Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 69
Filtrar
1.
Phys Rev E ; 109(1-1): 014107, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38366493

RESUMO

One of the main issues that real energy converters present, when they produce effective work, is the inevitable entropy production. Within the context of nonequilibrium thermodynamics, entropy production tends to energetically degrade human-made or living systems. On the other hand, it is not useful to think about designing an energy converter that works in the so-called minimum entropy production regime since the effective power output and efficiency are zero. In this paper we establish some energy conversion theorems similar to Prigogine's theorem with constrained forces. The purpose of these theorems is to reveal trade-offs between design and the so-called operation modes for (2×2)-linear isothermal energy converters. The objective functions that give rise to those thermodynamic constraints show stability. A two-mesh electric circuit was built as an example to demonstrate the theorems' validity. Likewise, we reveal a type of energetic hierarchy for power output, efficiency, and dissipation function when the circuit is tuned to any of the operating regimes studied here. These are maximum power output (MPO), maximum efficient power (MPη), maximum omega function (MΩ), maximum ecological function (MEF), maximum efficiency (Mη), and minimum dissipation function (mdf).

2.
Polymers (Basel) ; 15(6)2023 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-36987228

RESUMO

Due to the energy requirements for various human activities, and the need for a substantial change in the energy matrix, it is important to research and design new materials that allow the availability of appropriate technologies. In this sense, together with proposals that advocate a reduction in the conversion, storage, and feeding of clean energies, such as fuel cells and electrochemical capacitors energy consumption, there is an approach that is based on the development of better applications for and batteries. An alternative to commonly used inorganic materials is conducting polymers (CP). Strategies based on the formation of composite materials and nanostructures allow outstanding performances in electrochemical energy storage devices such as those mentioned. Particularly, the nanostructuring of CP stands out because, in the last two decades, there has been an important evolution in the design of various types of nanostructures, with a strong focus on their synergistic combination with other types of materials. This bibliographic compilation reviews state of the art in this area, with a special focus on how nanostructured CP would contribute to the search for new materials for the development of energy storage devices, based mainly on the morphology they present and on their versatility to be combined with other materials, which allows notable improvements in aspects such as reduction in ionic diffusion trajectories and electronic transport, optimization of spaces for ion penetration, a greater number of electrochemically active sites and better stability in charge/discharge cycles.

3.
Rev Gastroenterol Mex (Engl Ed) ; 88(3): 232-237, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-34972678

RESUMO

INTRODUCTION AND OBJECTIVES: Bariatric surgery is the most effective treatment for weight loss, with comorbidity control. With low complication rates, the reasons for reoperation are major complications or weight loss failure/weight regain. Nonsurgical problems can also present, such as anemia, dehydration, chronic pain, and malnutrition, among others. Our aim was to analyze the main causes of revisional surgery, reoperation, and hospital readmission, at a specialized bariatric center. METHODS: A retrospective study was conducted on patients that underwent bariatric surgery within the time frame of 2012 and 2019. The baseline analysis included demographic, anthropometric, and perioperative data, as well as a sub-analysis of the main readmission causes and complications. RESULTS: A total of 776 primary surgeries were performed (649 RYGBP, 127 SG, and 10 revisional surgeries), and 99 patients were identified for the study: 10 revisional surgeries, 44 reoperations, and 45 readmissions. The incidence of revisional surgery was 1.2%, reoperation was 5.6%, and readmission 5.8%. Fifty percent of the revisional surgeries were performed due to insufficient weight loss or weight regain; the most frequent causes of reoperation were cholecystitis (38.6%) and internal hernias (9.1%); and the most common causes of readmission were nonspecific abdominal pain (35.5%) and dehydration (24.4%). CONCLUSION: The most frequent causes of postoperative readmission were nonsurgical events, followed by non-bariatric reoperations, and finally revisional surgeries. There was a low incidence of early reoperations. Knowledge of the abovementioned data is important for identifying higher-risk patients, to prevent major complications.

4.
J Appl Microbiol ; 132(1): 571-583, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33982373

RESUMO

AIM: Intestinal dysfunction in cirrhosis patients is linked to death by bacterial infections. Currently, there is no effective therapy for this complication. This study aims to evaluate butyrate, a novel postbiotic, on the intestinal inflammatory response, tight junction proteins and the microbiota in the cholestasis model. METHODS AND RESULTS: Wistar rats underwent 15 days of bile duct ligation (BDL). We administered butyrate at a concentration of 1%. The BDL group did not receive treatment. The results showed that butyrate could significantly reduce pro-inflammatory cytokines (IL-17A, IFN-γ, TNF-α) in the ileum and colon while promoting IL-10 expression in the colon. Moreover, it significantly promotes tight junction protein (cld-1, occludin and ZO-1) expression in the ileum. A similar effect was observed in the colon except for ZO-1. Additionally, butyrate limited taxa diversity loss and promoted probiotic genera expansion such as Lachnospira, Prevotella and Lactobacillus. The increase in Turicibacter and Clostridiaceae distinguished the BDL group. CONCLUSIONS: Butyrate is effective in regulating the inflammatory response, tight junction proteins and limits bacterial diversity loss. SIGNIFICANCE AND IMPACT OF THE STUDY: This research reveals that butyrate could represent an interesting postbiotic metabolomic intervention for intestinal epithelium dysfunction in liver disease.


Assuntos
Colestase , Disbiose , Animais , Butiratos , Colestase/tratamento farmacológico , Fibrose , Humanos , Mucosa Intestinal , Ratos , Ratos Wistar
5.
Phys Chem Chem Phys ; 23(10): 5870-5877, 2021 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-33659971

RESUMO

The interaction between nitrogen-doped graphene defects (N3V1 and N4V2 pyridinic, and N3V1 and N3V3 pyrrolic) and benzene have been investigated by applying density functional theory (DFT), together with the vdW-DF correction. We discovered that only the N3V3 pyrrolic defect is a reactive site (6π-component), forming a cycloadduct with benzene (4π-component) that has energy barriers below 154.38 kJ mol-1 (1.60 eV). The conduction and valence bands (HOMO and LUMO) for N3V3 form a degenerate pair of orbitals at the gamma point, with the same ionization potential (IP) and electron affinity (EA). Likewise, inspection of the orbital symmetries for both systems confirms that these must undergo concerted reactions based on the Woodward and Hoffmann principles of orbital symmetry, with the appropriate orbital occupancies. This is the first time that substitutionally doped graphene has been demonstrated to participate as a 6π-component for cycloaddition reactions with benzene.

6.
Sci Total Environ ; 758: 143637, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33248780

RESUMO

The population of the Canary Islands has been exposed to high levels of persistent organic pollutants (POPs). Biomonitoring studies are essential to know the temporal trend in residue levels, particularly of substances banned decades ago. The purpose of this study was to analyze the distribution of plasma concentrations of 59 POPs in 175 participants from the PREDIMED-Plus trial (2014-2016), and to compare them with the distribution of these POPs in 343 participants in the PREDIMED trial (2006-2009). All participants had metabolic syndrome. No difference in the distribution of age, gender or BMI was observed between trials. POPs were determined by gas chromatography-mass spectrometry. Density plots -POP Geoffrey Rose curves- were used to represent the full population distribution of each compound. Three out of 59 POPs were detected and quantified in ≥95% of the samples (p,p'-DDE, median = 694.7 ng/g lipid; HCB, median = 57.0 ng/g lipid; and ß-HCH, median = 75.7 ng/g lipid). PCB congeners 138, 153 and 180 were detected in 64.6, 40.0 and 88.0% of the samples. Females showed highest concentrations of organochlorine pesticides and those subjects who lost ˃ 5 kg showed significant higher plasma concentrations of POPs. In a range of 6-14 years, plasma concentrations of POPs decreased 3.3-21.6 fold, being notable the decrease of 28.7-fold observed for HCB among women. Despite this sharp decline, levels of POPs are still higher than those reported in other regions, since one third of the subjects included in the present report had high concentration of more than three pollutants. Continuous biomonitoring studies are required to know the evolution of the levels of residues and to evaluate the effectiveness of environmental policies.


Assuntos
Poluentes Ambientais , Hidrocarbonetos Clorados , Praguicidas , Bifenilos Policlorados , Idoso , Monitoramento Biológico , Feminino , Humanos , Poluentes Orgânicos Persistentes , Espanha
7.
Sci Total Environ ; 706: 135750, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31841855

RESUMO

Heavy metals and other toxic elements are frequently detected in humans. Rare earth elements (REE) have arisen as a novel group of substances considered as emerging pollutants due to its dependence for high tech industry. We designed a study aimed to conduct the biomonitoring a total of 45 inorganic elements in the population of Andalusia (Spain). A total of 419 participants were recruited and their plasma samples analyzed. Concentration of elements, including elements in the ATSDR's priority pollutant list and REE were measured by ICP-MS in the blood plasma of participants. Arsenic, copper, lead, selenium, antimony, strontium, and bismuth were detected in ˃98% of subjects. Median values of arsenic, mercury and lead were 1.49, 1.46, and 5.86 ng/mL, respectively. These concentrations did not exceed reference values published by international agencies. We observed a positive correlation between age and plasma concentrations of arsenic, mercury, antimony and strontium. Sum of elements was lower in the group of subjects younger than 45 years old (P = 0.002). Positive correlations were observed between body mass index (BMI) and plasma concentrations of barium, cerium, osmium, tin, and ytterbium. 7 out of 26 REEs showed a percentage of detection ≥ 90%. Bismuth, yttrium, and cerium were quantified at the highest concentrations (median value = 7.7, 0.19, and 0.16 ng/mL, respectively). We found that plasma levels of 6 REEs were higher among males, and a positive correlation between REEs and age was detected. The present results suggest a potential interaction with the human physiology that deserves additional research. Given the high persistence of these elements in the environment, and the significant technological dependence on them, future studies are needed to elucidate the potential sources of exposure and possible adverse effects on health, especially in the most vulnerable populations.


Assuntos
Monitoramento Biológico , Estudos Transversais , Humanos , Masculino , Metais Pesados , Metais Terras Raras , Pessoa de Meia-Idade , Espanha
8.
J Forensic Leg Med ; 68: 101868, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31585334

RESUMO

The aim of this study was to analyze the prevalence of ethanol in individuals (277) subjected to a mandatory medico-legal autopsy in the Institute of Legal Medicine of Las Palmas (Canary Islands, Spain) during 2016-2017, comparing the results with data published in 2015. Blood and/or vitreous humor samples were analyzed by gas chromatography. 31.8% of the individuals were positive to ethanol. We observed a decrease in the prevalence of ethanol among males (p = 0.002). While the prevalence of ethanol was reduced, the concentration among those positive subjects has increased. 11.9% of the series died in a traffic accident and the percentage of positive to ethanol decreased in relation to 2015 (64.3, 25.0, and 35.3%). The number of suicides remains constant, although the age of the suiciders has been significantly reduced (p = 0.022). The results of this study indicate that ethanol is still heavily involved in non-natural deaths.


Assuntos
Acidentes de Trânsito/mortalidade , Depressores do Sistema Nervoso Central/análise , Etanol/análise , Suicídio Consumado/estatística & dados numéricos , Violência/estatística & dados numéricos , Corpo Vítreo/química , Adolescente , Adulto , Distribuição por Idade , Idoso , Idoso de 80 Anos ou mais , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Distribuição por Sexo , Espanha/epidemiologia , Adulto Jovem
10.
J Mol Model ; 24(9): 244, 2018 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-30128714

RESUMO

An effectiveway of enhancing hydrogen storage on adsorbent materials can be induced by the hydrogen spill-over mechanism, although to date there is no general consensus which satisfactorily explains the mechanism. In this work, a possible reaction path to explain hydrogen adsorption is shown. Density-functional calculations were used to study the dissociation of molecular hydrogen near to a stressed region, as a consequence of chemisorbed hydrogen at the graphene-nitrogen surface. We found that as a result of the buckling induced by the chemisorbed hydrogen, the dissociation barrier of molecular hydrogen diminished by 0.84 eV. The chemisorbed hydrogen is the final state in the spill-over mechanism on a graphene-nitrogen decorated with palladium clusters. This effect helps to create hydrogen nanoislands that may change the diffusion and detrapping of H. An electronic structure analysis suggests that these systems occasionally present metallic or semiconductor behavior. Graphical Abstract Hydrogen dissociation and adsorption process via buckling defect.

11.
Trop Anim Health Prod ; 50(3): 469-476, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29086149

RESUMO

The dual-purpose bovine system represents 98.4% of the bovine livestock of Veracruz, the main cattle-producing state of Mexico. This system supplies calves to meat companies, a sector in which Veracruz has been the national leader in the last decade. The objective of the present study was to analyze the effect of the altitudinal zonation of farms on livestock technology and productivity in a microbasin of the Gulf of Mexico where small farms predominate. Structured interviews were applied to producers located in three altitudinal zones (at average altitudes of 50, 140, and 450 m, respectively, for lower, middle, and upper zones). Sample size was 135 farms having similar land surface (within a range of 15-22 ha). The results indicated multiple differences among farms located in the three zones. Farms in the middle and lower zones presented higher productive indicators than those in the upper zone. Differences in herd structure and management resulted in important differences in productivity, income, and profits in milk and calf production. We concluded from this study that altitudinal zonation in Veracruz had a clear effect on the differentiation of small farms, which are representative of dual-purpose cattle. The upper zone performs cattle activity under conditions with greater disadvantages in the analyzed region.


Assuntos
Altitude , Indústria de Laticínios/métodos , Fazendas , Carne , Leite , Animais , Bovinos , Clima , Mudança Climática , Feminino , Geografia , Golfo do México , Gado , Masculino , México , Pobreza , Tamanho da Amostra
12.
Acta Ortop Mex ; 32(5): 279-282, 2018.
Artigo em Espanhol | MEDLINE | ID: mdl-30726589

RESUMO

OBJECTIVE: To describe the most common types of fractures in patients under 16 years of age at the forearm level, and to evaluate depending on the level of the fracture, the treatment with better results. MATERIAL AND METHODS: We perform a retrospective analysis to determine the frequency of forearm fractures in patients under 16 years, in the period from January 2013-July 2017. The following diagnoses were entered into the system: forearm fracture, radius fracture, ulnar fracture and bilateral fracture. RESULTS: We included 573 patients: 413 male, 160 females; right affected side: 230, left: 338, bilateral 5. Affected level: 438 distal, 102 mid-shaft and 33 proximal. The peak age of presentation was eight years. The initial treatment was conservative in 92%, followed by closed reduction and percutaneous fixation with 4.71 and 2.4% for open reduction and internal fixation with plates. There was a failed initial treatment at 3.83% when an inadequate reduction was found. DISCUSSION: We found that the treatment of this fractures in our institution is conservative in 92%, closed reduction and percutaneous fixation in 4.71% and open reduction and internal fixation in a 2.4% being The highest prevalence in patients older than 12 years with bilateral mid-shaft fractures.


OBJETIVO: Describir los tipos de fracturas más comunes en pacientes menores de 16 años de edad a nivel de antebrazo y evaluar, dependiendo del nivel de la fractura, el tratamiento con mejores resultados. MATERIAL Y MÉTODOS: Realizamos un análisis retrospectivo para determinar frecuencia de las fracturas de antebrazo en menores de 16 años, en el período de Enero 2013-Julio 2017. Se ingresó en sistema los siguientes diagnósticos: fractura de antebrazo, fractura de radio, fractura de cúbito y fractura radiocubital. RESULTADOS: Se incluyeron 573 pacientes: 413 hombres, 160 mujeres; lado afectado derecho: 230, izquierdo 338, bilateral 5; nivel afectado: 438 distales, 102 medias y 33 proximales. La edad pico de presentación fue a los ocho años. El tratamiento inicial fue conservador en 92%, seguido de reducción cerrada y fijación percutánea con 4.71% y se tuvo 2.4% para reducción abierta y fijación interna con placas. Se tuvo un tratamiento inicial fallido en 3.83% al encontrarse una reducción inadecuada. DISCUSIÓN: Encontramos que el tratamiento de las fracturas en nuestra institución es conservador en 92%, se usa la reducción cerrada y fijación percutánea sólo en 4.71% y sólo se realiza de primera intención la reducción abierta y fijación interna en 2.4% siendo la mayor prevalencia en pacientes mayores de 12 años con fracturas diafisarias medias radiocubitales.


Assuntos
Traumatismos do Antebraço , Fraturas do Rádio , Fraturas da Ulna , Adolescente , Criança , Feminino , Fixação Interna de Fraturas , Humanos , Masculino , Radiografia , Fraturas do Rádio/cirurgia , Estudos Retrospectivos , Resultado do Tratamento , Fraturas da Ulna/cirurgia
13.
Food Chem Toxicol ; 92: 236-44, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27106137

RESUMO

Meat is one of the staples of the human diet, which provides high-quality nutrients, but that also constitutes a relevant source of cholesterol and saturated fatty acids. Epidemiologic studies have linked consumption of red or processed meat with obesity, type 2 diabetes, cardiovascular diseases, and cancers. Most epidemiological studies suggest that a high intake of meat, especially processed meat, is associated with increased colorectal cancer risk. Potential reasons for the association between high meat intake and colorectal cancer risk include some chemicals naturally contained in meat, or generated by the processing and cooking. From the literature it can be concluded that there is enough epidemiological evidence linking processed meat intake and colorectal cancer risk, but there is limited evidence regarding unprocessed red meat intake and the disease. On the contrary, there is only limited evidence linking meat intake with other diseases such as cardiovascular disease, type 2 diabetes or other cancers. Nevertheless, the literature suggest that dietary intervention may be a promising approach for prevention of cancers of the colon, esophagus, liver, stomach and bladder, and type 2 diabetes and cardiovascular disease which still need to be confirmed by further well designed prospective studies and experimental research.


Assuntos
Doenças Cardiovasculares/etiologia , Diabetes Mellitus Tipo 2/etiologia , Carne/efeitos adversos , Neoplasias/etiologia , Culinária , Humanos , Fatores de Risco
14.
Prostate Cancer Prostatic Dis ; 19(1): 28-34, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26754263

RESUMO

BACKGROUND: Novel predictors of prognosis and treatment response for prostate cancer (PCa) are required to better individualize treatment. Single-nucleotide polymorphisms (SNPs) in four genes directly (XRCC5 (X-ray repair complementing defective repair in Chinese hamster cells 5) and XRCC6 (X-ray repair complementing defective repair in Chinese hamster cells 6)) or indirectly (PARP1 and major vault protein (MVP)) involved in non-homologous end joining were examined in 494 Spanish PCa patients. METHODS: A total of 22 SNPs were genotyped in a Biotrove OpenArray NT Cycler. Clinical tumor stage, diagnostic PSA serum levels and Gleason score at diagnosis were obtained for all participants. Genotypic and allelic frequencies were determined using the web-based environment SNPator. RESULTS: (XRCC6) rs2267437 appeared as a risk factor for developing more aggressive PCa tumors. Those patients carrying the GG genotype were at higher risk of developing bigger tumors (odds ratio (OR)=2.04, 95% confidence interval (CI) 1.26-3.29, P=0.004), present higher diagnostic PSA levels (OR=2.12, 95% CI 1.19-3.78, P=0.011), higher Gleason score (OR=1.65, 95% CI 1.01-2.68, P=0.044) and D'Amico higher risk tumors (OR=2.38, 95% CI 1.24-4.58, P=0.009) than those patients carrying the CC/CG genotypes. Those patients carrying the (MVP) rs3815824 TT genotype were at higher risk of presenting higher diagnostic PSA levels (OR=4.74, 95% CI 1.40-16.07, P=0.013) than those patients carrying the CC genotype. When both SNPs were analyzed in combination, those patients carrying the risk genotypes were at higher risk of developing D'Amico higher risk tumors (OR=3.33, 95% CI 1.56-7.17, P=0.002). CONCLUSIONS: We believe that for the first time, genetic variants at XRCC6 and MVP genes are associated with risk of more aggressive disease, and would be taken into account when assessing the malignancy of PCa.


Assuntos
Antígenos Nucleares/genética , Proteínas de Ligação a DNA/genética , Estudos de Associação Genética , Neoplasias da Próstata/genética , Partículas de Ribonucleoproteínas em Forma de Abóbada/genética , Quebras de DNA de Cadeia Dupla , DNA Helicases/genética , Reparo do DNA/genética , Predisposição Genética para Doença , Genótipo , Humanos , Autoantígeno Ku , Masculino , Gradação de Tumores , Estadiamento de Neoplasias , Poli(ADP-Ribose) Polimerase-1 , Poli(ADP-Ribose) Polimerases/genética , Polimorfismo de Nucleotídeo Único , Neoplasias da Próstata/patologia , Fatores de Risco
15.
J Agromedicine ; 21(1): 34-42, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26479327

RESUMO

The incidence of bladder cancer has increased significantly since the 1950s. Pesticide exposure has been linked with increasing bladder cancer incidence, although the evidence is inconclusive. However, most epidemiological studies did not evaluate the potential role played by the organochlorine pesticides, the most widely used pesticides in Western countries from the 1940s to the 1970s. Organochlorine pesticides were banned in the late 1970s because of their persistence in the environment and their carcinogenic and mutagenic effects. Organochlorine pesticides were employed in huge amounts in the Spanish archipelago of the Canary Islands; the authors, therefore, evaluated the role played by organochlorine pesticides exposure on bladder cancer. Serum levels of the most prevalent organochlorine pesticides used in the agriculture of these Islands (dichlorodiphenyltrichloroethane [p,p'-DDT], and its metabolites dichlorodiphenyldichloroethylene [p,p'-DDE] and dichlorodiphenyldichloroethane [p,p'-DDD], hexachlorobenzene, hexachlorocyclohexane isomers, aldrin, dieldrin, endrin, heptachlor, cis-chlordane, trans-chlordane, α- and ß-endosulfan, endosulfan sulfate, methoxychlor, and mirex) were measured in 140 bladder cancer cases and 206 controls. GST-M1 and GST-T1 gene polymorphisms were genotyped by polymerase chain reaction (PCR)-based methods. These results showed that serum levels of organochlorine pesticides did not increase bladder cancer risk. On the contrary, total burden of hexachlorocyclohexanes was found to be negatively associated to bladder cancer (odds ratio [OR] = 0.929, 95% confidence interval [CI]: 0.865-0.997; P = .041). This effect disappeared when the distribution of the gluthathione S-transferase polymorphisms was introduced in the statistical model. These results indicate that organochlorine pesticides are not a risk factor for bladder cancer. However, these findings provide additional evidence of gene-environment interactions for organochlorine pesticides and bladder cancer and reinforce the relevance of genes encoding xenobiotic-metabolizing enzymes in bladder cancer.


Assuntos
Hidrocarbonetos Clorados/sangue , Exposição Ocupacional/análise , Praguicidas/sangue , Neoplasias da Bexiga Urinária/etiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Fazendeiros , Feminino , Interação Gene-Ambiente , Glutationa Transferase/genética , Humanos , Hidrocarbonetos Clorados/toxicidade , Masculino , Pessoa de Meia-Idade , Exposição Ocupacional/efeitos adversos , Praguicidas/toxicidade , Polimorfismo Genético , Espanha , Neoplasias da Bexiga Urinária/sangue , Neoplasias da Bexiga Urinária/genética
16.
Artigo em Inglês | MEDLINE | ID: mdl-25353449

RESUMO

This paper discusses the possibility of using the Joule-Brayton cycle to determine the accessible value range for the coefficients a and b of the heat capacity at constant pressure C(p), expressed as C(p) = a + bT (with T the absolute temperature) by using the Carnot theorem. This is made for several gases which operate as the working fluids. Moreover, the landmark role of the Curzon-Ahlborn efficiency for this type of cycle is established.

17.
Clin Transl Oncol ; 16(10): 849-58, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24981589

RESUMO

Head and neck squamous cell carcinoma is the sixth most common cancer type worldwide. Also the 5-year survival rate of less than 50 % seems to be lower than other cancer types. There are some reasons behind this high mortality rate; one of them is the lack of knowledge about the biology and genomic instability behind the carcinogenic processes. These biological features could condition the failure of frontline treatment, in which case rescue treatment should be used, representing an overtreatment for the patients. For years many biological factors have been tested as prognostic and predictive factors in relation to treatment with a modest success. To find appropriate tests which could be used in the context of the individualized treatment decision, we have reviewed new biological markers, not only in tumor tissue, but also in normal tissue from head and neck carcinoma patients.


Assuntos
Biomarcadores Tumorais/metabolismo , Carcinoma de Células Escamosas/metabolismo , Neoplasias de Cabeça e Pescoço/metabolismo , Carcinoma de Células Escamosas/terapia , Neoplasias de Cabeça e Pescoço/terapia , Humanos , Prognóstico , Carcinoma de Células Escamosas de Cabeça e Pescoço
18.
Comput Math Methods Med ; 2014: 585306, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24688595

RESUMO

Thermography is a useful tool since it provides information that may help in the diagnostic of several diseases in a noninvasive and fast way. Particularly, thermography has been applied in the study of the diabetic foot. However, most of these studies report only qualitative information making it difficult to measure significant parameters such as temperature variations. These variations are important in the analysis of the diabetic foot since they could bring knowledge, for instance, regarding ulceration risks. The early detection of ulceration risks is considered an important research topic in the medicine field, as its objective is to avoid major complications that might lead to a limb amputation. The absence of symptoms in the early phase of the ulceration is conceived as the main disadvantage to provide an opportune diagnostic in subjects with neuropathy. Since the relation between temperature and ulceration risks is well established in the literature, a methodology that obtains quantitative temperature differences in the plantar area of the diabetic foot to detect ulceration risks is proposed in this work. Such methodology is based on the angiosome concept and image processing.


Assuntos
Pé Diabético/diagnóstico , Pé Diabético/patologia , Pé/fisiologia , Temperatura , Termografia/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco
19.
Strahlenther Onkol ; 190(2): 210-6, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24362501

RESUMO

BACKGROUND AND PURPOSE: A close relationship exists between immune response and tumor behavior. This study aimed to explore the associations between radiation-induced apoptosis (RIA) in peripheral blood lymphocytes (PBL) and clinical pathological variables. Furthermore, it assessed the role of RIA as a prognostic factor for survival in cervical carcinoma patients. PATIENTS AND METHODS: Between February 1998 and October 2003, 58 consecutive patients with nonmetastatic, localized stage I-II cervical carcinoma who had been treated with radiotherapy (RT) ± chemotherapy were included in this study. Follow-up ended in January 2013. PBL subpopulations were isolated and irradiated with 0, 1, 2 and 8 Gy then incubated for 24, 48 and 72 h. Apoptosis was measured by flow cytometry and the ß value, a parameter defining RIA of lymphocytes, was calculated. RESULTS: Mean follow-up duration was 111.92 ± 40.31 months. Patients with lower CD8 T lymphocyte ß values were at a higher risk of local relapse: Exp(B) = 5.137, confidence interval (CI) 95 % = 1.044-25.268, p = 0.044. Similar results were observed for regional relapse: Exp(B) = 8.008, CI 95 % = 1.702-37.679, p = 0.008 and disease relapse: Exp(B) = 6.766, CI 95 % = 1.889-24.238, p = 0.003. In multivariate analysis, only the CD8 T lymphocyte ß values were found to be of prognostic significance for local disease-free survival (LDFS, p = 0.049), regional disease-free survival (RDFS, p = 0.002), metastasis-free survival (MFS, p = 0.042), disease-free survival (DFS, p = 0.001) and cause-specific survival (CSS p = 0.028). CONCLUSION: For the first time, RIA in CD8 T lymphocytes was demonstrated to be a predictive factor for survival in cervical carcinoma patients.


Assuntos
Apoptose/efeitos da radiação , Linfócitos T CD8-Positivos/efeitos da radiação , Neoplasias do Colo do Útero/imunologia , Neoplasias do Colo do Útero/radioterapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Apoptose/efeitos dos fármacos , Apoptose/imunologia , Braquiterapia , Linfócitos T CD8-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/imunologia , Quimiorradioterapia , Cisplatino/administração & dosagem , Terapia Combinada , Intervalo Livre de Doença , Feminino , Citometria de Fluxo , Seguimentos , Humanos , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico , Dosagem Radioterapêutica , Neoplasias do Colo do Útero/tratamento farmacológico , Neoplasias do Colo do Útero/mortalidade , Neoplasias do Colo do Útero/patologia
20.
Artigo em Inglês | MEDLINE | ID: mdl-24329249

RESUMO

A new connection between maximum-power Curzon-Ahlborn thermal cycles and maximum-work reversible cycles is proposed. This linkage is built through a mapping between the exponents of a class of heat transfer laws and the exponents of a family of heat capacities depending on temperature. This connection leads to the recovery of known results and to a wide and interesting set of results for a class of thermal cycles. Among other results it was found that it is possible to use analytically closed expressions for maximum-work efficiencies to calculate good approaches to maximum-power efficiencies. Behind the proposed connection is an interpretation of endoreversibility hypothesis. Additionally, we suggest that certain reversible maximum-work cycles depending on working substance can be used as reversible landmarks for FTT maximum-power cycles, which also depend on working substance properties.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...