Soil Carbon Pool Management Index under Different Straw Retention Regimes

[Objective] To clarify the effects of different straw retention regimes on soil fertility in double cropping paddy field. [Method] The effects of different straw reten- tion regimes on total organic carbon （CToc）, active carbon （CA） and mineralized carbon （CM） were analyzed, and carbon pool active （A）, carbon pool active index （A/）, carbon pool index （CPI） and carbon pool management index （CPMi） for each treat- ment were calculated. [Result] Compared with the unfertilized treatment （CK）, CToc, CA, CM and the available ratio of soil carbon were increased in the treatment of re- turning early season and late season rice straws to field. With the same nutrient application, CToc, CA and the available ratio of soil carbon in the field with straw re- turned to field were higher than that of straw incineration and no straw returning, and the change in soil CA content was more significant. The difference in CPMI be- tween different treatments reached significant or very significant level, and the value was in the order of straw directly returned to field 〉 straw returned to field after in- cineration 〉 no straw returned to field. [Conclusion] This study provided theoretical bases for the increase of soil CA content and soil fertility in double rice fields.

A QSRR Study on the Chromatographic Retention Indices of Hydroxylated Polychlorinated Biphenyls

Hydroxylated Polychlorinated Biphenyls （HO-PCBs） are the metabolite of polychlorinated biphenyls and have drawn much attention because they have hazard on human health and ecosystems. Molecular connectivity index calculation has been performed for 19 HO-PCB compounds. A number of statistically based parameters have been extracted. Linear relationship between chromatographic retention index （RI） and the molecular connectivity index of 15 compounds in the training set has been established by multiple linear regression method. The other 4 HO-PCBs are used as the external test set. The result shows that the parameters can be well used to express the quantitative structure-retention relationship （QSRR） of HO-PCBs. Good stability and predictive ability have been demonstrated by leave-one-out cross-validation and the external test set.

Inverse Gas Chromatography Used to Study Lubricating Oil Oxidation Mechanism via Changes in Kovats and Flory-Huggins Retention Parameters

Inverse gas chromatographic technique(IGC) was attempted as a new approach to follow the chem-ical changes that occur during lubricating base oil oxidation.Three groups of the oxidized base oils were pre-pared at different oxygen flow rates,periods and temperatures according to IP48method.The corrected reten-tion volumes(VR) were calculated for a series of selected test solutes possessing different functional groups onthe oxidized base oils used as stationary phases.Kovats retention index(I),Flory-Huggins interaction parame-ter(κ1∞,2),and partial molar free energy of solution(ΔGL∞),were calculated for the given test solutes fromtheirVR.The relationships between theIvalues and the oxidation variables were plotted and discussed.Theobtained results were confirmed by potentiometric titration.The study reveals that the magnitudes of variationofI,κ1∞,2orΔG∞Lretention parameters depend on the oxidation degree of the base oil.Large differences be-tween theIvalues permit discrimination between the different oxidation steps.Key words: inverse gas chromatography(IGC);oxidation;lubricating base oil;Kovats retention

Quantitative Structure-retention Relationship Study of Polychlorinated Dibenzothiophenes by Molecular Electronegativity Distance Vector(MEDV)

Polychlorinated dibenzothiophenes（PCDTs） are classified as persistent organic pollutants in the environment,so the analysis of PCDTs by their gas chromatographic behaviors is of great significance.Quantitative structure-retention relationship（QSRR） analysis is a useful technique capable of relating chromatographic retention time to the molecular structure.In this paper,a QSRR study of 37 PCDTs was carried out by using molecular electronegativity distance vector（MEDV） descriptors and multiple linear regression（MLR） and partial least-squares regression（PLS） methods.The correlation coefficient R of established MLR,PLS models,leave-one-out（LOO） cross-validation（CV）,Q2ext were 0.9951,0.9942,0.9839（MLR） and 0.9925,0.9915,0.9833（PLS）,respectively.Results showed that the model exhibited excellent estimate capability for internal sample set and good predictive capability for external sample set.By using MEDV descriptors,the QSRR model can provide a simple and rapid way to predict the gas-chromatographic retention indices of polychlorinated dibenzothiophenes in conditions of lacking standard samples or poor experimental conditions.

Assessment of Retention Ponds and Its Impacts on Health of Residents in Mogadishu, Somalia: Mixed Methods

The purpose of this study was to evaluate the effects of retention ponds on the environment and population health by analyzing water samples from various ponds in Mogadishu, to determine the prevalence of waterborne illnesses that occur during the rainy season in Mogadishu, and to find out what experts thought about the effects of retention ponds on the environment as well as population health in Mogadishu. Methods: Mixed designs were used in the study. The first design is an exploratory study where samples are taken from different retention ponds in Mogadishu. The second design involves gathering secondary data from the online FSNAU Dashboard regarding the incidence of rainfall and waterborne illnesses including malaria and cholera. Additionally, a cross-sectional survey of expert opinions using questionnaires was the third design. The 10 water samples were taken from retention ponds in Mogadishu as part of the sample size. Data on the fourth month was also gathered using the FNSAU dashboard, and seventy sample sizes were used for the expert self-administered questionnaire for the third design. Excel was used for data analysis in the initial design. While BMI SPSS versions 22 were used to analyze the data from the Self-administered Questionnaire, additional methods were utilized to compute descriptive statistics, such as mean and standard deviation, and to analyze demographic data in a frequency table. Findings: The results show that three samples had unsatisfactory scores (Grade D): Yaqshid (Warshadda Bastada) had a WQI of 80.85, Boondheer (Bondher Pond) had a WQI of 80.64, and Wartanabad (Xamar Jadiid Pond) had a WQI of 80.89. The remaining samples were all rated as fair (grade), which indicates that they ranged from 50 to 75. The months with the largest rainfall already occurred in December, November, and October, when the prevalence of diseases during the rainy season was highest for cholera cases. Although October and December saw a significant number of malaria cases, November did not. Retention ponds’ overall effects on residential environments were evaluated, and the results showed that the standard deviation was 0.802 and the cumulative average mean scores were 4.41 overall. This indicates that the respondents were in agreement that retention ponds in Mogadishu, Somalia, had an effect on residential areas. Recommendation: The study suggested that in order to identify retention pond contamination and create treatment units for its management, the Ministry of Health forms a district-level public health committee. All districts must have a sewer system installed by the local government, and retention ponds must be made easier in order to move waste outside of the city.

前列腺外周带血流高阻力指数(RI)对前列腺癌的诊断价值

目的 探索彩色多普勒超声的血流指标对前列腺癌的诊断价值。方法 采用彩色多普勒双平面直肠腔内探头检测前列腺 ,重点检测前列腺外周带血流参数指标。结果 前列腺增生 67例 ,前列腺癌 5 8例。前列腺外周带血流 2级以上前列腺增生 5 8% ,前列腺癌 74.13 % ,P <0 .10 ;前列腺增生和前列腺癌的Vmax均值分别是 10 .77cm/s和12 .91cm/s ,RI分别是 0 .71和 0 .82 ,Vmax和RI在两组间有显著统计学差异 (P <0 .0 0 1) ;以RI 0 .75为临界值 ,对前列腺癌诊断的敏感性 87.5 %、特异性 92 .4%、准确性 75 %和阳性预测值 84%。结论 前列腺外周带血流增多 ,RI >0 .75时 ,对前列腺癌的诊断价值明显提高。

一种新的拓扑指数~0X(~1X)与气相色谱保留指数RI的相关性研究

在邻接矩阵的基础上 ,建立化合物的主量子数拓扑指数 mX :0 X =Σ(δi) 0 .5,1X =Σ(δi·δj) 0 .5,并计算了 13个系列 94个分子的0 X、1X值。发现0 X或1X与这些化合物的气相色谱保留指数RI有很好的相关性。相关系数均在 0 .97以上 ,略优于文献方法。并且物理意义明确 ,计算简单 ,使用方便。

RI指数联合超声对孕晚期胎儿肾积水预后预测价值的研究

目的探讨RI指数联合超声对孕晚期胎儿肾积水预后预测的价值．方法选取行超声检查发现的晚孕期肾积水胎儿141例，检测胎儿的肾实质厚度、肾盂前后直径（APD）、肾盂肾盏形态，并给予评分，累计3项指标评分分值；对胎儿行超声检查时测定积水肾脏肾门位置的RI值．将以上检测结果与胎儿出生后1a内行超声检查和临床诊断结果进行对照研究．结果141例胎儿共有170只。肾积水；出生后1a内行超声检查和临床诊断显示，非病理性肾积水121只，病理性49只．随着超声评分值增加，病理性。肾积水风险越高，其中超声评分≤3分均为非病理性肾积水，评分≥8分均为病理性肾积水．病理性肾积水与非病理性肾积水超声评分之间差异具有显著统计学意义（P〈0．01）．超声评分为5分时，为辨别诊断非病理性。肾积水和病理性。肾积水的截断值，特异度为88．61％，灵敏度为95．00％．超声评分≤5分的肾积水胎儿的肾动脉RI值在0．60～0．67，而超声评分〉5分的。肾积水胎儿。肾动脉RI值在0．70～0．78．结论超声评分法联合RI指数评估胎儿肾积水预后客观准确，具有较高实用价值，超声评分5分为诊断胎儿病理性肾积水的最佳截断值．

基于改进RI方法的文本聚类

旨在通过考虑特征词汇的潜在语义和自身的重要性来提高文本聚类效果,研究基于RI方法的文本向量表示方法。首先,对基于RI方法构建的特征词汇随机索引向量中+1和-1向量元素出现位置进行约束,以避免在构建特征词汇上下文向量时可能造成该特征词汇潜在语义丢失现象;其次,在生成文本向量时考虑特征词汇自身重要性来改进权值的计算;最后,在测试数据上对基于RI方法的文本向量表示进行聚类效果测试与对比分析,结果表明采用基于RI方法能提高文本聚类效果。

基于索引调制的RIS辅助SIMO通信系统信号检测算法

面对未来无线移动通信对通信质量和频谱效率的更高要求,该文融合索引调制(IM)与可重构智能表面(RIS)技术,建立基于IM的RIS辅助单输入多输出(SIMO)通信系统架构,并提出一种基于变分贝叶斯推断(VBI)的信号检测算法。首先,在该系统中,RIS单元被划分为若干子块,利用RIS子块的激活状态传递附加信息;接着,利用VBI给出激活RIS子块对应的相移矢量与待检测信号的近似后验分布;最后,利用RIS相移矢量近似后验分布的对数零梯度值结合正交匹配追踪算法(OMP)恢复出索引信息比特,进而利用待检测信号对数零梯度值,恢复出发送信号。同时,从理论上推导了基于IM的RIS辅助SIMO系统平均速率。仿真结果表明,与传统RIS辅助的SIMO通信系统相比,基于IM的RIS辅助SIMO系统具有更高的系统平均速率;并且与现有算法相比,该文算法具有更低的误比特率。

TVCDS与RI指数联合血清CA125、CA199水平检测对卵巢癌患者诊断效能的影响

目的探究经阴道彩色多普勒超声（TVCDS）与多普勒超声阻力指数（RI指数）联合血清糖类抗原125（CA125）、糖类抗原199（CA199）水平检测对卵巢癌患者诊断效能的影响。方法选取2014年1月至2017年2月本院卵巢癌早期患者44例（A组），卵巢良性肿瘤患者38例（B组），均经术后病理学证实，另选取同期健康体检者40例（C组）。均行TVCDS检查，以化学发光免疫分析法测定血清CA125、CA199水平。比较三组血清CA125、CA199水平及A组、B组TVCDS血流参数[收缩期峰值流速（PSV）、舒张末期流速（EDV）、RI指数1，分析TVCDS（RI）、血清CA125、CA125水平单独及联合诊断早期卵巢癌敏感度、特异度、准确度、漏诊率、误诊率。结果经单因素方差分析，三组间血清CA125、CA199水平比较，差异有统计学意义（P〈0．05），A组血清CA125、CA199水平明显高于B组、C组，差异有统计学意义（P〈0．05）；A组PSV、EDV高于B组，RI低于B组，差异具有统计学意义（P〈0．05）；联合检测早期卵巢癌敏感度93．18％（41，44）、特异度97．37％（37／38）、准确度95．12％（78／82），均高于TVCDs（RI）、血清CA125、CA199水平单独检测，差异具有统计学意义（P〈0．05）；联合检测漏诊率6．82％（3／44）、误诊率2．63％（1／38），均低于TVCDS（RI）、血清CA125、CA199水平单独检测，差异具有统计学意义（P〈0．05）。结论TVCDS与RI指数联合血清CA125、CA199水平检测卵巢癌患者，能及早发现恶性肿瘤，具有较高诊断价值，且能减少漏诊、误诊情况，值得临床推广应用。

脂肪醇气相色谱保留值RI的QSRR的研究

根据分子拓扑理论 ,新建了两个结构信息拓扑指数1χy 和 χd∶1χy=∑ (δyi·δyj) -0 5,χd=D/ (2× (nc- 2 ) )。将这两个新建的结构信息拓扑指数用于脂肪醇定量结构———气相色谱保留值RI的相关性 (QSRR)研究 ,发现1χy 和 χd 与脂肪醇在 6个不同固定相上的色谱保留值RI有优良的线性关系 ,相关系数R均在 0 99以上。并用新QSRR模型预测了不在训练集的一些脂肪醇、酸在SE - 30相上的色谱保留值RI ,预测值与实验值非常吻合。研究结果表明 ,1χy 和 χd 能较好地反映化合物的结构特征 ,新QSRR模型物理意义明确 ,计算值与实验值接近的程度优于其他模型。

心电图Morris、Macruz指数与经皮球囊二尖瓣成形术疗效的相关性分析

分析32例经皮球囊二尖瓣成形术(PBMV)前、后的心电图Morris指数(PTFv_1)和Macruz指数(Ⅱ导联P/P-R段比值),探讨心电图对判定PBMV疗效的价值。结果Morris指数术前—0.061±0.005mm·s,术后—0.038±0.003mm·s,Macruz指数术前2.54±0.12,术后2.02±0.15,均有极显著性差异(P<0.001)。将两指数分别与多项血流动力学和超声心动图测值比较,术前,后均有较好的相关。认为Morris指数和Macruz指数可作为PBMV后疗效判定及心功能随访的一种可靠而简便的方法。

拓扑指数F(′F)与气相色谱保留指数RI的相关性研究

用结构参数构成的矩阵定义了拓扑指数Ｆ（′Ｆ），计算了１０个系列９４个分子的 Ｆ（′Ｆ）值。发现Ｆ（′Ｆ）与这些化合物的气相色谱保留指数有好的相关性．相关系数均在０．９７ 以上。

脂肪醇气相色谱保留值RI的QSRR研究

根据分子拓扑理论 ,新建了两个结构信息拓扑指数1χy 和 χd:1χy=∑ (δyi·δyj) - 0 .5,χd=|D| / (2× (nC- 2 ) ) .将这两个新建的结构信息拓扑指数用于脂肪醇定量结构—气相色谱保留值RI的相关性 (QSRR)研究 ,发现1χy 和 χd 与脂肪醇在 6个不同固定相上的色谱保留值RI有较好的线性关系 ,相关系数R均在 0 .99以上 .用新QSRR模型预测了不在训练集的一些脂肪醇、酸在SE - 30相上的色谱保留值RI ,预测值与实验值非常吻合 .研究结果表明 ,1χy 和 χd 能较好地反映化合物的结构特征 ,新QSRR模型物理意义明确 。

Print Form^(TM) HR成形网的编织设计与应用

介绍了Voith公司新近开发的Print FormTM HR成形网的设计理念,叙述了在成形网性能指标的诸多要求中,采用综合折中的设计方法,实现成形网性能的最佳化。同时,也介绍了Print FormTM HR成形网在世界各国造纸企业中的应用实例。

食管癌患者血清NGAL、Hcy、sTNF-RI、白介素及食管动力学指标的变化观察

目的分析食管癌患者的血清NGAL、Hcy、sTNF-RI、白介素及食管动力学指标的变化情况。方法选取本院收治的66例食管癌患者为观察组,并选取同时间段的66名体检健康人员为对照组,然后将2组的血清NGAL、Hcy、sTNF-RI、白介素及食管动力学指标进行检测与比较,然后将观察组中不同食管癌分期者的检测指标进行比较。结果观察组的血清IL-2低于对照组,血清NGAL、Hcy、sTNF-RI及IL-6、IL-8、IL-18则均高于对照组,另外食管收缩压、蠕动性收缩比及食管括约肌松弛率低于对照组,且观察组中食管癌分期较高者的变化大于食管癌分期较低的患者,差异均有统计学意义(P<0.05)。结论食管癌患者的血清NGAL、Hcy、sTNF-RI、白介素及食管动力学指标呈现异常的状态,且其检测水平受疾病分期的影响较大。

老化条件对天然生胶塑性保持率(PRI)的影响

天然生胶塑性保持率PRI是加热老化30min后塑性值P30与未老化试样的塑性值P0之比乘以100。结果表明,在P0相同的条件下,P30在一定温度范围内随老化温度的升高,呈现下降趋势;在老化温度一致的情况下P30随老化时间的延长而降低。在P0相同的情况下,PRI与P30成正比,PRI在一定程度上也随老化温度的升高和老化时间的延长,呈现下降趋势。

The Physicochemical Changes of Farm-Raised Pacific White Shrimp (<i>Litopenaeus vannamei</i>) as Influenced by Iced Storage

Farm-raised Pacific white shrimp (Litopenaeus vannamei) freshly harvested was evaluated for differences in proximal composition (moisture, ash, fat, and protein contents), water activity (aw), water retention index (WRI), pH, colour and texture of up to 12 days of iced storage. Shortly after harvest, the proximate composition of shrimp appeared comparable across the farms. With ice storage, the pH significantly increased whereas fat content slowly decreased particularly between days 3 and 9 (P P > 0.05). Expressly, the protein content of shrimp specimens gradually decreased after day 8 (P aw) of shrimp specimens exhibited inconsequential differences during iced storage. While the lightness (L*) was significantly affected from day 2 onwards, the yellowness (b*) colour was so but only between days 6 and 10 (P < 0.05). In addition, the adhesiveness and hardness textures of shrimp specimens registered peak values at day 11. Overall, the physicochemical differences in farm-raised shrimp during iced storage of this study provide valuable information for relevant stakeholders of the shrimp industry. Importantly, the data provided at this study can serve as baseline for comparison and evaluation of preservative treatments applied to shrimp.

Study of Quantitative Structure-retention Relationship for Substituted Phenols

Quantum chemistry parameters of 20 substituted phenols were computed at the 6- 31G＊ level using DFT method. Based on theoretical linear solvation energy theory, the correlation equation that can predict the retention index （Ri） was developed using structural parameters of 15 substituted phenols with experimental data as theoretical descriptors, and the conventional correlation coefficient （R^2） is 0.9885. The correlation degree of each independent variable in the model was validated by variance inflation factors （VIF） and t-test. Cross-validation indicates that the model possesses high predicting ability. The correlation and predicting ability of the Ri equation are both more advantageous than those based on orientating group index, connectivity index, and topological index method. In addition, RI values of 5 compounds without experimental data were predicted with the model.