High ET Research Articles

Significance of Abnormalities of PPM1D in Myeloproliferative Neoplasms

The TP53 pathway has been shown to be dysregulated in myeloproliferative neoplasms (MPN) through several different mechanisms, including TP53 mutations, TP53 deletions and Murine Double Minute 2 (MDM2) overexpression. Downregulation of the TP53 pathway likely plays a role in MPN progression as evidenced by the association of TP53 loss of heterozygosity with transformation to acute leukemia and the presence of inactivating mutations of TP53 found in a proportion of MPN-blast phase (MPN-BP) cases (Kubesova et al, Leukemia. 2018;32(2):450-61). Furthermore, MDM2 inhibition induces TP53 pathway upregulation and consequent targeting of hematopoietic stem and progenitor cells in polycythemia vera (PV) and myelofibrosis (MF). The MDM2 inhibitor, idasanutlin, has shown activity in a Phase I trial of high-risk PV patients (Mascarenhas et al. Blood. 2019 Jun 5). An additional regulator of TP53 is protein phosphatase, Mg2+/Mn2+ dependent 1D (PPM1D) which by dephosphorylating TP53 and stabilizing MDM2 regulates the DNA damage response pathway and apoptosis. Somatic activating mutations of PPM1D are present in both solid and hematologic malignancies and are specifically associated with therapy-related myeloid disorders (Hsu et al. Cell Stem Cell. 2018 Nov 1;23(5):700-13). Grinfeld et al. (N Engl J Med. 2018 Oct 11;379(15):1416-30) recently reported that in their genomic analysis of 2035 MPN patients, PPM1D was the eighth most common mutated gene in MPNs at 1.9% frequency. To determine whether there was an association of PPM1D mutations with MPNs we analyzed the genomic data of patients who participated in several clinical trials executed by the Myeloproliferative Neoplasm Research Consortium (MPN-RC). Of 89 MPN-BP patients, 5 patients harbored a PPM1D mutation with a median variant allele frequency (VAF) of 17%. In comparison, 4 out of 135 high risk PV and ET patients harbored a PPM1D mutation with a median VAF of 24%. All mutations were truncating which is consistent with previous reports of PPMID mutations in malignancies. The PPM1D gene is located on the long arm of chromosome 17 (17q23.2) and we hypothesized that cytogenetic aberrations involving this gene locus might also contribute to abnormalities of PPM1D function. Through analysis of our cytogenetic database, 16/1,124 (1.4%) MPN patients were found to have cytogenomic abnormalities involving the region containing the PPM1D gene. Eight of these patients had karyotypic abnormalities, including 3 pts with isochromosome 17q resulting in a gain of 17q and a loss of 17p, including the TP53 gene. The other 4 patients had structural variations of 17q which might lead to aberrant expression of PPM1D. One patient by FISH analysis had gain of 17q. Ten patients had cytogenomic aberrations of 17q detected through analysis of array comparative genomic hybridization and single nucleotide polymorphism (aCGH+SNP), 2 of which had concurrent karyotypic abnormalities of 17q. All patients had a gain or copy neutral loss of heterozygosity (cnLOH) of the 17q22-24.2 region. CnLOH of this region could lead to aberrant overexpression of the PPM1D gene. One of the 8 patients with cnLOH of 17q harbored a PPM1D mutation. Of the 16 patients with 17q cytogenomic abnormalities, 7 (44%) had MPN-BP and 7 (44%) patients had ET or ET that progressed to myelofibrosis (MF) or MPN-BP indicating an association of these abnormalities with advanced disease. By quantitative real time-PCR we determined the PPM1D transcript levels in mononuclear cells from 31 MPN patients without known PPM1D mutations (7 polycythemia vera (PV), 6 ET, 14 MF, 4 MPN-BP) and compared the transcript levels to mononuclear cells from healthy control patients. Forty-two percent (13/31) patients had overexpression of PPM1D (>1.5 fold increase range). Fold increase ranged from 1.5-8 and overexpression was present in the following diagnoses: 4/7 PV, 1/6 ET, 8/14 MF and 0/4 MPN-BP. We have provided evidence that a number of abnormalities of PPM1D including activating mutations, cytogenetic aberrations and transcript overexpression are present in a significant proportion of MPN patients. These abnormalities in PPM1D can be additional events that lead to the downregulation of TP53 and contribute to MPN disease progression. We propose that inhibitors of PPM1D may be used in combination with other drugs that upregulate TP53 to treat MPN patients. Disclosures Rampal: Constellation, Incyte, and Stemline Therapeutics: Research Funding; Agios, Apexx, Blueprint Medicines, Celgene, Constellation, and Jazz: Consultancy. Mascarenhas:CTI Biopharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Research Funding; Roche: Consultancy, Research Funding; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; Pharmaessentia: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Research Funding; Promedior: Research Funding; Merus: Research Funding. Hoffman:Merus: Research Funding.

Spirophenylacridine‐2,7‐(diphenylphosphineoxide)‐fluorene: A Bipolar Host for High‐Efficiency Single‐Layer Blue Phosphorescent Organic Light‐Emitting Diodes

AbstractHerein, a high‐efficiency host material for single‐layer phosphorescent organic light‐emitting diodes (SL‐PhOLEDs) is reported. This host material is synthesized via an efficient approach and is constructed on the association of an electron‐rich phenylacridine unit connected by a spiro carbon atom to an electron‐deficient 2,7‐bis(diphenylphosphineoxide)‐fluorene. In addition to a high ET value and adequate highest occupied molecular orbital/lowest unoccupied molecular orbital energy levels, the key point in this molecular design is the suitable balance between hole and electron mobilities, which leads to a high‐performance blue SL‐PhOLED with an external quantum efficiency of 17.6% (current efficiency = 37.8 cd A−1 and power efficiency = 37.1 lm W−1) and a low Von of 2.5 V. This performance shows that the molecular design of the present host fulfills the criteria required for high‐efficiency SL‐PhOLEDs. The present performance is one of the highest reported to date for blue SL‐PhOLEDs and more importantly shows the potential of such a molecular design to reach very high‐performance single‐layer devices.

Effects of Cultivation Practices and Products on Bermudagrass Fairways in a Semiarid Region

High evapotranspirational demand combined with poor quality irrigation water increases salinity concerns in semiarid regions. Accumulated salts in the root zone may negatively affect bermudagrass (Cynodon spp.) growth and quality. The objective of this study was to examine the effectiveness of cultivation practices combined with products to enhance fairway conditions without applying leaching water levels. Two golf courses in Lubbock, TX, were selected for this research. Cultivation practices, including noncultivated control, core aerification, and slicing, were conducted in mid‐June of 2015 and 2016. Nine products recommended to enhance water movement or to disassociate sodium were applied within each cultivation treatment at label rates. Soil pH and electrical conductivity (EC) were determined from samples obtained in June, August, and October each year. Volumetric water content, visual turf quality, digital image analysis, normalized difference vegetation index, and ratio vegetation index were assessed from June to October in 2015 and 2016. Soil EC fluctuated with rainfall events. However, no treatment reduced soil EC. Gypsum‐based products increased soil EC but reduced pH at the conclusion of the research. Core aerification reduced aboveground parameters at Golf Course A because aerified holes remained visible throughout summer, whereas slicing and core aerification improved turf quality and ratio vegetation index at Golf Course B. These results emphasize the need to test irrigation water for the salinity hazard before implementing management strategies and the importance of leaching by rainfall or additional irrigation. Lastly, high surface disruption cultivation practices may inhibit bermudagrass recovery on higher clay content soils.Core Ideas Rainfall and high ET fluctuated soil EC of bermudagrass golf fairways. Gypsum products increased soil EC and reduced soil pH after 2 yr of applications. Bermudagrass recovery from core aerification was slowed with higher clay content. Cultivation practices improved parameters on high sand content soil after recovery.

Biochemical and histopathological impacts of rutile and anatase (TiO2 forms) in Mytilus galloprovincialis

Titanium dioxide (TiO2) particles have been widely used in various industrial applications and consumer products. Due to their large production and use, they will eventually enter into aquatic environments. Once in the aquatic environment TiO2 particles may interact with the organisms and induce toxic effects. Since the most common crystallographic forms of TiO2 are rutile and anatase, the present study evaluated the effect of these two forms of TiO2 particles in Mytilus galloprovincialis. For this, mussels were exposed to different concentrations of rutile and anatase particles (0, 5, 50, 100 µg/L) for twenty-eight days. Ti concentrations, histopathological alterations and biochemical effects were evaluated. Similar Ti concentrations were found in mussels exposed to rutile and anatase, with the highest values in mussels exposed to the highest exposure concentration. Histopathological results demonstrated that both forms of TiO2 induced alterations on gills and digestive glands along the increasing exposure gradient. Biochemical markers showed that mussels exposed to rutile maintained their metabolic capacity (assessed by the activity of the Electron Transport System, ETS), while anatase increased the metabolism of mussels. Mussels exposed to rutile increased their detoxifying defences which, due to the low tested concentrations, were sufficient to avoid cellular damage. On the other hand, mussels exposed to anatase suffered cellular damages despite the increase of the antioxidant defences which may be related to the high ETS activity. Both rutile and anatase particles were toxic to M. galloprovincialis, being the highest oxidative stress exerted by the crystalline form anatase.

Optoelectronic Properties of High Triplet σ-π-Conjugated Poly[(biphenyl group IV-A atom (C, Si, Ge, Sn)] Backbones.

A series of σ-π-conjugated polymers composed of biphenyl and X atom as backbone repeat unit (where X is the group IV-A atom: carbon, silicon, germanium, or tin) grafted with two alkoxy-substituted biphenyls at the X atom as side chains are synthesized and their optoelectronic properties are studied systematically. We choose biphenyl rather than alkyl as the side chain because its frontier molecular orbital distributions are close to those of our previously reported σ-π-conjugated polymer grafted with transport moieties. The present σ-π polymers with various X atoms show significant differences in triplet energy (ET) ranging from 2.58 to 2.83 eV with the sequence Ge > Si > C > Sn and in charge mobilities from 10-9 to 10-7 cm2/(V s) with the sequence Si > Ge > Sn > C, indicating that the properties of the σ-π polymers are largely affected by their X atoms. The Ge- and Sn-based σ-π-conjugated polymers show the highest and lowest ET values, respectively, due to their different levels of π-electron delocalization caused by size effects and (d-p)π orbital interaction. For their charge transport properties, the Si-based conjugated σ-π polymer gives the highest hole and electron mobilities due to the stronger σ-π conjugation and shorter Si-C bond length between the attached carbon atom in biphenyl and Si. On the contrary, the C-based σ-π-conjugated polymer gives the lowest charge mobilities due to a lack of d orbital in the C atom leading to a poor σ-π conjugation characteristic. These σ-π polymers with different ET levels and charge transport properties show a significant effect on their electroluminescence characteristics. Among them, the Ge-based σ-π-conjugated polymer when used as host shows the best device performance due to its higher ET and reasonable charge mobility. Such findings of different optoelectronic properties of these σ-π-conjugated polymers provide useful guidelines for the selection of backbone for designing σ-π-conjugated polymer host grafted with charge transport moieties.

Impact of energy turnover on the regulation of glucose homeostasis in healthy subjects

ObjectiveSedentary lifestyle increases the risk of type 2 diabetes. The aim of this study was to investigate the impact of different levels of energy turnover (ET; low, medium, and high level of physical activity and the corresponding energy intake) on glucose metabolism at zero energy balance, caloric restriction, and overfeeding.MethodsSixteen healthy individuals (13 men, 3 women, 25.1 ± 3.9 years, BMI 24.0 ± 3.2 kg/m2) participated in a randomized crossover intervention under metabolic ward conditions. Subjects passed 3 × 3 intervention days. Three levels of physical activity (PAL: low 1.3, medium 1.6, and high 1.8 achieved by walking at 4 km/h for 0, 3 × 55, or 3 × 110 min) were compared under three levels of energy balance (zero energy balance (EB): 100% of energy requirement (Ereq); caloric restriction (CR): 75% Ereq, and overfeeding (OF): 125% Ereq). Continuous interstitial glucose monitoring, C-peptide excretion, and HOMA–IR, as well as postprandial glucose and insulin were measured.ResultsDaylong glycemia and insulin secretion did not increase with higher ET at all conditions of energy balance (EB, CR, and OF), despite a correspondingly higher CHO intake (Δ low vs. high ET: +86 to 135 g of CHO/d). At CR, daylong glycemia (p = 0.02) and insulin secretion (p = 0.04) were even reduced with high compared with low ET. HOMA–IR was impaired with OF and improved with CR, whereas ET had no effect on fasting insulin sensitivity. A higher ET led to lower postprandial glucose and insulin levels under conditions of CR and OF.ConclusionLow-intensity physical activity can significantly improve postprandial glycemic response of healthy individuals, independent of energy balance.

Photodissociation dynamics of dichlorodifluoromethane (CF2Cl2) around 235 nm using time-sliced velocity map imaging technology

Photodissociation dynamics of dichlorodifluoromethane (CF2Cl2) around 235 nm has been studied using the time-sliced velocity map imaging technology in combination with the resonance enhanced multi-photon ionization technology. By measuring the raw images of chlorine atoms which are formed via one-photon dissociation of CF2Cl2, the speed and angular distributions can be directly obtained. The speed distribution of excited-state chlorine atoms consists of high translation energy (ET) and low ET components, which are related to direct dissociation on 3Q0 state and predissociation on the ground state induced by internal conversion, respectively. The speed distribution of ground-state chlorine atoms also consists of high ET and low ET components which are related to predissociation between 3Q0 and 1Q1 states and predissociation on the ground state induced by internal conversion, respectively. Radical dissociation channel is confirmed, nevertheless, secondary dissociation and three-body dissociation channels are excluded.

P‐174: Improved Operation Lifetime of Highly Efficient Sky‐Blue TADF OLEDs using Hexaphenylbenzene‐based Hole‐transporters

We successfully develped highly efficient 5TCzBN‐based sky‐blue TADF OLEDs exhibiting maximum external quantum efficiency (EQE) of 21.6 % and operation lifetime at 50 % (LT50) of approximately 1,800 hours at an initial luminance of 500 cd m–2. Here, novel hexaphenylbenzene‐based sterically bulky hole‐transporters named 4DBTHPB and 4DBFHPB with deep Ip of –5.8 eV and high ET of 2.7 eV were used to improve the operation lifetime.

P‐172: Novel Sterically Bulky Hole‐Transporters Realizing Enhanced Operation Lifetime in TADF OLEDs

We developed a series of sterically bulky hexaphenylbenzene‐based hole‐transporters named 4DBTHPB and 4DBFHPB with deep Ip of –5.8 eV and high ET of 2.7 eV. By using 4DBFHPB as a hole‐transporter, we realized a highly efficient and stable green TADF OLED exhibiting maximum external quantum efficiency of 19.4 % and operation lifetime at 50 % (LT50) of approximately 24,000 hrs at an initial luminance of 1000 cd m–2. Further, we investigated the effect of these hole‐transporters in sky‐blue TADF OLEDs.

A High Energy Turnover Improves Appetite Control at Different Levels of Energy Balance

Background: Weight control is hypothesized to be improved when physical activity and energy intake are both high (high energy turnover, ET). The impact of three levels of ET on appetite control is therefore investigated at fixed levels of energy balance. Methods: In a randomized controlled crossover trial, 16 healthy adults (25.1 ±3.9 y; BMI 24.0 ±3.2 kg/m2) spent 4 x 3 daylong protocols in a metabolic chamber. Energy requirement for different levels of energy turnover was measured at a baseline ad libitum intake condition. Four conditions of energy balance (ad libitum energy intake, zero energy balance, -25% caloric restriction and +25% overfeeding) were each performed at three levels of ET (low, medium and high ET, by walking on a treadmill). Levels of appetite hormones ghrelin, GLP-1 and insulin (tAUC) were measured over 14 hours. Subjective appetite ratings were assessed by Visual Analogue Scales. Results: Physical activity levels at low, medium and high ET were 1.3, 1.6 and 1.8 respectively. Compared to high ET, low ET led to decreased GLP-1 (at all energy balance conditions: p<0.001) and increased ghrelin levels (caloric restriction and overfeeding: p<0.001) which was consistent with higher feelings of hunger (zero energy balance: p<0.001) and desire to eat (all energy balance conditions: p<0.05) and a positive energy balance during ad libitum intake (+17.5%; p<0.001). Insulin levels were higher with low compared to high ET during overfeeding only (p<0.001). Conclusion: Appetite is regulated more effectively at a high level of energy turnover, whereas overeating and consequently weight gain is likely to occur at low levels of energy turnover. In contrast to the prevailing concept of body weight control, the positive impact of physical activity is independent from burning up more calories and is explained by improved appetite sensations.

Developing superior catalysts engineered by multichannel healing strategy for advanced oxidation

Catalyst deactivation derived from slow conversion of Fe(III)/Fe(II) is the critical problem restricting catalytic efficiency of advanced oxidation. Herein, a novel multichannel healing strategy is proposed for fast healing structural damage by designing rationally smart platform (TiO2-CDs-FeOOH hollow sandwich hybrid). This ingenious system shows remarkable catalytic activity (0.77 min−1) and stability towards the removal of organic contaminants. Systematic studies confirm that the excellent catalytic activity is attributed to multiple electron transfer (MET) behavior at interface between photocatalytic substrate and FeOOH, leading to highly efficient interfacial charge separation and then fast recovery of Fe(II) on FeOOH surface during H2O2 activation process. Notably, multichannel healing procedure and MET kinetic information are unveiled by UV–vis/scanning electrochemical microscopy (SECM) through an in situ probe scanning technique. A higher ET rate constant keff (0.92 × 10-2 cm s-1) was revealed over TiO2-CDs-FeOOH, two times that of TiO2-FeOOH, further confirming that multi-channel electron transfer could achieve fast Fe(III)/Fe(II) conversion. This work offers a new insight to design highly efficient catalysts for the practical applications of sustainable environmental remediation and energy conversion.

Transcriptomic analysis functionally maps the intrinsically disordered domain of EWS/FLI and reveals novel transcriptional dependencies for oncogenesis.

EWS/FLI is the pathognomic fusion oncoprotein that drives Ewing sarcoma. The amino-terminal EWS portion coordinates transcriptional regulation and the carboxy-terminal FLI portion contains an ETS DNA-binding domain. EWS/FLI acts as an aberrant transcription factor, orchestrating a complex mix of gene activation and repression, from both high affinity ETS motifs and repetitive GGAA-microsatellites. Our overarching hypothesis is that executing multi-faceted transcriptional regulation requires EWS/FLI to use distinct molecular mechanisms at different loci. Many attempts have been made to map distinct functions to specific features of the EWS domain, but described deletion mutants are either fully active or completely “dead” and other approaches have been limited by the repetitive and disordered nature of the EWS domain. Here, we use transcriptomic approaches to show an EWS/FLI mutant, called DAF, previously thought to be nonfunctional, displays context-dependent and partial transcriptional activity but lacks transforming capacity. Using transcriptomic and phenotypic anchorage-independent growth profiles of other EWS/FLI mutants coupled with reported EWS/FLI localization data, we have mapped the critical structure-function requirements of the EWS domain for EWS/FLI-mediated oncogenesis. This approach defined unique classes of EWS/FLI response elements and revealed novel structure-function relationships required for EWS/FLI activation at these response elements.

Time series trends of Landsat-based ET using automated calibration in METRIC and SEBAL: The Bekaa Valley, Lebanon

The Bekaa Valley in Lebanon currently hosts the highest number of refugees per capita in the world. It is also the primary agricultural production area in the country. Groundwater levels in some regions of the valley have decreased by >15 m in the last five years. Water use estimates at the regional and the field scale for this valley are crucial for enhancing resilience and for managing competing sectorial water demands. In this research, we derive a novel time series of field-scale actual evapotranspiration for the Bekaa Valley using two one-source energy balance models for the period 1984–2017, utilizing local weather data and all available original Level 1 Landsat thermal imagery and Level 2 surface reflectance products. We compare a modified METRIC model with an automated hot and cold pixel identification procedure run in batch mode to pySEBAL, a new version of SEBAL, which also has its automated anchors pixel selection algorithm. Analysis of 1200 cloud-masked and gap-filled Landsat-derived ET products show that the two models give comparable water use estimates at the seasonal and annual time steps. We estimate an average annual ET of 652 ± 53 mm (or 800 mcm) over the heavily cultivated valley in the last 34 years (with high agreement between both METRIC and pySEBAL models). Most (64%) of the ET is consumed from blue water in the dry season of May–October. ET in the wet season of November–April consumes >70% of the precipitation in the Bekaa valley. Annual analysis shows no discernable trend in ET across the valley, but there is an increase in irrigated agriculture in the Orontes Basin in the last five years. METRIC yields 15% higher ET than pySEBAL for the non-agricultural lands in summer. A water balance analysis shows that groundwater storage in the Litani basin is decreasing at a rate of 330 ± 50 mm yr−1. The outcome of this research also offers unique opportunities for estimating past and future trends of groundwater withdrawals. Results can provide insights into the sustainability of irrigated agriculture and the required international interventions in the water sector for enhancing the resilience of refugee and local communities.

Basin scale rainfall-evapotranspiration dynamics in a tropical semiarid environment during dry and wet years

In semiarid regions the occurrence of alternating long drought and heavy rainfall periods directly impacts water availability, affecting human water supply, agriculture development and the provision of ecosystem services. Because of that, research on the water input and output fluxes at the basin scale is of paramount importance. In this sense, rainfall-evapotranspiration (ET) dynamics play a critical role in water, soil and vegetation interactions, in hydrometeorological modelling and in the energy fluxes dynamics of semiarid regions. Therefore, the objective of this study was to quantify daily ET during a wet year and a dry year in a watershed located in the Brazilian Semiarid, by using remote sensing data and formulations based on the Simplified Surface Energy Balance Index (S-SEBI) and the Simplified Surface Energy Balance (SSEB) algorithms. Land surface temperature, albedo and NDVI data from MODIS sensor and solar radiation data from weather stations located in the basin were used. Rainfall analysis indicated 2009 and 2012 as being representatives of anomalously wet and dry years respectively, which were selected for the quantification of ET. The proposed algorithm was adjusted and verified with data from a flux tower equipped with eddy covariance system. Daily remote sensing ET estimates showed good agreement with observed values (RMSE = 0.79 mm.d−1) and the annual ET relative error was of 7.7% (35.4 mm.year−1). Results showed that the native vegetation can delay its dormant state for five months during wet years. During the wet year, ET differences between land cover classes were less noticeable due to soil saturation and the urgency of vegetated surfaces to meet their physiological needs. In dry year, however, differences were more evident, with bare soil presenting lower ET rates and vegetation classes showing higher ET values.

Effect of irrigation regime on yield, harvest index and water productivity of soybean grown under different precipitation conditions in a temperate environment

In temperate climatic regions, agricultural production depends on precipitation amount and its distribution during the growing season. A 3-year field study was conducted to investigate the effects of different irrigation regimes on yield parameters and water productivity of sprinkler-irrigated soybean [Glycine max (L.) Merr.], grown under wet, semi-dry and dry conditions in a temperate environment. Four irrigation levels were applied: full irrigation (I100), 65% and 40% of full irrigation (I65 and I40) and non-irrigated control (I0). On average, the I0 treatment resulted in the highest harvest index (HI) and I100 produced the lowest HI. A significant quadratic correlation between seed yield and crop water use was observed in dry and semi-dry year. The irrigation regime significantly influenced seed yield and water use. I65 treatment produced the highest seed yield (3.69 t ha–1) and showed the highest water productivity (WP) (0.90 kg m–3) and irrigation WP (1.08 kg m–3). The present study indicated that irrigation is necessary for soybean cultivation in semi-dry and dry years i.e., when seasonal precipitation is lower than about 300 mm. In wet years, with a favourable amount and distribution of precipitation during the growing season, yields are similar to those achieved with irrigation and high ET values of soybean are attributable to increased evaporation.

Water demands and biomass production of sorghum and maize plants in areas with insufficient precipitation in Central Europe

Evapotranspiration and transpiration measurements represent a tool for the assessment of crop water demand. The aim of this study was to compare sorghum and maize with respect to its potential for forage production in areas with insufficient precipitation in Central Europe. The values of the actual evapotranspiration (ET&lt;sub&gt;a&lt;/sub&gt;, Bowen ratio balance method), transpiration (sap flow method), leaf area index (LAI) and biomass production of sorghum and maize were measured continuously in years 2010–2012. Sorghum stand provided higher ET&lt;sub&gt;a&lt;/sub&gt; in comparison with maize in dry year 2012. Maize produced consistently more above-ground biomass yield and lower LAI over all evaluated years than sorghum. The sorghum provided similar or higher water use efficiency (WUE) than maize during the period of intensive prolongation growth, however, the higher WUE did not result in higher biomass production.

High Efficiency Deep‐Blue Phosphorescent Organic Light‐Emitting Diodes with CIE x, y (≤ 0.15) and Low Efficiency Roll‐Off by Employing a High Triplet Energy Bipolar Host Material

AbstractRecently, bipolar host materials are the most promising candidates for achieving high performance phosphorescent organic light‐emitting diodes (PHOLEDs) in order to maximize recombination efficiency. However, the development of host material with high triplet energy (E T) is still a great challenge to date to overcome the limitations associated with the present PHOLEDs. Herein, a highly efficient donor‐π‐acceptor (D‐π‐A) type bipolar host (4′‐(9H‐carbazol‐9‐yl)‐2,2′‐dimethyl‐[1,1′‐biphenyl]‐4‐yl)diphenylphosphine oxide (m‐CBPPO) comprising of carbazole, 2,2′‐dimethylbiphenyl and diphenylphosphoryl as D‐π‐A unit, respectively, is developed. Interestingly, a high E T of 3.02 eV is observed for m‐CBPPO due to highly twisted conformation. Furthermore, the new host material is incorporated in PHOLEDs as emissive layer with a new carbene type Ir(cb)3 material as a deep‐blue emitter. The optimized devices show an excellent external quantum efficiency (EQE) of 24.8% with a notable Commission internationale de l'éclairage (x, y) ≤ 0.15, (0.136, 0.138) and high electroluminescence performance with extremely low efficiency roll‐off. Overall, the above EQE is the highest reported for deep‐blue PHOLEDs with very low efficiency roll‐off and also indicate the importance of appropriate host for the development of high performance deep‐blue PHOLEDs.

Solvatochromic Response of Carbon Dots: Evidence of Solvent Interaction with Different Types of Emission Centers

The fluorescence emission of carbon dots (CDs) of ∼4 nm diameter was studied in a large number of solvents ranging from the weakly polar 1,4-dioxane to the strongly polar and protic water and formamide. The emission spectra in all solvents comprise of two major components, attributed to two distinct populations of emission centers, the edge-states at the periphery of the sp2-hybridized CD core and the surface fluorophores. Emission from both these centers are sensitive to solvent polarity and H-bonding capacity and undergo prominent redshift with solvent ET(30) polarity parameter, which reveals a comparable polar character of these centers and their strong interaction with solvent molecules. However, between these two centers, the emission of surface fluorophores is more drastically quenched at high ET(30) solvents, suggesting the opening up of additional nonradiative relaxation channels. This distinct solvatochromic response of these two emission centers also enables the CDs to perform as ratiometric pro...

Adaptation and Productivity of Selected Grain Legumes in Contrasting Environments of Kwazulu-Natal, South Africa

Underutilised grain legumes are being promoted as part of crop diversification efforts. However, the lack of comparable information to major legumes is limiting these efforts. The first benchmarking study to compare development and productivity of selected underutilised [bambara groundnut (Vigna subterranea) and cowpea (Vigna inguiculata) and major [groundnut (Arachis hypogaea) and common bean (Phaseolus vulgaris)] grain legumes under varying environments was conducted in KwaZulu-Natal, South Africa during 2015/16 and 2016/17. A completely randomised block design with three replications was used at all sites. Crop phenology, yield, water use (ET) and water productivity (WP) were determined for the crops. Data were analysed separately using ANOVA. Biplot analysis was done using GGE. Bambara groundnut was slow to emerge across sites and seasons (> 211 degree days). Common bean was early maturing ( 1699 degree days). Yield varied significantly (P < 0.05) across environments and seasons. For all environments, common bean had the lowest ET (208–313 mm); bambara groundnut had the highest ET (437 mm), which was recorded during 2015/16. The highest and lowest WP (0.98 and 0.12 kg m−3, respectively) were observed for groundnut. Cowpea had the most stable WP (0.28–0.38 kg m−3). Based on mean values, the major legumes out-yielded the underutilised grain legumes. Crops behaved differently across different environments. The potential of bambara groundnut was limited to sandy soils. There is need for investments in improving yield of underutilised grain legumes to make them more attractive for crop diversification.

High-Performance Exciplex-Type Host for Multicolor Phosphorescent Organic Light-Emitting Diodes with Low Turn-On Voltages

Rational design and selection of suitable donor and acceptor components for optimal thermally activated delayed fluorescence (TADF) exciplex-type emitters or hosts is presently challenging. Here, we constructed successfully a blue-emitting bulk exciplex system with efficient TADF emission and high triplet energy (ET) based on a donor of 4,4′,4′′-tris [3-methylphenyl(phenyl)amino]triphenylamine and an acceptor of 1,3,5-tri (m-pyrid-3-yl-phenyl)benzene. Systematic experimental and theoretical studies show that the matched frontier orbital energy levels, high ET, facile intersystem crossing, high oscillator strength of the exciplex, and efficient energy transfer channels should be the main considerations during the design of high-performance exciplex-type TADF emitters and bipolar host materials. Therefore, this bulk exciplex system can behave not only as blue emitters for organic light-emitting diodes (OLEDs) but also as universal hosts for the green, yellow, and red phosphorescent OLEDs (PhOLEDs). Impressi...