The aim of the article was to study the growth of Douglas-fir plantations in the region of the Training Experimental Forest Enterprise, Yundola （Central South Bulgaria）. The study sites were three Douglas-fir planta...The aim of the article was to study the growth of Douglas-fir plantations in the region of the Training Experimental Forest Enterprise, Yundola （Central South Bulgaria）. The study sites were three Douglas-fir plantations, ranging between 50 and 55 years of age at altitudinal range between 1,400 m and 1,600 m above sea level （masl）. The mean height, diameter at breast height, site class, stem volume as well as the mechanical resistance （H/D ratio） of Douglas-fir were measured for each plantation. The results showed that Douglas-fir had the best height growth of the studied plantations on slope facing South at altitude 1,600 masl and Douglas-fir with age 55 years old reached a mean height of 32.4 m. The average diameter at breast height of the studied plantations reaches approximately 30 cm, which shows that they are suitable for large scale wood harvesting. The average stem volume of Douglas-fir in the observed plantations up to age of 55 is within the range of 400-600 m3/ha, with an average annual volume increment from 7 m3/ha to 12 m3/ha each year. The high index of mechanical resistance （H/D ratio） indicated a risk for abiotic damages, which implicated the need for the immediate implementation of felling.展开更多
Background Diabetic nephropathy is a common complication of diabetes mellitus. This study aimed to explore whether mesenchymal stem cells （MSCs） transplantation could attenuate diabetic nephropathy in experimental d...Background Diabetic nephropathy is a common complication of diabetes mellitus. This study aimed to explore whether mesenchymal stem cells （MSCs） transplantation could attenuate diabetic nephropathy in experimental diabetic rats. Methods Sprague-Dawley rats received a single intraperitoneal injection of streptozotocin （STZ） （60 mg/kg）. Diabetic rats were randomized to four groups： diabetes control group （DC）, ciclosporin A group （CsA）, MSC group, and MSC＋CsA group （MSCA）. Bone marrow mesenchymal stem cells were cultured, identified and labeled by 5-bromo-2＇-deoxyuridine （BrdU） in vitro. Then they were transplanted to diabetic rats via introcardiac infusion. Ciclosporin A was administered daily at 5 mg/kg. At 1,2, 4, 8 weeks after transplantation, random blood glucose, urine albumin/creatinine ratio （AIb/Cr）, endogenous creatinine clearance rate and renal mass index were tested. Renal morphology and labeled cells were examined. Results Cultured MSCs expressed mesenchymal cell phenotype, and could be multidifferentiated to osteogenic and adipogenic cells. Labeled MSCs could be detected in the kidney of nephropathic rats, mainly in renal interstitium, but they did not propagate after engrafting in kidney. Over the course of the experiment, MSCA group showed a significant decrease in blood glucose compared with MSC group, CsA group and DC group （P 〈0.05, respectively）. The AIb/Cr in MSCA group and MSC group were significantly lower than CsA group and DC group （P〈0.05）. And the AIb/Cr in MSCA group showed a significant decrease compared with MSC group （0.74 vs 0.84, P 〈0.05）. There was a significant difference in renal mass index between the MSCA group and DC group （5.66 vs 6.37, P 〈0.05）. No significant difference was found in creatinine clearance rate among 4 groups （P 〉0.05）. Treatment with MSC＋CsA significantly ameliorated the morphology of diabetic kidney. Conclusion MSC could mildly ameliorate diabetic nephropathy by decreasing blood glucose, A展开更多
Objective ：To elucidate whether cell multiplication, apoptosis, glucose intake and p-Akt protein expression of bone Mesenchyreal Stem Cells（MSCs） of rats is influenced by a hypoxic environment ex vivo. Methods ：Pa...Objective ：To elucidate whether cell multiplication, apoptosis, glucose intake and p-Akt protein expression of bone Mesenchyreal Stem Cells（MSCs） of rats is influenced by a hypoxic environment ex vivo. Methods ：Passage 3 of bone marrow MSCs taken from Wistar rats,were cultured in a culturing chamber with 94%N2,1%O2,5%CO2 at 37℃. At different hypoxia time points ,0,0.5, 1,4 and 8 h, glucose uptake was assayed by using radiation isotope ^3H-G, Apoptotic Rate（AR） and dead rate（DR） were analyzed by flow cytometry（FCM） after Annexin V/PI staining, cell multiplication（by MTr methods） and p-Akt protein by immunocytochemistry and western blot. Results ：Assay for CD29^± ,CD44^± ,CD71^± ,CD34^-, Tn T^±（after 5-azacytidine agent inducing） and ALP^±（after bone differentiation agent inducing） suggested these bone-derived cells were MSCs. The ^3H-G intaking ratio （CPM/ flask value：157 ± 11,110 ± 11,107 ± 13,103 ± 10,100 ± 9 and 98 ± 10） of MSCs at different hypoxia time points, significantly decreased compared to that of normoxia（P 〈 0.01） and tended to descend slowly with hypoxia time duration, for which there was no statistical significance（P 〉 0.05）. The AR（0.09 ± 2.03%,12.9 ± 1.72%,13.7 ± 2.26%,13.8 ± 3.01%,14.1 ± 2.78% and 14.7 ± 4.01% at 0,0.5,1,4 and 8 h,respectively,P 〈 0.01） and DR （0.04, ± 1.79% ,0.93 ± 1.85% ,3.11 ± 2.14% ,4.09 ± 2.36% ,4.72 ± 2.05% and 4.91 ± 3.72% at 0,0.5,1,4 and 8 h, respectively, P 〈 0.05） at different hypoxia time points significantly increased compared to those time in normoxia; The AR further went up with time （P 〈 0.05）, however there was no statistical significance （P 〉 0.05） for the DR. Optical absorption value of MTr methods at different hypoxia time points significantly decreased compared to those with a corresponding normoxia time （P 〈 0.01） and degraded with time （in an hypoxic environment -P 〈 0.01）. IOD of p-Akt protein of MSCs at different hypoxia time points significant展开更多
为探明不同氮钾配比和玉米茎秆抗倒伏性能及产量特性的内在联系,在松嫩平原西部采用田间裂区设计(主区为施氮量,副区为施钾量),研究了不同氮钾水平(N:195、210、225、240 kg·hm-2;K2O:70、85、100、115 kg·hm-2)配比对灌浆期...为探明不同氮钾配比和玉米茎秆抗倒伏性能及产量特性的内在联系,在松嫩平原西部采用田间裂区设计(主区为施氮量,副区为施钾量),研究了不同氮钾水平(N:195、210、225、240 kg·hm-2;K2O:70、85、100、115 kg·hm-2)配比对灌浆期玉米茎秆形态力学特征及籽粒产量的影响。结果表明:氮肥单因素对株高、钾肥单因素对重心高度的影响明显,而氮钾肥互作对于株高、穗位高和重心高度均未达显著水平;氮、钾肥单因素及其互作对节间长度、茎粗、截面面积、节间充实度、抗折力、穿刺强度、断面模数、秆型指数、弯曲力矩、抗断弯距、弯曲应力均表现出显著(P<0.05)或极显著(P<0.01)的影响,在不同组合处理中,以210 kg N·hm-2+85 kg K2O·hm-2处理的抗倒伏指数最大,其次为225 kg N·hm-2+100kg K2O·hm-2和210 kg N·hm-2+100 kg K2O·hm-2处理,显著高于其他处理组合31.59%~80.86%,同时氮、钾肥对玉米抗倒伏指数的互作效应显著(FN×K=19.577**);综合玉米茎秆形态力学特性与产量水平,松嫩平原西部玉米丰产抗倒伏的氮钾肥优化配施方案为:施210~225 kg N·hm-2+85~100 kg K2O·hm-2,氮钾配比为1.75~1.88∶0.71~0.83。本研究结果可为松嫩平原玉米密植丰产提质增抗的养分高效运筹模式提供科学依据和技术途径。展开更多
文摘The aim of the article was to study the growth of Douglas-fir plantations in the region of the Training Experimental Forest Enterprise, Yundola （Central South Bulgaria）. The study sites were three Douglas-fir plantations, ranging between 50 and 55 years of age at altitudinal range between 1,400 m and 1,600 m above sea level （masl）. The mean height, diameter at breast height, site class, stem volume as well as the mechanical resistance （H/D ratio） of Douglas-fir were measured for each plantation. The results showed that Douglas-fir had the best height growth of the studied plantations on slope facing South at altitude 1,600 masl and Douglas-fir with age 55 years old reached a mean height of 32.4 m. The average diameter at breast height of the studied plantations reaches approximately 30 cm, which shows that they are suitable for large scale wood harvesting. The average stem volume of Douglas-fir in the observed plantations up to age of 55 is within the range of 400-600 m3/ha, with an average annual volume increment from 7 m3/ha to 12 m3/ha each year. The high index of mechanical resistance （H/D ratio） indicated a risk for abiotic damages, which implicated the need for the immediate implementation of felling.
文摘Background Diabetic nephropathy is a common complication of diabetes mellitus. This study aimed to explore whether mesenchymal stem cells （MSCs） transplantation could attenuate diabetic nephropathy in experimental diabetic rats. Methods Sprague-Dawley rats received a single intraperitoneal injection of streptozotocin （STZ） （60 mg/kg）. Diabetic rats were randomized to four groups： diabetes control group （DC）, ciclosporin A group （CsA）, MSC group, and MSC＋CsA group （MSCA）. Bone marrow mesenchymal stem cells were cultured, identified and labeled by 5-bromo-2＇-deoxyuridine （BrdU） in vitro. Then they were transplanted to diabetic rats via introcardiac infusion. Ciclosporin A was administered daily at 5 mg/kg. At 1,2, 4, 8 weeks after transplantation, random blood glucose, urine albumin/creatinine ratio （AIb/Cr）, endogenous creatinine clearance rate and renal mass index were tested. Renal morphology and labeled cells were examined. Results Cultured MSCs expressed mesenchymal cell phenotype, and could be multidifferentiated to osteogenic and adipogenic cells. Labeled MSCs could be detected in the kidney of nephropathic rats, mainly in renal interstitium, but they did not propagate after engrafting in kidney. Over the course of the experiment, MSCA group showed a significant decrease in blood glucose compared with MSC group, CsA group and DC group （P 〈0.05, respectively）. The AIb/Cr in MSCA group and MSC group were significantly lower than CsA group and DC group （P〈0.05）. And the AIb/Cr in MSCA group showed a significant decrease compared with MSC group （0.74 vs 0.84, P 〈0.05）. There was a significant difference in renal mass index between the MSCA group and DC group （5.66 vs 6.37, P 〈0.05）. No significant difference was found in creatinine clearance rate among 4 groups （P 〉0.05）. Treatment with MSC＋CsA significantly ameliorated the morphology of diabetic kidney. Conclusion MSC could mildly ameliorate diabetic nephropathy by decreasing blood glucose, A
文摘Objective ：To elucidate whether cell multiplication, apoptosis, glucose intake and p-Akt protein expression of bone Mesenchyreal Stem Cells（MSCs） of rats is influenced by a hypoxic environment ex vivo. Methods ：Passage 3 of bone marrow MSCs taken from Wistar rats,were cultured in a culturing chamber with 94%N2,1%O2,5%CO2 at 37℃. At different hypoxia time points ,0,0.5, 1,4 and 8 h, glucose uptake was assayed by using radiation isotope ^3H-G, Apoptotic Rate（AR） and dead rate（DR） were analyzed by flow cytometry（FCM） after Annexin V/PI staining, cell multiplication（by MTr methods） and p-Akt protein by immunocytochemistry and western blot. Results ：Assay for CD29^± ,CD44^± ,CD71^± ,CD34^-, Tn T^±（after 5-azacytidine agent inducing） and ALP^±（after bone differentiation agent inducing） suggested these bone-derived cells were MSCs. The ^3H-G intaking ratio （CPM/ flask value：157 ± 11,110 ± 11,107 ± 13,103 ± 10,100 ± 9 and 98 ± 10） of MSCs at different hypoxia time points, significantly decreased compared to that of normoxia（P 〈 0.01） and tended to descend slowly with hypoxia time duration, for which there was no statistical significance（P 〉 0.05）. The AR（0.09 ± 2.03%,12.9 ± 1.72%,13.7 ± 2.26%,13.8 ± 3.01%,14.1 ± 2.78% and 14.7 ± 4.01% at 0,0.5,1,4 and 8 h,respectively,P 〈 0.01） and DR （0.04, ± 1.79% ,0.93 ± 1.85% ,3.11 ± 2.14% ,4.09 ± 2.36% ,4.72 ± 2.05% and 4.91 ± 3.72% at 0,0.5,1,4 and 8 h, respectively, P 〈 0.05） at different hypoxia time points significantly increased compared to those time in normoxia; The AR further went up with time （P 〈 0.05）, however there was no statistical significance （P 〉 0.05） for the DR. Optical absorption value of MTr methods at different hypoxia time points significantly decreased compared to those with a corresponding normoxia time （P 〈 0.01） and degraded with time （in an hypoxic environment -P 〈 0.01）. IOD of p-Akt protein of MSCs at different hypoxia time points significant
文摘为探明不同氮钾配比和玉米茎秆抗倒伏性能及产量特性的内在联系,在松嫩平原西部采用田间裂区设计(主区为施氮量,副区为施钾量),研究了不同氮钾水平(N:195、210、225、240 kg·hm-2;K2O:70、85、100、115 kg·hm-2)配比对灌浆期玉米茎秆形态力学特征及籽粒产量的影响。结果表明:氮肥单因素对株高、钾肥单因素对重心高度的影响明显,而氮钾肥互作对于株高、穗位高和重心高度均未达显著水平;氮、钾肥单因素及其互作对节间长度、茎粗、截面面积、节间充实度、抗折力、穿刺强度、断面模数、秆型指数、弯曲力矩、抗断弯距、弯曲应力均表现出显著(P<0.05)或极显著(P<0.01)的影响,在不同组合处理中,以210 kg N·hm-2+85 kg K2O·hm-2处理的抗倒伏指数最大,其次为225 kg N·hm-2+100kg K2O·hm-2和210 kg N·hm-2+100 kg K2O·hm-2处理,显著高于其他处理组合31.59%~80.86%,同时氮、钾肥对玉米抗倒伏指数的互作效应显著(FN×K=19.577**);综合玉米茎秆形态力学特性与产量水平,松嫩平原西部玉米丰产抗倒伏的氮钾肥优化配施方案为:施210~225 kg N·hm-2+85~100 kg K2O·hm-2,氮钾配比为1.75~1.88∶0.71~0.83。本研究结果可为松嫩平原玉米密植丰产提质增抗的养分高效运筹模式提供科学依据和技术途径。
