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1.
Soft Matter ; 19(36): 6871-6874, 2023 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-37682026

RESUMO

Pure cyclic diamino acids (CdAA) gel differently than combinations of CdAAs, altering the gelation behavior to highly-branched colloidal protein crystal networks reminiscent of traditional fat crystal networks in canola oil, making it an exciting structuring agent for unsaturated oils.

2.
Chem Soc Rev ; 44(17): 6035-58, 2015 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-25941907

RESUMO

Rational design of small molecular gelators is an elusive and herculean task, despite the rapidly growing body of literature devoted to such gels over the past decade. The process of self-assembly, in molecular gels, is intricate and must balance parameters influencing solubility and those contrasting forces that govern epitaxial growth into axially symmetric elongated aggregates. Although the gelator-gelator interactions are of paramount importance in understanding gelation, the solvent-gelator specific (i.e., H-bonding) and nonspecific (dipole-dipole, dipole-induced and instantaneous dipole induced forces) intermolecular interactions are equally important. Solvent properties mediate the self-assembly of molecular gelators into their self-assembled fibrillar networks. Herein, solubility parameters of solvents, ranging from partition coefficients (log P), to Henry's law constants (HLC), to solvatochromic parameters (ET(30)), and Kamlet-Taft parameters (ß, α and π), and to Hansen solubility parameters (δp, δd, δh), are correlated with the gelation ability of numerous classes of molecular gelators. Advanced solvent clustering techniques have led to the development of a priori tools that can identify the solvents that will be gelled and not gelled by molecular gelators. These tools will greatly aid in the development of novel gelators without solely relying on serendipitous discoveries. These tools illustrate that the quest for the universal gelator should be left in the hands of Don Quixote and as researchers we must focus on identifying gelators capable of gelling classes of solvents as there is likely no one gelator capable of gelling all solvents.


Assuntos
Géis/química , Solventes/química , Modelos Químicos , Solubilidade , Termodinâmica
3.
Soft Matter ; 10(43): 8652-8, 2014 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-25252108

RESUMO

Molecular rotors may be utilized as non-invasive, non-disruptive and highly sensitive alternatives to conventional measures of bulk viscosity when the oil is entrained in a colloidal fat crystal network. Oil viscosity changes based on the molecular confinement of the oil, which is dependent on its molecular volume. Changes in micro-viscosity were not dependent on the solids content, but instead were strongly dependent on the box-counting fractal dimension in high-space filling colloidal fat crystal networks (i.e., D > 1.89). A bulk oil viscosity is often an overestimation of the actual viscosity of the entrained oil and may not be appropriate when predicting diffusion in multi-phase materials.

4.
ISA Trans ; 136: 267-274, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36437173

RESUMO

A data-driven controller is presented in this paper, which stems from the well known model-free adaptive control approach based on an equivalent linearized dynamical model of the plant. Inspired by the recent paper (Liu and Yang, 2019), the output tracking problem is here solved by a data-driven adaptive sliding-mode controller simultaneously ensuring prescribed performance constraints. To allow a rigorous stability analysis, the sliding variable, and the consequently derived controller, have been redesigned with respect to the inspiring paper. A proper setting of the gain of the discontinuous term is shown necessary to ensure closed loop stability. Validation of the technique has been extensively performed on the well assessed high-fidelity tool FAST (NREL) to solve the efficiency maximization problem using the proposed approach for a 5 MW wind turbine operating in the medium wind speed region.

5.
Nanoscale ; 15(42): 16933-16946, 2023 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-37850382

RESUMO

Substituting the sole primary hydroxyl group of the low molecular weight organogelator (LMOG), 1,3:2,4-dibenzylidene-D-sorbitol (DBS), with a halogen atom (Cl, Br, or I; i.e., 6-Cl-DBS, 6-Br-DBS, or 6-I-DBS) drastically alters the supramolecular self-assembled fibrillar network (SAFiN) that forms when the molecules aggregate. The SAFiN varies depending on the solvent properties, impacting the role of non-covalent hydrogen- and halogen-bonding interactions along and between fibers. The halogenated DBS derivatives have more coherent crystalline fibers than DBS, with larger length-to-width aspect ratios. High-resolution synchrotron powder X-ray diffraction of each wet-state gel in toluene and DFT optimization obtained complete structures for the three halogenated DBS derivatives in their SAFiNs. The presence of a halogen atom reduces the reliance on hydrogen bonding by enabling new halogen bonding interactions that impact the self-assembly behavior, especially in solvents of higher polarity. For 6-I-DBS and 6-Br-DBS, the primary forces driving molecular self-assembly are C-H⋯π and intermolecular halogen-to-halogen interactions, and there is one unique molecule in each unit cell. However, the Cl atoms of 6-Cl-DBS are not close, and its SAFiN structures rely more on hydrogen bonding. As a result, the enhanced hydrogen bonding, electronic differences among the halogens, and spatial factors allow its unit cell to include two independent molecules of 6-Cl-DBS.

6.
Food Chem ; 382: 132326, 2022 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-35152026

RESUMO

10 wt% oil-in-water emulsions with varied palm olein and stearin PO:PS ratios stabilized with 0.8 wt% Tween80 and tempered to obtain partially crystalline (CR) droplets (cooled from 80 to 4 °C and held overnight to induce nucleation/crystallization) or undercooled liquid (UC) droplets (cooled from 80 °C to 37 °C) produced emulsions with constant droplet size and polymorphism. However, zeta-potential decreased in undercooled emulsions due to crystallization/orientation of interfacial Tween, increasing alignment and ultimately a greater dipole moment. Significant differences in overall bioaccessibility between PO and PS present for the CR (PO bioaccessible fraction was 91%, whereas PS was 60%) and UC emulsions (PO and PS bioaccessibility were 96% and 77%).When only the solid fat content differs, and all other physical attributes remain constant, lipid digestibility decreases with increasing solid fat content; these findings, along with others, can be employed during food formulation and design more healthful foods.


Assuntos
Polissorbatos , Água , Cristalização , Digestão , Emulsões/química , Tamanho da Partícula , Polissorbatos/química , Água/química
7.
J Agric Food Chem ; 69(30): 8394-8402, 2021 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-34313430

RESUMO

Changes in the physical states, induced with different sous vide cooking temperatures, significantly (P < 0.05) altered lipid bioaccessibility measured in the TNO-simulated gastrointestinal tract model-1 of AAA boneless beef striploin, containing the longissimus lumborum muscle. The denaturation of actin significantly correlates with the total cumulative free fatty acid (FFA) bioaccessibility, whereby the striploin cooked to 60 °C presents the maximum lipid bioaccessibility (15.8 ± 1.0%), rate constant (ka) for FFA hydrolysis (0.087 ± 0.003 min-1), and greatest actin denaturation enthalpy (-0.57 ± 0.06 ΔH). Thus, thermal treatments above 60 °C significantly decrease the kinetics of lipolysis (70 °C = 0.042 ± 0.002 min-1 and 80 °C = 0.047 ± 0.002 min-1) and the resultant total lipid bioaccessibility (70 °C = 8.6 ± 0.7 and 80 °C = 8.3 ± 0.5%). This research highlights the potential to manipulate the physical food structure to alter digestion kinetics, supporting the need to understand supramolecular structures in food and their nutritional outcomes.


Assuntos
Culinária , Lipídeos , Animais , Bovinos , Músculos , Temperatura
8.
Phys Rev Lett ; 105(24): 243401, 2010 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-21231524

RESUMO

We report here the first successful synthesis of cold antihydrogen atoms employing a cusp trap, which consists of a superconducting anti-Helmholtz coil and a stack of multiple ring electrodes. This success opens a new path to make a stringent test of the CPT symmetry via high precision microwave spectroscopy of ground-state hyperfine transitions of antihydrogen atoms.

9.
Cir Pediatr ; 23(3): 161-4, 2010 Jul.
Artigo em Espanhol | MEDLINE | ID: mdl-23155662

RESUMO

BACKGROUND: Pressure ulcers are an emerging disease, due to survival increase of pediatric patients at risk (myelomeningocele, infantile cerebral paralysis, paraplegic, prematures with neurological sequelae, etc.), including as well, long time staging patients at intensive care units. OBJECTIVES: Provide for long-term treatment to pressure ulcer refractory to debridement procedures. METHODS: We used the biceps femoris muscular flap technique associated with fasciocutaneous flap in two patients, 16 year-olded, with tetraparesis secondary to cerebral palsy and, another 18 year-olded, with myelomeningocele sequelae. Both had sciatic ulcers refractory to treatment, 2 and 3 years evolutioned, respectively. RESULTS: The outcome was excellent in both cases, with definitive healing of the ulcer and no recurrence during one and two month follow-up. CONCLUSIONS: This technique, used in adults, can be applied to pediatric patients if no possibility of wandering. Muscle acts as a cuff between bone and skin and provides coating to the zone suffering pressure as an hypervascularized and no-functioning for active movement structure, but feasible in terms of trophism.


Assuntos
Úlcera por Pressão/cirurgia , Adolescente , Doença Crônica , Feminino , Humanos , Procedimentos Cirúrgicos Operatórios/métodos
10.
ISA Trans ; 96: 95-102, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31320141

RESUMO

The paper focuses on variable-rotor-speed/variable-blade-pitch wind turbines operating in the region of high wind speeds, where control is aimed at limiting the turbine energy capture to the rated power value. A robust sliding mode approach is proposed, using the blade pitch as control input, in order to regulate the rotor speed to a fixed rated value, in the presence of uncertainties characterizing the wind turbine model. Closed loop convergence of the overall control system is proved. The proposed control solution has been validated on a 5-MW three-blade wind turbine using the National Renewable Energy Laboratory (NREL) wind turbine simulator FAST (Fatigue, Aerodynamics, Structures, and Turbulence) code. A comparison with the standard FAST baseline controller (NWTC 2012 and Jonkman et al. 2009) has been also included.

11.
Adv Food Nutr Res ; 88: 1-45, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31151722

RESUMO

Nanotechnology is a rapidly developing toolbox that provides solutions to numerous challenges in the food industry and meet public demands for healthier and safer food products. The diversity of nanostructures and their vast, tunable functionality drives their inclusion in food products and packaging materials to improve their nutritional quality through bioactive fortification and probiotics encapsulation, enhance their safety due to their antimicrobial and sensing capabilities and confer novel sensorial properties. In this food nanotechnology state-of-the-art communication, matrix materials with particular focus on food-grade components, existing and novel production techniques, and current and potential applications in the fields of food quality, safety and preservation, nutrient bioaccessibility and digestibility will be detailed. Additionally, a thorough analysis of potential strategies to assess the safety of these novel nanostructures is presented.


Assuntos
Indústria Alimentícia/tendências , Alimentos/normas , Nanoestruturas/classificação , Nanotecnologia/métodos , Biopolímeros , Indústria Alimentícia/normas , Conservação de Alimentos/métodos , Inocuidade dos Alimentos/métodos , Marketing/tendências , Nanopartículas
12.
Health Phys ; 93(5): 547-59, 2007 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18049233

RESUMO

Almost 450 nuclear power plants are currently operating throughout the world and supplying about 17% of the world's electricity. These plants perform safely, reliably, and have no free-release of byproducts to the environment. Given the current rate of growth in electricity demand and the ever growing concerns for the environment, nuclear power can only satisfy the need for electricity and other energy-intensive products if it can demonstrate (1) enhanced safety and system reliability, (2) minimal environmental impact via sustainable system designs, and (3) competitive economics. The U.S. Department of Energy with the international community has begun research on the next generation of nuclear energy systems that can be made available to the market by 2030 or earlier, and that can offer significant advances toward these challenging goals; in particular, six candidate reactor system designs have been identified. These future nuclear power systems will require advances in materials, reactor physics, as well as thermal-hydraulics to realize their full potential. However, all of these designs must demonstrate enhanced safety above and beyond current light water reactor systems if the next generation of nuclear power plants is to grow in number far beyond the current population. This paper reviews the advanced Generation-IV reactor systems and the key safety phenomena that must be considered to guarantee that enhanced safety can be assured in future nuclear reactor systems.


Assuntos
Reatores Nucleares , Centrais Elétricas , Segurança
13.
G Ital Med Lav Ergon ; 29(3 Suppl): 849-50, 2007.
Artigo em Italiano | MEDLINE | ID: mdl-18409996

RESUMO

Contact dermatitis is more frequent among women for anatomical reasons and for extraprofessional exposure to irritants and detergents during homeworks. In addition sensitisation to contact haptens is different in sexes. The aim of our work was to evaluate the association between patch test skin sensitizations and professional exposure to metals analyzing data for gender. Of the 15.217 patients patch tested for dermatitis, 678 were metalworkers. The statistical analysis revealed a significant association between dermatitis and sensitisation to nickel in professional exposed women (OR = 1.68; LC50% 1.11-6.50) while metal sensitisation (Cr.Ni and Co) was not relevant in men: for them a significant association between dermatitis and sensitisation was found to quaternium (OR = 3.91; LC95% 1.18-12.9), to mercaptobenzothiazole (OR = 2.69; LC50% 1.11-6.50) and to ethylendiamine dichloride (OR = 2.53; LC95% 1-6.41). The authors stress the need to evaluate patch test sensitisation considering gender effects.


Assuntos
Dermatite Ocupacional/epidemiologia , Dermatite Ocupacional/etiologia , Metalurgia , Adulto , Feminino , Humanos , Masculino , Fatores Sexuais
14.
Cir Pediatr ; 19(2): 95-100, 2006 Apr.
Artigo em Espanhol | MEDLINE | ID: mdl-16846132

RESUMO

BACKGROUND: A gap greater than 3 cm between both esophageal pouches is observed in 1 of 20 cases of esophageal atresia. Our goal was to critically review our experience in the management of these patients. MATERIAL AND METHODS: During 1995-2004, 15 patients were treated for a long gap esophageal atresia (LEA). Gaps ranged from 3 to 8 cm. Ten patients presented a pure esophageal atresia. They were managed with a gastrostomy and delayed repair: 8 Schärli interventions and 2 esophageal flaps. The other 5 patients had an esophageal atresia with distal fistula (LEA-DF), and primary repair was attempted: 3 end-to-end esophageal anastomosis were achieved under a strong tension; 1 a Schärli procedure; 1 ligation of the fistula, feeding gastrostomy and delayed esophageal flap. The use of esophageal flaps is a late event in our series. since its introduction we've performed 5 esophageal atresia repairs using 3 flaps (2 pure atresias and 1 LEA-DF). RESULTS: From 9 Schärli we have to practice 2 reinterventions for anastomotic leak; there was 1 parahiatal hernia that needed surgery after 8 years. From 3 flaps 2 patients presented a persistent stricture that needed reintervention. All of the 3 E-E anastomosis had reintervention for persistent stricture and also anti-reflux procedures (Nissen). Eight patients showed a normal growth and development (4/9 Schärli, 3/3 flaps and 1/3 E-E). Seven patients are growth retarded (4/7 with associated malformations, 1/7 who developed an eosinophilic esophagitis and 2/7 preterm babies). CONCLUSIONS: The esophageal flap is our first choice, because the own esophagic tissue fills in the gap. In LEA-DF, we prefer fistula ligation, gastrostomy and delayed rise of a flap (as we did in our last patient) better than a very tense primary anastomosis. As a second option, a Schärli procedure offers satisfying mid-term results. Keeping the patient paralyzed and mechanically ventilated for 5-7 days after surgery helps to avoid disrupting forces on the anastomosis.


Assuntos
Atresia Esofágica/cirurgia , Gastrostomia/métodos , Aprendizagem , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Retalhos Cirúrgicos , Procedimentos Cirúrgicos Operatórios/métodos
15.
FEBS Lett ; 237(1-2): 85-90, 1988 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-3169242

RESUMO

The proton NMR characterization of bombesin has been carried out at 500 MHz in DMSO-d6 using two-dimensional homo- and 1H-13C hetero-correlated techniques. All resonances in the NMR spectra have been assigned and several coupling constants have been measured. The backbone J alpha CH-NH coupling constants have constant values that vary between 7.8 and 8.2 Hz and indicate an unfolded structure in DMSO-d6. Discrepancies with data recently obtained at 300 MHz [(1987) Eur. J. Biochem. 168, 193-199] are discussed.


Assuntos
Bombesina , Sequência de Aminoácidos , Bombesina/síntese química , Deutério , Dimetil Sulfóxido , Espectroscopia de Ressonância Magnética/métodos , Conformação Proteica
16.
Neuropsychologia ; 29(5): 361-78, 1991.
Artigo em Inglês | MEDLINE | ID: mdl-1886680

RESUMO

The main aim of the present study was to clarify whether different types of grasping may affect the transport component of prehension movements. To this purpose two experiments were carried out. In the first experiment the kinematics of arm movements (transport and manipulation components) were studied in eight normal subjects instructed to reach and grasp different objects located either 20 or 30 cm from their hand. The objects employed required two different types of grip: prehension with the whole hand and prehension with the index finger and the thumb (precision grip). In the second experiment subjects were instructed to point to the same objects employed in the first experiment. This experiment served as a control for the precision requirements related to the object size. The results showed that, once the precision requirements were taken into account, the transport component remained unmodified with the different types of grip. The time course of the manipulation component and its temporal relations with the transport component changed with the type of grasping. The maximal hand aperture was reached earlier in the precision grip than in the whole hand prehension and the temporal coupling with the transport component was weaker in the former condition than in the latter. The data are interpreted as further evidence in favour of independence between the transport and the manipulation "channels".


Assuntos
Braço/fisiologia , Mãos/fisiologia , Movimento/fisiologia , Adolescente , Humanos , Masculino , Estimulação Luminosa , Fatores de Tempo
17.
Int J Food Microbiol ; 95(2): 205-18, 2004 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-15282132

RESUMO

The isothermal survival curves of the heat resistant spores of Bacillus sporothermodurans IC4, in the range of 117-125 degrees C, were determined in chicken, mushroom and pea soups by the capillary method. They were all non-linear with a noticeable upper concavity and could be described by the equation log(10) [N(t)/N(0)]=-b(T)t(n) with a fixed power, n, of the order of 0.7-0.8. The temperature dependence of b(T) could be described by the equation b(T)=log(e)[1+exp[k(T-T(c))]], where T(c) is the temperature where intensive inactivation starts and k is the slope of b(T) at temperatures well above T(c). They were 121-123 degrees C and 0.2-0.4 degrees C(-1), respectively, depending on the soup. These parameters were used to estimate the survival curves of the spores in two non-isothermal heat treatments using the procedure originally proposed by Peleg and Penchina [Crit. Rev. Food Sci. Nutr. 40 (2000) 159]. The results were compared with experimental survival curves, determined by the direct injection method, in another laboratory. There was a general agreement, although not perfect, between the predicted and experimentally observed survival ratios. Also, the isothermal survival parameters, estimated directly from the non-isothermal inactivation data using the model, were in general agreement with those calculated from the isothermal data. This suggests that the heat inactivation patterns of B. sporothermodurans IC4 spores in soups can be at least roughly estimated using the same general survival model, which has until now only been experimentally validated for vegetative bacterial cells.


Assuntos
Bacillus/fisiologia , Microbiologia de Alimentos , Conservação de Alimentos/métodos , Temperatura Alta , Agaricales , Bacillus/crescimento & desenvolvimento , Cinética , Matemática , Modelos Biológicos , Pisum sativum/microbiologia , Produtos Avícolas/microbiologia , Valor Preditivo dos Testes , Esporos Bacterianos/crescimento & desenvolvimento , Fatores de Tempo
18.
IEEE Trans Biomed Eng ; 44(11): 1029-38, 1997 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9353982

RESUMO

In the present study, spontaneous postural behavior has been analyzed in freely standing multiple sclerosis (MS) patients, exhibiting no clinically assessable abnormalities of postural control. This population has been compared with two other groups, healthy people and hemiparetic patients. This latter group represents a situation where the central nervous system (CNS) lesion is precisely localized in one anatomical site and no signal-conduction disorders are present; i.e., it has an opposite anatomical character with respect to the MS at a preclinical stage. The hypothesis underlying the modeling study is the presence of a controller block working in a feedback posture control system. This controller block receives the body sway as input, and produces the corresponding ankle torque stabilizing the body, the latter being modeled as an inverted pendulum. The CNS damage, caused by MS, is supposed to be reflected in some detectable change in the structure of the controller of the posture control system. The identification of the controller has been performed by means of a parametric estimation procedure which employed as input sequences, data recorded by means of a movement-analysis (MA) system. Reported findings show a structural changes of the model of the controller block in the posture control system. This result may suggest the presence of an MS-specific reorganization of the posture control system. Some speculation is finally made on the black-box approach in comparison with traditional posturography, to arrive at hypothesizing a progression path for postural disorders.


Assuntos
Esclerose Múltipla/fisiopatologia , Postura/fisiologia , Adulto , Algoritmos , Retroalimentação/fisiologia , Feminino , Hemiplegia/fisiopatologia , Humanos , Masculino , Modelos Biológicos , Movimento/fisiologia
19.
IEEE Trans Biomed Eng ; 37(8): 812-9, 1990 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-2210790

RESUMO

Interaction with biomechanical data concerning human movement analysis implies the adoption of various experimental equipments and the choice of suitable models, data processing, and graphical data restitution techniques. The integration of measurement setups with the associated experimental protocols and the relative software procedures constitutes a computer-aided movement analysis (CAMA) system. In the present paper such integration is mapped onto the causes that limit the clinical acceptance of movement analysis methods. The structure of the system is presented. A specific CAMA system devoted to posture analysis is described in order to show the attainable features. Scientific results obtained with the support of the described system are also reported.


Assuntos
Processamento Eletrônico de Dados , Movimento/fisiologia , Fenômenos Biomecânicos , Humanos , Esclerose Múltipla/fisiopatologia , Postura/fisiologia , Valores de Referência , Software , Interface Usuário-Computador
20.
J Food Prot ; 64(5): 674-81, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11347999

RESUMO

Industrial microbial count records usually form an irregular fluctuating time series. If the series is truly random or weakly autocorrelated, the fluctuations can be considered as the outcome of the interplay of numerous factors that promote or inhibit growth. These factors usually balance each other, although not perfectly, hence, the random fluctuations. If conditions are unchanged, then at least in principle the probability that they will produce a coherent effect, i.e., an unusually high (or low) count of a given magnitude, can be calculated from the count distribution. This theory was tested with miscellaneous industrial records (e.g., standard plate count, coliforms, yeasts) of various food products, including a dairy-based snack, frozen foods, and raw milk, using the normal, log normal, Laplace, log Laplace, Weibull, extreme value, beta, and log beta distribution functions. Comparing predicted frequencies of counts exceeding selected levels with those actually observed in fresh data assessed their efficacy. No single distribution was found to be inherently or consistently superior. It is, therefore, suggested that, when the probability of an excessive count is estimated, several distribution functions be used simultaneously and a conservative value be used as the measure of the risk.


Assuntos
Contagem de Colônia Microbiana , Microbiologia de Alimentos , Modelos Estatísticos , Laticínios/microbiologia , Modelos Teóricos
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