黄土区农田土壤细菌和真菌群落对长期施氮的响应特征

【目的】细菌和真菌是调控土壤生态功能的重要因素,摸清细菌和真菌群落的变化有助于深入理解微生物在生态功能中的调节作用。【方法】黄土区渭北旱塬定位监测试验始于1984年。2022年选择其中5个不同施氮(N)量处理小区:0、45、90、135和180 kg/hm^(2)(分别记作N0、N45、N90、N135和N180),采集0—20 cm土层样品,采用16S rRNA和ITS高通量测序方法,分析细菌和真菌群落结构及其功能变化,同时测定土壤碳组分、微生物活性、根系生物量及土壤酶活性等。【结果】随着施氮量增加,土壤微生物量从113 mg/kg增加到177~234 mg/kg,微生物活性从4.92 g/(m^(2)·s)增加到5.83~7.26 g/(m^(2)·s),土壤植物根系量从1.73 t/hm^(2)增加到2.32~2.98 t/hm^(2)。施氮处理土壤细菌群落丰富度(Chao1)和多样性(Shannon)显著降低,分别下降4.0%~12.3%和1.6%~1.8%,但真菌群落丰富度和多样性无显著变化。施氮处理土壤变形菌门、芽单胞菌门、拟杆菌门相对丰度分别下降了2.4%~16.4%、2.1%~26.3%、24.1%~50.0%,细菌中座囊菌纲、伞菌纲相对丰度分别下降了29.4%~58.8%、44.4%~88.9%,而放线菌门、酸杆菌门、绿湾菌门等细菌相对丰度提高了10.4%~34.7%、37.8%~54.1%、14.3%~28.6%,子囊菌门、银耳纲等真菌的相对丰度分别提高了8.3%~73.8%、18.2%~45.5%。施氮后,土壤有机碳含量由6.50 g/kg提升到7.00~7.35 g/kg,可溶性有机碳含量由22.43 mg/kg提高到27.60~34.87 mg/kg,NO_(3)^(-)-N含量由1.38 mg/kg提高到1.78~2.25 mg/kg,C/N由8.90下降到8.64~7.74,微生物的硝化作用显著提高了14.3%~39.6%,好氧氨氧化功能提高了25.1%~48.2%,参与碳循环功能的木糖苷酶活性提高了13.5%~39.3%,纤维二糖水解酶活性提高了50.3%~126.8%。细菌丰富度和多样性变化与土壤有机碳(SOC)、可溶性有机碳、NO_(3)^(-)-N含量和C/N有关。施氮条件下细菌变形菌门丰度降低与土壤可溶性有机碳(DOC)含量升高有关,而放线菌丰度升高与SOC、DOC和NO_(3)^(-)-N含量的升高有关,但子囊菌和担子菌的丰度变化与土壤理化性质间的关系不显著。【结论】在黄土高原地区,细菌群落结构对氮肥施用的响应较真菌更为敏感。细菌群落组成的变化与土壤有机碳、可溶性有机碳和NO_(3)^(-)-N呈显著正相关,与全氮和C/N呈显著负相关。此外,氮肥施用增加了土壤中与碳循环相关的功能菌丰度,促进了木糖苷酶和纤维二糖水解酶的分泌。

2016-2020年邯郸市中心医院0~14岁体检儿童血铅水平分析

目的了解邯郸市儿童血铅暴露状况及影响因素,为儿童铅暴露提供指导性建议。方法采用钨舟原子吸收法对2016-2020年邯郸市中心医院儿科常规体检儿童血样进行检测,比较不同性别和年龄组血铅水平的差异。结果20715例0~14岁儿童血铅水平中位数(P_(25)~P_(75))为27.8(12.7~46.9)μg/L,高铅血症、铅中毒检出率分别为0.95%、0.28%,无重度铅中毒。男童血铅水平中位数(P_(25)~P_(75))为28.5(12.7~47.9)μg/L,高铅血症、铅中毒检出率分别为1.16%、0.35%,女童血铅水平中位数(P_(25)-P_(75))为26.1(12.0~44.7)μg/L,高铅血症、铅中毒检出率分别为0.59%和0.15%,男童血铅水平中位数、高铅血症、铅中毒检出率均显著高于女童(P均<0.05)。婴幼儿、学龄前、学龄、青少年血铅水平中位数(P_(25)~P_(75))分别为26.1(11.7~44.9)μg/L、27.7(12.7~46.9)μg/L、29.0(12.7~47.8)μg/L、29.8(14.0~47.7)μg/L,婴幼儿组显著低于其他组,差异有统计学意义(z=-8.739,P<0.001);高铅血症检出率分别为0.82%、1.03%、1.03%和1.0%,铅中毒检出率分别为0.34%、0.31%、0.23%和0.17%,四组间差异无统计学意义(P>0.05)。结论邯郸市儿童血铅暴露状况低于中国儿童铅暴露平均状况,但仍高于铅暴露的安全水平。

中国边疆研究中的“本土”与“世界”问题——基于近代西方西北探险与中国海外游记的探讨

中国边疆研究包含“中国的”与“世界的”两个层面。近代西方探险与中国海外考察兴起,使得东西方文化在中国西北边疆研究领域产生了碰撞与交织,促使了西北边疆史地体系的进一步发展。在东西方文化情景模式的转换过程中,“拿来主义”的态度对中国边疆研究产生了不利的影响。中国边疆研究的发展,必须具有世界场域的眼光,从“史源”上解决研究中存在的制约性因素,使得中国边疆研究能够从“中国的边疆”走向“世界”。

胃溃疡和胃癌患者血清叶酸及维生素B_(12)浓度水平检测的临床意义

目的:探讨胃溃疡和胃癌患者血清叶酸及维生素B_(12)浓度水平检测的临床意义,以指导胃溃疡、胃癌患者合理摄入与补充。方法:选取在医院诊治的61例胃溃疡患者和50例胃癌患者,分别将其纳入胃溃疡组(61例)和胃癌组(50例);另选取30名健康体检者纳入健康对照组(30名)。采用电化学发光法对3组的血清中叶酸及维生素B_(12)含量进行测定,对检测结果进行统计学处理及对比研究。结果:(1)健康对照组血清叶酸含量和维生素B_(12)含量分别为(9.68±3.26)nmol/L和(364.04±185.11)nmol/L;(2)胃溃疡组血清叶酸含量和维生素B_(12)含量分别为(9.15±3.53)nmol/L和(261.15±149.02)nmol/L,胃溃疡患者血清维生素B_(12)含量显著低于健康对照组,两组比较差异有统计学意义(t=1.699,P<0.05);(3)胃癌患者血清叶酸含量和维生素B_(12)含量分别为(7.04±4.21)nmol/L和(388.40±206.17)nmol/L,胃癌患者血清叶酸含量显著低于健康对照组,两组比较差异有统计学意义(t=1.462,P<0.05)。结论:胃溃疡患者血清维生素B_(12)浓度水平显著降低,胃癌患者血清叶酸浓度水平显著降低,其两项指标在胃溃疡、胃癌诊断中具有重要的临床价值。

中华民族共同体之历史地理空间演变——以先秦中原地区戎狄与诸夏互动为例

中原地区作为黄河文明的核心区,其特殊的区位优势,为先秦时期各民族的活动提供了地理基础;而冰后期第三次寒冷时期的气候变化,加快了戎狄与诸夏之间的互动进程。长期的戎夏交往交流交融,进一步缩小了两者之间的文化与心理距离,在此基础上历经后世各朝代的政治、文化塑造,不断丰富拓展了中原地区民族地理的内涵与外延,最终奠定了其在中华民族共同体中的地理基础。

寰椎侧块-枢椎椎弓根钉棒技术在先天性颅颈交界区畸形翻修手术中的应用

目的探讨寰椎侧块-枢椎椎弓根螺钉棒复位内固定技术对于已行不当后颅窝减压术的先天性颅颈交界区畸形患者进行翻修手术的可行性及临床疗效。方法回顾性分析2013年1月—2016年1月中国人民解放军总医院第一医学中心神经外科收治的21例先天性颅颈交界区畸形患者的临床资料。其中18例患者在外院已行后颅窝减压术,3例患者行后颅窝减压术+枕颈内固定术。患者术前及术后均行颅颈交界区3D-CT及MRI检查,评估寰枢椎脱位和上颈髓受压的程度;采用日本骨科协会(JOA)评分标准对患者的临床状况进行评价。所有患者均采用后路寰椎侧块-枢椎椎弓根螺钉-棒技术行寰枢复位内固定,并取髂后上棘松质骨颗粒植骨融合。结果本组患者的翻修手术均成功实施,术中未出现脊髓、椎动脉损伤。术后20例患者完成了6~24个月,平均12.2个月的随访。3D-CT复查示,19例患者(90.5%)获得垂直方向的完全复位,18例患者(85.7%)获得水平方向的完全复位;植骨均出现融合,未出现钉棒脱落或复位丢失者。MRI复查显示,上颈髓受压均获得缓解。术后3个月的JOA评分从术前的(9.8±2.1)分提高到(14.1±1.9)分,差异有统计学意义(P<0.01)。结论寰椎侧块-枢椎椎弓根螺钉-棒复位内固定技术治疗已行不当后颅窝减压术的先天性颅颈交界区畸形是安全有效且可行的。

近代“绥新”线视野下的西北区域边疆考察

“绥新”线狭义多指近代绥远经阿拉善、额济纳、甘边草地至新疆的“绥新”路;广义乃含清初阿尔泰军台歧路、绥远—喀什歧路,涵盖古居延北路、龙城故道、玉门道、阳关道,是一条杂合民间驼道、盐道、间道,联结京津、交通亚洲中部的道路体系。绥新歧路与干线相互交织构成近代西北丝绸之路,便利了商品和文化的交流,此种西北边疆商业区域的形成,维持了近代西北区域边疆的政治平衡,并最终奠定了近代西北区域边疆的格局。

14例腹腔镜胆囊切除术中意外发现胆囊癌患者的MRI、CT影像学特点分析

目的探讨腹腔镜胆囊切除术(LC)中意外发现胆囊癌(UGC)患者的核磁共振成像(MRI)、CT影像学特点。方法回顾性分析我院14例UGC患者行LC的术前MRI和CT检查资料,与病理检查结果进行对比。结果 14例UGC患者术后病理检查均确诊为胆囊癌,腺癌12例,鳞癌2例,影像学检查漏诊9例,误诊5例。结论 LC术前应全面分析胆囊癌高危人群的临床资料,规范术前影像学检查技术,尽量避免漏诊或误诊,术中发现UGC应及时进行根治手术,并积极采取预防切口转移的措施。

患者结肠镜检查前肠道准备失败风险预测模型的系统评价

目的系统地评价患者结肠镜检查前肠道准备失败的风险预测模型。方法计算机检索中国知网(CNKI)、中国生物医学文献数据库(SinoMed)、万方数据知识服务平台、维普中文科技期刊数据库(VIP)、PubMed MeDILINE、Cochrane Library、Embase、CINAHL、Web of Science数据库,检索出符合本研究的文献,由2名研究者独立提取信息,并使用PROBAST工具进行质量评价。结果共纳入8篇研究,其中6篇为前瞻性队列研究,2篇为回顾性病例对照研究。3篇研究开展了内部验证,1篇研究开展了外部验证。8篇研究的ROC曲线下面积为0.63~0.87,预测性能良好,但仍存在偏倚风险,主要是在数据分析部分未报告缺失数据的处理方法以及数据复杂性,部分研究筛选预测因子的方法不恰当,并且未对模型进行内外部验证。Meta分析结果显示,慢性便秘[OR=2.51,95%CI(2.15,2.92),Z=11.81,P<0.001]、糖尿病[OR=2.14,95%CI(1.79,2.56),Z=8.26,P<0.05]、服用抗抑郁药物[OR=5.46,95%CI(3.48,8.58),Z=7.37,P<0.001]是患者结肠镜检查前肠道准备失败的独立危险因素。结论肠道准备失败预测模型还处于发展阶段,各项模型均存在一定的偏倚风险,未来可开展模型的验证研究或开发本土化预测模型,并将其运用于临床,检验其有效性。医护人员应重点关注慢性便秘、糖尿病、服用抗抑郁药物患者的肠道准备情况,提前给予干预策略。

对内镜下肠息肉日间手术患者的全程护理的效果

目的探索对肠息肉患者实施日间手术全程护理的可行性与有效性。方法抽取昆明医科大学第二附属医院采取肠息肉日间手术的86例患者为试验组,同期选配86例采用择期手术常规住院的肠息肉患者为对照组。试验组实施日间手术全程护理,包括制定日间手术多学科、全程化护理路径;采取宣传手册、口头讲解、微信公众号等多样化日间手术宣教形式。结果试验组术前等待时间、住院天数、直接医疗费用皆小于对照组,差异有统计学意义(P<O.001);患者满意度试验组(98.8%)高于对照组(84.9%),差异有统计学意义(P=0.001);2组肠道准备不充分率与术后并发症发生率比较,差异无统计学意义(P>0.05)。结论对肠息肉患者实施日间手术全程护理具有可行性与有效性,可增加患者满意度,提升患者就医体验。

血清CysC、Hcy和Lp(a)水平升高与急性脑梗死病情严重程度的关系

目的探讨胱抑素C(cystatin C,CysC)、同型半胱氨酸(homocysteine,Hcy)、载脂蛋白a[Lp(a)]的水平变化与急性脑梗死(acute cerebral infarction,ACI)患者病情严重程度的关系。方法选取我院2016年8月至2017年9月确诊的ACI患者116例(ACI组)、选取年龄及性别与ACI组基本匹配的58例健康对象作为对照组,检测两组的血清CysC、Hcy和Lp(a)水平,将ACI患者根据NIHSS评分、梗死病灶大小进行亚组分析。结果 ACI组的血清CysC、Hcy和Lp(a)水平显著高于对照组,差异均具有统计学意义( P <0.05);轻度组、中度组和重度组的ACI患者的血清CysC、Hcy和Lp(a)水平组间比较,差异均具有统计学意义( P <0.05),组间呈逐渐升高的趋势;小梗死组、中梗死组及大梗死组的ACI患者的血清CysC、Hcy和Lp(a)水平组间比较,差异均具有统计学意义( P <0.05),组间呈逐渐升高的趋势。结论 ACI患者的血清CysC、Hcy和Lp(a)水平显著升高,并且与神经功能缺损程度及梗死病灶大小有关。

Monel400合金热压缩变形流变应力本构方程

目的研究Moenl400合金的热变形流变行为,确定合金热压缩变形的流变应力本构方程。方法在Gleeble1500热模拟机上对Ni-Cu固溶体单相合金Monel400进行等温热压缩实验,研究Monel400合金在变形温度为1173~1423 K、应变速率为0.01~10 s^(-1)时的流变应力;Monel400合金的本构模型为含有ZenerHollomon参数的双曲正弦函数模型,通过回归分析获得了材料常数Q,ln A,n,α与真应变ε的关系;并对不同变形条件下的实测值与计算值进行对比。结果 Moenl400合金的流变应力随温度的升高和应变速率的降低而降低;Moenl400合金流变应力的计算值与实验值吻合较好。结论通过计算得到的本构模型能够较好地表征Monel400合金的高温流变特性。

Wheat Grain Yield and Yield Stability in a Long-Term Fertilization Experiment on the Loess Plateau

To provide a scientific basis for sustainable land management, a 20-year fertility experiment was conducted in Changwu County, Shaanxi Province, China to investigate the effects of long-term application of chemical fertilizers on wheat grain yield and yield stability on the Loess Plateau using regression and stability analysis. The experiment consisted of 17 fertilizer treatments, containing the combinations of different N and P levels, with three replications arranged in a randomized complete block design. Nitrogen fertilizer was applied as urea, and P was applied as calcium superphosphate. Fertilizer rates had a large effect on the response of wheat yield to fertilization. Phosphorus, combined with N, increased yield significantly (P < 0.01). In the unfertilized control and the N or P sole application treatments, wheat yield had a declining trend although it was not statistically significant. Stability analysts combined with the trend analysis indicated that integrated use of fertilizer N and P was better than their sole application in increasing and sustaining the productivity of rainfed winter wheat.

Phosphorus Changes and Sorption Characteristics in a Calcareous Soil Under Long-Term Fertilization

Knowledge of phosphorus(P)behavior in long-term fertilized soils is essential for programming fertilization practices and for sustaining environmental quality.The long-term(1984-1997)effects of various fertilization treatments on P changes and sorption isotherms as well as the relationship of soil properties to P sorption and P forms were evaluated in an Ustic Isohumisol,a calcareous soil,on the Loess Plateau,China.Compared to 1984,after 13 years of crop production,total soil P in the no-P treatments(control and N treatment)decreased by 5%-7%,but in the phosphorus fertilizer alone(P), nitrogen and phosphorus fertilizers in combination(NP),manure alone(M),and nitrogen and phosphorus fertilizers and manure in combination(NPM)treatments,it increased by 22%,19%,28%,and 58%,respectively.Residual fertilizer P was found mainly in NH_4Ac-soluble P(Ca_8-P),followed by NaHCO_3-soluble P(NaHCO_3-P),and NH_4F-soluble P (A1-P).Phosphorus sorption in the soils with different fertilization practices fit the Langmuir equations.Phosphorus sorption capacity in the no-P treatments increased,whereas it decreased in the P-included treatments(P,NP,and NPM treatments).Phosphorus sorption maximum(Q_m)was significantly and negatively correlated to inorganic P including NaHCO_3-P,Ca_8-P,NaOH-Na_2CO_3-soluble P(Fe-P),and Al-P(P≤0.01).Moreover,long-term fertilization increased soil organic carbon in the NP,M,and NPM treatments and decreased pH in the NP and NPM treatments.Thus,the ability of the soil to release sorbed P to the environment increased under long-term P fertilization.

Effect of Nitrogen Management on Yield and Water Use Efficiency of Rainfed Wheat and Maize in Northwest China

A field experiment with four treatments and four replicates in a randomized complete block design was conducted at the Changwu Experimental Station in Changwu County, Shaanxi Province, of Northwest China from 1998 to 2002. The local cropping sequence of wheat, wheat-beans, maize, and wheat over the 4-year period was adopted. A micro-plot study using 15N-labelled fertilizer was carried out to determine the fate of applied N fertilizer in the first year. When N fertilizer was applied wheat (years 1, 2 and 4) and maize (year 3) grain yield increased significantly (P<0.05) (>30%), with no significant yield differences in normal rainfall years (Years 1, 2 and 3) for N application at the commonly application rate and at 2/3 of this rate. Grain yield of wheat varied greatly between years, mainly due to variation in annual rainfall. Results of 15N studies on wheat showed that plants recovered 36.6%-38.4% of the N applied, the N remained in soil (0-40 cm) ranged from 29.2% to 33.6%, and unaccounted-for N was 29.5%-34.2%. The following crop (wheat) recovered 2.1%-2.8% of the residual N from N applied to the previous wheat crop with recovery generally decreasing in the subsequent three crops (beans, maize and wheat).

多舱室爆炸致比格犬血清皮质醇、生长激素、泌乳素的变化及其与伤情的关系

目的探讨比格犬多舱室爆震伤后血清快速反应激素皮质醇和非快速反应激素[生长激素(GH)、泌乳素(PRL)]的变化,及其与颅脑损伤程度的关系。方法建造与实际舰船等大小的相邻舱室,并取健康成年比格犬48只随机置于当舱和邻舱。海军用炮弹于当舱进行静爆,利用压力传感器记录舱室内压力变化情况并测定爆炸前及爆炸后0.5、3、18 h当舱与邻舱实验犬血清神经元特异性烯醇化酶(NSE)、皮质醇、GH和PRL的含量。结果当舱内压力在起爆后出现明显的单个波峰(压力>3 000kPa),远高于邻舱最高峰(压力<170 k Pa)。当舱实验犬总死亡率(70.83%)明显高于邻舱实验犬(12.50%;P<0.05)。当舱和邻舱实验犬血清NSE、GH、皮质醇在爆炸后均持续高于爆炸前(P<0.05),而血清PRL未出现明显波动(P>0.05)。伤后18 h,当舱实验犬血清GH水平明显高于邻舱实验犬(P<0.05)。结论当舱实验犬较邻舱实验犬遭受到更为严重的颅脑爆震伤,伤后超急性期血清GH的测定可能有助于伤情的判断。

Divergent responses of tiller and grain yield to fertilization and fallow precipitation:Insights from a 28-year long-term experiment in a semiarid winter wheat system

Tillering is an important phenological stage,which is strongly related to the yield in spike components and final grain yield during winter wheat growth.Precipitation during the fallow season(fallow precipitation)influences tillering in winter wheat on the semi-arid Chinese Loess Plateau.However,little work has been done regarding tiller number changes under various types of fertilization and amounts of fallow precipitation on a long-term scale.Effects of fallow precipitation and fertilization on tiller were investigated in a winter wheat(Triticum aestivum L.)system in a 28-year field study(1990 to 2017)in a semiarid agro-ecosystem.Tiller number,spike number and grain yield were measured in four fertilization conditions:control without fertilizer(CK);mineral nitrogen fertilizer alone(N);mineral phosphorus fertilizer alone(P);mineral nitrogen and phosphorus fertilizer together(NP).Based on the long-term annual fallow precipitation,dry years(mean annual fallow precipitation)were distinguished.Phosphorus fertilization alone significantly increased the mean annual tiller number(23%),and the increase in tiller number was higher in wet years(29%)than in the dry years(17%).However,nitrogen fertilization alone had little effect on mean tiller number,while nitrogen and phosphorus together significantly increased mean annual tiller number(30%),mean tiller number in wet years(45%)and mean tiller number in dry years(17%).Tiller number was significantly and positively correlated with fallow precipitation in dry years for all fertilizer treatments,whereas it was weakly and either positively or negatively correlated with fallow precipitation in wet years depending on the treatment.This study found positive correlations between tiller number and fallow precipitation in the CK and NP treatments,and it found negative correlations between tiller number and fallow precipitation in the treatments with nitrogen fertilization alone or phosphorous fertilization alone in wet years.Understanding the impacts of fallow precipitation and fertilization on tiller development shed light on ways to improve crop production in rain-fed agricultural regions.

Synthesis and Crystal Structure of Dinuclear Copper(Ⅱ)Complex Cu_2(μ-PhCOO)_4(amet)_2·2CH_3COCH_3

Reaction of copper powder, dibenzoyl peroxide and 2-amino-4methyl-5-ethoxycarbonyl thiazole (amet) by refluxing in acetone yielded the dinuclearcopper(Ⅱ) complex Cu2 (μ-PhCOO)4 (amet)2- 2CH3COCH3. Crystal structure determination showed that each copper atom is coordinated by four bridged benzoxy and oneamet molecule with an M-M bond (Cu-Cu (A) = 2.6899 (7 ) ), therefore the coor-dination environment around the copper center is a distorted square pyramid with N(1)at the apical position. Blocks of Cu2 (μ-PhCOO)4 (amet)2·2CH3COCH3 crystallize inthe triclinic space group Ph, with Mr= 1100.14, a= 9. 631 (1), b=10. 446 (2), c=12. 758(2) ; a=91. 31 (1), β=95. 50(1),γ= 94. 87(1)°, V=1272. 4(3), Z=1, Dc= 1. 436 g/cm3, F(000) = 570, μ=0. 986 mm-1 and R=0.033, Rw=0.049.The IR spectra, which are of great interest since the molecule has ketone, ester andcarboxylate group simultaneously, are also discussed.

Thermal Expansion of CsNiCl_(3)by Electron Paramagnetic Resonance and Optical Absorption Spectra

Electron paramagnetic resonance(EPR)measurement of CsNiCl_(3)compound has been performed at 192 GHz in the temperature range from 300 to 5 K,along the axes of main g tensor.The energy levels and the g-factors are calculated.The linear thermalexpansion coefficient(2.77×10^(-5)K^(-1))for the Ni^(2+)-Cl^(-)bond distance is studied by combining EPR and optical absorption spectra with changing temperature.

8-酰基咖啡因类似物的合成研究

以茶碱和溴代烷为原料,合成了中间体7-烷基咖啡因。在硝酸银催化和过硫酸钾氧化作用下,7-烷基咖啡因与α-羰基酸发生自由基取代反应,得到4种8-酰基咖啡因类似物,并对其结构进行了表征。考察了催化剂用量、氧化剂用量、溶剂体系、反应温度等因素对产品收率的影响,优化反应条件为:催化剂硝酸银的用量为20%、n(7-丁基咖啡因)∶n(过硫酸钾)=1.0∶2.0、反应溶剂为乙腈/水、反应温度100℃。优化条件下,目标化合物1的总收率为54.5%~59.2%。