In the present study, FTIR spectroscopy was applied to observe the process of postmortem degradation in rat's brain and a lot of useful data for the estimation of postmortem interval (PMI) were provided. Sprague-Dawley male rats (weight 240 +/- 10 g) were chosen and sacrificed by cervical dislocation. The bodies were kept in a controlled environmental chamber set at (20 +/- 2) degrees C, and their brain cortex as the measuring sample which was extracted at 0, 12, 24, 48, 72, 96, 120, 144 and 168 h from the 8 rats. The tissues were freeze dried in a vacuum at -50 degrees C overnight in order to dehydrate them. About 2 mg freeze dried tissues were mixed with 200 mg KBr and then ground in an agate mortar for 5 min. The mixture then was pressed into a pellet with a thickness of 0. 4 mm and a diameter of 12 mm. The FTIR spectra were quantitatively recorded at room temperature in the range 4 000-400 cm(-1) on a Shimadzu 8400S spectrometer (Shimadzu, Japan). IR solution 1.10 software (Shimadzu, Japan) was used for the analysis of the FTIR spectra and for recording the data from the spectra. With the PMI increasing, the peak position of main absorbance bands in the FTIR spectra showed no significant difference, but there was a dramatic variance in the intensity: (1) The relative intensity at 1 080 and 1 238 cm(-1) (I1 080/I1 398 and I1 238/I 398) related with nucleic acid tended to decrease obviously. (2) The intensity ratio at amide II and I (I1 541/I1 647) increased with the PMI increasing. The intensity at 1 338 and 1 313 cm(-1) varied slightly, but their intensity ratio to 1 398 cm(-1) decreased. (3) The intensity at 1 456 and 1 398 cm(-1) showed a trend of decreasing and increasing respectively. (4) Compared with the intensity at 2 871 cm(-1), the intensity at 2 852, 2 871, 2 923 and 2 958 cm(-1) tended to increase, but the increasing tendency at 2 871 cm(-1) was slight. It is concluded that FTIR spectroscopy is going to be an effective method for estimating the PMI in medicolegal practice and the brain tissue may be a suitable marker as a potential sample.
Estimation of the time since death (postmortem interval, PMI) is one of the most difficult problems in forensic investigations and many methods currently are utilized to estimate the PMI. The aim of this study was to investigate the changes of Fourier transform infrared (FT-IR) spectra of rat kidney cortex from time zero to 168 h postmortem at molecular level. The spectra of rat kidney cortex displayed the prominent changes with increasing postmortem interval. (1) Significant increase in the intensity of the C-H stretching bands at 2958, 2925, 2871, 2852 cm −1 ,t he=C-H stretching band at 3012 cm −1 , the CO2 − symmetric stretching band at 1396 cm −1 and the N-H bend, C-N stretching at 1541 cm −1 ; (2) significant decrease in the intensity of the PO2 − stretching band at 1238, 1080 cm −1 ; (3) the intensity of at 3303, 1652 and 1170 cm −1 remained relatively stable. The linear regression analysis of the various absorption intensity and area ratios against the PMI shows a close correlation, maximum for A1541/A1396 ratio (R 2 = 0.95) and minimum for I1080/I1396 ratio (R 2 = 0.70). Our results indicate
To study the clinical significance of serum protein expression level in patients with megaloblastic anemia(MA).A total of 47 patients with MA were enrolled in this study between November 2013 and November 2015, and 50 healthy people in the same period were selected as controls. The levels of total protein (TP), albumin (Alb), ferritin (FER), transferrin (TRF) and soluble transferrin receptor (sTfR) were compared between 2 groups, and the serum protein expression levels in different types of MA, varous anemia degrees of MA were analyzed.The leves of TP, Alb and FER in MA patients were significantly lower than those in control group, the levels of TRF and sTfR were statistically significantly higher than those in control group(P<0.05); the levels of TP, Alb and FER in the patients with mild anemia were significantly higher than those in the patients with moderate and severe anemia, the levels of TRF and sTfR were statistically significantly lower(P<0.05), while the levels of TP, Alb and FER in patients with moderate anemia were significantly higher than those in the patients with severe anemia, the levels of TRF and sTfR were significantly lower(P<0.05). Compared with levels before treatment, the levels of TP, Alb and FER significantly increased after treatment, while the TRF and sTfR levels significantly decreased (P<0.05).Serum levels of TP, Alb, FER, TRF and sTfR can provide a basis for the diagnosis of MA, and contribute to predict the disease to some extent.
Adiabatic pulses can induce uniform spin rotations despite wide variations in radiofrequency field strength, B1.Adiabatic pulses are particularly advantageous when using transmitter coils, such as a surface coil, which produce highly inhomogeneous BI.Above a threshold 61 where the pulse begins to operate according to adiabatic principles, the pulse performance generally remains uniform even when the BI increases by an order of magnitude or more.
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