Convertible subspaces that arise from different numberings of the vertices of a graph

In this paper, we describe subspaces of generalized Hessenberg matrices where the determinant is convertible into the permanent by affixing ± signs. These subspaces can arise from different numberings of the vertices of a graph. With this numbering process, we obtain some well-known sequences of integers. For instance, in the case of a path of length n, we prove that the number of these subspaces is the (n + 1)th Fibonacci number.info:eu-repo/semantics/publishedVersio

Strategies to obtain designer polymers based on cyanobacterial extracellular polymeric substances (EPS)

Biopolymers derived from polysaccharides are a sustainable and environmentally friendly alternative to the synthetic counterparts available in the market. Due to their distinctive properties, the cyanobacterial extracellular polymeric substances (EPS), mainly composed of heteropolysaccharides, emerge as a valid alternative to address several biotechnological and biomedical challenges. Nevertheless, biotechnological/biomedical applications based on cyanobacterial EPS have only recently started to emerge. For the successful exploitation of cyanobacterial EPS, it is important to strategically design the polymers, either by genetic engineering of the producing strains or by chemical modification of the polymers. This requires a better understanding of the EPS biosynthetic pathways and their relationship with central metabolism, as well as to exploit the available polymer functionalization chemistries. Considering all this, we provide an overview of the characteristics and biological activities of cyanobacterial EPS, discuss the challenges and opportunities to improve the amount and/or characteristics of the polymers, and report the most relevant advances on the use of cyanobacterial EPS as scaffolds, coatings, and vehicles for drug delivery.This work was financed by FEDER—Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020 - Operacional Programme for Competitiveness and Internationalisation (POCI), Portugal 2020, and by Portuguese funds through FCT—Fundação para a Ciência e a Tecnologia/Ministério da Ciência, Tecnologia e Ensino Superior in the framework of the project POCI-01-0145-FEDER-028779, contract DL57/2016/CP1327/CT0007 and fellowship SFRH/BD/119920/2016

Intrahepatic Colangiocarcinoma

Introdução: o colangiocarcinoma intra-hepático (CCIhp) é um tumor maligno raro, normalmente diagnosticado num estadio avançado. São objectivos deste estudo avaliar os resultados da terapêutica do CCIhp e os factores prognósticos com significado estatístico na sobrevida de doentes com esta entidade nosológica tratados no nosso Serviço. Material e métodos: Vinte e um doentes submetidos a tratamento por CCIhp nos últimos anos, dos quais onze foram operados com intuitos curativos: quatro hepatectomias esquerdas, duas hepatectomias esquerdas alargadas aos segmentos V e VIII, duas hepatectomias direitas, duas bissegmentectomias e uma trissegmentectomia. Resultados: a mortalidade per-operatória foi de 0% e a pós-operatória (três meses) de 6%. As sobrevidas cumulativas aos 5 anos foram de 14% no total da população, 26% nos doentes submetidos a cirurgia com intuitos curativos e 26% para a sobrevida cumulativa livre de doença. Observou-se recidiva tumoral hepática em cinco doentes, a qual ocorreu aos 1,09 ± 0,82 anos (limites: 0,24-2,08). Os factores que influenciaram a sobrevida da globalidade dos doentes foram o tratamento cirúrgico com intuitos curativos (p=0,028), a presença de invasão vascular (p=0,002) e o valor da fosfatase alcalina no momento do diagnóstico (p=0,044). Entre os doentes operados com intuitos curativos, a presença de invasão vascular influenciou a sobrevida global (p=0,025) e a sobrevida livre de doença (p=0,002). Conclusões: A ressecção cirúrgica com intuitos curativos aumentou, de forma estatisticamente significativa, a sobrevida dos doentes com CCIhp. No entanto, sendo o diagnóstico geralmente tardio, apenas uma pequena percentagem destes doentes pode beneficiar deste tratamento.info:eu-repo/semantics/publishedVersio

Perioperative tumor cell dissemination in patients with primary or metastatic colorectal cancer

INTRODUCTION: Although there is general correlation between the TNM stage of colorectal cancer (CRC) and its prognosis, there is often significant variability of tumor behaviour and individual patient outcome, which is unaccounted for by pathologic factors alone. Our aim was to estimate perioperative tumor cell dissemination in patients with primary or CRC liver metastases as a possible factor influencing the outcome. METHODS: Forty patients were prospectively enrolled in the study from the year 2007 to 2008. Eighteen patients had histologically proven CRC (50% rectal, 44% colonic, 6% colonic and rectal). Sixteen patients (47%) had CRC liver metastases only. The remaining six patients who underwent colon or liver resection for benign conditions, acted as the control group. All patients with malignant pathologies had R0 resections. Blood samples were taken before the surgical incision (T0), immediately after tumor resection (T1) and at the end of the surgical intervention (T2). Data acquisition was performed using a dual-laser FACSCalibur flow cytometer. Circulating malignant cells were identified as being CD45-/cytokeratin+. RESULTS: The analysis of patients overall (CRC resection subgroup and hepatectomy subgroup) revealed that there was no statistically significant difference of the tumoral cell count in the blood per million of hematopoietic cells at T0, T1 and T2. CONCLUSIONS: This study demonstrates no differences in the detected circulating numbers of tumor cells at different stages of surgical intervention

Evolução do estado nutricional e da composição corporal após cirurgia electiva major

Introduction: Despite recognition of its high prevalence and adverse clinical impact, malnutrition remains undervalued and often aggravates during the hospital stay. Objective: To characterize the progression of nutritional status and body composition in the early postoperative period of major elective surgery and to correlate results with the clinical evolution. Material and methods: Prospective study including 71 operated patients with evaluation of nutritional status based on anthropometric, laboratorial and functional (hand grip strength) parameters and determination of body composition by bioelectrical impedance analysis, in the day before surgery, in the first and fifth days of the postoperative period and at the moment of hospital discharge. Results: Patient ́s mean age was 60,4±12,8 (30-91) years, Charlson ́s comorbidity index 3,1±2,8 (0-9) and Surgical Risk Index 8,3±1,14 (6-11). Operative mortality and morbi- dity rates were 7 and 31%, respectively and the mean postoperative hospital stay was 12,4±10,1 (1-61) days. Weight loss referred in the day before surgery was 3,6±7,4% (-12,8-31,1); 1,6% of patients presented a body mass index lower than 20 kg/m2 and 72% an index over 21 kg/m2. Artificial nutritional support was used in 20% of cases. In the postoperative period, a significant deterioration of nutritional and body composition parameters occurred, with a reduction of 1,9% in body weight, 3,4% in tricipital skinfold, 2,6% in mid-arm circumference, 32,2% in pre-albuminemia, 16,8% in transferrinemia, 18,3% in albuminemia, 13,1% in lymphocyte percentage, 12,4% in hand grip strength, 4,3% in body fat mass index and 4,2% in fat-free mass index. Such degradation was pro- portional to the length of postoperative hospital stay, with the exceptions of laboratorial parameters and body fat mass. Mortality was significantly related with greater relative reductions of fat-free mass (20,1 versus 3,7%; p=0,033) and total body water (22,2 versus 2,9%; p=0,013) and morbidity was associated with greater relative reductions of body weight (7,7 versus 1%; p=0,031) and muscular strength (16,8 versus 10%; p=0,014). Conclusions: Those results seem to corroborate the importance of a systematic surveillance of nutrition status during the perioperative hospital stay and of a timely therapeutic intervention. Keywords: Nutritional status, body composition, elective surgery, malnutrition Abbreviations: B.M.I.: body mass index; n.s.: statistically not significant; RR: relative risk; vs: versus; f: Spearman ́s correlation coefficient Introdução: Apesar do reconhecimento da sua elevada prevalência e seu adverso impacto clínico, a desnutrição permanece subvalori- zada no contexto hospitalar e agrava-se frequentemente no decurso do internamento. Objectivos: Caracterizar a progressão do estado nutricional e da composição corporal no período pós-operatório imediato de cirurgia electiva major e correlacioná-la com a evolução clínica. Material e métodos: Estudo prospectivo envolvendo 71 doentes operados com avaliação do estado nutricional por parâmetros antropométricos, analíticos e funcionais (dinamometria manual) e da composição corporal por impedância bioeléctrica, na véspera da intervenção, no primeiro e quinto dias pós-operatórios e no momento da alta hospitalar. Resultados: A idade média dos doentes estudados foi de 60,4±12,8 (30-91) anos, o índice de comorbilidade de Charlson de 3,1±2,8 (0-9) e o Índice de Risco Cirúrgico de 8,3±1,1 (6-11). As taxas de mortalidade e de morbilidade operatórias foram de 7 e 31%, respectivamente e a duração do internamento pós-operatório de 12,4±10,1 (1-61) dias. A perda ponderal referida na véspera da intervenção foi de 3,6±7,4% (-12,8-31,1); 1,6% dos doentes apresentavam um índice de massa corporal inferior a 20 kg/m2 e 72% um índice superior a 21 kg/m2. Foi realizado suporte nutricional artificial em 20% dos casos. No período pós-operatório, verificou-se uma significativa deterioração dos parâmetros nutricionais e de composição corporal, com uma redução de 1,9% no peso, 3,4% na prega cutânea tricipital, 2,6% no perímetro braquial, 32,2% na pré-albuminémia, 16,8% na transferrinémia, 18,3% na albuminémia, 13,1% na percentagem de linfócitos, 12,4% na força muscular, 4,3% no índice de massa gorda e 4,2% no índice de massa “não gorda”. A referida degradação foi proporcional à duração do internamento pós-operatório, excepto nos parâmetros analíticos e na massa gorda. A mortalidade relacionou-se significativamente com maiores reduções percentuais de massa “não gorda” (20,1 versus 3,7%; p=0,033) e de água (22,2 versus 2,9%, p=0,013) e a morbilidade com maiores reduções relativas de peso (7,7 versus 1%, p=0,031) e de força muscular (16,8 versus 10%, p=0,014). Conclusões: Estes resultados corroboram a necessidade de uma vigilância sistemática do estado nutricional no decurso do internamento hospitalar peri-operatório que possibilite e oriente uma atempada intervenção terapêutica. Palavras-chave: Estado nutricional, composição corporal, cirurgia electiva, desnutrição Abreviaturas: I.M.C.: índice de massa corporal; n.s.: estatisticamente não significativo; RR: risco relativo; vs: versus; f: Coeficiente de correlação de Spearman

Quaternionic eigenvalue problem

We discuss the (right) eigenvalue equation for $\mathbb{H}$, $\mathbb{C}$ and $\mathbb{R}$ linear quaternionic operators. The possibility to introduce an isomorphism between these operators and real/complex matrices allows to translate the quaternionic problem into an {\em equivalent} real or complex counterpart. Interesting applications are found in solving differential equations within quaternionic formulations of quantum mechanics.Comment: 13 pages, AMS-Te

Mathematica tools for quaternionic polynomials

In this paper we revisit the ring of (left) one-sided quaternionic polynomials with special focus on its zero structure. This area of research has attracted the attention of several authors and therefore it is natural to develop computational tools for working in this setting. The main contribution of this paper is a Mathematica collection of functions QPolynomial for solving polynomial problems that we frequently find in applications.(undefined)info:eu-repo/semantics/publishedVersio

Changes in microphytobenthos fluorescence over a tidal cycle: implications for sampling designs

Intertidal microphytobenthos (MPB) are important primary producers and provide food for herbivores in soft sediments and on rocky shores. Methods of measuring MPB biomass that do not depend on the time of collection relative to the time of day or tidal conditions are important in any studies that need to compare temporal or spatial variation, effects of abiotic factors or activity of grazers. Pulse amplitude modulated (PAM) fluorometry is often used to estimate biomass of MPB because it is a rapid, non-destructive method, but it is not known how measures of fluorescence are altered by changing conditions during a period of low tide. We investigated this experimentally using in situ changes in minimal fluorescence (F) on a rocky shore and on an estuarine mudflat around Sydney (Australia), during low tides. On rocky shores, the time when samples are taken during low tide had little direct influence on measures of fluorescence as long as the substratum is dry. Wetness from wave-splash, seepage from rock pools, run-off, rainfall, etc., had large consequences for any comparisons. On soft sediments, fluorescence was decreased if the sediment dried out, as happens during low-spring tides on particularly hot and dry days. Surface water affected the response of PAM and therefore measurements used to estimate MPB, emphasising the need for care to ensure that representative sampling is done during low tide

Flavored CP asymmetries for type II seesaw leptogenesis

A novel contribution to the leptonic CP asymmetries in type II seesaw leptogenesis scenarios is obtained for the cases in which flavor effects are relevant for the dynamics of leptogenesis. In the so-called flavored leptogenesis regime, the interference between the tree-level amplitude of the scalar triplet decaying into two leptons and the one-loop wave function correction with leptons in the loop, leads to a new nonvanishing CP asymmetry contribution. The latter conserves total lepton number but violates lepton flavor. Cases in which this novel contribution may be dominant in the generation of the baryon asymmetry are briefly discussed

Polynomials over quaternions and coquaternions: a unified approach

This paper aims to present, in a unified manner, results which are valid on both the algebras of quaternions and coquaternions and, simultaneously, call the attention to the main differences between these two algebras. The rings of one-sided polynomials over each of these algebras are studied and some important differences in what concerns the structure of the set of their zeros are remarked. Examples illustrating this different behavior of the zero-sets of quaternionic and coquaternionic polynomials are also presented.(undefined)info:eu-repo/semantics/publishedVersio