Triose phosphate utilization in leaves is modulated by whole-plant sink-source ratios and nitrogen budgets in rice.

Triose phosphate utilization (TPU) is a biochemical process indicating carbon sink-source (im)balance within leaves. When TPU limits leaf photosynthesis, photorespiration-associated amino acid exports probably provide an additional carbon outlet and increase leaf CO2 uptake. However, whether TPU is modulated by whole-plant sink-source relations and nitrogen (N) budgets remains unclear. We address this question by model analyses of gas-exchange data measured on leaves at three growth stages of rice plants grown at two N levels. Sink-source ratio was manipulated by panicle pruning, by using yellower-leaf variant genotypes, and by measuring photosynthesis on adaxial and abaxial leaf sides. Across all these treatments, higher leaf N content resulted in the occurrence of TPU limitation at lower intercellular CO2 concentrations. Photorespiration-associated amino acid export was greater in high-N leaves, but was smaller in yellower-leaf genotypes, panicle-pruned plants, and for abaxial measurement. The feedback inhibition of panicle pruning on rates of TPU was not always observed, presumably because panicle pruning blocked N remobilization from leaves to grains and the increased leaf N content masked feedback inhibition. The leaf-level TPU limitation was thus modulated by whole-plant sink-source relations and N budgets during rice grain filling, suggesting a close link between within-leaf and whole-plant sink limitations.

When dispatcher assistance is not saving lives: assessment of process compliance, barriers and outcomes in out-of-hospital cardiac arrest in a metropolitan city in China.

BACKGROUND: Several Chinese cities have implemented dispatcher-assisted cardiopulmonary resuscitation (DA-CPR), although out-of-hospital cardiac arrest (OHCA) survival rates remain low. We aimed to assess the process compliance, barriers and outcomes of OHCA in one of the earliest implemented (DA-CPR) programmes in China. METHODS: We retrospectively reviewed OHCA emergency dispatch records of Suzhou emergency medical service from 2014 to 2015 and included adult OHCA victims (>18 years) with a bystander-witnessed atraumatic OHCA that was subsequently confirmed by on-site emergency physician. The circumstances and DA-CPR process related to the OHCA event were analysed. Dispatch audio records were reviewed to identify potential barriers to implementation during the DA-CPR process. RESULTS: Of the 151 OHCA victims, none survived. The median time from patient collapse to call for emergency services and that from call to provision of cardiopulmonary resuscitation instructions was 30 (IQR 20-60) min and 115 (IQR 90-153) s, respectively. Only 110 (80.3%) bystanders/rescuers followed the dispatcher instructions; of these, 51 (46.3%) undertook persistent chest compressions. Major barriers to following the DA-CPR instructions were present in 104 (68.9%) cases, including caller disconnection of the call, distraught mood or refusal to carry out either compressions or ventilations. CONCLUSIONS: The OHCA survival rate and the DA-CPR process were far from optimal. The zero survival rate is disproportionally low compared with survival statistics in high-income countries. The prolonged delay in calling the emergency services negated and rendered futile any DA-CPR efforts. Thus, efforts targeted at developing public awareness of OHCA, calling for help and competency in DA-CPR should be increased.