ABSTRACT
RESUMO Objetivo: Descrever a transferência de energia do ventilador mecânico para os pulmões; o acoplamento entre a transferência de oxigênio por oxigenação por membrana extracorpórea venovenosa (ECMO-VV) e o consumo de oxigênio do paciente; a remoção de dióxido de carbono com ECMO; e o efeito potencial da oxigenação venosa sistêmica na pressão arterial pulmonar. Métodos: Modelo matemático com cenários hipotéticos e utilização de simulações matemáticas por computador. Resultados: A transição de ventilação protetora para ventilação ultraprotetora em um paciente com síndrome da angústia respiratória aguda grave e complacência respiratória estática de 20mL/cmH2O reduziu a transferência de energia do ventilador para os pulmões de 35,3 para 2,6 joules por minuto. Em um paciente hipotético, hiperdinâmico e ligeiramente anêmico com consumo de oxigênio de 200mL/minuto, é possível atingir saturação arterial de oxigênio de 80%, ao mesmo tempo em que se mantém o equilíbrio entre a transferência de oxigênio pela ECMO e o consumo de oxigênio do paciente. O dióxido de carbono é facilmente removido e a pressão parcial de dióxido de carbono normal é facilmente obtida. A oxigenação do sangue venoso, por meio do circuito da ECMO, pode direcionar o estímulo da pressão parcial de oxigênio na vasoconstrição pulmonar por hipóxia para valores normais. Conclusão: A ventilação ultraprotetora reduz amplamente a transferência de energia do ventilador para os pulmões. A hipoxemia grave no suporte com ECMO-VV pode ocorrer, a despeito do acoplamento entre a transferência de oxigênio, por meio da ECMO, e o consumo de oxigênio do paciente. A faixa normal de pressão parcial de dióxido de carbono é fácil de atingir. O suporte com ECMO-VV potencialmente alivia a vasoconstrição pulmonar hipóxica.
ABSTRACT Objective: To describe (1) the energy transfer from the ventilator to the lungs, (2) the match between venous-venous extracorporeal membrane oxygenation (ECMO) oxygen transfer and patient oxygen consumption (VO2), (3) carbon dioxide removal with ECMO, and (4) the potential effect of systemic venous oxygenation on pulmonary artery pressure. Methods: Mathematical modeling approach with hypothetical scenarios using computer simulation. Results: The transition from protective ventilation to ultraprotective ventilation in a patient with severe acute respiratory distress syndrome and a static respiratory compliance of 20mL/cm H2O reduced the energy transfer from the ventilator to the lungs from 35.3 to 2.6 joules/minute. A hypothetical patient, hyperdynamic and slightly anemic with VO2 = 200mL/minute, can reach an arterial oxygen saturation of 80%, while maintaining the match between the oxygen transfer by ECMO and the VO2 of the patient. Carbon dioxide is easily removed, and normal PaCO2 is easily reached. Venous blood oxygenation through the ECMO circuit may drive the PO2 stimulus of pulmonary hypoxic vasoconstriction to normal values. Conclusion: Ultraprotective ventilation largely reduces the energy transfer from the ventilator to the lungs. Severe hypoxemia on venous-venous-ECMO support may occur despite the matching between the oxygen transfer by ECMO and the VO2 of the patient. The normal range of PaCO2 is easy to reach. Venous-venous-ECMO support potentially relieves hypoxic pulmonary vasoconstriction.
Subject(s)
Humans , Female , Adult , Oxygen/metabolism , Respiratory Distress Syndrome, Newborn/therapy , Extracorporeal Membrane Oxygenation/methods , Models, Theoretical , Oxygen Consumption , Computer Simulation , Carbon Dioxide/metabolism , Pulmonary Gas Exchange , Energy Transfer , Hypertension, Pulmonary/physiopathology , Lung/metabolism , Lung/pathologyABSTRACT
This study examined the mechanism of action of a local anesthetic, lidocaine.HCl. Energy transfer between the surface fluorescent probe, 1-anilinonaphthalene-8-sulfonic acid, and the hydrophobic fluorescent probe, 1,3-di(1-pyrenyl) propane, was used to determine the effect of lidocaine.HCl on the thickness (D) of the synaptosomal plasma membrane vesicles (SPMV) isolated from the bovine cerebral cortex, and liposomes of the total lipids (SPMVTL) and phospholipids (SPMVPL) extracted from the SPMV. The thickness (D) of the intact SPMV, SPMVTL and SPMVPL were 1.044+/-0.008, 0.914+/-0.005 and 0.890+/-0.003 (arbitrary units, n=5) at 37degrees C (pH 7.4), respectively. Lidocaine.HCl decreased the thickness of the neuronal and model membrane lipid bilayers in a dose-dependent manner with a significant decrease in the thickness, even at 0.1 mM. The decreasing effect of lidocaine.HCl on the membrane thickness might be responsible for some, but not all of its anesthetic action.
Subject(s)
Anilino Naphthalenesulfonates , Cell Membrane , Cerebral Cortex , Energy Transfer , Lipid Bilayers , Liposomes , Membranes , Neurons , Phospholipids , PropaneABSTRACT
A combination of spectral experiment and molecular modeling techniques has been used to characterize the binding mechanism between an active component 5-hydroxymethyl-furfural (5-HMF) of traditional Chinese medicine and human serum albumin (HSA) or bovine serum albumin (BSA). The interaction mechanism of 5-HMF binding with HSA/BSA is analyzed. Although the drug can bind with HSA/BSA to form stable complexes, there are some differences in the bond strength. The values of binding distances (r) are different and low, which indicated the occurrence of energy transfer. The drug had conformational effect on HSA/BSA, which resulted in different changes of hydrophobic environment of the binding domain in HSA/BSA. The 'phase diagram' of fluorescence revealed that the changes on the conformational pattern of proteins have been affected by drug conformed to the "all-or-none" pattern. The interactions between drug and protein influenced by Co(II) were also discussed. Its effects acting on 5-HMF-HSA/BSA interactions are different. The computational modeling method was used to study the interaction between 5-HMF and HSA/BSA. The results of molecular model studies revealed that the binding modes for drug-serum albumin systems are mainly hydrophobic interactions and hydrogen bonding. These results are in accordance with spectral results. The research results have given a better theoretical reference for the study of pharmacological mechanism of 5-hydroxymethyl-furfural.
Subject(s)
Animals , Humans , Drugs, Chinese Herbal , Chemistry , Energy Transfer , Furaldehyde , Chemistry , Metabolism , Hydrogen Bonding , Hydrophobic and Hydrophilic Interactions , Ions , Chemistry , Models, Molecular , Molecular Conformation , Protein Binding , Serum Albumin , Chemistry , Metabolism , Serum Albumin, Bovine , Chemistry , Metabolism , Spectrometry, Fluorescence , Spectrophotometry, UltravioletABSTRACT
The purpose of this study is to investigated the mechanism of pharmacological action of local anesthetic and provide the basic information about the development of new effective local anesthetics. Fluorescent probe techniques were used to evaluate the effect of lidocaine.HCl on the physical properties (transbilayer asymmetric lateral and rotational mobility, annular lipid fluidity and protein distribution) of synaptosomal plasma membrane vesicles (SPMV) isolated from bovine cerebral cortex, and liposomes of total lipids (SPMVTL) and phospholipids (SPMVPL) extracted from the SPMV. An experimental procedure was used based on selective quenching of 1,3-di(1-pyrenyl)propane (Py-3-Py) and 1,6-diphenyl-1,3,5-hexatriene (DPH) by trinitrophenyl groups, and radiationless energy transfer from the tryptophans of membrane proteins to Py-3-Py. Lidocaine.HCl increased the bulk lateral and rotational mobility of neuronal and model membrane lipid bilayes, and had a greater fluidizing effect on the inner monolayer than the outer monolayer. Lidocaine.HCl increased annular lipid fluidity in SPMV lipid bilayers. It also caused membrane proteins to cluster. The most important finding of this study is that there is far greater increase in annular lipid fluidity than that in lateral and rotational mobilities by lidocaine.HCl. Lidocaine.HCl alters the stereo or dynamics of the proteins in the lipid bilayers by combining with lipids, especially with the annular lipids. In conclusion, the present data suggest that lidocaine, in addition to its direct interaction with proteins, concurrently interacts with membrane lipids, fluidizing the membrane, and thus inducing conformational changes of proteins known to be intimately associated with membrane lipid.
Subject(s)
Anesthetics, Local , Cell Membrane , Cerebral Cortex , Diphenylhexatriene , Energy Transfer , Lidocaine , Lipid Bilayers , Liposomes , Membrane Lipids , Membrane Proteins , Membranes , Neurons , Phospholipids , Proteins , TryptophanABSTRACT
Energy saving bulbs are promoted for their efficiency and capacity to reduce the emission of greenhouse gases; the acknowledged cause of global warming and climate change. They however contain varying quantity of mercury that can easily contaminate the environment. Mercury is a neuro-toxin; but damage has also been reported in the kidney; skin and the cardiovascular system. There is therefore an urgent need to emphasize the safe disposal of the energy-saving bulbs as their use increase in Nigeria. Recycling programme should be institutionalized; with the active participation of the manufacturers and importers of the bulbs; while education programme should be mounted on the handling and safe disposal of broken bulbs
Subject(s)
Disease Eradication , Education , Energy Transfer , Environmental Pollution , Mercury Poisoning , Nigeria , Plant RootsABSTRACT
This study evaluates the sensitivity of the surface albedo simulated by the Integrated Biosphere Simulator (IBIS) to a set of Amazonian tropical rainforest canopy architectural and optical parameters. The parameters tested in this study are the orientation and reflectance of the leaves of upper and lower canopies in the visible (VIS) and near-infrared (NIR) spectral bands. The results are evaluated against albedo measurements taken above the K34 site at the INPA (Instituto Nacional de Pesquisas da Amazônia) Cuieiras Biological Reserve. The sensitivity analysis indicates a strong response to the upper canopy leaves orientation (x up) and to the reflectivity in the near-infrared spectral band (rNIR,up), a smaller sensitivity to the reflectivity in the visible spectral band (rVIS,up) and no sensitivity at all to the lower canopy parameters, which is consistent with the canopy structure. The combination of parameters that minimized the Root Mean Square Error and mean relative error are Xup = 0.86, rVIS,up = 0.062 and rNIR,up = 0.275. The parameterizations performed resulted in successful simulations of tropical rainforest albedo by IBIS, indicating its potential to simulate the canopy radiative transfer for narrow spectral bands and permitting close comparison with remote sensing products.
Este estudo avalia a sensibilidade do albedo da superfície pelo Simulador Integrado da Biosfera (IBIS) a um conjunto de parâmetros que representam algumas propriedades arquitetônicas e óticas do dossel da floresta tropical Amazônica. Os parâmetros testados neste estudo são a orientação e refletância das folhas do dossel superior e inferior nas bandas espectrais do visível (VIS) e infravermelho próximo (NIR). Os resultados são avaliados contra observações feitas no sítio K34 pertencente ao Instituto Nacional de Pesquisas da Amazônia (INPA) na Reserva Biológica de Cuieiras. A análise de sensibilidade indica uma forte resposta aos parâmetros de orientação das folhas do dossel superior (x up ) e à refletância na banda do infravermelho próximo (pNIR,up), uma menor sensibilidade à refletância na banda espectral do visível (pVISup) e nenhuma sensibilidade aos parâmetros da parte inferior do dossel, o que é consistente com a estrutura do dossel. A combinação de parâmetros que minimizaram a raiz do erro quadrado médio e o erro relativo médio são Xup= 0, 86, pVISup = 0, 062 e pNIR,up = 0, 275. As parametrizações realizadas resultaram em simulações bem sucedidas do albedo de floresta tropical pelo IBIS, indicando seu potencial para simular a transferência radiativa do dossel para bandas espectrais estreitas, permitindo a comparação com produtos de sensoriamento remoto.
Subject(s)
Luminescence , Models, Biological , Photosynthesis/physiology , Trees/metabolism , Energy Transfer , Plant Leaves/physiology , Tropical Climate , Trees/anatomy & histology , Trees/physiologyABSTRACT
A series of experiments were performed for toluene decomposition from a gaseous influent at normal temperature and atmospheric pressure by nonthermal plasma coupled with a combination of catalysts technology. Nonthermal plasma was generated by dielectric barrier discharge. gamma -Al[2]O[3]3 was used to be a sorbent and a catalyst carrier. Nanocatalysts were MnO[2]/ gamma-Al[2]O[3] coupled with modified ferroelectric of nano-Ba[0.8]Sr[0.2]Zr[0.1]Ti[0.9]O[3]. gamma-Al[2]O[3] played an important role in prolonging reaction time of nonthermal plasma with volatile organic compounds molecules. MnO[2]/ gamma-Al[2]O[3] has an advantage for ozone removal, while nano-Ba[0.8]Sr[0.2]Zr[0.1]Ti[0.9]O[3] is a kind of good ferroelectric material for improving energy efficiency. Thus these packed materials were incorporated together to strengthen nonthermal plasma power for volatile organic compounds decomposition. The results showed the synergistic technology resulted in greater enhancement of toluene removal and energy efficiencies and a better inhibition for ozone formation in the gas exhaust. Based on the data analysis of the Fourier transforms infrared spectrum, the reaction process of toluene decomposition and the mechanism of synergistic effect are discussed. The results showed in a complex oxidation mechanism of toluene via several pathways, producing either ringretaining or ringopening products. The final products were carbon dioxide and water
Subject(s)
Energy Transfer , TolueneABSTRACT
Based on a simple deconvolution model of multi-layer interfaces, the reasons of wave number variation of the interfacial echo signal were analyzed to explore a method for feature recognition of the superficial soft tissue interfaces. The interfacial echo signal data were decomposed and reconstructed by Mallat multisolution analysis, with the number of the reconstructed interface signal as the feature. The results showed that the deconvolution model was effective for extracting the interface echo signal features in the superficial soft tissue and allowed identification and location of tissue defects.
Subject(s)
Animals , Computer Simulation , Connective Tissue , Diagnostic Imaging , Energy Transfer , Physiology , Image Interpretation, Computer-Assisted , Models, Theoretical , Scattering, Radiation , Skin , Diagnostic Imaging , Subcutaneous Tissue , Diagnostic Imaging , Swine , UltrasonographyABSTRACT
The interaction mechanism between rhaponticin (RT) and human serum albumin (HSA) has been studied by fluorescence spectroscopy and absorbance spectra. The mediation effect that the metal ions took part in the interaction has also been discussed in this paper. Based on different theoretical models of fluorescence quenching, the binding constant (K) and binding sites (n) of the interaction were determined and analyzed comparatively. The quenching mechanism of the binding reaction has also been discussed. The binding distance (r) and energy-transfer efficiency (E) between RT/RT-Co(II)/RT-Ni(II) and HSA were also obtained by virtue of the Förster theory of non-radiation energy transfer. The effect of RT acting on the HSA's conformation was analyzed by synchronous fluorescence spectroscopy. The result showed that the result calculated by different theoretical models is generally equivalent and RT bound HSA strongly by forming stable complex, which indicates that HSA under physiological conditions can act as a carrier for RT to be transported to exert effects. The microconformation of HSA changed significantly due to hydrophobicity change in the chemical environment of some fluorescence chromophores in the subdomain IIA and IIB of HSA. Metal ions Co(II) and Ni(II) can mediate RT-HSA interaction, making the binding of the drug to protein stronger, which indicates that Co(II) and Ni(II) can enhance rhaponticin's medical efficacy under physiological conditions.
Subject(s)
Humans , Binding Sites , Drug Interactions , Energy Transfer , Hydrophobic and Hydrophilic Interactions , Ions , Pharmacology , Metals , Pharmacology , Models, Molecular , Protein Binding , Protein Conformation , Serum Albumin , Chemistry , Metabolism , Spectrometry, Fluorescence , Spectrophotometry, Ultraviolet , Stilbenes , Chemistry , MetabolismABSTRACT
In this paper is proposed a new PCB coreless planar circular spiral inductor coils-based transcutaneous energy transfer method for use in implantable biomedical devices. Firstly, the main factor, coupling coefficient k between transmitting and receiving coils, which affected the efficiency of the energy transfer, was determined by setting up the circuit model of transcutaneous energy transfer. Then, the coupling coefficient was analyzed and calculated by using the method of equivalent circular filaments. Finally, experiments were carried out to demonstrate the feasibility of the proposed method.
Subject(s)
Humans , Electric Power Supplies , Electromagnetic Fields , Electronics, Medical , Energy Transfer , Equipment Design , Equipment Failure Analysis , Prostheses and ImplantsABSTRACT
Biotic tissues are a kind of highly scattering random media; studies on laser light propagation in biotic tissues play an important role in bio-medical diagnostics and therapeutics. The propagation and distribution of infinitely narrow photon beam in tissues are simulated by Monte Carlo method in this paper. Also presented are the energy distribution with regard to depths, light distribution in tissues, reflection and transmittance on the upper and lower surface. The optical parameters adopted in this study are g, albedo and microa, which have influence on energy distribution. The results show: The energy distribution decreases more quickly with the increase of depths and reveals a peak value close to the surface; g factor plays an important part in the lost energy on the upper surface and lower surface; the decrease of g factor causes weaking of the forward moving ability, so the penetration depth becomes smaller and the energy becomes dispersives variation of albedo has distinct effect on the shallow and deep tissues.
Subject(s)
Computer Simulation , Energy Transfer , Light , Models, Biological , Monte Carlo Method , Optics and Photonics , Photochemotherapy , Methods , Scattering, RadiationABSTRACT
OBJECTIVE: This study evaluated the glass transition temperature (Tg) and degree of conversion (DC) of a light-cured (Fill Magic) versus a chemically cured (Concise) orthodontic composite. MATERIAL AND METHODS: Anelastic relaxation spectroscopy was used for the first time to determine the Tg of a dental composite, while the DC was evaluated by infrared spectroscopy. The light-cured composite specimens were irradiated with a commercial LED light-curing unit using different exposure times (40, 90 and 120 s). RESULTS: Fill Magic presented lower Tg than Concise (35-84ºC versus 135ºC), but reached a higher DC. CONCLUSIONS: The results of this study suggest that Fill Magic has lower Tg than Concise due to its higher organic phase content, and that when this light-cured composite is used to bond orthodontic brackets, a minimum energy density of 7.8 J/cm² is necessary to reach adequate conversion level and obtain satisfactory adhesion.
Subject(s)
Humans , Composite Resins/chemistry , Glass/chemistry , Orthodontic Brackets , Resin Cements/chemistry , Transition Temperature , Bisphenol A-Glycidyl Methacrylate/chemistry , Composite Resins/radiation effects , Curing Lights, Dental/classification , Elastic Modulus , Energy Transfer , Friction , Glass/radiation effects , Hot Temperature , Light , Materials Testing , Polymers/chemistry , Resin Cements/radiation effects , Spectroscopy, Fourier Transform Infrared , Spectrum Analysis , Time FactorsABSTRACT
In recent years, investigation focusing on biophysical characteristics of moxibustion results in advancement. The investigations aiming at elucidating the mechanism of maoxibustion from the angle of biophysics show that the effectiveness of moxibustion results not only from thermal effect, but also from the combine effects of spectral radiation, bio-thermal effect and non-thermal-bio effect. Currently, multi-discipline techniques are applied in research about biophysical characteristics of moxibustion which received broad attention. These researches show a good way and method to elucidating the mechanism of moxibustion; furthermore, they provid experimental evidence for the advancement in clinical practices and the research and design of imitating moxibustion instruments. This paper states the researches focusing on the effect of moxibustion on local body temperature, the infrared spectrum characteristics of moxibustion, bio-thermal effect and energy conversion of moxibustion, bio-heat transfer of moxibustion and microcirculation.
Subject(s)
Animals , Humans , Biophysics , Body Temperature , Energy Transfer , Microcirculation , MoxibustionABSTRACT
The thermodynamic function Gibbs energy for the dissolution processes of triclosan (TS) was calculated from solubility values obtained at 25.0 °C in organic solvents with different hydrogen-bonding capability. TS solubility was determined in ethanol, octanol, water-saturated octanol, isopropyl myristate, chloroform, and heptane. The excess Gibbs energy and the activity coefficients of the solute were also calculated. In addition, the corresponding Gibbs energies of the drug transfer process from water to the organic solvents under investigation were also calculated by means of previous reports. In all cases, this thermodynamic property comprised a negative value, indicating the preference of TS for all the organic media evaluated.
En este trabajo se presentan las energías de Gibbs para los procesos de disolución del triclosan (TS) en solventes orgánicos de diferente capacidad de formación de enlace de hidrógeno, las cuales fueron calculadas a partir de los valores de solubilidad a 25,0 °C. La solubilidad del TS se determinó en etanol, octanol, octanol saturado de agua, miristato de isopropilo, cloroformo, y heptano. Así mismo se calcularon las energías de Gibbs de exceso y los coeficientes de actividad del soluto en los mismos solventes. Adicionalmente, mediante el uso de valores previamente reportados en la literatura, se calcularon las energías de Gibbs de transferencia del TS desde el agua hasta los solventes orgánicos comprendidos en el estudio. En todos los casos, esta propiedad termodinámica fue negativa demostrando la preferencia del TS por los medios orgánicos evaluados.
Subject(s)
Energy Transfer , Organic Chemicals , Solubility , Solutions , Solvents , Thermodynamics , TriclosanABSTRACT
Mediante métodos Monte Carlo se calcularon las dosis en los órganos internos de una mujer, con tres meses de embarazo, debidas al radioiodo captado por su tiroides, así como a 1 metro de la glándula. Se utilizó un modelo tridimensional del cuerpo de la mujer y mediante Monte Carlo, los fotones de radioiodo se transportaron isotrópicamente desde la tiroides hacia todo el cuerpo y se calculó la dosis absorbida por sus órganos internos. También se determinó el Kerma en aire (K) y la dosis equivalente ambiental (H*(10)) a 1 m de la glándula. Se determinaron dos factores de actividad a dosis, también llamados Factores Gamma, que permiten estimar la dosis que la paciente produce a personas a su alrededor. De la radiación gamma que emite el 131I en la tiroides se encontró que el timo recibe la mayor dosis mientras que el útero es el órgano que menor dosis recibe. Los factores gamma determinados fueron: ΓKAire = 52.06 μGy-m2-h-1-GBq-1, y ΓH*(10) = 67.72 μSv-m2-h-1-GBq-1. La distribución de la dosis absorbida por los órganos internos se atribuye a la distancia relativa entre la tiroides y los otros órganos, al blindaje inter-órganos, su tamaño y a su composición elemental. Los factores ΓKAire y ΓH*(10) permiten estimar la exposición que la paciente produce sobre el personal a su alrededor. Con esto, el médico nuclear, el físico médico o el responsable de la seguridad radiológica en el hospital pueden dar indicaciones mas precisas sobre el comportamiento de las personas en torno al paciente.
Subject(s)
Humans , Female , Pregnancy , Monte Carlo Method , Iodine Radioisotopes/administration & dosage , Iodine Radioisotopes/pharmacokinetics , Radiometry/methods , Computer Simulation , Tissue Distribution , Radiation Dosage , Thyroid Gland/radiation effects , Mammary Glands, Human/radiation effects , Models, Biological , Pregnancy Trimester, First , Gamma Rays , Energy Transfer , Uterus/radiation effectsABSTRACT
The interaction between warfarin and bovine serum albumin (BSA) under pseudophysiological conditions was investigated by UV-Vis absorption spectrometry and spectrofluorimetry. The quenching mechanism of BSA by warfarin was discussed. It showed that the quenching process was a dynamic quenching, and the quenching constants were 6.05 x 10(4) L x mol(-1) at 16 degrees C and 6. 14 x 10(4) L x mol(-1) at 37 degrees C, separately. Based on the Förster theory of non-radiative energy transfer, the energy transfer efficiency and the distance of BSA to warfarin were calculated, which was 0.37 and 3.15 nm, respectively.
Subject(s)
Energy Transfer , Protein Binding , Serum Albumin, Bovine , Chemistry , Spectrometry, Fluorescence , Methods , Spectrophotometry, Ultraviolet , Methods , Thermodynamics , Warfarin , ChemistryABSTRACT
Ionotropic glutamate receptors are major excitatory receptors in the central nervous system and also have a far reaching influence in other areas of the body. Their modular nature has allowed for the isolation of the ligand-binding domain and for subsequent structural studies using a variety of spectroscopic techniques. This review will discuss the role of specific ligand:protein interactions in mediating activation in the a-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid subtype of glutamate receptors as established by various spectroscopic investigations of the GluR2 and GluR4 subunits of this receptor. Specifically, this review will provide an introduction to the insight gained from X-ray crystallography and nuclear magnetic resonance investigations and then go on to focus on studies utilizing vibrational spectroscopy and fluorescence resonance energy transfer to study the behavior of the isolated ligand-binding domain in solution and discuss the importance of specific ligand:protein interactions in the mechanism of receptor activation.
Subject(s)
Humans , Receptors, Glutamate/chemistry , Energy Transfer , Excitatory Amino Acid Antagonists/chemistry , Excitatory Amino Acid Antagonists/metabolism , Ligands , Magnetic Resonance Spectroscopy , Protein Binding , Protein Conformation , Receptors, Glutamate/metabolism , Spectroscopy, Fourier Transform Infrared , Structure-Activity Relationship , /chemistry , /metabolismABSTRACT
To set up a new pattern of quality control and evaluation for Chinese medicine. By investigating the limitation of quality control pattern for Chinese medicine, the differences and similarities in the chemical substantial style as well as quality control patterns among Chinese medicine, chemical synthetic drugs and Biologicals, combining with the author's experience on the research of geo-authentic medicinal material and theory of Chinese medicinal nature, a new pattern of quality control for Chinese medicine has been explored and designed. A more rational pattern of quality control for Chinese medicine should be referred to Biologicals instead of chemical synthetic drugs, there are more similarity in chemical substantial style and quality control pattern for Chinese medicine between Chinese medicine and Biologicals than that between Chinese medicine and chemical synthetic drugs. Based on geo-authentic medicinal material and bioassay or biopotency detection, a new pattern of quality control for Chinese medicine could be built and applied.
Subject(s)
Biological Assay , Drugs, Chinese Herbal , Chemistry , Reference Standards , Energy Transfer , Evaluation Studies as Topic , Medicine, Chinese Traditional , Reference Standards , Pattern Recognition, Automated , Plants, Medicinal , Chemistry , Quality Control , Technology, Pharmaceutical , MethodsABSTRACT
In the present investigation, an experimental dental arch model fabricated in epoxy was assayed in Kratos universal testing machine to study the mechanical behavior of ethylene and vinyl acetate copolymer (EVA) in the form of mouthguard for sports and flat plate. The following variables were considered: thickness (3 and 4-mm plates), temperature (room and mouth temperature) and presence/absence of artificial saliva. Mechanical properties of EVA were tested under compressive strength: apparent absorbed energy (J.mm-1), maximum tension (N.mm-1), maximum dislocation (mm) and maximum strength (N). Data were recorded and modeled mathematically. Regarding the absorbed energy, maximum tension and maximum force, it was verified that the higher the thickness of the mouthguards, the better the results of force dissipation and redirection to the system and to several regions of the dental arch. In the presence of saliva and close to mouth temperature, the material responded positively to these alterations, resenting increased ductibility as well as improved mechanical responses. Regarding maximum dislocation, it was observed a better accommodation of the occlusion under conditions that simulate those observed in the oral environment. In conclusion, EVA proved to be an adequate material for fabrication of mouthguards and interocclusal splints. In addition, EVA showed good results in force dissipation and demonstrated a shock-absorbing capacity and a great protection potential.
Um modelo experimental de arco dentário, obtido em epóxi, acoplado a uma máquina universal de ensaios Kratos, foi utilizado para estudar o comportamento mecânico do copolímero de etileno e acetato de vinila (EVA), na forma de protetor bucal para esporte e placa plana. As seguintes variáveis foram observadas: espessura (lâminas de 3 e 4 mm), temperatura (ambiente e bucal) e presença ou ausência de saliva artificial. As propriedades mecânicas do EVA, foram testadas ao esforço compressivo: energia aparente absorvida (J.mm-1), tensão máxima (N.mm-1), deslocamento máximo (mm) e força máxima (N). Dados foram registrados e modelados matematicamente. Considerando a energia aparente absorvida, tensão máxima e força máxima, verificou-se que com o aumento da espessura dos protetores bucais houve melhores resultados de dissipação de forças compressivas e seu redirecionamento para o sistema e diversas regiões do arco dental. Com a presença de saliva e temperatura próxima a bucal o material respondeu positivamente a essas alterações aumentando sua ductibilidade apresentando assim melhora em sua resposta mecânica. Com respeito ao deslocamento máximo observou-se que houve melhor acomodação da oclusão quando em condições próximas à bucal. Conclue-se que o EVA provou ser um material adequado para a confecção de protetores bucais para esporte e placas interoclusais.O EVA mostrou melhores resultados na dissipação de forças demonstrando sua grande capacidade amortecedora e grande potencial de proteção.