Technologies for reducing corn leaf burn caused by foliar spray of urea-ammonium nitrate (UAN) during the early growing season are limited. A field experiment was carried out to evaluate the effects of humic acid on c...Technologies for reducing corn leaf burn caused by foliar spray of urea-ammonium nitrate (UAN) during the early growing season are limited. A field experiment was carried out to evaluate the effects of humic acid on corn leaf burn caused by foliar spray of undiluted UAN solution on corn canopy at Jackson, TN in 2018. Thirteen treatments of the mixtures of UAN and humic acid were evaluated at V6 of corn with different UAN application rates and different UAN/humic acid ratios. Leaf burn during 1 2, 3, 4, 5, 6, 7, and 14 days after UAN foliar spray significantly differed between with or without humic acid addition. The addition of humic acid to UAN significantly reduced leaf burn at each UAN application rate (15, 25, and 35 gal/acre). The reduction of leaf burn was enhanced as the humic acid/UAN ratio went up from 10% to 30%. Leaf burn due to foliar application of UAN became severer with higher UAN rates. The linear regression of leaf burn 14 days after application with humic acid/UAN ratio was highly significant and negative. However, the linear regression of leaf burn 14 days after application with the UAN application rate was highly significant and positive. In conclusion, adding humic acid to foliar-applied UAN is beneficial for reducing corn leaf burn during the early growing season.展开更多
Urea as a source of cheap non-protein nitrogen is used to adulterate fish and meat meals which are basic components of broiler diets. The present study was carried out to elucidate the effects of urea on weight gain, ...Urea as a source of cheap non-protein nitrogen is used to adulterate fish and meat meals which are basic components of broiler diets. The present study was carried out to elucidate the effects of urea on weight gain, and hematological and biochemical profiles. A total of 48 broiler chicks were randomly allotted into 4 groups, designated Groups 1, 2, 3 and 4 of 12 birds each. Birds in Groups 2, 3 and 4 were fed on diets containing urea at the levels of 1%, 2.5% and 4%, respectively. Birds in Group 1 served as control and were not exposed to urea. Experimentation period was for 3 weeks and experiment was terminated when birds were 42 days of age. Body weight of all intoxicated birds at the various intervals was significantly decreased in comparison with that of the untreated control. Compared with control, all intoxicated broilers manifested significant (P ≤ 0.05) decrease in all hematological parameters involving erythrocytic and total leucocytic counts, Hemoglobin (Hb) and Packed Cell Volume (PCV) on a dose- and time-pattern. In comparison with the control levels, biochemical profile of the intoxicated birds disclosed significant decrease in blood glucose level and significant increase in serum uric acid, urea, Alkaline Phosphatase (ALP) and Lactate Dehydrogenase (LDH) levels. Based upon the present data, it was concluded that the addition of urea to broiler diets bears serious sequences concerning the general health condition, performance, weight gain, and hematological and biochemical profiles.展开更多
The amorphous boron nitride ceramic powders were prepared at 750-950 ℃ by the low-cost urea route, and the effects of preparation temperatures, molar ratios of the raw materials and oxidation treatment on the composi...The amorphous boron nitride ceramic powders were prepared at 750-950 ℃ by the low-cost urea route, and the effects of preparation temperatures, molar ratios of the raw materials and oxidation treatment on the composition, structure and surface morphology of the products were investigated through FT-IR, XRD and SEM. The results show that the products ceramize and crystallize gradually with the increase of the temperature. When the molar ratio and reaction temperature are 3：2 and 850 ℃, respectively, the products have high purity, compact structure and nice shape. The oxidation treatment at 450 ℃ will not impair the composition and structure of boron nitride but effectively remove the impurities.展开更多
目的:探究尿素氮与白蛋白比值(blood urea nitrogen to serum albumin ratio,B/A)对老年慢性阻塞性肺疾病急性加重期(acute exacerbation of chronic obstructive pulmonary disease,AECOPD)合并肾功能不全患者,无创机械通气(non-invasi...目的:探究尿素氮与白蛋白比值(blood urea nitrogen to serum albumin ratio,B/A)对老年慢性阻塞性肺疾病急性加重期(acute exacerbation of chronic obstructive pulmonary disease,AECOPD)合并肾功能不全患者,无创机械通气(non-invasive mechanical ventilation,NIV)预后的预测价值。方法:选择2021年1月至2023年1月,在连云港市第二人民医院肾内科,收治的老年AECOPD合并肾功能不全患者接受NIV患者220例,依据患者住院NIV治疗后28 d的生存情况分为:生存组(180例)和死亡组(40例),比较两组患者的B/A,运用Logistic回归性分析和受试者工作特征曲线ROC评价入院初24 h的B/A预测AECOPD合并肾功能不全患者NIV治疗后28 d预后的价值。结果:生存组白蛋白、血红蛋白和血小板显著高于死亡组患者(P <0.05),生存组尿素氮、B/A、急性生理和慢性健康评分(acutephysiology and chronic health evaluationⅡ,APACHEⅡ)显著低于死亡组患者(P <0.05)。Logistic回归分析结果显示B/A和APACHEⅡ评分是导致患者死亡的危险因素(P <0.05)。ROC分析显示,B/A的曲线下面积、敏感度、特异度均较APACHEⅡ评分增高,B/A与APACHEⅡ评分的AUC差异无统计学意义(t=1.686,P=0.093)。结论:B/A和APACHEⅡ评分均可用于评估老年AECOPD合并肾功能不全患者NIV预后,与APACHEⅡ评分比,B/A在评估老年AECOPD患者NIV预后的效能更高。展开更多
背景随着人口老龄化的加剧,心力衰竭(heart failure,HF)患病率呈上升趋势,老年心力衰竭的预警、风险分层研究对改善预后具有重要意义。目的探讨血尿素氮-白蛋白比值(blood urea nitrogen to albumin ratio,BAR)对老年心力衰竭患者1年内...背景随着人口老龄化的加剧,心力衰竭(heart failure,HF)患病率呈上升趋势,老年心力衰竭的预警、风险分层研究对改善预后具有重要意义。目的探讨血尿素氮-白蛋白比值(blood urea nitrogen to albumin ratio,BAR)对老年心力衰竭患者1年内死亡的预测价值;建立包含BAR在内的列线图,并验证其临床价值。方法建模数据来自解放军总医院2016年1月—2021年10月诊断为心力衰竭的1259例老年患者,验证队列来自2021年10月—2022年10月诊断为心力衰竭的314例老年患者。以1年病死率为结局指标,采用Logistic回归分析筛选预后因素,根据预后因素构建列线图;ROC曲线、校准曲线和临床决策曲线分析(decision curve analysis,DCA)用于评估模型的区分度、一致性和临床效益;通过计算ROC曲线下面积和DCA,比较列线图与N端脑钠肽前体(N-terminal pro-B-type natriureticpeptide,NT-proBNP)及BIOSTATCHF预测模型的性能。结果训练队列和验证队列中分别有27.2%(343/1259)和25.2%(79/314)患者在1年内死亡。多因素Logistic回归结果显示,年龄、D-二聚体、NT-proBNP、BAR、血管紧张素转化酶抑制剂(angiotensin converting enzyme inhibitor,ACEI)/血管紧张素受体阻滞剂(angiotensin receptor blockers,ARB)使用与死亡结局独立关联(P<0.05)。基于以上5个因素构建列线图,列线图展现出良好的区分度(AUC=0.838,P<0.001)、一致性(Hosmer-Lemeshowχ2=4.251,P=0.834)和临床效益。列线图模型与NT-proBNP和欧洲BIOSTAT-CHF预测模型相比预测效能均更佳(0.838 vs 0.703和0.825,P<0.05)。DCA结果提示,列线图相比NT-proBNP、BIOSTAT-CHF预测模型均增加了更多的净获益。结论BAR是老年心力衰竭患者1年内死亡的独立预测因子。包含BAR在内的列线图展现出优异的辨别力和校准能力,为预后评估提供有力支持。展开更多
目的探讨血尿素氮与白蛋白比值(blood urea nitrogen and albumin ratio,B/A)在妇科肿瘤及女性乳腺癌重症患者预后评估中的临床价值。方法收集重症监护医学信息数据库(Medical Information Mart for Intensive Care,MIMIC)中在重症监护...目的探讨血尿素氮与白蛋白比值(blood urea nitrogen and albumin ratio,B/A)在妇科肿瘤及女性乳腺癌重症患者预后评估中的临床价值。方法收集重症监护医学信息数据库(Medical Information Mart for Intensive Care,MIMIC)中在重症监护病房(intensive care unit,ICU)住院的妇科肿瘤和女性乳腺癌患者的一般临床资料。根据患者360d的预后情况将其分为存活组(n=472)和死亡组(n=388),比较两组患者的一般情况。根据B/A水平将患者分为低B/A组(B/A<0.075,n=435)和高B/A组(B/A≥0.075,n=425)。采用Kaplan-Meier法绘制生存曲线,并建立Cox风险比例模型,比较B/A与患者360d全因死亡风险的相关性。结果死亡组患者的B/A显著高于生存组(P<0.05)。B/A与患者360d全因死亡风险整体呈非线性趋势关系(χ^(2)=18.790,P<0.001)。生存分析显示,无论是总体人群还是妇科肿瘤或乳腺癌患者中,高B/A患者的累积生存率均显著低于低B/A患者(P<0.001)。Cox回归分析提示B/A≥0.075是妇科肿瘤及女性乳腺癌重症患者360d全因死亡的独立危险因素(HR=1.529,95%CI:1.197~1.952,P=0.001)。结论入住ICU时高B/A是妇科肿瘤及女性乳腺癌重症患者长期死亡风险增加的独立危险因素,有助于临床医生及护理人员早期识别高危患者。展开更多
目的分析尿素氮与肌酐比值(UCR)与血乳酸清除率(LCR)预测老年重症肺炎患者死亡风险的价值。方法选择南京鼓楼医院来安分院2018年5月至2022年3月呼吸重症监护室(RICU)收治的老年重症肺炎患者83例,收集患者临床资料,根据患者入院28 d的预...目的分析尿素氮与肌酐比值(UCR)与血乳酸清除率(LCR)预测老年重症肺炎患者死亡风险的价值。方法选择南京鼓楼医院来安分院2018年5月至2022年3月呼吸重症监护室(RICU)收治的老年重症肺炎患者83例,收集患者临床资料,根据患者入院28 d的预后情况分为生存组(n=22)与死亡组(n=61)。分析老年重症肺炎患者死亡的危险因素,以及入院6 h UCR、LCR和二者联合对老年重症肺炎患者死亡风险的预测价值。结果死亡组入院时急性生理学与慢性健康状况评分系统Ⅱ(APACHEⅡ)评分、年龄、入院时肺炎严重指数(PSI)分级>3级病例数占比、入院6 h超敏C反应蛋白(hs-CRP)、中性粒细胞与淋巴细胞比值(NLR)、红细胞分布宽度(RDW)、白细胞(WBC)计数和UCR高于生存组(P<0.05),入院6 h LCR低于生存组(P<0.05)。入院时PSI分级>3级、入院6 h UCR升高、LCR降低为老年重症肺炎患者死亡的危险因素(P<0.05)。入院后6 h UCR与LCR及二者联合预测老年重症肺炎患者死亡风险的曲线下面积(AUC)分别为0.715、0.701和0.805(P<0.05)。结论入院时PSI分级>3级、入院6 h UCR升高、LCR降低是老年重症肺炎患者死亡的影响因素;入院6 h UCR与LCR可用于预测老年重症肺炎患者的死亡风险,二者联合对于老年重症肺炎患者的死亡风险预测价值更高。展开更多
文摘Technologies for reducing corn leaf burn caused by foliar spray of urea-ammonium nitrate (UAN) during the early growing season are limited. A field experiment was carried out to evaluate the effects of humic acid on corn leaf burn caused by foliar spray of undiluted UAN solution on corn canopy at Jackson, TN in 2018. Thirteen treatments of the mixtures of UAN and humic acid were evaluated at V6 of corn with different UAN application rates and different UAN/humic acid ratios. Leaf burn during 1 2, 3, 4, 5, 6, 7, and 14 days after UAN foliar spray significantly differed between with or without humic acid addition. The addition of humic acid to UAN significantly reduced leaf burn at each UAN application rate (15, 25, and 35 gal/acre). The reduction of leaf burn was enhanced as the humic acid/UAN ratio went up from 10% to 30%. Leaf burn due to foliar application of UAN became severer with higher UAN rates. The linear regression of leaf burn 14 days after application with humic acid/UAN ratio was highly significant and negative. However, the linear regression of leaf burn 14 days after application with the UAN application rate was highly significant and positive. In conclusion, adding humic acid to foliar-applied UAN is beneficial for reducing corn leaf burn during the early growing season.
文摘Urea as a source of cheap non-protein nitrogen is used to adulterate fish and meat meals which are basic components of broiler diets. The present study was carried out to elucidate the effects of urea on weight gain, and hematological and biochemical profiles. A total of 48 broiler chicks were randomly allotted into 4 groups, designated Groups 1, 2, 3 and 4 of 12 birds each. Birds in Groups 2, 3 and 4 were fed on diets containing urea at the levels of 1%, 2.5% and 4%, respectively. Birds in Group 1 served as control and were not exposed to urea. Experimentation period was for 3 weeks and experiment was terminated when birds were 42 days of age. Body weight of all intoxicated birds at the various intervals was significantly decreased in comparison with that of the untreated control. Compared with control, all intoxicated broilers manifested significant (P ≤ 0.05) decrease in all hematological parameters involving erythrocytic and total leucocytic counts, Hemoglobin (Hb) and Packed Cell Volume (PCV) on a dose- and time-pattern. In comparison with the control levels, biochemical profile of the intoxicated birds disclosed significant decrease in blood glucose level and significant increase in serum uric acid, urea, Alkaline Phosphatase (ALP) and Lactate Dehydrogenase (LDH) levels. Based upon the present data, it was concluded that the addition of urea to broiler diets bears serious sequences concerning the general health condition, performance, weight gain, and hematological and biochemical profiles.
基金Funded by the National Natural Science Foundation of China (Nos.50902150 & 90916019)the Graduate Innovation Foundation of the National University of Defense Technology(No.S100103)
文摘The amorphous boron nitride ceramic powders were prepared at 750-950 ℃ by the low-cost urea route, and the effects of preparation temperatures, molar ratios of the raw materials and oxidation treatment on the composition, structure and surface morphology of the products were investigated through FT-IR, XRD and SEM. The results show that the products ceramize and crystallize gradually with the increase of the temperature. When the molar ratio and reaction temperature are 3：2 and 850 ℃, respectively, the products have high purity, compact structure and nice shape. The oxidation treatment at 450 ℃ will not impair the composition and structure of boron nitride but effectively remove the impurities.
文摘目的:探究尿素氮与白蛋白比值(blood urea nitrogen to serum albumin ratio,B/A)对老年慢性阻塞性肺疾病急性加重期(acute exacerbation of chronic obstructive pulmonary disease,AECOPD)合并肾功能不全患者,无创机械通气(non-invasive mechanical ventilation,NIV)预后的预测价值。方法:选择2021年1月至2023年1月,在连云港市第二人民医院肾内科,收治的老年AECOPD合并肾功能不全患者接受NIV患者220例,依据患者住院NIV治疗后28 d的生存情况分为:生存组(180例)和死亡组(40例),比较两组患者的B/A,运用Logistic回归性分析和受试者工作特征曲线ROC评价入院初24 h的B/A预测AECOPD合并肾功能不全患者NIV治疗后28 d预后的价值。结果:生存组白蛋白、血红蛋白和血小板显著高于死亡组患者(P <0.05),生存组尿素氮、B/A、急性生理和慢性健康评分(acutephysiology and chronic health evaluationⅡ,APACHEⅡ)显著低于死亡组患者(P <0.05)。Logistic回归分析结果显示B/A和APACHEⅡ评分是导致患者死亡的危险因素(P <0.05)。ROC分析显示,B/A的曲线下面积、敏感度、特异度均较APACHEⅡ评分增高,B/A与APACHEⅡ评分的AUC差异无统计学意义(t=1.686,P=0.093)。结论:B/A和APACHEⅡ评分均可用于评估老年AECOPD合并肾功能不全患者NIV预后,与APACHEⅡ评分比,B/A在评估老年AECOPD患者NIV预后的效能更高。
文摘目的探讨血尿素氮与白蛋白比值(blood urea nitrogen and albumin ratio,B/A)在妇科肿瘤及女性乳腺癌重症患者预后评估中的临床价值。方法收集重症监护医学信息数据库(Medical Information Mart for Intensive Care,MIMIC)中在重症监护病房(intensive care unit,ICU)住院的妇科肿瘤和女性乳腺癌患者的一般临床资料。根据患者360d的预后情况将其分为存活组(n=472)和死亡组(n=388),比较两组患者的一般情况。根据B/A水平将患者分为低B/A组(B/A<0.075,n=435)和高B/A组(B/A≥0.075,n=425)。采用Kaplan-Meier法绘制生存曲线,并建立Cox风险比例模型,比较B/A与患者360d全因死亡风险的相关性。结果死亡组患者的B/A显著高于生存组(P<0.05)。B/A与患者360d全因死亡风险整体呈非线性趋势关系(χ^(2)=18.790,P<0.001)。生存分析显示,无论是总体人群还是妇科肿瘤或乳腺癌患者中,高B/A患者的累积生存率均显著低于低B/A患者(P<0.001)。Cox回归分析提示B/A≥0.075是妇科肿瘤及女性乳腺癌重症患者360d全因死亡的独立危险因素(HR=1.529,95%CI:1.197~1.952,P=0.001)。结论入住ICU时高B/A是妇科肿瘤及女性乳腺癌重症患者长期死亡风险增加的独立危险因素,有助于临床医生及护理人员早期识别高危患者。
文摘目的分析尿素氮与肌酐比值(UCR)与血乳酸清除率(LCR)预测老年重症肺炎患者死亡风险的价值。方法选择南京鼓楼医院来安分院2018年5月至2022年3月呼吸重症监护室(RICU)收治的老年重症肺炎患者83例,收集患者临床资料,根据患者入院28 d的预后情况分为生存组(n=22)与死亡组(n=61)。分析老年重症肺炎患者死亡的危险因素,以及入院6 h UCR、LCR和二者联合对老年重症肺炎患者死亡风险的预测价值。结果死亡组入院时急性生理学与慢性健康状况评分系统Ⅱ(APACHEⅡ)评分、年龄、入院时肺炎严重指数(PSI)分级>3级病例数占比、入院6 h超敏C反应蛋白(hs-CRP)、中性粒细胞与淋巴细胞比值(NLR)、红细胞分布宽度(RDW)、白细胞(WBC)计数和UCR高于生存组(P<0.05),入院6 h LCR低于生存组(P<0.05)。入院时PSI分级>3级、入院6 h UCR升高、LCR降低为老年重症肺炎患者死亡的危险因素(P<0.05)。入院后6 h UCR与LCR及二者联合预测老年重症肺炎患者死亡风险的曲线下面积(AUC)分别为0.715、0.701和0.805(P<0.05)。结论入院时PSI分级>3级、入院6 h UCR升高、LCR降低是老年重症肺炎患者死亡的影响因素;入院6 h UCR与LCR可用于预测老年重症肺炎患者的死亡风险,二者联合对于老年重症肺炎患者的死亡风险预测价值更高。
