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41.
A. W. Shahrom P. Vanezis R. C. Chapman A. Gonzales C. Blenkinsop M. L. Rossi 《International journal of legal medicine》1996,108(4):194-200
A facial image was reconstructed from the skull, part of a complete skeleton found in woodland, of a male person who had hanged himself from a tree. In addition, video superimposition was carried out with antemortem photographs of a person suspected of being the victim, and a good match was obtained. In a further case, a cheaper video-transparency superimposition was carried out, with identity later being confirmed on the basis of dental records. The techniques and the problems encountered are discussed. According to our experience, 3D computer reconstruction and video superimposition have a useful role in the process of identification, particularly in the early stages of an investigation and when other more definitive methods may not be available. 相似文献
42.
A. Ménard F. Dachet V. Prouzet-Mauleon M. Oleastro F. Mégraud 《Clinical microbiology and infection》2005,11(4):281-287
A simple real-time fluorescence resonance energy transfer (FRET) PCR, targeting the gyrA gene outside the quinolone resistance-determining region, was developed to identify Campylobacter jejuni and Campylobacter coli. These species were distinguished easily, as the corresponding melting points showed a difference of 15 degrees C. A second assay using the same biprobe and PCR conditions, but different PCR primers, was also developed to identify the less frequently encountered Campylobacter fetus. These assays were applied to 807 Campylobacter isolates from clinical specimens. Compared to phenotypic identification tests, the FRET assay yielded the same results for all except three of the isolates. Analysis by standard PCR and 16S rDNA sequencing demonstrated that two of these isolates were hippurate-negative C. jejuni strains, resulting in an erroneous phenotypic identification, while the third was an isolate of C. coli that contained a gyrA gene typical of C. jejuni, resulting in misidentification by the FRET assay. The FRET assay identified more isolates than standard PCR, which failed to yield amplification products with c. 10% of isolates. It was concluded that the FRET assays were rapid, reliable, reproducible and relatively cost-efficient, as they require only one biprobe and can be performed directly on boiled isolates. 相似文献
43.
ABSTRACTThe H7 subtype avian influenza virus (AIV) has been reported to infect not only poultry but also humans. The haemagglutinin (HA) protein is the major surface antigen of AIV and plays an important role in viral infection. In this study, five monoclonal antibodies (mAbs, 2F8, 3F6, 5C11, 5E2 and 5C12) against the HA protein of H7 virus were produced and characterized. Epitope mapping indicated that 103RESGSS107 was the minimal linear epitope recognized by the mAbs 2F8/3F6/5C11, and mAbs 5E2/5C12 recognized the epitope 103-145aa. The protein sequence alignment of HA indicated that the two epitopes were not found in other subtypes of AIV, and none of the five mAbs cross-reacted with other subtypes, suggesting these mAbs are specific to H7 virus. The epitope 103RESGSS107 was highly conserved among Eurasian lineage strains of H7 AIV, whereas three amino acid substitutions (E104R, E104K and E104G) in the epitope occurred in 98.44% of North-American lineage strains. Any of these single mutations prevented the mutated epitope from being recognized by mAbs 2F8/3F6/5C11; thus, these mAbs can distinguish between Eurasian and North-American lineages of H7 strains. Furthermore, the mAbs 2F8, 3F6 and 5C11 could be highly blocked with H7-positive serum in blocking assays, revealing that 103RESGSS107 may be a dominant epitope stimulating the production of antibodies during viral infection. These results may facilitate future investigations into the structure and function of HA protein, as well as surveillance and detection of H7 virus.RESEARCH HIGHLIGHTS
Five mAbs against HA protein of H7 AIV were generated and characterized.
Two novel epitopes 103RESGSS107 and 103-145aa were identified.
The epitope 103RESGSS107 differs between Eurasian and North-American lineages.
The mAbs 2F8, 3F6 and 5C11 could distinguish two lineages of H7 strains.
44.
45.
To describe the relaxed expiration by a two-compartment model, we introduced a gas/energy transfer between the lung compartment (V1) and a second one (V2). If V2 were a real volume, the rate-constants (i.e. the flow/volume ratios) of the compartments would describe a real gas-exchange. Alternatively, if a viscoelastic behaviour of the lung or an energy-exchange between compartments was simulated, V2 would become a "pseudo-volume". We studied nine mechanically ventilated subjects. Changes in volume were transduced by respiratory inductive plethysmography. The rate-constants were assumed (together with the initial volumes of the compartments) as parameters to fit the total volume [V1(t)+V2(t)]. Once the best fitting was performed using these "physiological" parameters, the system was directly identified and the compartments were independently analysed. The time profile of the second compartment showed a maximum that depended on the value of the rate-constants. Appropriate tests confirmed the reliability of our procedure. In conclusion, our analysis demonstrated that the energy/volume of the second compartment may increase at the beginning of expiration and then decrease, showing a maximum, even though the total curve can only be a decreasing one. In other words, the slowing down of the curve representing expiratory volume is due not only to the longer emptying of the second compartment, but also to the interaction between the two compartments. As presently proposed, this interaction can be represented by either a gas exchange between two actual volumes, or a mechanical energy transfer between the lung and the tissue compartment. 相似文献
46.
The study aimed to model the cerebrovascular system, using a linear ARX model based on data simulated by a comprehensive physiological
model, and to assess the range of applicability of linear parametric models. Arterial blood pressure (ABP) and middle cerebral
arterial blood flow velocity (MCAV) were measured from 11 subjects non-invasively, following step changes in ABP, using the
thigh cuff technique. By optimising parameters associated with autoregulation, using a non-linear optimisation technique,
the physiological model showed a good performance (r=0.83±0.14) in fitting MCAV. An additional five sets of measured ABP of length 236±154 s were acquired from a subject at rest.
These were normalised and rescaled to coefficients of variation (CV=SD/mean) of 2% and 10% for model comparisons. Randomly
generated Gaussian noise with standard deviation (SD) from 1% to 5% was added to both ABP and physiologically simulated MCAV
(SMCAV), with ‘normal’ and ‘impaired’ cerebral autoregulation, to simulate the real measurement conditions. ABP and SMCAV
were fitted by ARX modelling, and cerebral autoregulation was quantified by a 5 s recovery percentage R5% of the step responses
of the ARX models. The study suggests that cerebral autoregulation can be assessed by computing the R5% of the step response
of an ARX model of appropriate order, even when measurement noise is considerable. 相似文献
47.
The mechanical impedance of the ankle joint during electrical stimulation of the soleus is studied by applying constant-velocity
10° angular perturbations to the ankle and measuring the resultant torque. Both neurologically intact subjects and spinal
cord injured subjects are tested. Lumped, piecewise linear models are developed to predict the torque from the measured displacement
and acceleration signals. The commonly used second-order mass-spring-dashpot model fails to predict the changes in torque
that occur following imposed movements. A fiveelement, directionally-dependent piecewise linear model is much better at predicting
the measured responses for velocities up to 50° s−1. Numerical least squared error indentification techniques are used to estimate the model parameters for three neurologically
intact and three spinal cord injured subjects. The average error between the model’s response and the measured response across
all subjects is 10·9%. There is some evidence that a velocity-dependent non-linear model could produce better results than
the directionally-dependent piecewise linear model. 相似文献
48.
W. F. Genadry R. E. Kearney I. W. Hunter 《Medical & biological engineering & computing》1988,26(5):489-496
Stochastic system identification techniques were used to determine the dynamic relationship between the electromyogram (EMG)
and torque in the ankle muscles of normal human subjects. EMG and torque were recorded while subjects modulated ankle torque
by tracking a computer-generated stochastic waveform. Nonparametric impulse response functions (IRFs) relating EMG to ankle
torque were computed and parameterised by determining the parameters of the second-order system which provided the best least-squares
fit. Two sets of experiments were carried out. In the first, the mean level of torque was varied from 5 per cent of the maximum
voluntary contraction (MVC) to 30 per cent MVC while the depth of modulation was held constant at ±5 per cent of MVC. In the
second series of experiments the mean torque was held constant at 25 per cent MVC while the depth of modulation was varied
from ±2.5 per cent to ±25 per cent. The major findings were: (1) A second-order, low-pass filter provided a good quasilinear
model of the EMG/force dynamics under all conditions; (2) The model parameters depended only weakly on the mean level of torque;
(3) In contrast, the model parameters depended strongly on the amplitude with which the contraction was modulated; the natural
frequency increased significantly with the depth of modulation. 相似文献
49.
50.
Methylglyoxal induces apoptosis mediated by reactive oxygen species in bovine retinal pericytes 总被引:4,自引:0,他引:4
One of the histopathologic hallmarks of early diabetic retinopathy is the loss of pericytes. Evidences suggest that the pericyte loss in vivo is mediated by apoptosis. However, the underlying cause of pericyte apoptosis is not fully understood. This study investigated the influence of methylglyoxal (MGO), a reactive alpha-dicarbonyl compound of glucose metabolism, on apoptotic cell death in bovine retinal pericytes. Analysis of internucleosomal DNA fragmentation by ELISA showed that MGO (200 to 800 microM) induced apoptosis in a concentration-dependent manner. Intracellular reactive oxygen species were generated earlier and the antioxidant, N-acetyl cysteine, inhibited the MGO-induced apoptosis. NF-kappaB activation and increased caspase-3 activity were detected. Apoptosis was also inhibited by the caspase-3 inhibitor, Z-DEVD-fmk, or the NF-kappaB inhibitor, pyrrolidine dithiocarbamate. These data suggest that elevated MGO levels observed in diabetes may cause apoptosis in bovine retinal pericytes through an oxidative stress mechanism and suggests that the nuclear activation of NF-kappaB are involved in the apoptotic process. 相似文献