissue health.


Asunto(s)
Implantes Dentales , Periimplantitis , Implantes Dentales/efectos adversos , Estudios de Seguimiento , Humanos , Periimplantitis/cirugía , Índice Periodontal , Estudios Prospectivos , Colgajos Quirúrgicos
10.
Neural Netw ; 18(8): 1040-50, 2005 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-16181770

RESUMEN

In this paper, we introduce a new recursive neural network model able to process directed acyclic graphs with labelled edges. The model uses a state transition function which considers the edge labels and is independent both from the number and the order of the children of each node. The computational capabilities of the new recursive architecture are assessed. Moreover, in order to test the proposed architecture on a practical challenging application, the problem of object detection in images is also addressed. In fact, the localization of target objects is a preliminary step in any recognition system. The proposed technique is general and can be applied in different detection systems, since it does not exploit any a priori knowledge on the particular problem. Some experiments on face detection, carried out on scenes acquired by an indoor camera, are reported, showing very promising results.


Asunto(s)
Simulación por Computador , Redes Neurales de la Computación , Reconocimiento de Normas Patrones Automatizadas/métodos , Cara , Humanos , Interpretación de Imagen Asistida por Computador/métodos , Almacenamiento y Recuperación de la Información/métodos , Fantasmas de Imagen
11.
J Immunol Methods ; 252(1-2): 191-7, 2001 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-11334979

RESUMEN

Oligonucleotide aptamer(s), obtained by using the SELEX procedure, has been used as reagents to recognize different molecules with high affinity and specificity. However, until recently, it was not possible to obtain oligonucleotide-based reagents able to recognize proteins with high specificity in assays typical of antibodies, such as immunohistochemistry, Western blotting and immunoprecipitations. Here, we show the results obtained by applying the strategy of "target switching" to obtain specific polyclonal and monoclonal oligobodies against the protein ERK2. We were able to develop highly specific polyclonal oligobodies by using only one selection step with a temporary target and one selection step with the final target (ERK2). Since only two selection steps were required, these results demonstrate that it is possible to obtain specific reagents against a protein without a need for an "in vitro evolution" using many selection steps, or error-prone polymerases. After one additional selection step, the polyclonal oligobodies were cloned to obtain a highly specific monoclonal oligobody.


Asunto(s)
Anticuerpos Monoclonales/inmunología , Proteína Quinasa 1 Activada por Mitógenos/análisis , Secuencia de Aminoácidos , ADN de Cadena Simple/inmunología , Humanos , Proteína Quinasa 1 Activada por Mitógenos/inmunología , Datos de Secuencia Molecular , Desnaturalización Proteica , Células Tumorales Cultivadas
12.
Toxicon ; 37(6): 841-65, 1999 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-10340826

RESUMEN

The literature on Conium maculatum biochemistry and toxicology, dispersed in a large number of scientific publications, has been put together in this review. C. maculatum is a weed known almost worldwide by its toxicity to many domestic animals and to human beings. It is an Umbelliferae, characterized by long, hollow stems, reaching up to 2 m height at maturity, producing a large amount of lush foliage during its vegetative growth. Its flowers are white, grouped in umbels formed by numerous umbellules. It produces a large number of seeds that allow the plant to form thick stands in modified soils, sometimes encroaching on cultivated fields, to the extent of impeding the growth of any other vegetation inside the C. maculatum area of growth. Eight piperidinic alkaloids have been identified in this species. Two of them, gamma-coniceine and coniine are generally the most abundant and they account for most of the plant acute and chronic toxicity. These alkaloids are synthesized by the plant from eight acetate units from the metabolic pool, forming a polyketoacid which cyclises through an aminotransferase and forms gamma-coniceine as the parent alkaloid via reduction by a NADPH-dependent reductase. The acute toxicity is observed when animals ingest C. maculatum vegetative and flowering plants and seeds. In a short time the alkaloids produce a neuromuscular blockage conducive to death when the respiratory muscles are affected. The chronic toxicity affects only pregnant animals. When they are poisoned by C. maculatum during the fetuses organ formation period, the offspring is born with malformations, mainly palatoschisis and multiple congenital contractures (MCC; frequently described as arthrogryposis). Acute toxicity, if not lethal, may resolve in the spontaneous recovery of the affected animals provided further exposure to C. maculatum is avoided. It has been observed that poisoned animals tend to return to feed on this plant. Chronic toxicity is irreversible and although MCC can be surgically corrected in some cases, most of the malformed animals are lost. Since no specific antidote is available, prevention is the only way to deal with the production loses caused by this weed. Control with herbicides and grazing with less susceptible animals (such as sheep) have been suggested. C. maculatum alkaloids can be transferred to milk and to fowl muscle tissue through which the former can reach the human food chain. The losses produced by C. maculatum chronic toxicity may be largely underestimated, at least in some regions, because of the difficulty in associate malformations in offspring with the much earlier maternal poisoning.


Asunto(s)
Alcaloides/envenenamiento , Animales Domésticos , Cicutas (Apiáceas) , Intoxicación por Plantas/veterinaria , Plantas Tóxicas , Enfermedad Aguda , Alcaloides/química , Animales , Enfermedad Crónica , Femenino , Cicutas (Apiáceas)/química , Dosificación Letal Mediana , Masculino , Embarazo , Especificidad de la Especie , Relación Estructura-Actividad
13.
IEEE Trans Neural Netw ; 12(5): 953-67, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-18249925

RESUMEN

Recursive neural networks are a powerful tool for processing structured data, thus filling the gap between connectionism, which is usually related to poorly organized data, and a great variety of real-world problems, where the information is naturally encoded in the relationships among the basic entities. In this paper, some theoretical results about linear recursive neural networks are presented that allow one to establish conditions on their dynamical properties and their capability to encode and classify structured information. A lot of the limitations of the linear model, intrinsically related to recursive processing, are inherited by the general model, thus establishing their computational capabilities and range of applicability. As a byproduct of our study some connections with the classical linear system theory are given where the processing is extended from sequences to graphs.

14.
IEEE Trans Neural Netw ; 5(2): 167-77, 1994.
Artículo en Inglés | MEDLINE | ID: mdl-18267788

RESUMEN

Many researchers have recently focused their efforts on devising efficient algorithms, mainly based on optimization schemes, for learning the weights of recurrent neural networks. As in the case of feedforward networks, however, these learning algorithms may get stuck in local minima during gradient descent, thus discovering sub-optimal solutions. This paper analyses the problem of optimal learning in recurrent networks by proposing conditions that guarantee local minima free error surfaces. An example is given that also shows the constructive role of the proposed theory in designing networks suitable for solving a given task. Moreover, a formal relationship between recurrent and static feedforward networks is established such that the examples of local minima for feedforward networks already known in the literature can be associated with analogous ones in recurrent networks.

15.
IEEE Trans Neural Netw ; 12(6): 1464-70, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-18249974

RESUMEN

Recursive neural networks are conceived for processing graphs and extend the well-known recurrent model for processing sequences. In Frasconi et al. (1998), recursive neural networks can deal only with directed ordered acyclic graphs (DOAGs), in which the children of any given node are ordered. While this assumption is reasonable in some applications, it introduces unnecessary constraints in others. In this paper, it is shown that the constraint on the ordering can be relaxed by using an appropriate weight sharing, that guarantees the independence of the network output with respect to the permutations of the arcs leaving from each node. The method can be used with graphs having low connectivity and, in particular, few outcoming arcs. Some theoretical properties of the proposed architecture are given. They guarantee that the approximation capabilities are maintained, despite the weight sharing.

16.
IEEE Trans Neural Netw ; 6(2): 512-5, 1995.
Artículo en Inglés | MEDLINE | ID: mdl-18263337

RESUMEN

Gradient descent learning algorithms may get stuck in local minima, thus making the learning suboptimal. In this paper, we focus attention on multilayered networks used as autoassociators and show some relationships with classical linear autoassociators. In addition, by using the theoretical framework of our previous research, we derive a condition which is met at the end of the learning process and show that this condition has a very intriguing geometrical meaning in the pattern space.

17.
IEEE Trans Neural Netw ; 6(3): 749-56, 1995.
Artículo en Inglés | MEDLINE | ID: mdl-18263359

RESUMEN

Learning from examples plays a central role in artificial neural networks. The success of many learning schemes is not guaranteed, however, since algorithms like backpropagation may get stuck in local minima, thus providing suboptimal solutions. For feedforward networks, optimal learning can be achieved provided that certain conditions on the network and the learning environment are met. This principle is investigated for the case of networks using radial basis functions (RBF). It is assumed that the patterns of the learning environment are separable by hyperspheres. In that case, we prove that the attached cost function is local minima free with respect to all the weights. This provides us with some theoretical foundations for a massive application of RBF in pattern recognition.

18.
Parassitologia ; 29(1): 37-47, 1987 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-3508508

RESUMEN

A study was conducted on the parasitofauna of Anguilla anguilla caught in the section of the Tiber river south of Rome (Italy). The sample examined consisted of 417 specimens that were classified by stage (elver, young yellow eel, yellow eel and silver eel) and season of sampling. The following species were identified: Trypanosoma granulosum, Eimeria anguillae, Myxidium giardi, Sphaerospora reichenowi, Myxobolus sp., Trichodina anguilli, Ichthyohodo sp., Gyrodactylus anguillae, Bothriocephalus claviceps, Proteocephalus macrocephalus, Raphidascaris acus, Acanthocephalus clavula. Each parasite species was considered in its prevalence according to stage and season. For some parasite the pathogenic effect was also examined in a histological study of serial sections. The results of the statistical analysis of the single parasitic infection as related to different seasons pointed to marked seasonal trends only in some species (Trypanosoma granulosum and Gyrodactylus anguillae). The intensity of infection assessed for acanthocephalan infection only was found to affect neither weight nor condition index (weight/length3). No difference in weight or condition index was found to be ascribable to the presence or absence of a species. An attempt to find a rule-of-thumb algorithm to gauge the overall effect to parasitic diseases failed to give sufficiently significant results.


Asunto(s)
Anguilla/parasitología , Helmintiasis/parasitología , Infecciones por Protozoos/parasitología , Acantocéfalos/parasitología , Anguilla/crecimiento & desarrollo , Animales , Agua Dulce , Helmintiasis/patología , Italia , Infecciones por Protozoos/patología , Estaciones del Año
19.
Minerva Urol Nefrol ; 43(2): 69-73, 1991.
Artículo en Italiano | MEDLINE | ID: mdl-1957232

RESUMEN

This article takes into account the diagnostic reliability of ultrasounds (US) in the ureteral lithiasis localisation. A stone has been ultrasonographically localised in 82.3% of 119 patients, this rate rising up to 89.4% in the last 85 consecutive patients. From a clinical point of view, 104 patients presented renal signs, whereas 10 out of them showed an atypical symptomatology, which at first led to a suspicion of acute appendicitis (5), intestinal obstruction (4), acute pancreatitis (1). A stone was accidentally detected in five asymptomatic patients. In 80% of the cases, the stone was situated in the proximal or juxtavesical ureter; in 20%, in the middle or distal ureter. A particular stress is laid in the ultrasonographic follow-up, by which the stone was uncovered in 6 cases, at first considered negative at US. Eight patients had to be referred to treatment with ESWL.


Asunto(s)
Cálculos Ureterales/diagnóstico por imagen , Dolor Abdominal/diagnóstico por imagen , Dolor Abdominal/etiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Diagnóstico Diferencial , Enfermedades del Sistema Digestivo/diagnóstico , Estudios de Evaluación como Asunto , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Recurrencia , Estudios Retrospectivos , Ultrasonografía , Cálculos Ureterales/complicaciones
20.
Eur J Pediatr Surg ; 4(2): 110-2, 1994 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-8025092

RESUMEN

A newborn with congenital aplasia of the dorso-lumbar muscles is described. The lesion seemed to be a congenital lumbar hernia and is a very uncommon feature. The child underwent surgery and although it was a very large bilateral defect, it was repaired without using prosthetic patch. The surgical technique and the results are discussed. The function of the region was conserved as demonstrated at the check-up of the child at 6 and 12 months of age.


Asunto(s)
Hernia/congénito , Músculos/anomalías , Herniorrafia , Humanos , Recién Nacido , Región Lumbosacra , Masculino
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