Utility of proximal plant sensors to support nitrogen fertilization in Chrysanthemum

Chrysanthemum morifolium Ramat. is a commonly grown ornamental worldwide. A proper timing of nitrogen (N) supply is essential for a qualitative crop and the return on investment for growers. Sub-optimal nitrogen nutrition negatively influences the commercial plant quality, while supra-optimal N has an environmental impact due to nitrate leaching. Therefore, (a) reliable indicator(s) of plant nitrogen status is/are needed. Two field-grown potted Chrysanthemum cultivars, 'Maya' and 'Orlando' were studied for three consecutive years (2016-2018). Three different N treatments were applied in order to obtain a variation in N content. Plant quality measurements consisted of plant height, diameter, leaf mass per area (2017 and 2018 only), biomass and foliar and plant N content analysis. Optical measurements were performed with a SPAD sensor (2016 and 2017) and a Dualex Scientific sensor (2017 and 2018) on leaf level and with a GreenSeeker NDVI meter on canopy level. Biomass, height and diameter tended to be smaller in the minimal fertilizer treatments. Leaf mass per area did influence the relation between N and chlorophyll measured with SPAD and Dualex. Epidermal polyphenolics measured with Dualex correlated better with foliar nitrogen than non-destructive chlorophyll measurements and the nitrogen balance index. Since abaxial epidermal polyphenolics were highly correlated with foliar nitrogen and convenient to measure in-field, we propose this measurement for decision support in Chrysanthemum fertilization. Because of cultivar and sometimes year-to-year variability, reference plots can be of help for growers and advisors. NDVI was found to be more susceptible for yearly variation, but very high correlation with several quality parameters and convenience in use make this vegetation index useful for detecting the extent of spatial quality variability and thus support site dependent N requirements to reach the desired plant diameter at the end of the growing season

Application of proximal optical sensors to fine-tune nitrogen fertilization : opportunities for woody ornamentals

Today, high amounts of residual nitrogen are regularly being reported in the open field production of hardy nursery stock. In some cases, excessive fertilizers or side-dressings are applied when circumstances are not favorable for uptake. Aquatic as well as terrestrial ecosystems are sensitive to enrichment with nutrients, but growers also benefit when losses are avoided. In this study, the potential of proximal optical sensors to optimize nitrogen fertilization was investigated in four woody species: Acer pseudoplatanus L., Ligustrum ovalifolium Hassk., Prunus laurocerasus 'Rotundifolia' L. and Tilia cordata Mill. For three consecutive growing seasons, plants were grown under three different fertilization levels to generate different nitrogen contents. Plant growth and nitrogen uptake were monitored regularly and combined with sensor measurements including Soil Plant Analysis Development (SPAD), Dualex and GreenSeeker. Here, we show that optical sensors at the leaf level have good potential for assisting growers in the sustainable management of their nursery fields, especially if leaf mass per area is included. Nevertheless, care should be taken when plants with different leaf characteristics (e.g., wax-layer, color, and leaf thickness) are measured. When all measuring years were considered, high correlations (R-2 >= 0.80) were found between area-based foliar nitrogen content and its non-destructive proxy (i.e., chlorophyll)measured by Dualex or SPAD. Based on our results, we recommend a relative rather than absolute approach at the nursery level, as the number of species and cultivars produced is very diverse. Hence, knowledge of absolute threshold values is scarce. In this relative approach, a saturation index was calculated based on the sensor measurements of plants grown in a reference plot with an ample nitrogen supply

Complement inhibition prevents glial nodal membrane injury in a GM1 antibody-mediated mouse model

The involvement of the complement pathway in Guillain–Barré syndrome pathogenesis has been demonstrated in both patient biosamples and animal models. One proposed mechanism is that anti-ganglioside antibodies mediate neural membrane injury through the activation of complement and the formation of membrane attack complex pores, thereby allowing the uncontrolled influx of ions, including calcium, intracellularly. Calcium influx activates the calcium-dependent protease calpain, leading to the cleavage of neural cytoskeletal and transmembrane proteins and contributing to subsequent functional failure. Complement inhibition has been demonstrated to provide effective protection from injury in anti-ganglioside antibody-mediated mouse models of axonal variants of Guillain–Barré syndrome; however, the role of complement in the pathogenesis of demyelinating variants has yet to be established. Thus, it is currently unknown whether complement inhibition would be an effective therapeutic for Guillain–Barré syndrome patients with injuries to the Schwann cell membrane. To address this, we recently developed a mouse model whereby the Schwann cell membrane was selectively targeted with an anti-GM1 antibody resulting in significant disruption to the axo-glial junction and cytoplasmic paranodal loops, presenting as conduction block. Herein, we utilize this Schwann cell nodal membrane injury model to determine the relevance of inhibiting complement activation. We addressed the early complement component C2 as the therapeutic target within the complement cascade by using the anti-C2 humanized monoclonal antibody, ARGX-117. This anti-C2 antibody blocks the formation of C3 convertase, specifically inhibiting the classical and lectin complement pathways and preventing the production of downstream harmful anaphylatoxins (C3a and C5a) and membrane attack complexes. Here, we demonstrate that C2 inhibition significantly attenuates injury to paranodal proteins at the node of Ranvier and improves respiratory function in ex vivo and in vivo Schwann cell nodal membrane injury models. In parallel studies, C2 inhibition also protects axonal integrity in our well-established model of acute motor axonal neuropathy mediated by both mouse and human anti-GM1 antibodies. These data demonstrate that complement inhibition prevents injury in a Schwann cell nodal membrane injury model, which is representative of neuropathies associated with anti-GM1 antibodies, including Guillain–Barré syndrome and multifocal motor neuropathy. This outcome suggests that both the motor axonal and demyelinating variants of Guillain–Barré syndrome should be included in future complement inhibition clinical trials

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Nitrogen fertilization in ornamental plant production based on in-season demands through proximal sensing and soil modelling

The ornamental plant production sector produces high quality products, but faces challenges in times of increasing environmental constraints. Growth patterns and nitrogen uptake dynamics of five ornamental crops were determined during three growing seasons (2016-2018). This resulted in nitrogen uptake quantities sufficient for optimum plant quality. Open field production of herbaceous and woody ornamentals is characterized by a very broad range of species and cultivars, differing in growth dynamics, biomass accumulation as well as cultivation method. The Flemish ornamental plant sector produces high-value plants but faces plenty of challenges to maintain this high quality in times of increasing environmental constraints. For open field production, Flanders imposes nitrogen fertilization standards in order to comply with the European Nitrates Directive (91/676/EEC). To keep ornamental plant growers competitive on the national and international markets and to comply with these environmental restrictions, the sector needs a differentiated nitrogen (N) recommendation system, based on in-season demands. Indeed, high quantities of residual nitrate can be measured in the soil profile after the growing season, which is partly due to fertilizer gifts that all too often exceed the crop demand. In periods of high precipitation, this nitrate is susceptible to leaching through the soil profile, which subsequently leads to ground and surface water contamination. Limited information was available about the nitrogen requirements of open field ornamental plants, despite this being an essential input variable of fertilizer recommendation systems. Therefore, N uptake dynamics of five ornamental plants species was assessed during three growing seasons (2016-2018). This was done through regular measuring and sampling on trial fields with different fertilization levels and nurseries where business-as-usual practices were applied. Chrysanthemum morifolium (potted chrysanthemum, cultivars 'Maya' and 'Orlando'), Acer pseudoplatanus (sycamore, deciduous tree, forest seedling production), Ligustrum ovalifolium (Korean privet, semi-evergreen shrub), Prunus laurocerasus 'Rotundifolia' (cherry laurel, evergreen shrub) and Tilia cordata (small-leaved lime, deciduous avenue tree) were selected as representative for the open field ornamental plant production. This resulted in N uptake ranges that may be considered as adequate for a good plant quality. Because different plant ages and management practices were considered, we repeatedly demonstrated that N uptake was influenced more by age, planting density, transplanting of perennials, etc. than by the species itself. Furthermore, gathering data over a period of three growing seasons revealed that the N uptake is strongly affected by year-to-year varying climatic conditions, stressing the importance of multi-year nitrogen uptake datasets. These findings highlight the importance of split-applications and in-season determination of plant N demand and soil N supply. With regard to the latter, based on our results, we would propose a soil analysis early in July and early in August for the woody ornamentals (A. pseudoplatanus, L. ovalifolium, P. laurocerasus 'Rotundifolia' and T. cordata) and C. morifolium, respectively. To determine in-season N status of the plants on the other hand, the potential of proximal leaf and canopy sensors was explored in this thesis. To date, these techniques are underexploited for (woody) ornamentals, yet they offer countless opportunities to support N fertilization. At leaf level, we found that epidermal polyphenolic compounds measured with the Dualex sensor were highly correlated with foliar N% in C. morifolium. For the woody species, chlorophyll measured with both a SPAD meter and a Dualex sensor were a reliable proxy for foliar N%, but only when the leaf mass per area was considered. These results prove that proximal leaf sensors can be valuable decision-support tools to assess the in-season nitrogen status of both C. morifolium and different woody ornamental species. Nevertheless, some caution is recommended when different plant species are used, especially if leaf characteristics differ (e.g. presence of a wax layer). A relative approach, where a saturation index was calculated using a nitrogen-rich reference field, was considered to improve the usability because there are no absolute reference values available for an optimal (foliar) N% for the many different species and cultivars grown in nurseries. At canopy level, the GreenSeeker was used for three consecutive growing seasons on the one hand. This widely used sensor measures red and infrared light reflected by the plant canopy and subsequently calculates the NDVI, a vegetation index related with photosynthetically active biomass. The obtained correlations between NDVI and biomass and N uptake were generally high, but species-specific. Furthermore, we also encountered saturation problems when the canopy closed. It was concluded that NDVI measurements can be useful to identify the need for additional fertilization and potential in-field variability, but do not serve as a proxy for plant N%. Here as well, a relative approach can help to rule out other parameters except an N deficiency, as long as the reference plot is representative for the rest of the field and a threshold value for action can be set. On the other hand, the potential of a novel hyperspectral spectroradiometer was assessed in 2018. This device measures reflectance continuously in the visual and near infrared part of the electromagnetic spectrum (340-820 nm) and allows the comparison of multiple vegetation indices or the exploitation of multiple wavelengths through multivariate statistics. Although other vegetation indices besides NDVI were highly correlated with biomass and N uptake (especially for C. morifolium), mainly partial least squared regression (PLRS) was considered promising to provide site-specific diagnostics of crop performance. Here, for plant N% as well, high correlations were obtained on species-level. For both C. morifolium as for the woody ornamental species, end-of-season specific difficulties, including flower bud initiation and the relocation of N towards perennial storage organs (roots/stem), interfered with the correlation; however, as additional fertilization is often unfavorable around that period, these dates could be excluded during further research. More data confirming the robustness of the correlations are needed to develop a decision support system based on the prediction models. Because plant growth is generally determined by interactions with the soil in a bottom-up manner, an important chapter in this thesis is devoted to soil N release, with emphasis on the influence of mechanical weed control and the opportunities of catch crops. For the case of avenue tree production, characterized by a low planting density, a low N uptake and repeated mechanical weed control, a field experiment was set up at two nurseries. During three growing seasons following the application of farmyard manure, soil mineral N was monitored by means of regular soil sampling. At one of the nurseries, we showed that at least 30% of the applied N was released in the second year. Partly due to the heterogeneity of animal manure, results were not always significant or consistent over time, nevertheless, the N release tended to continue the second year after application at the other nursery as well. Attempts were made to validate the results obtained by the field experiment through a model-based approach in order to be able to quantify nitrogen release and leaching. As both processes strongly depend on water availability and flow, a soil water balance was used to simulate daily water movement. Furthermore, the mineralization speed of the soil and the farmyard manure were calculated through an incubation experiment in laboratory conditions, however, due the inhomogeneous nature of the manure (and perhaps other unknown interactions), results could not be translated into field conditions. Therefore, the model approach needed more fine-tuning than expected. Nevertheless, the nitrogen balance models were useful as an exploratory tool to quantify N release and leaching after management practices for the first time. At both nurseries, there was a considerable mismatch between nitrogen fertilization and uptake by the trees, which could have been almost entirely covered by the N release after soil cultivation (if its timing would be synchronized with plant demand). N release succeeding a soil disturbance event was depending on time of the year, number of events and model decisions, but resulted in an additional N release of minimum 109 kg N ha-1 during the three experimental years at both fields. Average estimated N release after soil disturbance varied between 8 and 71 kg N ha-1; the more soil cultivation events were carried out, the less N tended to be released each time. In-field differences in nitrate content could be mostly attributed to the different weed control management, which shows that its impact should not be neglected. For example, an autumn rotovation of the soil following chemical weed control resulted in an exceptionally high amount of residual nitrogen and a doubling of modelled nitrate leaching during winter (± 108 NO3--N ha-1 compared with ± 54 kg NO3--N ha-1 in the other years). Lastly, we were able to associate catch crops, even when sown late, with a reduced N leaching of 33.5% on average. We therefore suggest delaying the control period for obligatory residual soil sampling for perennial crop growers in Flanders. Based on our results, we would recommend advancing the first soil cultivation, and thus (cold hardy) catch crop incorporation, to increase N availability at the start of the growing season instead of applying a mineral fertilizer.status: publishe

When neighbors talk : colon cancer cell invasion and tumor microenvironment myofibroblasts

Historically, the word cancer is derived from the Latin cancer, as the red swollen arteries near a tumor reminded the physician Galenus and his fellow Romans of a red crab. Currently, cancer remains the disease to beat as it remains a leading cause of death worldwide (WHO). Tumors do not simply consist of cancer cells, as they can recruit normal cells, which will form the tumor-associated stroma. These stromal cells together with the extracellular matrix, constitute the tumor microenvironment. Reciprocal communication between tumor-associated stromal cells and cancer cells is important for the induction of epithelial-to-mesenchymal transition and invasion. A detailed knowledge of this communication can spark the development of novel therapeutic strategies aimed at tackling yet unaddressed regulators of invasion and thus metastasis. Therefore, this review will focus not only on epithelial-to-mesenchymal transition and invasion, but also on communication between tumor cells, in particular colon cancer cells, and their stroma, with a primordial focus on cancer-associated fibroblasts, and lastly this review will discuss how this communication can affect the cancer cell's ability to invade its surroundings and form metastases

Utility of proximal plant sensors to support nitrogen fertilization in Chrysanthemum

© 2019 Elsevier B.V. Chrysanthemum morifolium Ramat. is a commonly grown ornamental worldwide. A proper timing of nitrogen (N)supply is essential for a qualitative crop and the return on investment for growers. Sub-optimal nitrogen nutrition negatively influences the commercial plant quality, while supra-optimal N has an environmental impact due to nitrate leaching. Therefore, (a)reliable indicator(s)of plant nitrogen status is/are needed. Two field-grown potted Chrysanthemum cultivars, ‘Maya’ and ‘Orlando’ were studied for three consecutive years (2016–2018). Three different N treatments were applied in order to obtain a variation in N content. Plant quality measurements consisted of plant height, diameter, leaf mass per area (2017 and 2018 only), biomass and foliar and plant N content analysis. Optical measurements were performed with a SPAD sensor (2016 and 2017)and a Dualex Scientific sensor (2017 and 2018)on leaf level and with a GreenSeeker NDVI meter on canopy level. Biomass, height and diameter tended to be smaller in the minimal fertilizer treatments. Leaf mass per area did influence the relation between N and chlorophyll measured with SPAD and Dualex. Epidermal polyphenolics measured with Dualex correlated better with foliar nitrogen than non-destructive chlorophyll measurements and the nitrogen balance index. Since abaxial epidermal polyphenolics were highly correlated with foliar nitrogen and convenient to measure in-field, we propose this measurement for decision support in Chrysanthemum fertilization. Because of cultivar and sometimes year-to-year variability, reference plots can be of help for growers and advisors. NDVI was found to be more susceptible for yearly variation, but very high correlation with several quality parameters and convenience in use make this vegetation index useful for detecting the extent of spatial quality variability and thus support site dependent N requirements to reach the desired plant diameter at the end of the growing season.status: publishe

Application of Proximal Optical Sensors to Fine-Tune Nitrogen Fertilization: Opportunities for Woody Ornamentals

status: publishe

Demonstrating the use of thin film gauges for heat flux measurements in ICEs: measurements on an inlet valve in motored operation

To optimize internal combustion engines (ICEs), a good understanding of engine operation is essential. The heat transfer from the working gases to the combustion chamber walls plays an important role, not only for the performance, but also for the emissions of the engine. Besides, thermal management of ICEs is becoming more and more important as an additional tool for optimizing efficiency and emission aftertreatment. In contrast little is known about the convective heat transfer inside the combustion chamber due to the complexity of the working processes. Heat transfer measurements inside the combustion chamber pose a challenge in instrumentation due to the harsh environment. Additionally, the heat loss in a spark ignition (SI) engine shows a high temporal and spatial variation. This poses certain requirements on the heat flux sensor. In this paper we examine the heat transfer in a production SI ICE through the use of Thin Film Gauge (TFG) heat flux sensors. An inlet valve has been equipped with 7 TFG sensors in a row. In literature only measurements on the piston, cylinder liner or cylinder head could be found. First, the construction of the heat flux sensor will be discussed. Second, the heat flux measurement technique and the implementation of the TFG sensors are discussed. The choice for Thin Film sensors is highlighted. Only compression operation (motored) measurements are currently considered and compared to literature. The effect of a variation in manifold air pressure on the heat flux is analysed