ABSTRACT
A torsional thrust balance has been designed and validated by Surrey Space Centre and Added Value Solutions UK Ltd. in collaboration with the UK Space Agency. The thrust stand has been tested with two electric propulsion (EP) systems operating with xenon: the Halo thruster and the XJET thruster. The first consists of a low-power (<1 kW) Hall effect-based thruster, whose thrust level is between 3 and 20 mN, depending on the power of the system. The second is an electron cyclotron resonance thruster whose operative point is in the 0.3-1.5 mN thrust range. The thruster is mounted on a titanium rotating beam, whose movement is measured by an optical fiber displacement sensor. The thrusters' direct current electrical connections are routed through room temperature liquid metal pots and microwave power is transmitted via a wireless transfer system, minimizing friction effects. To reduce thermal issues during long thruster operations, the torsional thrust balance is designed with a water-cooling hub around the flex pivot. Noise from the laboratory environment is lessened by using four vibration-dampening spring systems as thrust balance feet. The tests on the two EP systems have shown accurate and repeatable results, demonstrating that the balance can be used to characterize different EP systems in the µN-mN thrust range.
ABSTRACT
The high incidence of bone metastasis secondary to carcinomas and its serious functional repercussion are motives for constant study and advance in the methods of evaluation, diagnosis and treatment. Pain is the most frequently shown symptom, although at times the start is a pathological fracture. The classic tests of detection and evaluation of the spread of the metastatic disease, simple radiology and gammagraphy, are today complemented by others such as computerised tomography (CT) and magnetic resonance (MR), improving the information on the characteristics of the lesion both inside and outside the bone. On the other hand, positron emission tomography (PET) is showing a far higher sensitivity than gammagraphy and will probably be the test of the future for the early detection of metastasis and of silent primary tumours. The possibilities of treatment of bone metastasis are based on the use of bone regenerators, radiotherapy and surgery. The former two are indicated in lesions already detected in radiography, whether symptomatic or not, if there is no foreseeable risk of fracture. Surgery is indicated in situations of poor or null response to those treatments, when the risk of fracture is high or a pathological fracture has been produced. Before any therapeutic planning, a detailed evaluation of the patient must be carried out, both at a local level (size, site, extension of the metastasis) and general (type of primary tumour, phase of treatment and response, estimated survival).
Subject(s)
Bone Neoplasms/diagnosis , Bone Neoplasms/therapy , Bone Neoplasms/secondary , HumansABSTRACT
La alta incidencia de metástasis óseas secundarias a carcinomas y la grave repercusión funcional que provocan, son motivos de constante estudio y avance en los métodos de evaluación, diagnóstico y tratamiento. El dolor es el síntoma más frecuente de presentación, aunque a veces el comienzo es una fractura patológica. Las pruebas clásicas de detección y valoración de extensión en la enfermedad metastásica, la radiología simple y la gammagrafía, se complementan en la actualidad con otras como la tomografía computarizada (TC) y la resonancia magnética (RM), mejorando la información sobre las características de la lesión tanto dentro como fuera del hueso. Por otra parte la tomografía por emisión de positrones (PET) está mostrando una sensibilidad muy superior a la gammagrafía y se perfila como la prueba de futuro para la detección precoz de metástasis y de tumores primarios de curso silente. Las posibilidades de tratamiento de las metástasis óseas se basan en el empleo de los regeneradores óseos, la radioterapia y la cirugía. Los dos primeros tienen su indicación en las lesiones ya detectadas en la radiología, sintomáticas o no, si no existe riesgo previsible de fractura. La cirugía tiene su indicación en situaciones de pobre o nula respuesta a estos tratamientos, cuando el riesgo de fractura es alto o ya se ha producido una fractura patológica. Antes de cualquier planificación terapéutica se debe realizar una valoración minuciosa del paciente, tanto a nivel local (tamaño, localización, extensión de la metástasis) como general (tipo de tumor primario, fase de tratamiento y respuesta, supervivencia estimada) (AU)
The high incidence of bone metastasis secondary to carcinomas and its serious functional repercussion are motives for constant study and advance in the methods of evaluation, diagnosis and treatment. Pain is the most frequently shown symptom, although at times the start is a pathological fracture. The classic tests of detection and evaluation of the spread of the metastatic disease, simple radiology and gammagraphy, are today complemented by others such as computerised tomography (CT) and magnetic resonance (MR), improving the information on the characteristics of the lesion both inside and outside the bone. On the other hand, positron emission tomography (PET) is showing a far higher sensitivity than gammagraphy and will probably be the test of the future for the early detection of metastasis and of silent primary tumours. The possibilities of treatment of bone metastasis are based on the use of bone regenerators, radiotherapy and surgery. The former two are indicated in lesions already detected in radiography, whether symptomatic or not, if there is no foreseeable risk of fracture. Surgery is indicated in situations of poor or null response to those treatments, when the risk of fracture is high or a pathological fracture has been produced. Before any therapeutic planning, a detailed evaluation of the patient must be carried out, both at a local level (size, site, extension of the metastasis) and general (type of primary tumour, phase of treatment and response, estimated survival) (AU)
Subject(s)
Humans , Bone Neoplasms/diagnosis , Bone Neoplasms/therapy , Bone Neoplasms/secondaryABSTRACT
Two cases of fracture of the ceramic head of a total hip replacement are presented. In both cases the damaged components were replaced with satisfactory results.
Subject(s)
Hip Prosthesis , Ceramics , Female , Humans , Male , Middle Aged , Prosthesis FailureABSTRACT
Rasa Aragonesa ewes (n = 89) received 2 embryos on Day 6 of the estrous cycle (Day 0 = estrus) from 46 donors of the same breed that had been superovulated with FSH-p. The influence of several variables on fertility and prolificacy after transfer was studied by discriminant analysis. Our results showed that the main variables that contributed to a high fertility rate were the degree of synchrony (better outcome if donors come into estrus later than the recipients); Fluorogestone acetate (FGA) to estrus interval and interval from previous lambing in the recipients, ovulation rate of the donors and recipients (better if superior to the mean); prolificacy of recipients in the previous lambing; and difference in developmental stage of the pair of transferred embryos (better if inferior to the mean). The main variables affecting prolificacy were the ovulation rate and weight of the donors and progesterone concentrations of the recipients (better if lower than the mean); age of the donors and difference in progesterone concentrations between donors minus those of the recipients (better if higher than the mean). The percentage of ewes correctly classified into lambing or not lambing status was 73% (P < 0.001) and that of the ewes correctly classified as lambing 1 or 2 lambs was 81.8% (P < 0.001). Whether or not the criteria we have established for optimum transfer results are applicable to conditions other than our own still needs to be confirmed.
ABSTRACT
Synopsis Diffusion tests of anionic, amphoteric and mixtures of amphoteric/anionic surfactants have been performed using a collagen film. A sensitive potentiometric method has been developed to determine the surfactant diffused avoiding the interferences observed in the usual analytical measurements due to the simultaneous presence of amphoteric/anionic surfactants. From the results obtained it is evident that the surfactant mixtures exhibit a synergistic behaviour as there is a mutual inhibition of the surfactant diffused through the collagen film. Empirical equations have been derived to describe the diffusion process of both the individual surfactants and mixtures of surfactants which allow the diffusion of the individual surfactants and the inhibition of diffusion in mixtures to be quantified.
ABSTRACT
Three more cases of osteoid osteoma located in epiphysis are presented. All of them had special features, as a reactive synovitis due to the proximity of the lesion to the joint and the lower movility arch of these joints. The x-ray was essential for the diagnosis and definitive treatment was surgical resection.
Subject(s)
Bone Neoplasms , Epiphyses , Femoral Neoplasms , Fingers , Osteoma, Osteoid , Radius , Adult , Bone Neoplasms/diagnostic imaging , Bone Neoplasms/pathology , Epiphyses/diagnostic imaging , Epiphyses/pathology , Female , Femoral Neoplasms/diagnostic imaging , Femoral Neoplasms/pathology , Femur Head/diagnostic imaging , Femur Head/pathology , Fingers/diagnostic imaging , Fingers/pathology , Humans , Male , Osteoma, Osteoid/diagnostic imaging , Osteoma, Osteoid/pathology , Radiography , Radius/diagnostic imaging , Radius/pathologyABSTRACT
The extraction of nickel from aqueous media (0.1M NaClO(4)) with 3-(2-furyl)-2-mercaptopropenoic acid (FMPA) in dichloroethane at 25 degrees has been studied. The extraction is efficient only if a suitable counter-ion is present to form an ion-associate with the Ni-FMPA complex. The diphenylguanidinium ion has been found suitable as the counter-ion.
ABSTRACT
Non tuberculous spondylodiscitis of the rachis is an uncommon entity that affects boys and male adults with greater frequency. The zone with higher incidence of affection is the lumbar region. Usually the causal germ travels through the hematogenous via from an extrarachidial infectious area. Clinical manifestations begin with an acute segmentary rachialgia and paravertebral muscular contracture while presenting fever. In special cases of little boys or when having radiated pain, the presenting form could be confusing. There is always a vertebral rigidity when performing the physical exam and an increase of the globular sedimentation rate. A septic leukocytal formula is not always present. Between the onset of symptoms and the appearance of radiologic alterations (decrease in the height of the disc, erosion and vertebral destruction, reactive bone neo-formation) there is a variable two to eight weeks latency period. Scintigraphy with Tc99 and Ga67 and CAT scan are very important when facing definite diagnosis. To be able to reach a bacteriological diagnosis, we employ puncture-aspiration of the disc. The isolated germ in most cases is staphylococcus aureus. The most complex differential diagnosis is with tuberculous spondylodiscitis. The evolution is favorable if the treatment is initiated early and if it is adequate (antibiotic therapy and immobilization). If this is not done, recurrences and chronicity of the infection can occur, as well as orthopaedic (Kyphosis) and neurological complications.
