Three-dimensional printing (3DP) forming technology can shape personalized porous implant material with complex shape and fine structure to meet the various needs of different patients. In this paper, the green parts of porous titanium implants with diameter 25 mm x 20 mm were prepared using 3DP, and then debinded at 500 degrees C under vacuum. Finally they were sintered in the argon gas at 1 300 degrees C. The pore sizes were observed, and they were between 50-150 microm under SEM. The results of porosity, bulk density, Vickers hardness, compressive strength and elastic modulus were (44.26% +/- 2.43)%, (2.59 +/- 0.81)g/cm3, 134.2-151.6 (61.2 +/- 3.2) MPa, (3.25 +/- 1.08) GPa, respectively. That shows excellent biomechanical compatibility. It is concluded that 3DP has wide application for fabrication of personalized porous titanium implant.
Biocompatible Materials ; chemistry ; Bone Substitutes ; chemistry ; Computer-Aided Design ; Materials Testing ; Porosity ; Prostheses and Implants ; Stress, Mechanical ; Tensile Strength ; Titanium ; chemistry

This paper is aimed to evaluatethe thyroglobulin autoantibody (TgAb) interference in measurement of thyroglobulin (Tg) between electrochemiluminescent assay (ECLIA) and radioimmunoassay (RIA). Tg and TgAb of 84 sera, including 22 Graves' hyperthyroidism(GD), 24 Hashimoto thyroiditis (HT) and 38 differentiated thyroid carcinomas (DTC), were measured by RIA and ECLIA, respectively. Recovery tests were carried out in 3 groups. The sera samples of the first group were added 3 different amount of Tg calibrator; the sera samples of the second group were diluted 5 times, then 100 ng/ml Tg calibrator was added; the sera samples of the third group were divided into different subgroups depending on TgAb concentration with adding 100 ng/ml Tg calibrator,Tg and TgAb were measured in each dilution by ECLIA and RIA. Recovery rate was calculated. The Tg and TgAb values measured by ECLIA were correlated with that measured by RIA (r = 0.676, P = 0.000; r = 0.677, P = 0.000, respectively). When TgAb concentration increased, the Tg values decreased by ECLIA and increased by RIA. The TgAb values were decreased when sera were diluted, and the Tg values also reduced by RIA and increased by ECLIA. The added different amount of Tg calibrator had not significant influence on Tg recovery rates. When TgAb concentration increased, recovery rates of Tg were decreased by ECLIA and increased by RIA. When sera were diluted, the recovery rates of Tg were increased by ECLIA while decreased by RIA. RIA and ECLIA have good correlation with Tg measurement in 10-400 ng/ml. ECLIA has wider measuring range and higher sensitivity than RIA. RIA and ECLIA have good correlation with TgAb measurement. When TgAb is positive, Tg values are underestimated by ECLIA and overestimated by RIA. When sera are diluted, Tg value and the recovery rate are increasing by ECLIA and decreased by RIA. Recovery test can not efficiently rectify Tg value when TgAb is positive.
Adolescent ; Adult ; Aged ; Autoantibodies ; blood ; Child ; Electrochemical Techniques ; Female ; Graves Disease ; blood ; Hashimoto Disease ; blood ; Humans ; Luminescent Measurements ; methods ; Male ; Middle Aged ; Radioimmunoassay ; methods ; Thyroglobulin ; blood ; immunology ; Thyroid Neoplasms ; blood ; Young Adult

The present paper is to verify the accuracy of DPM, a Monte Carlo-based dose calculation algorithm, in homogeneous and inhomogeneous tissues. DPM was applied to calculate (1) depth dose curves and off-axis ratios at a depth of 10 cm in water using a 6 MeV photon beam with a 3 cm x 3 cm field and phase space file simulated Varian 60 degrees C medical linear accelerator with a 10 cm x 10 cm field at SSD = 100 (cm); (2) depth dose curves using 6 MeV photon beam in inhomogeneous tissues, such as water (6 cm)/lung (6 cm)/water (8 cm) with a 3 cm x 3 cm field and water (6 cm)/ bone (2 cm)/water (12 cm) with a 10 cm x 10 cm field; (3) depth dose curves using 6 MeV photon beam based on the CT data of a patient's head and abdomen. The doses based on DPM are compared to the doses calculated by DOSXYZnrc under the same condition. The error was within 3% in water phantom while the error was within 3% in inhomogeneous tissues, except a few points. It has been concluded that the DPM can accurately predict the dose to homogeneous and inhomogeneous tissues.
Algorithms ; Computer Simulation ; Humans ; Monte Carlo Method ; Photons ; Radiation Dosage ; Radiometry ; methods ; Radiotherapy Planning, Computer-Assisted ; methods ; Software

Gamma amino butyric acid (GABA) is the major inhibitory neurotransmitter in the human brain. Alterations in GABAergic function are associated with a variety of neurological and psychiatric disorders. However, noninvasive in vivo measurement of GABA is difficult because of its low concentration and the presence of overlapping resonances. To study GABA concentration in the occipital cortex in major depressive disorder (MDD), a group of medication-naive, first episode depressed patients (n = 18, HAMD > 17), and a group of healthy controls (n = 23) were investigated using a Point Resolved Spectroscopy (MEGA-PRESS) on a 3.0 T MR scanner. The results showed that occipital GABA levels were significantly lower (P < 0.001) in the patient group than those in the healthy controls, yet the correlations between the severity of MDD (HAMD, BDI) and the GABA concentration is insignificant. Therefore, our data suggest that patients with first episode, unmedicated MDD have changes in cortical concentrations of GABA. This biochemical abnormality may be a marker of a trait vulnerability to mood disorder, and may explain the visual problem of severe MDD patients.
Adolescent ; Adult ; Depressive Disorder, Major ; metabolism ; Female ; Humans ; Magnetic Resonance Spectroscopy ; Male ; Occipital Lobe ; metabolism ; Young Adult ; gamma-Aminobutyric Acid ; analysis ; metabolism

Epilepsy is a common neurological disease accompanied with laden economic burdens and heavy social resources consuming. Temporal lobe epilepsy (TLE) is an important subtype of the epilepsies. Our experiment was aimed to characterize the regional brain function alteration among the treatment na? ve TLE patients using ReHo. We found that elevated regional ReHo was in the left insula in the TLE patients, and the right one was cingulated, while the decreasing ReHo was in right putamen. Our result demonstrated that the key components associated with the epilepsy symptoms had altered the regional function in the TLE patients, and the disruption of cortex-thalamus-striatum loop. Our experiment provides evidence on the pathophysiological alteration in treatment na? ve TLE patients.
Adult ; Brain ; physiopathology ; Cerebral Cortex ; physiopathology ; Depression ; physiopathology ; Epilepsy, Temporal Lobe ; physiopathology ; Female ; Gyrus Cinguli ; physiopathology ; Humans ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Signal Processing, Computer-Assisted

The term "burst-suppression" is used to describe the electroencephalogram (EEG) pattern characterized by theta or delta waves, at times intermixed with faster waves, and intervening periods of relative quiescence. Burst-suppression pattern can reflect the seriously suppressed brain activity under deep anesthesia. To investigate the relationship between burst-suppression features and anesthetic concentration, we adopted four straightforward indexes, i. e., burst-suppression ratio (BSR), burst frequency, burst amplitude and suppression amplitude, and used them to analyze the EEG recordings in ten isoflurane-anesthetized rats. It was found that all the four burst-suppression indexes changed along with anesthetic concentration, that BSR and burst amplitude increased with higher concentration of isoflurane while burst frequency and suppression amplitude decreased, and that BSR was the most sensitive and consistent measurement to indicate isoflurane concentration so it constituted a valuable tool for timely evaluation of burst-suppression feature under deep anesthesia. The result also showed that the composition of carrier gas (i. e. pure oxygen vs. mixed oxygen) did not influence the effect of anesthesia significantly; and the four indexes of burst-suppression features could keep relatively stable within 60 min under the isoflurane concentration of 2%. The present study provides quantitative information of burst-suppression features under different anesthetic depth and may help to develop a clinically satisfied system that could quantify the characteristics of EEG and rigorously evaluate the cerebral state of patients.
Anesthesia, Inhalation ; Anesthetics, Inhalation ; pharmacology ; Animals ; Brain ; metabolism ; Electroencephalography ; drug effects ; Isoflurane ; pharmacology ; Male ; Rats ; Rats, Wistar ; Signal Processing, Computer-Assisted

To relax the presumption of strictly linear patterns in the common spatial patterns (CSP), we studied the kernel CSP (KCSP). A new multi-class KCSP (MKCSP) approach was proposed in this paper, which combines the kernel approach with multi-class CSP technique. In this approach, we used kernel spatial patterns for each class against all others, and extracted signal components specific to one condition from EEG data sets of multiple conditions. Then we performed classification using the Logistic linear classifier. Brain computer interface (BCI) competition III_3a was used in the experiment. Through the experiment, it can be proved that this approach could decompose the raw EEG singles into spatial patterns extracted from multi-class of single trial EEG, and could obtain good classification results.
Algorithms ; Brain ; physiology ; Brain-Computer Interfaces ; Data Interpretation, Statistical ; Electroencephalography ; methods ; Pattern Recognition, Automated ; methods ; Signal Processing, Computer-Assisted ; instrumentation ; User-Computer Interface

At present, ray-casting algorithm is the most widely used algorithm in the field of medical image visualization, and it can achieve the best image quality. Due to large amounts of computation like sampling, gradient, lighting and blending calculation, the cost of ray-casting algorithm is very large. The characteristic of Streaming single instruction multiple datum extensions (SSE) instruction--supporting vector computation--can satisfy the property of ray-casting algorithm well. Therefore, in this paper, we improved the implementation efficient significantly by vectorization of gradient, lighting and blending calculation, and still achieved a high quality image at the same time.
Algorithms ; Humans ; Image Interpretation, Computer-Assisted ; methods ; Image Processing, Computer-Assisted ; methods ; Pattern Recognition, Automated ; methods

The performance of an electroencephalography (EEG) automatic detection and classification system mainly depends on the feature extraction of EEG signal. This paper analyses the advantages and disadvantages of the current EEG feature extraction methods, and then presents a new EEG feature extraction method based on echo state networks (ESN). The new method is a nonlinear method, and can extract the EEG features reversibly. Therefore, the information lost in the process of feature extraction is much less than that of the traditional EEG. Additionally, the realization of this method just needs to compute the pseudo inverse of a matrix, which keeps it efficient. Experimental results have showed that the new method could well accomplish the task of automatic detection and classification of EEG signals.
Algorithms ; Brain Waves ; physiology ; Electroencephalography ; instrumentation ; methods ; Epilepsy ; physiopathology ; Humans ; Neural Networks (Computer) ; Signal Processing, Computer-Assisted

Medical image registration is a key step of image processing and analysis and the first problem of medical image fusion to be solved. In this paper, we focus on magnetic resonance images registration for preoperative and postoperative of deep brain stimulation for the Parkinson's disease. First of all, mutual distance is brought into the mutual information in this paper, realize the two groups of MR slices (for both preoperative and postoperative) mapping, and then 3D images are reconstructed from the corresponding MR slices. Finally, we use Powell algorithm to register 3D images. After the 3D images is registered, we can analyze the relative position between planted electrode (postoperative) and the subthalamic nucleus (preoperative), and measure the quality of deep brain stimulation scientifically.
Algorithms ; Deep Brain Stimulation ; methods ; Electric Stimulation ; Humans ; Image Processing, Computer-Assisted ; methods ; Imaging, Three-Dimensional ; Magnetic Resonance Imaging ; methods ; Parkinson Disease ; pathology ; therapy ; Subthalamic Nucleus ; pathology