Diffusion-weighted magnetic resonance imaging reflects activation of signal transducer and activator of transcription 3 during focal cerebral ischemia/reperfusion

Signal transducer and activator of transcription（STAT）is a unique protein family that binds to DNA,coupled with tyrosine phosphorylation signaling pathways,acting as a transcriptional regulator to mediate a variety of biological effects.Cerebral ischemia and reperfusion can activate STATs signaling pathway,but no studies have confirmed whether STAT activation can be verified by diffusion-weighted magnetic resonance imaging（DWI）in rats after cerebral ischemia/reperfusion.Here,we established a rat model of focal cerebral ischemia injury using the modified Longa method.DWI revealed hyperintensity in parts of the left hemisphere before reperfusion and a low apparent diffusion coefficient.STAT3 protein expression showed no significant change after reperfusion,but phosphorylated STAT3 expression began to increase after 30 minutes of reperfusion and peaked at 24 hours.Pearson correlation analysis showed that STAT3 activation was correlated positively with the relative apparent diffusion coefficient and negatively with the DWI abnormal signal area.These results indicate that DWI is a reliable representation of the infarct area and reflects STAT phosphorylation in rat brain following focal cerebral ischemia/reperfusion.

Program evaluation and its application to equipment based on super-efficiency DEA and gray relation projection method

For the gray attributes of the equipment program and its difficulty to carry out the quantitative assessment of the equipment program information, the gray relation projection method is simply reviewed. Combining the super-data envelopment analysis（DEA） model and the gray system theory, a new super-DEA for measuring the weight is proposed, and a gray relation projection model is established to rank the equipment programs. Finally, this approach is used to evaluate the equipment program. The results are verified valid and can provide a new way for evaluating the equipment program.

Study on Hydrodynamic Characteristics of Pipelines in Open Trenches

Based on hydrodynamic model tests, the relationship between relative hydrodynamic coefficient and cycle coefficient K-c is obtained by introducing the relative trench shape coefficient a(r); there isa good relation for the shallow trench. According to a(r) of the designed trench shape and pre-chosen K-c, the reduction coefficient and sheltering effect can be decided by the result provided in this paper.

Consistency between magnetic resonance diffusion-weighted images and pathological findings in a hyperacute cerebral infarction rabbit model

BACKGROUND： Because magnetic resonance diffusion-weighted imaging is sensitive to water molecule movement, it has particular advantages for early diagnosis of cerebral infarction. However, the relationship between apparent diffusion coefficient changes with ischemia time, particularly relative apparent diffusion coefficient and tissue pathological changes remains controversial. OBJECTIVE： To explore the correlation between apparent diffusion coefficient changes and pathologic changes in hyperacute cerebral infarction. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment of neuroimaging. The study was performed at the Laboratory of Radiology Department, Longgang Central Hospital of Shenzhen from October 2007 to October 2008. MATERIALS： Magnetic resonance scanner was purchased from Philips Medical Systems, Best, the Netherlands. METHODS： A total of 42 healthy, adult, New Zealand rabbits were randomly assigned into sham-operation, ischemia 0.5-, 1-, 2-, 3-, 4-, and 6-hour groups, with six animals in each group. Local cerebral ischemia model was established by right middle cerebral artery occlusion, and cranial MRI scanning and pathologic observation were performed, respectively, at 0.5, 1,2, 3, 4, and 6 hours following ischemia. The middle cerebral artery of sham-operation group was only exposed, but not occluded. Images at the above-mentioned time points were also collected. MAIN OUTCOME MEASURES： Apparent diffusion coefficient and relative apparent diffusion coefficient values of abnormal signal on diffusion-weighted imaging were calculated and compared with pathological changes in the ischemic region. RESULTS： No abnormal diffusion-weighted imaging signals or pathological changes were observed in the sham-operation group. Abnormal signal intensity on diffusion-weighted imaging was first observed in the 0.5-hour group. Apparent diffusion coefficient and relative apparent diffusion coefficient values decreased in all middle cerebral artery occlusion rabbits and reached lowest levels at 3 hours, followed by a gradual increase. The right ischemic basal ganglia region with high signal intensity on diffusion-weighted imaging extended with increasing time of occlusion, and the pathologic outcome corresponded with MRI changes. CONCLUSION： Relative apparent diffusion coefficient values changed regularly with ischemia time and displayed good correspondence to pathological manifestations.

On the evidential reasoning rule for dependent evidence combination

Evidential Reasoning(ER)rule,which can combine multiple pieces of independent evidence conjunctively,is widely applied in multiple attribute decision analysis.However,the assumption of independence among evidence is often not satisfied,resulting in ER rule inapplicable.In this paper,an Evidential Reasoning rule for Dependent Evidence combination(ERr-DE)is developed.Firstly,the aggregation sequence of multiple pieces of evidence is determined according to evidence reliability.On this basis,a calculation method of evidence Relative Total Dependence Coefficient(RTDC)is proposed using the distance correlation method.Secondly,as a discounting factor,RTDC is introduced into the ER rule framework,and the ERr-DE model is formulated.The aggregation process of two pieces of dependent evidence by ERr-DE is investigated,which is then generalized to aggregate multiple pieces of non-independent evidence.Thirdly,sensitivity analysis is carried out to investigate the relationship between the model output and the RTDC.The properties of sensitivity coefficient are explored and mathematically proofed.The conjunctive probabilistic reasoning process of ERr-DE and the properties of sensitivity coefficient are verified by two numerical examples respectively.Finally,the practical application of the ERr-DE is validated by a case study on the performance assessment of satellite turntable system.

Changes in visibility with PM_(2.5) composition and relative humidity at a background site in the Pearl River Delta region

In fall–winter, 2007–2013, visibility and light scattering coefficients（b sp） were measured along with PM_（2.5）mass concentrations and chemical compositions at a background site in the Pearl River Delta（PRD） region. The daily average visibility increased significantly（p 〈 0.01） at a rate of 1.1 km/year, yet its median stabilized at ~13 km. No haze days occurred when the 24-hr mean PM_（2.5）mass concentration was below 75 μg/m^3. By multiple linear regression on the chemical budget of particle scattering coefficient（b sp）, we obtained site-specific mass scattering efficiency（MSE） values of 6.5 ± 0.2, 2.6 ± 0.3, 2.4 ± 0.7 and 7.3 ± 1.2 m2/g,respectively, for organic matter（OM）, ammonium sulfate（AS）, ammonium nitrate（AN） and sea salt（SS）. The reconstructed light extinction coefficient（b ext） based on the Interagency Monitoring of Protected Visual Environments（IMPROVE） algorithm with our site-specific MSE revealed that OM, AS, AN, SS and light-absorbing carbon（LAC） on average contributed 45.9% ± 1.6%,25.6% ± 1.2%, 12.0% ± 0.7%, 11.2% ± 0.9% and 5.4% ± 0.3% to light extinction, respectively.Averaged b ext displayed a significant reduction rate of 14.1/Mm·year（p 〈 0.05）; this rate would be 82% higher if it were not counteracted by increasing relative humidity（RH） and hygroscopic growth factor（f（RH）） at rates of 2.5% and 0.16/year-1（p 〈 0.01）, respectively, during the fall–winter, 2007–2013. This growth of RH and f（RH） partly offsets the positive effects of lowered AS in improving visibility, and aggravated the negative effects of increasing AN to impair visibility.

Optimizing soil dissolved organic matter extraction by grey relational analysis

Dissolved organic matter(DOM)in soil plays an important role in the fate and transport o f contaminants.It is typically composed of many compounds,but the effect of different extraction factors on the abundance of different DOM components is unknown.In this study,DOM was extracted from three soils(paddy field,vegetable field and forest soils)with various extraction time,liquid to solid ratios(LSRs).extractant types,and extractant concentrations.The LSR had a significant effect on DOM content,which increased by 0.5-4.0 times among the three soils when LSR increased from 2:1 to 10:1(P<0.05).Dissolved organic matter content increased by 4%-53%when extraction time increased from 10 to 300 min(P<0.05).Extractant concentration had different effects on DOM content depending on the extractant.Higher concentrations of KC1 promoted DOM extraction,while higher concentrations o f KH2PO4 inhibited DOM extraction.Therefore,grey relational analysis was used to further quantitatively evaluate the effect of extraction time,LSR,and extractant concentration on DOM,using KC1 as an extractant.For the paddy field and forest soils,the impact of these three factors on DOM extraction efficiency was in the following order:KC1 concentration>LSR>extraction time.However,the effect was different for the vegetable field soil:LSR>extraction time>KCI concentration.Taking all these factors into account,1.50 mol L^-1 KC1 and an LSR of 10:1 with a shaking time of 300 min was recommended as the most appropriate method for soil DOM extraction.

Oxygen transfer characteristics of water and bubble mixture pipe flow through two sudden contractions and expansions

The dissolved oxygen （DO） concentration is an important index of water quality. This paper studies the dissolved oxygen recovery of the water and bubble mixture pipe flow through two sudden contractions and expansions. A 3-D computational fluid dy- namics model is established to simulate the water and bubble mixture flow with a DO transport model. An experiment is conducted to validate the mathematical model. The mathematical model is used to evaluate the effect of geometric parameters on the head loss coefficient, the relative saturation coefficient and the oxygen absorption efficiency. It is found that the contraction ratio is a signi- ficant influencing factor, other than the relative length and the relative distance. Given the same relative length and relative distance, the head loss coefficient, the relative saturation coefficient and the oxygen absorption efficiency increase with the decrease of the contraction ratio, respectively. Given the same relative length and contraction ratio, the head loss coefficient increases with the in- crease of the relative distance firstly, and then decreases gradually, in contrast, the relative saturation coefficient and the oxygen ab- sorption efficiency decrease with the increase of the relative distance firstly, and then increase gradually, the relative saturation coefficient and the oxygen absorption efficiency are inversely proportional to the head loss coefficient, respectively.