Study on the difference of high frequency dielectric properties of biological tissues measured by air and packed coaxial probe / 生物医学工程学杂志

In this paper, the differences between air probe and filled probe for measuring high-frequency dielectric properties of biological tissues are investigated based on the equivalent circuit model to provide a reference for the methodology of high-frequency measurement of biological tissue dielectric properties. Two types of probes were used to measure different concentrations of NaCl solution in the frequency band of 100 MHz-2 GHz. The results showed that the accuracy and reliability of the calculated results of the air probe were lower than that of the filled probe, especially the dielectric coefficient of the measured material, and the higher the concentration of NaCl solution, the higher the error. By laminating the probe terminal, liquid intrusion could be prevented, to a certain extent, to improve the accuracy of measurement. However, as the frequency decreased, the influence of the film on the measurement increased and the measurement accuracy decreased. The results of the study show that the air probe, despite its simple dimensional design and easy calibration, differs from the conventional equivalent circuit model in actual measurements, and the model needs to be re-corrected for actual use. The filled probe matches the equivalent circuit model better, and therefore has better measurement accuracy and reliability.

Experimental study on temperature dependence of dielectric properties of biological tissues at 2 450 MHz / 生物医学工程学杂志

The temperature dependence of relative permittivity and conductivity of

Retalho mamário de pedículo superior / Upper Pedicle Breast Flap

Introdução: É proposto uma tática para preenchimento do polo superior das mamas que se esvaziam pelo processo de ptose em casos primários e secundários, permitindo assim obtenção de mamas anatomicamente bonitas, em casos de volume mamário suficiente. Objetivo: Descrever retalho de tecido mamário com a finalidade de preenchimento do polo mamário superior, quando exista volume adequado ou excedente. Métodos: Em mamas primárias ou secundárias, se a medida do ponto A até o sulco submamário é longa e deste até o rebordo glandular superior é curta, obtêm-se da diferença entre elas um retalho com pedículo superior, revirado em "folha de livro" e suturado no polo mamário superior. Descolamentos glandulares preservando a espessura de pele com tecido subcutâneo em todas as manobras igualmente à do tórax adjacente. Baseando-se na anatomia vascular da glândula mamária que é irrigada e inervada desde à superfície subcutânea para dentro da glândula. Resultados: As seis pacientes não apresentaram complicação na irrigação do retalho. A forma e volume mamários adequados foram alcançados através da inversão de medidas entre polo inferior e superior. Discussão: Propõe-se uma ideia e inovação, de preenchimento o polo superior das mamas com tecidos próprios, através de retalho de pedículo superior mamário. Deve ser analisado a longo prazo um maior número de casos para análise dos resultados obtidos. Conclusão: O retalho se presta ao preenchimento do polo superior da mama quando o maior volume está no polo inferior.

Introduction: Here we propose a tactic to fill the upper poles of breasts that are emptied by ptosis in primary and secondary cases to obtain anatomically beautiful breasts with sufficient breast volume. Objective: To describe breast tissue flaps used to fill the upper breast pole when there is adequate or surplus volume. Methods: In primary or secondary cases, if the measurement from point A to the submammary fold is long and that to the upper glandular ridge is short, one obtains from the difference between them a flap with an upper pedicle, termed a "book leaf," and sutured at the upper mammary pole. Glandular detachment preserves the skin's thickness with subcutaneous tissue in all maneuvers similar to the adjacent thorax according to the mammary gland's vascular anatomy, which is irrigated and innervated from the subcutaneous tissue to the gland. Results: The six patients presented no complications related to flap irrigation. Adequate mammary shape and volume were achieved by inverting measurements between the lower and upper poles. Discussion: Here we proposed an innovative manner to fill the upper pole of the breast with a breast upper pedicle flap. A larger number of cases should be analyzed in the long term. Conclusion: The flap is used to fill the upper pole of the breast when the largest volume is in the lower pole.

Sensing volume of tissue dielectric property measurement with open-ended coaxial probe / 南方医科大学学报

OBJECTIVE@#To investigate the sensing volume of open-ended coaxial probe technique for measurement of dielectric characteristics.@*METHODS@#A measurement model combining macro- measurement device with a layer model of dielectric properties parameters was established for evaluating the sensing volume of open-ended coaxial probe technique. We defined sensing depth and sensing diameter to describe the distance that could be detected in vertical and horizontal direction. Using a variety of materials with different dielectric properties (Teflon, deionized water, ethanol, and gradient concentration sodium chloride solution), a layered model of dielectric properties differentiation was established. The total combined uncertainties (TCU) were calculated for different output power, and the output power was controlled to increase from -50 dBm to 15 dBm to calibrate the error range of the dielectric properties measurement system. The optimal output power range was determined based on the results of TCU test. In sensing volume measurement experiment, we set the control groups based on measurement parameters that potentially affect the sensing volume including output power (-10, -5, 0, 3, 6, and 9 dBm), frequency (1-500 MHz), Teflon, deionized water, and ethanol to form a dielectric constant difference between high and low contrast groups. Different concentrations of sodium chloride solution and Teflon were used to generate a conductivity difference between high and low contrast groups. These groups were tested in the sensing depth and sensing diameter measurement experiments.@*RESULTS@#The result of TCU test indicated that accurate and stable measurement results could be obtained when the output power was greater or equal to-10 dBm (TCU < 2%). Sensing volume measurement experiment revealed a positive correlation between the sensing depth and output power ( < 0.05). As the measured power increased, the sensing depth gradually increased in deionized water and ethanol, and the difference reached 70 μm. The sensing depth was negatively correlated frequency ( < 0.05). As the concentration of sodium chloride solution increased, the corresponding sensing depth gradually decreased, with a difference reaching 270 μm. The sensing depth of high dielectric materials was greater than that pf low dielectric materials. The results of sensing diameter measurement were not obviously affected by the measurement parameters, and the sensing diameter was stable in a fixed range (1.0 to 1.8 mm) between the diameter of the inner conductor and the diameter of the insulation layer, and was less than the diameter of the probe.@*CONCLUSIONS@#The sensing volume of open-ended coaxial probe technique is affected by measurement parameters and dielectric properties of materials, which significantly affect the sensing depth.

Direct Analysis of Phospholipids in Biological Tissues Using Internal Exlractive Electrospray Ionization Mass Spectrometry / 分析化学

Phospholipids and their metabolites play an important role in a variety of cellular processes including cell-cell adhesion, cell growth and differentiation, apoptosis, phagocytosis as well as storage of energy. In this study, the phospholipid composition of cancer tissue and adjacent normal tissue from humans and animals were analyzed by internal extractive electrospray ionization mass spectrometry ( iEESI-MS ) . Extractive solvent at high voltage (+5. 5 kV) was injected into tissue samples using a fused silica capillary at a flow rate of 0. 5-1 μL/min, producing fine charged droplets containing analytes of tissue samples at the tip of the sample. Charged droplets were directly sampled to the atmospheric inlet of a mass spectrometer. Out of 21 different ratios of CH3 OH ∶H2 O solvent mixture, the ratio CH3 OH ∶ H2 O=30∶70 ( V/V ) showed the optimal phospholipids extraction and visibility in MS. A large number of phospholipids from different tissue samples ( such as cancer tissue and adjacent normal tissue of lung cancer, esophageal cancer tissue, pork, beef, porcine heart and porcine lung) were obtained simultaneously by iEESI-MS analysis. The experimental results demonstrated that iEESI-MS was characterized by minimal sample pretreatment, low sample consumption, and rapid analysis ( the analysis time per sample was less than 1 min) , and the selectivity and sensitivity of iEESI-MS could be improved by choosing proper solvent. Importantly, the experimental results provided new information for further studies of phospholipids in biological tissues.

New Progress of MALDI-TOF-IMS in the Study of Proteomics / 法医学杂志

Matrix-assisted laser desorption/ionization tim e-of-flight im aging m ass spectrom etry (MALDI-TOF-IMS ) has been a classical technique for studying proteom ics in present and a tool for analyzing the distribution of proteins and sm all m olecules w ithin biological tissue sections. MALDI-TOF-IMS can analyze m ultiple unknow n com pounds in biological tissue sections sim ultaneously through a single m ea-surem ent w hich can obtain m olecule im aging of the tissue w hile m aintaining the integrity of cellular and m olecules in tissue. In recent years, im aging m ass spectrom etry technique develops relatively quickly in all biom edical dom ain. T his paper based on the relevant data and review s the present developing level of MALDI-TOF-IMS, the principle of im aging m ass spectrom etry, m ethology and the prospect in foren-sic pathology.

Low-intensity laser therapy and led (light emitting diode) therapy in mechanical resistance of Rattus norvegicus chest inscision with implant of steel wire for sternal suture

INTRODUCTION: Low-intensity laser (LILT) and LED therapy are indicated in repairing surgical incisions, which occur in cardiac surgery. One major concern in this case is the presence of metallic wire used for sternal sutures, its temperature may rise while using a laser or LED. This study aimed to analyze the tensiometric properties of the skin tissue with longitudinal incision and metallic wire implant used for sternal suture irradiated with LILT and LED. METHODS: Twenty-five subjects (Rattus norvegicus) were submitted to thoracic incision with implantation of metallic wire, and subsequently divided into five groups: GI (control group); GII (laser group 6J/cm²); GIII (laser group 10J/cm²); GIV (LED group 6 J/cm²); and GV (LED 10J/cm²). Photobiomodulation was performed on a daily basis for eight consecutive days and the local temperature was measured before and after phototherapy. After euthanasia the tissues were subjected to tensiometric and histological analysis. RESULTS: All irradiated groups showed increase in break strength (p = 0.009), and decrease in tissue deformation strength compared with the control group (p = 0.03). CONCLUSION: Both LILT and LED can promote wound healing at the tested doses with increased tissue resistance, although its elasticity is reduced. The imprecision of the assessing instruments precluded an accurate measurement of a possible local tissue heating post irradiation and future studies are need to elucidate this effect.

Ação da l-arginina na evolução de retalhos cutâneos de ratos sob exposição à nicotina / L-arginine action in cutaneous flap evolution under nicotine exposure in rats

OBJETIVO: Avaliar se o tratamento com L-arginina influencia a cicatrização de retalhos cutâneos em ratos expostos à nicotina. MÉTODOS: Foram utilizados 40 ratos Wistar pesando 142,4±10,1g separados em quatro grupos: GC- tratamento com solução tampão fosfatos pH 7,4, confecção de retalho cutâneo, observação por 10 dias; GN- exposição à nicotina por quatro semanas, confecção de retalho cutâneo, observação por dez dias; GA- tratamento com solução tampão fosfatos pH 7,4 por quatro semanas, confecção de retalho cutâneo, tratamento com arginina por dez dias; GAN- exposição à nicotina por quatro semanas, confecção de retalho cutâneo, tratamento com arginina por dez dias. Foram avaliadas as áreas de necrose, re-epitelização, reação inflamatória e formação de tecido de granulação, pela coloração HE, a área de deposição total e a diferenciação de colágenos I e III por histometria com a coloração de picrosirius, e, através da marcação imunoistoquímica com anticorpo monoclonal anti-CD34, a densidade vascular cicatricial. RESULTADOS: As porcentagens de áreas de necrose de GN e GNA foram maiores (p<0,001) do que GC e GA. Nos escores histológicos, a deposição de colágeno e a porcentagem de colágeno tipo I, no GC e GA foram similares (p>0,05) e maiores (p<0,001) do que em GA e em GNA e, nas densidades vasculares, GN e GAN foram menores (p<0,001) do que em GC e em GA. CONCLUSÃO: A exposição à nicotina inibiu os efeitos da arginina, e nos ratos não expostos, induziu melhora na angiogênese e na deposição de colágeno total nos retalhos cutâneos.

OBJECTIVE: To evaluate whether treatment with L-arginine influences the healing of skin flaps in rats exposed to nicotine. METHODS: 40 male Wistar rats weighing 142.4 ± 10.1 g were separated into four groups: GC: treatment with 7.4 pH phosphate buffer, submitted to skin flap and observation for ten days; GN: exposure to nicotine for four weeks, submitted to skin flap and observation for ten days; GA: treatment with 7.4 pH phosphate buffer for four weeks, submitted to skin flap and arginine treatment for ten days; GAN: exposure to nicotine for four weeks, submitted to skin flap and treatment with arginine for ten days. We evaluated: areas of necrosis, re-epithelialization, inflammatory reaction and formation of granulation tissue by HE stain; the total area of deposition and differentiation of collagens I and III by histometry with picrosirius staining; and the scar vascular density by immunohistochemical staining with monoclonal anti-CD34 antibodies. RESULTS: The percentages of necrotic areas in GN and GNA were higher (p <0.001) than in GC and GA. In histological scores, collagen deposition, and the percentage of type I collagen, GA and GC were similar to each other (p> 0.05), but higher (p <0.001) than GA and GNA; as for vascular densities, they were lower in GN and GAN (p <0.001) than in GC and GA. CONCLUSION: Exposure to nicotine inhibited the effects of arginine and in unexposed mice there was induction of angiogenesis and improvement in the total collagen deposition in the skin flaps.

Three-dimensional finite element analysis of stress in the bending root of maxillary first molar / 中国组织工程研究

BACKGROUND:The stress distribution in the periodontal ligament of bending root can provide reference for the size and manner of force in orthodontic treatment. On this account, it can optimize the design of orthodontic force. OBJECTIVE:To analyze the stress distribution of root and periodontal ligament in the bending roots of the maxil ary first molar under different orthodontic forces. METHODS:The maxil ary first molars with normal roots and bending roots were selected, and then the finite element models of maxil ary first molars and periodontal ligaments were established through CT scan and Workbench 11.0 finite element analysis software. The models were loaded with six different methods to analyze the stress distribution. RESULTS AND CONCLUSION:The stress distribution of bending root was mainly concentrated in the tooth neck, fol owed by the apex. During the overal tooth movement, the stress was smal est on the root, periodontal ligament and alveolar bone. Correction of bending roots needs more accurate positioning and traction.

Determination of optical properties by measuring intensity distribution in tissue sample / 国际生物医学工程杂志

Objective To design a new method of determining optical properties of biological tissue by measuring light intensity distribution.Methods The light distribution in Intralipid-10％ suspension at 650 nm was measured by optical fiber probe.The optical parameters were derived from nonlinear regression of the diffusion equation for intensity.The distribution and anisotropy of intensity was abtained by the determined optical parameters and the diffusion equation for intensity.ResultsThis new method was feasible by comparing the experimental data with published results.ConclusionThe experiment results would provide useful information for radiative transfer equation,marine optical remote sensing measurement and laser therapeutic applications.-

Apósito biológico esterilizado con gas óxido de etileno / A biological dressing sterilized using ethylene oxide gas

Objetivo: se presentó el resultado de una investigación preclínica dirigida a comprobar el poder esterilizante del gas óxido de etileno sobre la piel porcina empleada como apósito biológico. Métodos: se contaminaron 2 grupos de 60 muestras cada uno, de piel porcina liofilizada con una cepa de estafilococo coagulasa positivo y Pseudomona aeruginosa, respectivamente. El 25 por ciento de las muestras de cada grupo se envió al laboratorio de microbiología para comprobar la efectividad del método de contaminación. El 75 por ciento restante se trató durante diferentes períodos en una cámara de gas óxido de etileno y, posteriormente, se enviaron al laboratorio de microbiología para comprobar el grado de esterilidad. Resultados: se demostró la alta efectividad del gas óxido de etileno para esterilizar la piel porcina que es empleada como apósito biológico. Conclusiones: este método es seguro, por lo que es apropiado para el empleo en la clínica médica

Objective: to present the result from a preclinical research aimed to verify the sterilizing power of ethylene oxide gas on the porcine skin used as a biological dressing. Methods: two groups of 60 samples each of lyophilized porcine skin were contaminated with a strain of positive-coagulase staphylococcus and Pseudomona aeruginosa, respectively. The 25 percent of samples of each group was sent to microbiology laboratory to verify the effectiveness of contamination method. The remainder 75 percent was treated in different periods in a chamber of ethylene oxide gas and later, was sent to the above laboratory to verify the sterility degree. Results: it was demonstrated the effectiveness of the ethylene oxide gas to sterilize the porcine skin, which is used as a biological dressing. Conclusions: this method is safe, therefore it is appropriate to use in the medical clinic

Numerical Simulation on Phase Change Heat Transfer Process of Biological Tissue in Cryosurgery / 航天医学与医学工程

Objective To study the mechanism of heat transfer by simulating a complete freezing-thawing process of biological tissue.Methods A numerical model of phase change heat transfer in biological tissue was developed with consideration of the difference of thermophysical properties for normal biological tissue and tumor.The biological tissue was assumed as a porous media.The different thermophysical properties between tissue framework and tissue fluid(as water in tissue,etc) were considered.An apparent heat capacity method was applied to solve the phase change heat transfer problem.Results It was showed that the temperature of biological tissue decreased more quickly during the freezing process when the initial cryoprobe temperature was lower and the cooling-rate of cryoprobe was faster.The temperature of biological tissue increased more quickly with faster warming-rate of cryoprobe in the thawing process.It was also showed that the porosity,blood perfusion rate and metabolic heat generation of the biological tissue had effects on tissue freezing temperature in biological tissue.Conclusion To study the thermal process of biological tissue in cryosurgery will be very helpful for further application in cryosurgery.

Detection for optical properties of biological tissue based on time-correlated single-photon counting technology / 医疗卫生装备

Some issues of time-correlated single-photon counting technology for detection for optical properties of biological tissue are discussed,including its basic principle,components and conventional methods applying the technology.