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D-p-hydroxyphenylglycine (D-HPG) is an important intermediate for the synthesis of sweeteners and drugs. An innovative continuous chromatographic process was developed to recover D-HPG from crystallization mother liquor, with the aim of reducing the process cost and improving the quality of D-HPG. The thickening properties of different nanofiltration membranes on mother liquor were investigated by pre-treatment test, and the Applexion NF200 nanofiltration membrane was selected to enrich D-HPG. The separation properties of different resins were analyzed by single column experiment, and the separation degree of Applexion XA945 resin to D-HPG and ammonium sulfate could reach 16. Based on the results, the way of sequential simulated moving bed separation was further studied. The results showed that after separation by the sequential simulated moving bed, the average purity of D-HPG in feeding was increased from 42.2% to 96.3%, and the average yield was 91%. The continuous chromatographic system is a promising method for the recovery of D-HPG from crystallization mother liquor. Compared with the traditional process, the new process not only ensures the total yield of D-HPG, but also greatly reduces the process cost and improves the product quality.

To apply anti-marine biofouling agents in the fields of marine engineering and ships, not only the antifouling effectiveness, but also their impact on the corrosion safety of engineering structural materials should be seriously considered and evaluated. Effects of the addition of an agent that would be applied to the anti-marine biofouling of the ship’s sea-access structure on the corrosion behavior and rate of two representative ship metal structural materials, TA24 titanium alloy and 907A alloy steel, in seawater environment were studied. From the comprehensive analysis and evaluation of corrosion morphology, weight loss rate, open circuit potential, polarization curve and alternating-current impedance, it could be obtained that the agent had little effect on the corrosion behavior of these two materials and would not accelerate the corrosion significantly.

A closed gas-up reactor was selected for self-cultured Chlorella pyrenoidosa, the ventilation of carbon dioxide from carbon source obtained by univariate optimization was 2%, and the sodium nitrate of nitrogen source was 10 g/L. More suitable medium components were obtained through the uniform design of Chlorella pyrenoidosa culture medium: K2HPO4 of 0.6 g/L, MgSO4 of 0.2 g/L, NaNO3 of 11 g/L, K2SO4 of 0.8 g/L, ammonium ferric citrate of 0.006 g/L, CaCl2 of 0.05 g/L, vitaminB1 of 0.11 g/L, EDTANa2 of 0.01 g/L, Na2WO4 of 0.08×10–3 g/L, NiCl2 of 0.02×10–3 g/L; In the experiment, a suitable light source with intermediate white light and surrounding colored light was used, and the oxygen was maintained at about 20% with an oxygen scavenger, under which 8.648 g/L dry cell was obtained finally. The protein content of Chlorella pyrenoidosa is as high as 58 g/100 g, and the amino acid and mineral elements of Chlorella pyrenoidosa is also rich by analysis. We studied the replacement of wormwood powder with Chlorella pyrenoidosa, and produced Chlorella pyrenoidosa qingtuan.

According to the technological process of extracting rare earth in Bao Tou Mine, the content of total rare earth ranges from x%-xx%. The national standard of the oxalate gravimetric method is applied to detecting high content of rare earth, which yields between 20% and 80%, but the operation of the method separating interference elements is complex. In fact, Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) could quickly determine each rare earth element content, and avoid complicated separating steps. However, it was difficult to obtain accurate results by ICP-AES, as a consequence of unfavourable precision for high contents rare earth. The method of alkali fusion combined with ICP-AES was applied to overcome problems of complex components and difficult decomposition in acid for rare earth ores from Bao Tou Mine and is reported herein. The sample was melted by sodium hydroxide and sodium peroxide, and leached with deionized water, in order to transfer all kinds of elements into solution as forms of ions or hydroxide. The interference of elements in the solution was reduced by filtering aluminum, silicon, phosphorus, and a mass of sodium ion. During determination of rare earth contents with ICP-AES, the instrument stability and matrix effect were adjusted by adding an internal standard with scandium. When rare earth content in the sample was 2%, RSD was less than 1.2%. When rare earth content in the sample was between 30% and 50%, the method was successfully used with RSD < 0.7%. The recoveries were in the range of 98.0%-103.3%. The method is simpler than the national standard. Compared with ICP-AES reported in the literatur, the precision of the method was significantly improved. Rare earth content in Bao Tou Mine between 2%-50% was quickly and accurately measured using this method.

The element Al is determined frequently in rare earth ore since Al is a common impurity element in this ore. At present, the Inductively Coupled Plasma-Atomic Emission Spectrometric (ICP-AES) method, which has certain requirements of the Al blank and the matrix concentration, is used to determine the content of Al in ore with a matrix matching calibration. Because Al has complicated patterns in many kinds of rare earth ores, it is difficult to dissolve Al completely into solution for determination by a routine acid-leaching method. In this paper, a new method is described, whereby the sample is digested by alkali fusion and the filtrate acidulated before the content Al in rare earth ore is determined by ICP-AES. The effect of spectrum interferences of REEs and Th on the Al was studied. The detection limit was reduced effectively by eliminating the interferences of coexisting elements. The matrix correction mode was undertaken to eliminate the salt influence. The determination limit of the method was from 0.021 mg/g to 0.035 mg/g and the determination content range was from 0.50 % to 8.00%. The RSD was less than 7.1%. The result of the samples with the presented method is consistent with the volumetric method. The method is fast with a wide measuring range and extremely high precision.

The standard unit 0.02 µs generated by 50 MHz FPGA crystal counts on base signal during the pulse width. Firstly, these data which have a linear relationship between phase-offset are obtained correspondingly. Secondly, the measured data have been transmitted to the main control unit MSP430 by the dataport of FPGA. Finally the values of phase-offset between two signals have been processed by real-time MSP430. Entire simulation module contains frequency module, signal generator control module, counting module and data output module. The process and waveform of each module simulation are given in this paper. The results indicate that the measuring of the phase-offset in this way should be approximately accurate. [ABSTRACT FROM AUTHOR]

In order to probe into the biological health effects of mercury pollution in Guizhou Wanshan mercury mine, this paper studied the MDA contents, SOD and GSH-px activities in blood , liver and brain of ducks which were grown on the spot for 8 months and of rats which were exposed to the rice from Guizhou Wanshan mercury mine for 20 d or 30 d. The expression of c-JUN protein in the cortex of rats were observed using immunocytochemical methods. The results show the GSH-px and superoxide dismutase (SOD) activity in blood, liver and brain of the ducks significantly increase compared to the control groups, but MDA content has no significant change; the MDA contents, SOD and GSH-px activities in blood, liver and brain of the rats have no significant change compared to the control groups except the MDA contents in the brain of the rats exposed for 20 d; the expression of c-JUN protein in the cortex of the rats increases significantly. It is concluded that selenium has strong protective capability to the oxidative damage induced by mercury; lipid peroxidation seems not or partially to involve in inducing the expression of c-JUN protein in the process of mercury exposure. [ABSTRACT FROM AUTHOR]

Based on ground monitoring data, we explored the spatiotemporal characteristics and drivers of PM 2.5 in the Yangtze River Economic Belt (YREB) in 2018 using spatial autocorrelation analysis and geodetector modeling methods. The results showed that:① the PM 2.5 concentration in the YREB posed the obvious characteristics of low values in summer and high values in winter, seasonal variation in spring and autumn, monthly U-shaped variation, and daily pulse variation. The low value area was mainly concentrated in the south bank of the upper reaches, whereas the high value area was located in the north of the middle-lower reaches of the YREB. ② PM 2.5 pollution in the YREB had a stable positive spatial correlation, and the local association pattern showed a significant HH and LL spatial convergence. ③ The spatial correlation of PM 2.5 in the YREB decreased with the increase in geographical distance, and its spatial autocorrelation threshold was approximately 870 km, within which the spatial agglomeration of PM 2.5 pollution was strong. ④ The influences of natural and anthropogenic factors on PM 2.5 had significant spatial differences. Altitude, relief, and population density were the high impact factors of PM 2.5 pollution in the YREB. The interaction of factors had a far greater explanatory power on PM 2.5 pollution than that of single factors. The dominant interaction factor was industrial structure ∩ altitude, which reflected the complexity of the drivers of air pollution in the YREB.

This study aimed to explore the mechanism of Xiaoyao San(XYS) in the treatment of three diseases of liver depression and spleen deficiency, ie, depression, breast hyperplasia, and functional dyspepsia, and to provide a theoretical basis for the interpretation of the scientific connotation of &quot;treating different diseases with the same method&quot; of traditional Chinese medicines. Traditional Chinese medicine systems pharmacology database and analysis platform(TCMSP) was used to screen the active components of XYS which underwent principal component analysis(PCA) with the available drugs for these three diseases to determine the corresponding biological activities. The targets of XYS on depression, breast hyperplasia, and functional dyspepsia were obtained from GeneCards, TTD, CTD, and DrugBank databases. Cytoscape was used to plot the &quot;individual herbal medicine-active components-potential targets&quot; network. The resulting key targets were subjected to Kyoto encyclopedia of genes and genomes(KEGG) pathway analysis and gene ontology(GO) enrichment analysis. A total of 121 active components of XYS and 38 common targets in the treatment of depression, breast hyperplasia, and functional dyspepsia were collected. The key biological pathways were identified, including advanced glycation and products(AGEs)-receptor for advanced glycation and products(RAGE) signaling pathway in diabetic complications, HIF-1 signaling pathway, and cancer-related pathways. The key targets of XYS in the treatment of depression, breast hyperplasia, and functional dyspepsia included IL6, IL4, and TNF, and the key components were kaempferol, quercetin, aloe-emodin, etc. As revealed by the molecular docking, a strong affinity was observed between the key components and the key targets, which confirmed the results. The therapeutic efficacy of XYS in the treatment of diseases of liver depression and spleen deficiency was presumedly achieved by reducing the inflammatory reactions. The current findings are expected to provide novel research ideas and approaches to classify the scientific connotation of &quot;treating different diseases with the same method&quot; of Chinese medicines, as well as a theoretical basis for understanding the mechanism of XYS and exploring its clinical applications.

Depression is a common affective disorder. The application of antidepressants can significantly alleviate the symptoms of depression, which is the most important way to treat depression in clinical practice. Due to the complex etiology, wide variety, as well as diversity and severity of serious concomitant symptoms, rational addition of other drugs into antidepressants can significantly improve the cure rates of depression, reduce adverse reactions, and improve patient compliances. Therefore, the combined applications of differential drugs have been commonly used in clinic. In this paper, more than 600 literatures about depression from 2010 to 2019 were collected based on the key words of antidepressant, depression, combined medication, synergism and increase efficiency. Based on this, by summarizing and classifying the existing combinations of antidepressant drugs, this paper systematically expounds the current combined applications of antidepressant drugs in three categories, i.e. western medicines combined with western medicines, western medicines combined with traditional Chinese medicines, and traditional Chinese medicines combined with traditional Chinese medicines, in the expectation of providing the direction and basis for the selection of rational combinations of antidepressant drugs in clinic.

Objective: To observe the effect of electroacupuncture (EA) pretreatment on the number of survival neurons and the expression of glucose regulated protein 78 (GRP 78) and growth arrest and DNA damage-inducible gene 153 (GADD 153) in the hippocampus in rats with global cerebral ischemia /reperfusion injury (CI/R), so as to study its underlying mechanism in neuroprotective action., Methods: SD male rats were randomly divided into 3 groups (n =48 each):sham operation,Cl/R model and EA pretreatment group. Global CI/R model was induced by 4-vessel occlusion (bilateral vertebral artery cauterization and bilateral carotid artery ligation for 5 min, followed by reperfusion). Before modeling, EA pretreatment of "Baihui" (GV 20) and "Dazhui" (GV 14, 2 Hz/15 Hz, 1 mA) was given to rats of the EA pretreatment group for 30 min, once daily for 5 days. At 6, 12, 24 and 48 h after CI/R, the hippocampus tissues of rats in different subgroups were separately sampled to be stained with H. E. method for detecting the number of the survived neurons, stained with TUNEL method for assaying the apoptotic neurons in the CA 1 region, and processed with Western blot (WB) for assaying the expression of GRP 78 and GADD 153 proteins., Results: Compared with the sham group, the number of hippocampal survival neurons was significantly decreased at the time-points of 12 h, 24 h and 48 h after CI/R in the model group (P<0. 05) and was apparently increased by EA pretreatment at 24 h and 48 h (P<0. 05). The number of the apoptotic neurons in the hippocampal CA 1 region at the time-points of 6 h, 12 h, 24 h and 48 h after CI/R was significantly bigger in the model group than in the sham group (P<0. 05), and was obviously decreased at 12 h, 24 h, 48 h after CI/R in the EA pretreatment group (P<0.05). WB detection showed that the expression levels of hippocampal GRP 78 and GADD 153 proteins at the four time-points after CI/R were significantly higher in the model group than in the sham group (P<0. 05). Compared with the model group, hippocampal GRP 78 protein expression levels at the 4 time-points were further markedly up-regulated (P<0.05), while GADD 153 protein expression levels at the 4 time-points were significantly suppressed in the EA pretreatment group (P<0.05)., Conclusion: EA pretreatment can effectively suppress the number of hippocampal apoptotic neurons and increase survival rate of neurons in CI/R rats, which may be closely associated with its effects in up-regulating the expression of GRP 78 protein and down-regulating the expression of GADD 153 protein in the hippocampus.

Objective: To explore the effects and action mechanism of electroacupuncture (EA) pretreatment on rats with transient cerebral ischemia/reperfusion., Methods: A total of 144 healthy SD male rats were randomly divided into a sham operation group (group S), an ischemia/reperfusion group (group I/R) and an EA pretreatment group (group EA), 48 rats in each one. The model of cerebral ischemia/reperfusion was established by using 4-vessel occlusion method in the group I/R; after 5 min of cerebral ischemia, the reperfusion was performed. The group EA was treated with EA at "Dazhui" (GV 14) and "Baihui" (GV 20) 5 days before model establishment, 30 min per time, once a day. In group S, bilateral foramen alares were exposed without burning on the vertebral arteries, and bilateral common carotid arteries were unfolded and not occluded. The rats in the group I/R and group EA were sacrificed 6 h, 12 h, 24 h and 48 h after reperfusion and those in the group S were sacrificed at corresponding time to collect hippocampus example. The Western-blot method was used to measure the expression of glucose-regulated protein 78 (GRP 78), and HE staining method was used to count the number of surviving neurons, and TUNEL method was used to measure the number of apoptotic neurons., Results: Compare with the group S, the number of surviving neurons in hippocampus was reduced at each reperfusion time point and the number of apoptotic neurons was increased (all P<0.05) in the group I/R and the group EA; the expression of GRP 78 at each reperfusion time point in group I/R and group EA was increased (P<0.05). Compared with the group I/R, the number of surviving neurons in hippocampus was increased at each reperfusion time point and the number of apoptotic neurons was reduced in the group EA (P<0.05); the expression of GRP 78 at each reperfusion time point was further increased (P<0.05)., Conclusion: The electroacupuncture pretreatment has obvious cerebral protection on rats with ischemia/reperfusion, which is related with further increasing the expression of GRP 78 in ischemia area, leading to relieved endoplasmic reticulum stress.

Hippocampal neuronal network oscillation is closely related to the memory, anxiety and behavioral inhibition of mammalian. The cognitive decline and behavioral disinhibition in the patients with Alzheimer's disease (AD) may be relevant to amyloid β protein (Aβ)-induced impairment in hippocampal neuronal cooperative activity. However, it is not well known whether intrahippocampal injection of Aβ could induce behavioral disinhibition and neuronal network disorder, as well as cognition decline in animals. In the present study, we observed the effects of intracerebral injection of Aβ(1-42) on the spatial memory and behavioral inhibition of rats by using Morris water maze and elevated plus-maze tests. Further, we analyzed hippocampal theta rhythm by recording hippocampal local field potential. The results showed that: (1) bilateral hippocampal injection of Aβ(1-42) reduced the anxious behavior of rats, with a significant behavioral disinhibition in the elevated plus-maze test, representing as an increase in the mean entering times and mean residence time in the open arm; (2) Aβ(1-42) injection resulted in a significant impairment of spatial memory in rats, with significantly increased mean escape latencies in hidden platform test; (3) Aβ(1-42) disrupted the induction of theta rhythm induced by tail pinch, with a significant reduction in the peak power, not the peak power frequency of the theta rhythm. These experimental results indicate that intrahippocampal injection of Aβ(1-42) can induce behavioral disinhibition and theta rhythm suppression, as well as spatial memory impairment in rats, which suggests that the cognition deficits and behavior impairments in AD are probably associated with the Aβ-induced disruption of hippocampal theta rhythm and consequent down-regulation of synaptic plasticity.

Amyloid β protein (Aβ) is closely involved in the pathogenesis of Alzheimer's disease (AD), and one of the main strategies for AD treatment is antagonizing the neurotoxicity of Aβ or even clearing the Aβ deposited in the brain. The present study was aimed to observe the effects of intrahippocampal injection of Aβ₃₁₋₃₅ on the spatial learning and memory of rats by using Morris water maze technique, and explore the neuroprotective effects and possible mechanism of [Gly14]-humanin (HNG) against Aβ-induced deficits in learning behavior. The results showed that bilateral intrahippocampal injection of 2.0 nmol Aβ₃₁₋₃₅ significantly increased the mean traveled distance of rats in searching for the hidden underwater platform and decreased the distance percentage in the target quadrant in probe test after withdrawal of platform, whereas pretreatment with HNG (0.2 nmol and 2.0 nmol) suppressed Aβ₃₁₋₃₅-induced increase in the traveled distance and decrease in swimming distance percentage. Application of Genistein (40 nmol), a specific tyrosine kinase inhibitor, almost completely blocked the antagonistic effects of HNG against Aβ₃₁₋₃₅. These results indicate that HNG can dose-dependently prevent against Aβ₃₁₋₃₅-induced impairment in spatial learning and memory of rats, and the neuroprotective effects of HNG might involve the activation of endogenous tyrosine kinase pathway, suggesting that up-regulation of the tyrosine kinase signaling by using HNG might be of great significance for the improvement of cognitive function in AD.

Objective: To observe the protective effect of serum derived from rats undergone auricular electroacupuncture (EA) stimulation on the incubated cerebral microvascular endotheliocytes with diabetic injury so as to investigate the underlying mechanism of cholinergic anti-inflammatory action., Methods: SD rats were randomized into normal group (n = 10), diabetic model group (n = 6), auricular EA group (n = 8), vagotomy + EA group (n = 7, received ipsilateral vagotomy before auricular EA stimulation), atropine + EA group (n = 8), hexamethonium + EA group (n = 7) and alpha-bungarotoxin + EA group (n = 7). Diabetic mellitus model was established by feeding the rats with high sugar, high fat forage and intraperitoneal injection of 1% streptozotocin injection (STZ, 35 mg/kg). EA was applied to ipsilateral "Yi-Dan"-point and "Er-Shenmen" for 30 min, once daily for 10 days. Atropine (0.1 mg/kg, an anticholinergic drug), hexamethonium (10 mg/kg, an antagonist of the nicotinic acetylcholine receptors located in sympathetic and parasympathetic ganglia) and alpha-bungarotoxin (1.0 microg/kg, a type of alpha-neurotoxin that is known to bind irreversibly and competitively to the nicotinic acetylcholine receptors) were given to the rats by tail venous injection, respectively, before ipsilateral auricular EA intervention, once daily for 10 days. Blood samples from rats of each group were then collected. Normally cultured rat brain microvascular endotheliocytes were randomly divided into the same 7 groups. The diabetic-like damage model of cerebral microvascular endotheliocytes was established in the 6 groups except the normal group by adding the fluid containing glucose (20 mmol/L), insulin (100 mU/L) and oxidized low density lipoprotein (200 mg/L) to the culture medium. After 48 hours' incubation, the conditional culture solutions were collected for filtration and degerming. Morphological changes and cellular ultra-microstructure were examined using light microscope and transmission electron microscope, respectively. Tumor necrosis factor-alpha (TNF-alpha) mRNA expression of the cultured microvascular endotheliocytes was assayed using RT-PCR, and the soluble cell adhesion factor-1 (sICAM-1) and soluble vascular intercellular adhesion molecule-1 (sVCAM-1) concentrations in 1 mL culture fluid were measured using ELISA., Results: Compared to the normal control group, the cultured cerebral microvascular endotheliocytes in the model group displayed a cluster-like or floating state, enlargement of the space, and increase of refractivity under light microscope, and showed swelling of the mitochondria with broken cristae and expansion of the space and even with membrane fusion or disappearance under electron microscope. This situation was relatively lighter in both auricular EA and atropine groups, and severe in the vagotomy, hexamethonium and alpha-bungarotoxin groups. TNF-alpha mRNA expression and sICAM-1 and sVCAM-1 concentrations were significantly higher in the model group than in the normal group, but significantly lower in both auricular EA group and atropine group than in the model group (P < 0.01, P < 0.05). No remarkable diffe-rences were found among the model, vagotomy, hexamethonium and alpha-bungarotoxin groups in the levels of TNF-alpha mRNA expression and sICAM-1 and sVCAM-1 concentrations (P > 0 05)., Conclusion: Auricular EA intervention rat serum can lighten diabetic cellular injury, suppress TNFalpha mRNA expression and reduce ICAM-1 and sVCAM-1 concentrations of rat cerebral microvascular endotheliocytes, which is closely associated with the intact vagus nerve and normal nicotinic acetylcholine receptors in rats.

Objective: To explore significance of preoperative color Doppler flow imaging (CDFI) for screening deep vein thrombosis in upper limbs fracture., Methods: From January 2009 to December 2011, 1200 patients with upper limb fracture caused by trauma were respectively analyzed. There were 833 males and 367 females,ranging from 20 to 78 (mean 41.94 +/- 15.41) years. All patients had swelling and pain in injured limbs when enrolled. CDFI was used to examine upper limbs vein at 3 to 10 d after improvement of swelling, 1 day before reduction. Relationship among occurrence of thrombosis, gender, age and fracture sites were analyzed. Patients with DVT were analyzed with respective study to decide whether combined with diabetes, hypertension and hyperlipidemia., Results: All patients were checked by CDFI,which confirmed 9 cases with DVT. The rate of thrombosis was 0.75%, women than men (P < 0.01). The risk of blood clots occurred over 30 years, and the occurrence of thrombosis in humerus fracture was higher than radius ulnar fracture. One of 9 patients combined with hypertension and hyperlipidemia, 1 case combined with diabetes, and 7 cases with no complication., Conclusion: Upper trauma fracture may occur deep vein thrombosis; CDFI should be used to check DVT in qualified hospital,which can maintain medical safety,decrease occurrence of medical disputes, and ganrantee patient's safety.

Objective: To investigate treatment and prognostic factors of gastrointestinal stromal tumor(GIST) in the small intestine., Methods: The clinicopathological data of 64 patients with GIST in the small intestine admitted to the Tianjin Medical University Affiliated Cancer Hospital between April 2002 and November 2010 were analyzed retrospectively and the prognostic factors were evaluated., Results: No patients in this cohort received chemotherapy or radiation therapy. Fourteen patients underwent post-operative imatinib targeted therapy. The overall 5-year survival rate was 51.2% and the post-operative recurrence rate of 61 cases undergoing R0 resection was 44.3%. Univariate analysis revealed that the complete tumor resection(P=0.001), tumor size(P=0.018), adhesion or invasion to surrounding tissue and organs (P=0.015), concurrent distant metastasis(P=0.000), tumor hemorrhage (P=0.032), Fletcher classification (P=0.027) and symptom(P=0.012) were associated with prognosis. Multivariate analysis demonstrated that adhesion or invasion to surrounding tissue and organs(P=0.026), concurrent distant metastasis(P=0.000) and symptom(P=0.019) were independent prognostic factors for survival., Conclusion: The survival evaluation of patients with small intestinal GIST depends on surgery, tumor size, adhesion or invasion to surrounding tissue and organs, concurrent distant metastasis, tumor hemorrhage, symptom, Fletcher classification, and use of targeted therapy.

Alzheimer's disease (AD) has become one of the most important and most interesting focuses in the field of medical and scientific research. Up to now, the pathogenesis of AD has not been completely clarified. However, the high-density of amyloid β-protein (Aβ) in senile plaques of AD brain and the neurotoxicity of Aβ have been indisputable facts. The mechanisms underlying Aβ neurotoxicity are very complicated, involving calcium overload, inflammation, ion channel dysfunction, oxidative stress and so on. Among all of those, the mechanism of oxidative stress in Aβ neurotoxicity and the experimental progress of antioxidants in AD treatment have been widely reported in recent years. This review mainly discussed current research progresses on the oxidative stress of Aβ, so as to provide readers with some clues to the antioxidant therapy of AD.

Objective: To assess the predictive value of heart rate turbulence (HRT) in patients with acute myocardial infarction., Methods: One hundred and twenty-five patients with acute myocardial infarction were enrolled in this study. During the period from 6 to 21 days after onset of acute myocardial infarction, they were undergone 24-hour Holter recordings to collect the mean RR interval and heart rate variability (HRV) SDNN. The Holter files were processed with software of "HRT! View V0.60-1" to obtain the value of Turbulence Onset (TO) and Turbulence Slope (TS) and the value of "heart rate variability (HRV) SDNN". LVEF and EDD were measured by Ultrasonic Cardiography. Endpoint of follow-up was cardiac death. According to the results, patients were divided into two groups (the "survivors" and the "nonsurvivors"). The predictive value for high-risk patients with acute myocardial infarction was assessed by variables between the two groups., Results: In the period of follow-up (mean 225.4 +/- 99.8 days), 14 patients died and 111 patients survived. In the univariate Cox regression analysis, "TS" was a strong univariate predictor of mortality (hazard ratio 11.46, P < 0.01); "TO" was a relatively weak predictor and the hazard ratio was 2.76 (P > 0.05). Combination of abnormal TO and abnormal TS was the strongest mortality predictor (hazard ratio 26.70, P < 0.01); in the multivariate Cox regression analysis, TS < or = 2.5 ms/RR and EDD > or = 5.6 cm were the independent predictors of mortality with hazard ratios 9.49 (P < 0.01) and 3.64 (P < 0.05), respectively., Conclusions: The absence of the heart rate turbulence after ventricular premature beats is a very potent post-infarction risk predictor which is independent of and stronger than other known risk predictors.