In this paper, the theoretical expressions of wood thermal conductiv ity in the choral and radical direction are derived from the micro-structure of wood by applying some basic principles in physical mechanics. The t...In this paper, the theoretical expressions of wood thermal conductiv ity in the choral and radical direction are derived from the micro-structure of wood by applying some basic principles in physical mechanics. The thermal conduc tivities of about twenty species of trees were calculated by means of the expres sions and compared with its experimental values under the same condition. The av erage relative error is about 5%, so the calculation result is satisfactory.展开更多
目的急性胎儿宫内窘迫是导致围产儿死亡的主要原因,大多系胎盘及脐带因素导致胎儿缺氧所致。通过检测晚期正常妊娠及急性胎儿宫内窘迫的胎盘表达神经轴突导向因子-1(neuron towards axon guidance factor-1,Netrin-1)水平、相应脐带情...目的急性胎儿宫内窘迫是导致围产儿死亡的主要原因,大多系胎盘及脐带因素导致胎儿缺氧所致。通过检测晚期正常妊娠及急性胎儿宫内窘迫的胎盘表达神经轴突导向因子-1(neuron towards axon guidance factor-1,Netrin-1)水平、相应脐带情况及患者娩出新生儿出生状况,从而探讨Netrin-1在急性胎儿宫内窘迫中发病的可能机制。方法选取2012年10月1日—2013年9月30日间剖宫产终止妊娠孕妇共27例。其中15例正常足月妊娠孕妇为对照组,12例急性胎儿宫内窘迫患者为研究组。检测所有入选病例胎盘中Netrin-1表达水平,观察2组胎儿娩出时脐带情况,测定相应新生儿出生体重及出生后1 min Apgar评分。结果 2组患者胎盘Netrin-1表达水平、新生儿出生体重及出生后1 min Apgar评分差异均无统计学意义(P>0.05)。对照组未见明显脐带异常。12例胎儿宫内窘迫10例存在脐带绕颈,1例脐带螺旋。10例脐带绕颈中3例脐带绕颈两周;7例脐带绕颈1周,脐带绕颈1周新生儿患者中3例存在脐带水肿。但所有娩出胎盘均未见明显异常。与对照组相比,急性胎儿宫内窘迫组脐带异常明显(P<0.05)。结论 Netrin-1在急性胎儿宫内窘迫胎盘维持功能过程中作用较小。孕晚期急性胎儿宫内窘迫发生多因脐带因素所致。展开更多
基金Natural Science Foundation of Fujia n Province. Theoretical Research on Wood Thermal Property.
文摘In this paper, the theoretical expressions of wood thermal conductiv ity in the choral and radical direction are derived from the micro-structure of wood by applying some basic principles in physical mechanics. The thermal conduc tivities of about twenty species of trees were calculated by means of the expres sions and compared with its experimental values under the same condition. The av erage relative error is about 5%, so the calculation result is satisfactory.
文摘目的急性胎儿宫内窘迫是导致围产儿死亡的主要原因,大多系胎盘及脐带因素导致胎儿缺氧所致。通过检测晚期正常妊娠及急性胎儿宫内窘迫的胎盘表达神经轴突导向因子-1(neuron towards axon guidance factor-1,Netrin-1)水平、相应脐带情况及患者娩出新生儿出生状况,从而探讨Netrin-1在急性胎儿宫内窘迫中发病的可能机制。方法选取2012年10月1日—2013年9月30日间剖宫产终止妊娠孕妇共27例。其中15例正常足月妊娠孕妇为对照组,12例急性胎儿宫内窘迫患者为研究组。检测所有入选病例胎盘中Netrin-1表达水平,观察2组胎儿娩出时脐带情况,测定相应新生儿出生体重及出生后1 min Apgar评分。结果 2组患者胎盘Netrin-1表达水平、新生儿出生体重及出生后1 min Apgar评分差异均无统计学意义(P>0.05)。对照组未见明显脐带异常。12例胎儿宫内窘迫10例存在脐带绕颈,1例脐带螺旋。10例脐带绕颈中3例脐带绕颈两周;7例脐带绕颈1周,脐带绕颈1周新生儿患者中3例存在脐带水肿。但所有娩出胎盘均未见明显异常。与对照组相比,急性胎儿宫内窘迫组脐带异常明显(P<0.05)。结论 Netrin-1在急性胎儿宫内窘迫胎盘维持功能过程中作用较小。孕晚期急性胎儿宫内窘迫发生多因脐带因素所致。
