沙棘果实中主要活性成分质量分布

沙棘作为一种抗逆性、适应性、萌蘖性较强的植物资源，被广泛应用于黄土丘陵地区荒山绿化、土壤改良、水土保持和砒砂岩治理。沙棘不仅具有良好的生态价值，其果实中富含多种生物活性物质。本文凝练了沙棘果实中活性化合物的构成、分布及活性特征，并对沙棘果实活性物质的研究进行展望。基于相关文献，针对黄酮、花青素、酚酸、有机酸、肌醇、维生素、类胡萝卜素、不饱和脂肪酸、甾醇等广泛存在于沙棘果实中的化学成分进行总结分析，提供沙棘果实中上述活性物质分布情况的综合信息。研究表明，针对沙棘果实中活性物质的构成、分布和活性特征的研究较为丰富，但在部分领域仍缺乏研究，如栽培技术条件对活性物质的影响，活性物质与沙棘果实加工中异味的关联性等。本文为沙棘果实在食品、药品及保健品行业中的综合利用提供了理论支撑，为促进沙棘资源在经济中的全面发展提供参考。      

高压直流接地极对埋地管道腐蚀的影响和管控思考

高压直流输电、油气长输管道建设促进了全国范围内的能源优化配置,但高压直流接地极放电对埋地管道的强直流干扰问题应该引起足够关注。为进一步加强相关风险管控,回顾中国高压直流输电网的发展历程,对高压直流接地极放电影响管道的典型特点进行分析,结合当前实际提出后续风险管控的发展方向。研究结果表明:邻近油气长输管道路由的高压直流输电线路和接地极对管道的影响具有干扰时间不确定、干扰机理复杂、干扰程度大及缓解困难的特点,是管道当前面临的突出安全风险。高压直流输电网调试或故障运行过程中,接地极单极放电会加速管道腐蚀。后续应从加强沟通协调和联合测试,深化腐蚀机理和规律研究,采取综合治理措施等方面提升检测、研究及治理水平,全方位保障国家能源通道的安全稳定。     

Glacier mass balance in High Mountain Asia inferred from a GRACE release-6 gravity solution for the period 2002–2016

We provide estimates of glacier mass changes in the High Mountain Asia (HMA) area from April2002 to August 2016 by employing a new version of gravity solutions of the Gravity Recovery and ClimateExperiment (GRACE) twin-satellite mission. We find a total mass loss trend of the HMA glaciers at a rateof –22.17 (±1.96) Gt/a. The largest mass loss rates of –7.02 (±0.94) and –6.73 (±0.78) Gt/a are found forthe glaciers in Nyainqentanglha Mountains and Eastern Himalayas, respectively. Although most glaciers inthe HMA area show a mass loss, we find a small glacier mass gain of 1.19 (±0.55) and 0.77 (±0.37) Gt/a inKarakoram Mountains and Western Kunlun Mountains, respectively. There is also a nearly zero massbalance in Pamirs. Our estimates of glacier mass change trends confirm previous results from the analysisof altimetry data of the ICESat (ICE, Cloud and Land Elevation Satellite) and ASTER (AdvancedSpaceborne Thermal Emission and Reflection Radiometer) DEM (Digital Elevation Model) satellites inmost of the selected glacier areas. However, they largely differ to previous GRACE-based studies which weattribute to our different post-processing techniques of the newer GRACE data. In addition, we explicitlyshow regional mass change features for both the interannual glacier mass changes and the 14-a averagedseasonal glacier mass changes. These changes can be explained in parts by total net precipitation (netsnowfall and net rainfall) and net snowfall, but mostly by total net radiation energy when compared to datafrom the ERA5-Land meteorological reanalysis. Moreover, nearly all the non-trend interannual masschanges and most seasonal mass changes can be explained by the total net radiation energy data. The massloss trends could be partly related to a heat effect due to increased net rainfall in Tianshan Mountains, QilianMountains, Nyainqentanglha Mountains and Eastern Himalayas. Our new results for the glacier mass changein this study could help improve the understanding of glacier variation in the HMA area and contribute tothe study of global change. They could also serve the utilization of water resources there and in neighboringareas.     

酒糟和醋糟营养成分差异及其瘤胃降解特性分析

本试验旨在评价酒糟、醋糟等非常规饲料资源的饲用价值，为酒糟醋糟资源应用于肉牛养殖提供数据参考。试验选用山西不同地区酒糟、醋糟试样5个，试样编号分别为白酒糟、啤酒糟、醋糟1、醋糟2、醋糟3，发酵原料分别为白酒糟（高粱）、啤酒糟（大麦+大米）、醋糟1（高粱+大麦）、醋糟2（大麦+玉米）、醋糟3（高粱+玉米）。通过实验室常规方法测定样品常规营养成分以及利用体外产气法和尼龙袋法评价其饲用价值，同时建立体外法与尼龙袋法测定干物质降解率的回归方程。结果表明：5个样品的干物质（DM）含量为23.25% ~ 42.96%，粗蛋白质（CP）含量分别为啤酒糟（31.84%）>白酒糟（14.58%）>醋糟3（14.40%）>醋糟1（12.21%）>醋糟2（8.46%）。醋糟1的中性洗涤纤维（NDF）、酸性洗涤纤维（ADF）含量均为最高，其次为醋糟2、醋糟3，白酒糟NDF含量最低。啤酒糟的72 h产气量（GP72）显著高于白酒糟（P < 0.05）。体外产气法和尼龙袋法测定的酒糟72 h干物质降解率（IVDMD72、DMD72）显著高于醋糟（P < 0.05）。5个试样的IVDMD72与DMD成正相关，随着降解时间增加其相关性逐渐增加。综上，酒糟的CP含量较高（14.58% ~ 31.84%），醋糟NDF、ADF含量相对较高（59.59% ~ 64.91%，38.78% ~ 54.78%）。结合GP、IVDMD及DMD结果，酒糟消化性能优于醋糟。以IVDMD建立估算DMD的回归公式为DMD72=-19.215+1.645IVDMD72（R2=0.912，P < 0.05）|以IVDMD建立估算DM有效降解率（ED）的回归公式为ED=-12.448+1.045IVDMD72（R2=0.929，P < 0.01）。 [关键词] 醋糟|酒糟|体外产气法|尼龙袋法     

Poorly crystalline iron and aluminium oxides contribute to the carbon saturation and sorption of dissolved organic carbon in the soil

Soil carbon (C) saturation implies an upper limit to a soil's capacity to store C depending on the contents of silt + clay and poorly crystalline Fe and Al oxides. We hypothesized that the poorly crystalline Fe and Al oxides in silt + clay fraction increased the C saturation and thus reduced the capacity of the soil to sorb additional C input. To test the hypothesis, we studied the sorption of dissolved organic carbon (DOC) on silt + clay fractions (<53 µm) of highly weathered oxic soils, collected from three different land uses (i.e., improved pasture, cropping and forest). Soils with high carbon saturation desorbed 38% more C than soils with low C saturation upon addition of DOC, whereas adsorption of DOC was only observed at higher concentration (>15 g kg^?1). While high Al oxide concentration significantly increased both the saturation and desorption of DOC, the high Fe oxide concentration significantly increased the desorption of DOC, supporting the proposition that both oxides have influence on the DOC sorption in soil. Our findings provide a new insight into the chemical control of stabilization and destabilization of DOC in soil.     

A comparison of the effects of carbon dioxide and medical air for abdominal insufflation on respiratory parameters in xylazine-sedated sheep undergoing laparoscopic artificial insemination

AIMS: To determine if abdominal insufflation with medical air will improve oxygenation and ventilation parameters when compared to insufflation with CO₂ in xylazine-sedated sheep undergoing laparoscopic artificial insemination (AI).

METHODS: Forty-seven sheep underwent oestrus synchronisation and were fasted for 24 hours prior to laparoscopic AI. Each animal was randomised to receive either CO₂ or medical air for abdominal insufflation. An auricular arterial catheter was placed and utilised for serial blood sampling. Respiratory rates (RR) and arterial blood samples were collected at baseline, after xylazine (0.1?mg/kg I/V) sedation, 2 minutes after Trendelenburg positioning, 5 minutes after abdominal insufflation, and 10 minutes after being returned to a standing position. Blood samples were collected in heparinised syringes, stored on ice, and analysed for arterial pH, partial pressure of arterial O₂ (PaO₂), and CO₂ (PaCO₂). The number of ewes conceiving to AI was also determined.

RESULTS: Repeated measures ANOVA demonstrated temporal effects on RR, PaO₂, PaCO₂ and arterial pH during the laparoscopic AI procedure (p<0.001), but no difference between insufflation groups (p>0.01). No sheep experienced hypercapnia (PaCO₂>50?mmHg) or acidaemia (pH<7.35). Hypoxaemia (PaO₂<70?mmHg) was diagnosed during the procedure in 14/22 (64%) ewes in the CO₂ group compared with 8/23 (35%) ewes in the medical air group (p=0.053). Overall, 15/20 (75%) ewes in the CO₂ group conceived to AI compared with 16/22 (72.7%) in the medical air group (p=0.867).

CONCLUSIONS AND CLINICAL RELEVANCE: There were no statistical or clinical differences in RR, PaO₂, PaCO₂, pH, or conception to AI when comparing the effects of CO₂ and medical air as abdominal insufflation gases. None of the sheep experienced hypercapnia or acidaemic, yet 42% (19/45) of sheep developed clinical hypoxaemia, with a higher percentage of ewes in the CO₂ group developing hypoxaemia than in the medical air group. Based on the overall analysis, medical air could be utilised as a comparable alternative for abdominal insufflation during laparoscopic AI procedures.     

鹰嘴豆短肽的分步酶解法制备及其营养价值评价

以鹰嘴豆蛋白为原料,建立复合酶分步酶解法制备鹰嘴豆短肽的工艺。在鹰嘴豆蛋白碱性蛋白酶Alcalase水解的基础上,进一步采用中性蛋白酶和风味蛋白酶Flavourzyme继续水解鹰嘴豆蛋白碱性蛋白酶Alcalase酶解物,并对各影响因素进行研究,建立短肽得率与各影响因素的回归模型,利用高效液相色谱法和氨基酸自动分析仪等测定鹰嘴豆短肽的相对分子质量、氨基酸组成、一般营养成分,评价鹰嘴豆短肽的营养价值。结果表明,中性蛋白酶和风味蛋白酶Flavourzyme制备鹰嘴豆短肽的最佳工艺参数为:复合酶添加量5 678 U/g,pH 7.0,水解时间216 min,水解温度55℃,在此条件下,短肽得率为63.79%,与碱性蛋白酶Alcalase单独酶解相比明显提高,水解度为26.74%;大部分水解产物的相对分子质量低于1 000、脂肪含量低,蛋白质、必需氨基酸等含量丰富,与FAO/WHO推荐的成人需求量模式相比,其第一限制氨基酸是蛋氨酸和半胱氨酸,与学龄儿童需求量模式相比,其第一限制氨基酸是苏氨酸,氨基酸分分别高达138.18和103.25;必需氨基酸与非必需氨基酸比值(EAA/NEAA)为0.73,接近FAO/WHO参考标准值0.6。该研究为进一步开发利用和工业化生产鹰嘴豆短肽奠定了基础。     

我国典型茶区化学氮肥施用与生产运输过程的温室气体排放量估算

基于相关统计数据和文献调研方法,估算了我国14个典型茶区中化学氮肥施用、生产及运输过程中的温室气体排放量。结果表明,化学氮肥施用导致的土壤N₂O直接排放和生产过程中的温室气体排放是茶园化学氮肥消费带来的温室气体主要排放源;14个典型茶区消费的化学氮肥产生的温室气体排放量(以CO₂排放当量计算)为16.81~344.80万t·a^-1,其中贵州、云南、湖北和四川4省的茶园消费的化学氮肥带来的温室气体排放量较高,均超过200万t·a^-1,占全部区域温室气体排放量的59.98%;单位面积温室气体排放量为3.22~9.76 t·hm^-2·a^-1,单位产量温室气体排放量为2.10~12.96 t·t^-1·a^-1、单位产值温室气体排放量0.39~1.90 t·万元^-1·a^-1;总体而言,贵州、云南、湖北、湖南和四川5省的茶园消费的化学氮肥带来的温室气体排放量、单位面积温室气体排放量、单位产量温室气体排放量和单位产值温室气体排放量较高,福建、河南省及重庆市3个茶区相对较低。在茶园化学氮肥施用量控制为300 kg·hm^-2和450 kg·hm^-2两种情景下,茶园生态系统温室气体减排总量为617.07万t·a^-1和228.94万t·a^-1,减排潜力为34.12%和12.66%,减排潜力较大的区域主要有湖北、四川、贵州、湖南和江西等5省。     

棉籽壳中除草活性物质提取及鉴定

为了开发利用棉籽壳中的除草活性物质，分别以无水乙醇、正丁醇、石油醚和乙酸乙酯为溶剂，采用索氏提取法对棉籽壳中的活性物质进行了提取，并对各溶剂粗提物进行了除草活性测定。结果发现:用无水乙醇提取的粗提物对稗草生长的抑制活性最高，经气相色谱-质谱(GC-MS)联用分析，发现该粗提物中主要含有甘油、三环己基3-烯-6-辛酮、4-乙烯基-2-甲氧基苯酚、(邻甲基苯酚)-2-溴-2氯-乙酰酯、十四酸、十四酸乙酯、十六烷酸、辛酸异戊酯和亚油酸9种化合物。进一步的除草活性测定结果表明，亚油酸、辛酸异戊酯、4-乙烯基-2-甲氧基苯酚和(邻甲基苯酚)-2-溴-2氯-乙酰酯4种化合物对稗草表现出一定的除草活性，其中亚油酸活性最强，其IC₅₀值为14.5 mg/L。     

超高效液相色谱—串联质谱法检测鸡血液样品中喹诺酮类药物残留

旨在建立鸡血液样品中多种喹诺酮类药物残留的超高效液相色谱—串联质谱方法。样品经乙腈提取,经Waters Acquity UPLC BEH C₁₈色谱柱分离,以甲醇和0.1%甲酸水溶液为流动相进行梯度洗脱,电喷雾正离子（ESI⁺）模式电离,MRM扫描模式检测。经方法学验证,该方法的线性关系、回收率、精密度均符合要求。应用超高效液相色谱—串联质谱法建立了鸡血液样品中多种喹诺酮类药物同时检测的方法,实现了动物血液样品中12种喹诺酮类药物同时定性、定量分析。