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1.
J Endocrinol Invest ; 2023 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-37938428

RESUMO

PURPOSE: To assess the effect of letrozole, an aromatase inhibitor (AI), in patients with resistant prolactinoma that presented an increase in serum prolactin (PRL) levels during testosterone replacement therapy (TRT). METHODS: A retrospective cohort study in a single tertiary care center. From March 2012 to July 2023, 53 male patients over 18 years with prolactinoma were followed in our Neuroendocrine Unit. Of those, 90.6% presented macroadenomas, 41% of them were resistant to cabergoline and 25% presented persistent hypogonadism to whom TRT was indicated. Among them, five presented a significant increase in PRL levels and AI was initiated. All five patients had resistant prolactinomas. One of them was excluded due to tumor aggressiveness and concomitant use of temozolomide during AI therapy. RESULTS: Four patients were included in the analysis, with a mean age of 28.5 (± 7.5) years, median prolactin of 1060 (600 to 6700) ng/mL and median of the largest tumor diameter of 3.6 (1.5 to 5) cm at the time of prolactinoma diagnosis. On TRT, all presented an increase in serum PRL levels (231 to 396%), with a subsequent decrease (61 to 93%) after adding AI. During AI treatment for a median time of 60.5 (21 to 120) months, tumor shrinkage was observed in two cases (-8 and -3 mm in the maximum diameter) and tumor stability in the other two. No major side effects occurred and AI was well tolerated. CONCLUSION: AI might be an option for men with resistant prolactinoma who have an increase in PRL levels on TRT. Nevertheless, prospective randomized clinical trials are needed to ensure efficacy and security for this approach.

2.
Acta Endocrinol (Buchar) ; 15(4): 522-525, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-32377252

RESUMO

INTRODUCTION: Agranulocytosis induced by thioamides is rare, occurring only in 0.2-0.5% of cases. CASE PRESENTATION: We present the case of a 45-year-old woman previously diagnosed with Graves' disease that discontinued the use of methimazole on her own. She attended the Emergency Department presenting fever (40.5¯C), agitation and diaphoresis. A thyroid storm diagnosis was initially thought, but after laboratory results showing neutrophil count near 0.06x109/L, sepsis due to neutropenia seemed the most logical hypothesis. Cephepime was promptly initiated. For thyrotoxicosis management, cholestyramine and atenolol were prescribed. In her second day of hospitalization, subcutaneous granulocyte colony-stimulating factor was started for an earlier medullar response. The patient was discharged after 7 days with atenolol 50mg/day and instructed to have a definite treatment for Graves disease as soon as possible. CONCLUSION: Such case purpose is to remember clinicians that sepsis diagnosis can be challenged, especially when a thyroid storm is a possible diagnosis as well. In this particular case, both conditions should be treated, but life-threatening sepsis should have the focus for a quick therapeutic approach.

4.
Trop Anim Health Prod ; 49(4): 851-856, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28332069

RESUMO

Lameness can negatively affect production, but there is still controversy about the perception of pain in dairy cows. This study aimed to verify the effects of hoof affections in dairy cows on locomotion score, physiological attributes, pressure nociceptive threshold, and thermographic variables, as well as assess improvement on these variables after corrective trimming and treatment. Thirty-four lame lactating cows were gait-scored, and all cows with locomotion score ≥4 were retained for this study 1 day before trimming. Lame cows were diagnosed, pressure nociceptive threshold at sound, and affected hooves were measured, thermographic images were recorded, and physiological attributes were evaluated. Hooves with lesions were trimmed and treated and cows were re-evaluated 1 week after such procedures. The experimental design was a completely randomized design. Each cow was considered an experimental unit and traits were analyzed using paired t test, linear correlation, and linear regression. Digital and interdigital dermatitis were classified as infectious diseases while laminitis sequels, sole ulcers, and white line were classified as non-infectious diseases. After 1 week, the locomotion score was reduced on average in 1.5 points. Trimming increased the pressure nociceptive threshold for cows with non-infectious affections while tended to increase the pressure nociceptive threshold for cows with infectious affections. Physiological attributes and thermographic values did not change with trimming. Trimming and treatment have benefic effects on animal welfare as gait is improved and sensitivity to pain is reduced.


Assuntos
Doenças dos Bovinos/fisiopatologia , Casco e Garras/fisiopatologia , Coxeadura Animal , Locomoção , Medição da Dor/métodos , Animais , Bovinos , Doenças Transmissíveis , Feminino , Marcha , Lactação , Dor , Limiar da Dor , Fenótipo
5.
Unfallchirurg ; 118(3): 279-82, 2015 Mar.
Artigo em Alemão | MEDLINE | ID: mdl-25783693

RESUMO

We describe the case of an 88-year-old woman who presented with painful symptoms of the pelvis after low-energy trauma. Conservative treatment with pain therapy and pain-adapted mobilization was unsuccessful. Diagnostics showed a fragility fracture of the pelvic ring; therefore, we performed photodynamic bone stabilization (IlluminOss™) of the pubic bone and percutaneous cement-augmented fixation of the iliosacral joint assisted by computed tomography (CT) fluoroscopy. Imaging showed a stable healed fracture 4 months after surgery.


Assuntos
Cimentos Ósseos/uso terapêutico , Fraturas por Osteoporose/terapia , Ossos Pélvicos/lesões , Ossos Pélvicos/cirurgia , Idoso de 80 Anos ou mais , Cimentos Ósseos/efeitos da radiação , Terapia Combinada/métodos , Feminino , Humanos , Luz , Fraturas por Osteoporose/diagnóstico por imagem , Ossos Pélvicos/diagnóstico por imagem , Radiografia , Resultado do Tratamento
6.
Mol Biol Evol ; 28(3): 1141-55, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21059793

RESUMO

Sensing the environment and responding appropriately to it are key capabilities for the survival of an organism. All extant organisms must have evolved suitable sensors, signaling systems, and response mechanisms allowing them to survive under the conditions they are likely to encounter. Here, we investigate in detail the evolutionary history of one such system: The phage shock protein (Psp) stress response system is an important part of the stress response machinery in many bacteria, including Escherichia coli K12. Here, we use a systematic analysis of the genes that make up and regulate the Psp system in E. coli in order to elucidate the evolutionary history of the system. We compare gene sharing, sequence evolution, and conservation of protein-coding as well as noncoding DNA sequences and link these to comparative analyses of genome/operon organization across 698 bacterial genomes. Finally, we evaluate experimentally the biological advantage/disadvantage of a simplified version of the Psp system under different oxygen-related environments. Our results suggest that the Psp system evolved around a core response mechanism by gradually co-opting genes into the system to provide more nuanced sensory, signaling, and effector functionalities. We find that recruitment of new genes into the response machinery is closely linked to incorporation of these genes into a psp operon as is seen in E. coli, which contains the bulk of genes involved in the response. The organization of this operon allows for surprising levels of additional transcriptional control and flexibility. The results discussed here suggest that the components of such signaling systems will only be evolutionarily conserved if the overall functionality of the system can be maintained.


Assuntos
Escherichia coli K12/genética , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Evolução Molecular , Transativadores/genética , Transativadores/metabolismo , Sequência de Bases , Escherichia coli K12/metabolismo , Proteínas de Escherichia coli/classificação , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica , Estudos de Associação Genética , Genoma Bacteriano , Instabilidade Genômica/fisiologia , Genômica , Óperon , Filogenia , Estresse Fisiológico/fisiologia , Transativadores/classificação , Transcrição Gênica
7.
Opt Lett ; 37(21): 4428-30, 2012 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-23114318

RESUMO

We investigate the dynamics of the carrier-envelope-offset (CEO) frequency, f(CEO), controlled by a pump current on the self-referencing of an optical frequency comb generated from a diode-pumped solid-state laser at 1.56 µm. We observe a reversal point in the tuning of f(CEO) with the pump current. Between the low- and high-frequency region in the dynamic response of f(CEO) to pump current modulation, we observe a significant phase shift of ≈180 deg in the transfer function. As a result, it is impossible to stabilize f(CEO) at a pump current above the reversal point, although the free-running CEO beat at this point has a higher signal-to-noise ratio than underneath the reversal point at which the locking is straightforward. Our results indicate that a high signal-to-noise ratio and a low-noise CEO beat are not sufficient indicators for the feasibility of comb self-referencing in cases for which CEO dynamics play a dominant role.

8.
Bull Math Biol ; 74(2): 356-74, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21870201

RESUMO

Protein interaction networks comprise thousands of individual binary links between distinct proteins. Whilst these data have attracted considerable attention and been the focus of many different studies, the networks, their structure, function, and how they change over time are still not fully known. More importantly, there is still considerable uncertainty regarding their size, and the quality of the available data continues to be questioned. Here, we employ statistical models of the experimental sampling process, in particular capture-recapture methods, in order to assess the false discovery rate and size of protein interaction networks. We uses these methods to gauge the ability of different experimental systems to find the true binary interactome. Our model allows us to obtain estimates for the size and false-discovery rate from simple considerations regarding the number of repeatedly interactions, and provides suggestions as to how we can exploit this information in order to reduce the effects of noise in such data. In particular our approach does not require a reference dataset. We estimate that approximately more than half of the true physical interactome has now been sampled in yeast.


Assuntos
Modelos Químicos , Mapeamento de Interação de Proteínas/métodos , Mapeamento de Interação de Proteínas/estatística & dados numéricos , Mapas de Interação de Proteínas , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/metabolismo
9.
Rev Gastroenterol Mex (Engl Ed) ; 87(4): 506-508, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36374814

RESUMO

Whether preoperative parameters can predict weight loss following bariatric surgery is a matter of debate. We conducted a longitudinal and prospective pilot study on 35 patients that underwent bariatric surgery, with a 12-month follow-up. In the preoperative period, a high HOMA-beta index, lower fasting blood glucose, and lower HbA1c were correlated with a lower BMI at 12 months. Traditional preoperative factors, such as weight and BMI, were correlated with the postoperative BMI values. The presence of well-controlled diabetes may influence weight loss after surgery.


Assuntos
Cirurgia Bariátrica , Humanos , Estudos Prospectivos , Projetos Piloto , Cirurgia Bariátrica/efeitos adversos , Redução de Peso
10.
Science ; 371(6526)2021 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-33446527

RESUMO

Multicellular organisms are composed of cells connected by ancestry and descent from progenitor cells. The dynamics of cell birth, death, and inheritance within an organism give rise to the fundamental processes of development, differentiation, and cancer. Technical advances in molecular biology now allow us to study cellular composition, ancestry, and evolution at the resolution of individual cells within an organism or tissue. Here, we take a phylogenetic and phylodynamic approach to single-cell biology. We explain how "tree thinking" is important to the interpretation of the growing body of cell-level data and how ecological null models can benefit statistical hypothesis testing. Experimental progress in cell biology should be accompanied by theoretical developments if we are to exploit fully the dynamical information in single-cell data.


Assuntos
Linhagem da Célula , Filogenia , Análise de Célula Única , Animais , Caenorhabditis elegans/citologia , Caenorhabditis elegans/crescimento & desenvolvimento , Biologia Celular/tendências , Humanos , Células-Tronco/citologia , Células-Tronco/fisiologia
11.
Br J Cancer ; 101(9): 1513-21, 2009 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-19861998

RESUMO

BACKGROUND: The aim of this study was to investigate the prognostic effect of tumour-infiltrating lymphocytes (TILs) in serous stage III ovarian carcinoma to determine TIL clonality and to correlate this to Her2/neu expression. METHODS: Formalin-fixed and paraffin-embedded ovarian carcinomas were examined for CD20-, CD3-, CD4- and CD8-positive lymphocytes (n=100), and for Her2/neu-positive tumour cells (n=55/100) by immunohistochemistry. Clonality analysis was carried out by T-cell receptor gamma (TCRgamma) gene rearrangements (n=93/100). Statistical analyses included experimental and clinico-pathological variables, as well as disease-free (DFS) and overall (OS) survival. RESULTS: CD20-positive B lymphocytes were present in 57.7% (stromal)/33.0% (intraepithelial) and CD3-positive T lymphocytes in 99.0% (stromal)/90.2% (intraepithelial) of ovarian carcinomas. Intraepithelial CD3-positive T lymphocytes were correlated with improved DFS in optimally debulked patients (P=0.0402). Intraepithelial CD8-positive T lymphocytes were correlated with improved OS in all optimally debulked patients (P=0.0201) and in those undergoing paclitaxel/carboplatin therapy (P=0.0092). Finally, rarified and clonal TCRgamma gene rearrangements were detected in 37 out of 93 (39.8%) and 15 out of 93 (16.1%) cases, respectively. This was marginally associated with improved DFS (P=0.0873). Despite a significant correlation of HER2/neu status and intraepithelial CD8-positive lymphocytes (P=0.0264), this was non-directional (R=-0.257; P=0.0626). CONCLUSION: Improved survival of ovarian cancer patients is related to the infiltration, clonal selection and intraepithelial persistence of T lymphocytes.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Linfócitos do Interstício Tumoral/imunologia , Neoplasias Ovarianas/imunologia , Neoplasias Ovarianas/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Rearranjo Gênico da Cadeia gama dos Receptores de Antígenos dos Linfócitos T , Humanos , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Neoplasias Ovarianas/patologia , Receptor ErbB-2/análise
12.
Science ; 290(5499): 2084-6, 2000 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-11187834

RESUMO

A power law called the species-area relationship describes the finding that the number of species is proportional to the size of the area in which they are found, raised to an exponent (usually, a number between 0.2 and 0.3). In their Perspective, May and Stumpf discuss new results from a survey of five tropical forest census areas containing a total of a million trees. They explain how this large data set can be used to fine-tune the existing power law so that it provides a better prediction of species diversity in small census samples.


Assuntos
Ecossistema , Árvores , Clima Tropical , Índia , Malásia , Matemática , Panamá , Tailândia
13.
Science ; 291(5509): 1738-42, 2001 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-11249819

RESUMO

Population genetics has emerged as a powerful tool for unraveling human history. In addition to the study of mitochondrial and autosomal DNA, attention has recently focused on Y-chromosome variation. Ambiguities and inaccuracies in data analysis, however, pose an important obstacle to further development of the field. Here we review the methods available for genealogical inference using Y-chromosome data. Approaches can be divided into those that do and those that do not use an explicit population model in genealogical inference. We describe the strengths and weaknesses of these model-based and model-free approaches, as well as difficulties associated with the mutation process that affect both methods. In the case of genealogical inference using microsatellite loci, we use coalescent simulations to show that relatively simple generalizations of the mutation process can greatly increase the accuracy of genealogical inference. Because model-free and model-based approaches have different biases and limitations, we conclude that there is considerable benefit in the continued use of both types of approaches.


Assuntos
Evolução Biológica , Variação Genética , Genética Populacional , Cromossomo Y/genética , Demografia , Emigração e Imigração , Feminino , Marcadores Genéticos , Humanos , Masculino , Modelos Genéticos , Modelos Estatísticos , Mutação , Linhagem , Polimorfismo Genético
14.
Science ; 253(5026): 1415-7, 1991 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-1716786

RESUMO

Bean leaf stomata provide a topographical signal that induces germlings of the phytopathogen Uromyces appendiculatus to develop specialized infection structures. Protoplasts from germ tubes of this fungus, when examined with patch-clamp electrodes, displayed the activities of a 600-picosiemen mechanosensitive ion channel. This channel passes a variety of cations, including Ca2+, and is blocked by Gd3+ at 50 micromolar. This channel could transduce the membrane stress induced by the leaf topography into an influx of ions, including Ca2+, that may trigger differentiation.


Assuntos
Basidiomycota/fisiologia , Canais Iônicos/fisiologia , Bário/farmacologia , Basidiomycota/ultraestrutura , Membrana Celular/fisiologia , Membrana Celular/ultraestrutura , Gadolínio/farmacologia , Canais Iônicos/efeitos dos fármacos , Canais Iônicos/ultraestrutura , Mecanorreceptores/fisiologia , Potenciais da Membrana , Pressão , Tetraetilamônio , Compostos de Tetraetilamônio/farmacologia
15.
Nucleic Acids Res ; 35(Database issue): D71-5, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17202172

RESUMO

There has been widespread and growing interest in genetic markers suitable for drawing population genetic inferences about past demographic events and to detect the effects of selection. In addition to single nucleotide polymorphisms (SNPs), microsatellites (or short tandem repeats, STRs) have received great attention in the analysis of human population history. In the SNPSTR database (http://www.imperial.ac.uk/theoreticalgenomics/data-software) we catalogue a relatively new type of compound genetic marker called SNPSTR which combines a microsatellite marker (STR) with one or more tightly linked SNPs. Here, the SNP(s) and the microsatellite are less than 250 bp apart so each SNPSTR can be considered a small haplotype with no recombination occurring between the two individual markers. Thus, SNPSTRs have the potential to become a very useful tool in the field of population genetics. The SNPSTR database contains all inferable human SNPSTRs as well as those in mouse, rat, dog and chicken, i.e. all model organisms for which extensive SNP datasets are available.


Assuntos
Bases de Dados de Ácidos Nucleicos , Repetições de Microssatélites , Polimorfismo de Nucleotídeo Único , Animais , Galinhas/genética , Cães , Marcadores Genéticos , Humanos , Internet , Camundongos , Ratos , Interface Usuário-Computador
16.
Zentralbl Chir ; 134(3): 242-8, 2009 Jun.
Artigo em Alemão | MEDLINE | ID: mdl-19536719

RESUMO

BACKGROUND: Despite improved surgical techniques, anastomotic leakage is still a serious complication in colorectal surgery, resulting in increased morbidity and mortality. This study was initiated to investigate those clinical risk factors which may influence the onset of anastomotic wound-healing complications. METHODS: The postoperative courses were assessed in 400 consecutive patients who underwent colonic or rectal resection. Possible clinical risk factors were investigated by unvariate and multivariate analysis. RESULTS: 23 patients developed an anastomotic leakage (5.8 %). 10 patients could be treated conservatively, 13 had a second operation. In the multivariate analysis significant risk factors were perioperative radiotherapy (OR = 3.76 [95 % CI 1.03-13.7]), blood transfusion (OR = 2.98 [95 % CI 1.18-7.54]), alcohol consumption (OR = 2.94 [95 % CI 1.06-8.17]), and steroid medication (OR = 3.91 [95 % CI 1.17-13.07]). CONCLUSION: The clinically most important risk factors for leakage were radiotherapy and blood transfusion. Further analyses with a focus on the extracellular matrix, including other clinical factors may be valuable in identifying targets for improvement.


Assuntos
Doenças do Colo/cirurgia , Neoplasias Colorretais/cirurgia , Complicações Pós-Operatórias/etiologia , Doenças Retais/cirurgia , Deiscência da Ferida Operatória/etiologia , Corticosteroides/administração & dosagem , Corticosteroides/efeitos adversos , Adulto , Idoso , Consumo de Bebidas Alcoólicas/efeitos adversos , Transfusão de Sangue , Colectomia , Colo/efeitos da radiação , Neoplasias Colorretais/radioterapia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Terapia Neoadjuvante , Complicações Pós-Operatórias/cirurgia , Lesões por Radiação/etiologia , Lesões por Radiação/cirurgia , Reto/efeitos da radiação , Reto/cirurgia , Estudos Retrospectivos , Fatores de Risco , Grampeadores Cirúrgicos , Deiscência da Ferida Operatória/cirurgia , Técnicas de Sutura , Adulto Jovem
17.
Breast Cancer Res Treat ; 112(3): 523-31, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18172758

RESUMO

OBJECTIVE: To assess whether the Memorial Sloan Kettering Cancer Center (MSKCC) nomogram for prediction of NSLN metastasis is useful in a German breast cancer population and whether the characteristics of the breast tumor and the sentinel lymph node (SLN) are able to predict the likelihood of non-sentinel lymph node (NSLN) metastasis. METHODS: A total of 545 patients with primary breast cancer and SLN examination were evaluated. The MSKCC nomogram was applied to 98 patients with a positive SLN who subsequently had completion axillary lymph node dissection (ALND). Predictive accuracy was assessed by calculating the area under the receiver-operator characteristic (ROC) curve. The collective was evaluated by correlating the prevalence of NSLN and SLN metastasis to pathological features. RESULTS: The MSKCC nomogram achieved a ROC of 0.58 indicating a bad accuracy of the nomogram. Tumor size, histology, lymphovascular infiltration, multifocality, Her-2-neu positivity, and nuclear grade correlated with the probability of SLN metastasis. Histology and primary tumor localization correlated significantly with the probability of NSLN metastasis. CONCLUSIONS: The MSKCC nomogram did not provide a reliable predictive model in our study population. However, the likelihood of SLN metastasis correlated with the presumed risk factors and no obvious differences between the MSKCC population and our population could be seen. In order to achieve interinstitutional reproducibility, standardization of surgical procedure and of the pathological assessment of the SLN is desirable.


Assuntos
Neoplasias da Mama/diagnóstico , Neoplasias da Mama/patologia , Nomogramas , Adulto , Feminino , Alemanha , Humanos , Funções Verossimilhança , Metástase Linfática , Oncologia/métodos , Pessoa de Meia-Idade , Metástase Neoplásica , Valor Preditivo dos Testes , Curva ROC , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
18.
Opt Express ; 16(14): 10572-9, 2008 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-18607472

RESUMO

We present a low coherence light source by direct super-continuum generation from a diode-pumped, passively modelocked Er:Yb:glass-laser, which generates 198 fs transform-limited pulses with an average power of 100 mW at a repetition rate of 75 MHz. The pulse train is launched into a dispersion optimized highly nonlinear fiber for spectral broadening. The optical bandwidth spans from 1150 nm to 2400 nm, which is more than one octave. The potential for ultrahigh-resolution optical coherence tomography (OCT) is demonstrated by coherence measurements supporting an axial resolution of 3.5 microm in air.


Assuntos
Érbio/química , Lasers , Óptica e Fotônica , Tomografia de Coerência Óptica/instrumentação , Itérbio/química , Desenho de Equipamento , Vidro , Interferometria/métodos , Espalhamento de Radiação , Fatores de Tempo , Tomografia de Coerência Óptica/métodos
19.
MMW Fortschr Med ; 150 Suppl 1: 31-5, 2008 Apr 10.
Artigo em Alemão | MEDLINE | ID: mdl-18540330

RESUMO

Patients' compliance or adherence to medical therapy recommendations has been identified to be a pivotal element in achievement of treatment success. Nonadherence is a commonly-found phenomenon among patients suffering chronic pain. Its negative impact on the individual health status and on health systems has put forth strategies to improve adherence in the therapy of chronicpain. These include the use of medications with reliable and high efficacy combined with low rate and severity of side effects, limited need of medication to manage breakthrough pain as well as the reduction of application frequency.


Assuntos
Analgésicos Opioides/uso terapêutico , Dor/tratamento farmacológico , Cooperação do Paciente , Recusa do Paciente ao Tratamento , Administração Oral , Analgésicos Opioides/administração & dosagem , Doença Crônica , Doença das Coronárias/tratamento farmacológico , Doença das Coronárias/mortalidade , Diabetes Mellitus/tratamento farmacológico , Diabetes Mellitus/mortalidade , Alemanha , Nível de Saúde , Insuficiência Cardíaca/tratamento farmacológico , Insuficiência Cardíaca/mortalidade , Humanos , Infarto do Miocárdio/tratamento farmacológico , Infarto do Miocárdio/mortalidade , Dor/economia , Guias de Prática Clínica como Assunto , Qualidade de Vida , Fatores de Tempo , Organização Mundial da Saúde
20.
Phys Rev E ; 98(2-1): 022136, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30253467

RESUMO

The construction of effective and informative landscapes for stochastic dynamical systems has proven a long-standing and complex problem. In many situations, the dynamics may be described by a Langevin equation while constructing a landscape comes down to obtaining the quasipotential, a scalar function that quantifies the likelihood of reaching each point in the state space. In this work we provide a novel method for constructing such landscapes by extending a tool from control theory: the sum-of-squares method for generating Lyapunov functions. Applicable to any system described by polynomials, this method provides an analytical polynomial expression for the potential landscape, in which the coefficients of the polynomial are obtained via a convex optimization problem. The resulting landscapes are based on a decomposition of the deterministic dynamics of the original system, formed in terms of the gradient of the potential and a remaining "curl" component. By satisfying the condition that the inner product of the gradient of the potential and the remaining dynamics is everywhere negative, our derived landscapes provide both upper and lower bounds on the true quasipotential; these bounds becoming tight if the decomposition is orthogonal. The method is demonstrated to correctly compute the quasipotential for high-dimensional linear systems and also for a number of nonlinear examples.

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