Embracing 3D Complexity in Leaf Carbon–Water Exchange

Leaves are a nexus for the exchange of water, carbon, and energy between terrestrial plants and the atmosphere. Research in recent decades has highlighted the critical importance of the underlying biophysical and anatomical determinants of CO2 and H2O transport, but a quantitative understanding of how detailed 3D leaf anatomy mediates within-leaf transport has been hindered by the lack of a consensus framework for analyzing or simulating transport and its spatial and temporal dynamics realistically, and by the difficulty of measuring within-leaf transport at the appropriate scales. We discuss how recent technological advancements now make a spatially explicit 3D leaf analysis possible, through new imaging and modeling tools that will allow us to address long-standing questions related to plant carbon–water exchange.</p

A multi-lake comparative analysis of the General Lake Model (GLM): stress-testing across a global observatory network

The modelling community has identified challenges for the integration and assessment of lake models due to the diversity of modelling approaches and lakes. In this study, we develop and assess a one-dimensional lake model and apply it to 32 lakes from a global observatory network. The data set included lakes over broad ranges in latitude, climatic zones, size, residence time, mixing regime and trophic level. Model performance was evaluated using several error assessment metrics, and a sensitivity analysis was conducted for nine parameters that governed the surface heat exchange and mixing efficiency. There was low correlation between input data uncertainty and model performance and predictions of temperature were less sensitive to model parameters than prediction of thermocline depth and Schmidt stability. The study provides guidance to where the general model approach and associated assumptions work, and cases where adjustments to model parameterisations and/or structure are required

Benchmarks in Pancreatic Surgery: A Novel Tool for Unbiased Outcome Comparisons

OBJECTIVE: To use the concept of benchmarking to establish robust and standardized outcome references after pancreatico-duodenectomy (PD). BACKGROUND: Best achievable results after PD are unknown. Consequently, outcome comparisons among different cohorts, centers or with novel surgical techniques remain speculative. METHODS: This multicenter study analyzes consecutive patients (2012-2015) undergoing PD in 23 international expert centers in pancreas surgery. Outcomes in patients without significant comorbidities and major vascular resection (benchmark cases) were analyzed to establish 20 outcome benchmarks for PD. These benchmarks were tested in a cohort with a poorer preoperative physical status (ASA class ≥3) and a cohort treated by minimally invasive approaches. RESULTS: Two thousand three hundred seventy-five (38%) low-risk cases out of a total of 6186 PDs were analyzed, disclosing low in-hospital mortality (≤1.6%) but high morbidity, with a 73% benchmark morbidity rate cumulated within 6 months following surgery. Benchmark cutoffs for pancreatic fistulas (B-C), severe complications (≥ grade 3), and failure-to-rescue rate were 19%, 30%, and 9%, respectively. The ASA ≥3 cohort showed comparable morbidity but a higher in hospital-mortality (3% vs 1.6%) and failure-to-rescue rate (16% vs 9%) than the benchmarks. The proportion of benchmark cases performed varied greatly across centers and continents for both open (9%-93%) and minimally invasive (11%-62%) PD. Centers operating mostly on complex PD cases disclosed better results than those with a majority of low-risk cases. CONCLUSION: The proposed outcome benchmarks for PD, established in a large-scale international patient cohort and tested in 2 different cohorts, may allow for meaningful comparisons between different patient cohorts, centers, countries, and surgical techniques

Defining Benchmark Outcomes for Pancreatoduodenectomy With Portomesenteric Venous Resection

OBJECTIVE: The aim of this study was to establish clinically relevant outcome benchmark values using criteria for pancreatoduodenectomy (PD) with portomesenteric venous resection (PVR) from a low-risk cohort managed in high-volume centers.SUMMARY BACKGROUND DATA: PD with PVR is regarded as the standard of care in patients with cancer involvement of the portomesenteric venous axis. There are, however, no benchmark outcome indicators for this population which hampers comparisons of patients undergoing PD with and without PVR resection.METHODS: This multicenter study analyzed patients undergoing PD with any type of PVR in 23 high-volume centers from 2009 to 2018. Nineteen outcome benchmarks were established in low-risk patients, defined as the 75th percentile of the median outcome values of the centers (NCT04053998).RESULTS: Out of 1462 patients with PD and PVR, 840 (58%) formed the benchmark cohort, with a mean age was 64 (SD11) years, 413 (49%) were females. Benchmark cutoffs, among others, were calculated as follows: Clinically relevant pancreatic fistula rate (International Study Group of Pancreatic Surgery): 6414%; in-hospital mortality rate: 644%; major complication rate Grade 653 and the CCI up to 6 months postoperatively: 6436% and 6426, respectively; portal vein thrombosis rate: 6414% and 5-year survival for patients with pancreatic ductal adenocarcinoma: 659%.CONCLUSION: These novel benchmark cutoffs targeting surgical performance, morbidity, mortality, and oncological parameters show relatively inferior results in patients undergoing vascular resection because of involvement of the portomesenteric venous axis. These benchmark values however can be used to conclusively assess the results of different centers or surgeons operating on this high-risk group

Defining Benchmark Outcomes for Pancreatoduodenectomy With Portomesenteric Venous Resection

OBJECTIVE: The aim of this study was to establish clinically relevant outcome benchmark values using criteria for pancreatoduodenectomy (PD) with portomesenteric venous resection (PVR) from a low-risk cohort managed in high-volume centers. SUMMARY BACKGROUND DATA: PD with PVR is regarded as the standard of care in patients with cancer involvement of the portomesenteric venous axis. There are, however, no benchmark outcome indicators for this population which hampers comparisons of patients undergoing PD with and without PVR resection. METHODS: This multicenter study analyzed patients undergoing PD with any type of PVR in 23 high-volume centers from 2009 to 2018. Nineteen outcome benchmarks were established in low-risk patients, defined as the 75th percentile of the median outcome values of the centers (NCT04053998). RESULTS: Out of 1462 patients with PD and PVR, 840 (58%) formed the benchmark cohort, with a mean age was 64 (SD11) years, 413 (49%) were females. Benchmark cutoffs, among others, were calculated as follows: Clinically relevant pancreatic fistula rate (International Study Group of Pancreatic Surgery): ≤14%; in-hospital mortality rate: ≤4%; major complication rate Grade≥3 and the CCI up to 6 months postoperatively: ≤36% and ≤26, respectively; portal vein thrombosis rate: ≤14% and 5-year survival for patients with pancreatic ductal adenocarcinoma: ≥9%. CONCLUSION: These novel benchmark cutoffs targeting surgical performance, morbidity, mortality, and oncological parameters show relatively inferior results in patients undergoing vascular resection because of involvement of the portomesenteric venous axis. These benchmark values however can be used to conclusively assess the results of different centers or surgeons operating on this high-risk group

The Impact of Neoadjuvant Treatment on Survival in Patients Undergoing Pancreatoduodenectomy With Concomitant Portomesenteric Venous Resection: An International Multicenter Analysis

OBJECTIVE: The aim of this study was to evaluate whether neoadjuvant therapy (NAT) critically influenced microscopically complete resection (R0) rates and long-term outcomes for patients with pancreatic ductal adenocarcinoma who underwent pancreatoduodenectomy (PD) with portomesenteric vein resection (PVR) from a diverse, world-wide group of high-volume centers. SUMMARY OF BACKGROUND DATA: Limited size studies suggest that NAT improves R0 rates and overall survival compared to upfront surgery in R/BR-PDAC patients. METHODS: This multicenter study analyzed consecutive patients with R/BR-PDAC who underwent PD with PVR in 23 high-volume centers from 2009 to 2018. RESULTS: Data from 1192 patients with PD and PVR were collected and analyzed. The median age was 68 [interquartile range (IQR) 60-73] years and 52% were males. Some 186 (15.6%) and 131 (10.9%) patients received neoadjuvant chemotherapy (NAC) alone and neoadjuvant chemoradiotherapy, respectively. The R0/R1/R2 rates were 57%, 39.3%, and 3.2% in patients who received NAT compared to 46.6%, 49.9%, and 3.5% in patients who did not, respectively (P =0.004). The 1-, 3-, and 5-year OS in patients receiving NAT was 79%, 41%, and 29%, while for those that did not it was 73%, 29%, and 18%, respectively (P <0.001). Multivariable analysis showed no administration of NAT, high tumor grade, lymphovascular invasion, R1/R2 resection, no adjuvant chemotherapy, occurrence of Clavien-Dindo grade 3 or higher postoperative complications within 90 days, preoperative diabetes mellitus, male sex and portal vein involvement were negative independent predictive factors for OS. CONCLUSION: Patients with PDAC of the pancreatic head expected to undergo venous reconstruction should routinely be considered for NAT

The Impact of Neoadjuvant Treatment on Survival in Patients Undergoing Pancreatoduodenectomy With Concomitant Portomesenteric Venous Resection: An International Multicenter Analysis

OBJECTIVE: The aim of this study was to evaluate whether neoadjuvant therapy (NAT) critically influenced microscopically complete resection (R0) rates and long-term outcomes for patients with pancreatic ductal adenocarcinoma who underwent pancreatoduodenectomy (PD) with portomesenteric vein resection (PVR) from a diverse, world-wide group of high-volume centers. SUMMARY OF BACKGROUND DATA: Limited size studies suggest that NAT improves R0 rates and overall survival compared to upfront surgery in R/BR-PDAC patients. METHODS: This multicenter study analyzed consecutive patients with R/BR-PDAC who underwent PD with PVR in 23 high-volume centers from 2009 to 2018. RESULTS: Data from 1192 patients with PD and PVR were collected and analyzed. The median age was 68 [interquartile range (IQR) 60-73] years and 52% were males. Some 186 (15.6%) and 131 (10.9%) patients received neoadjuvant chemotherapy (NAC) alone and neoadjuvant chemoradiotherapy, respectively. The R0/R1/R2 rates were 57%, 39.3%, and 3.2% in patients who received NAT compared to 46.6%, 49.9%, and 3.5% in patients who did not, respectively (P =0.004). The 1-, 3-, and 5-year OS in patients receiving NAT was 79%, 41%, and 29%, while for those that did not it was 73%, 29%, and 18%, respectively (P <0.001). Multivariable analysis showed no administration of NAT, high tumor grade, lymphovascular invasion, R1/R2 resection, no adjuvant chemotherapy, occurrence of Clavien-Dindo grade 3 or higher postoperative complications within 90 days, preoperative diabetes mellitus, male sex and portal vein involvement were negative independent predictive factors for OS. CONCLUSION: Patients with PDAC of the pancreatic head expected to undergo venous reconstruction should routinely be considered for NAT