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1. Comparative performance of Fe‐ MO_x / SiO₂ (M = V, Mn, Co, Ni, Cu, Mo) and FeO_x / SiO₂ catalysts in reductive liquefaction of switchgrass in ethanol

   https://doi.org/10.1002/bbb.2720  

   Amarasekara, Ananda S; Morales, Gabriel Murillo; Kommalapati, Raghava R (March 2025, Biofuels, Bioproducts and Biorefining)

   Abstract The catalytic hydrothermal liquefaction of biomass under a hydrogen atmosphere is a promising technology to produce stable biocrude oil as a sustainable alternative to petroleum crude. A series of iron‐based non‐noble mix metal‐oxide‐on‐silica catalysts were evaluated to mimic the natural transformation that may have led to the conversion of terrestrial biomass to fossilized fuels. Switchgrass powder was liquefied to a stable bio‐oil with a 71.2% yield by using FeO_x/SiO₂catalyst in ethanol under a 5.5 MPa hydrogen atmosphere at 210 °C. The use of Fe‐MO_x/SiO₂(M = V, Mn, Co, Ni, Cu and Mo) type bimetallic oxide catalysts instead of FeO_x/SiO₂can produce improvements in liquefaction yields by using Mn, Co, Ni, and Cu as the second metal. The highest liquefaction yield of 78.8% was observed with the Fe‐CuO_x/SiO₂catalyst. Liquefaction oils were formed that were composed of complex mixtures of C6‐C12 alcohols, esters, aldehydes, and phenols. The lignin products:holocellulose products ratio changed in the range 0.35 to 0.15 and the composition of oils changed significantly with the use of mixed metal oxides in place of single metal FeO_x/SiO₂The most effective catalyst, Fe‐CuO_x/SiO₂could be reused in five cycles with a small loss in liquefaction yield from 78.8% to 70.0% after four reuse cycles and after regeneration of the catalyst at 500 °C for 3 h in air. 

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2. Resolving the contrasting leaf hydraulic adaptation of C₃ and C₄ grasses

   https://doi.org/10.1111/nph.20341  

   Baird, Alec_S; Taylor, Samuel_H; Pasquet‐Kok, Jessica; Vuong, Christine; Zhang, Yu; Watcharamongkol, Teera; Cochard, Hervé; Scoffoni, Christine; Edwards, Erika_J; Osborne, Colin_P; et al (January 2025, New Phytologist)

   Summary Grasses are exceptionally productive, yet their hydraulic adaptation is paradoxical. Among C₃grasses, a high photosynthetic rate (A_area) may depend on higher vein density (D_v) and hydraulic conductance (K_leaf). However, the higherD_vof C₄grasses suggests a hydraulic surplus, given their reduced need for highK_leafresulting from lower stomatal conductance (g_s).Combining hydraulic and photosynthetic physiological data for diverse common garden C₃and C₄species with data for 332 species from the published literature, and mechanistic modeling, we validated a framework for linkages of photosynthesis with hydraulic transport, anatomy, and adaptation to aridity.C₃and C₄grasses had similarK_leafin our common garden, but C₄grasses had higherK_leafthan C₃species in our meta‐analysis. Variation inK_leafdepended on outside‐xylem pathways. C₄grasses have highK_leaf : g_s, which modeling shows is essential to achieve their photosynthetic advantage.Across C₃grasses, higherA_areawas associated with higherK_leaf, and adaptation to aridity, whereas for C₄species, adaptation to aridity was associated with higherK_leaf : g_s. These associations are consistent with adaptation for stress avoidance.Hydraulic traits are a critical element of evolutionary and ecological success in C₃and C₄grasses and are crucial avenues for crop design and ecological forecasting. 

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3. The role of indium composition in In_xGa_1−xN prestrained layer towards optical characteristics of EBL free GaN / InGaN nanowire LEDs for enhanced luminescence

   https://doi.org/10.1002/jnm.3169  

   Das, Samadrita; Lenka, Trupti Ranjan; Talukdar, Fazal Ahmed; Nguyen, Hieu_Pham Trung; Crupi, Giovanni (March 2024, International Journal of Numerical Modelling: Electronic Networks, Devices and Fields)

   Abstract In this work, an electron blocking layer (EBL) free light emitting diode (LED) nanowire is proposed with alternate prestrained layers of In_xGa_1−xN/GaN, which are inserted between the GaN/InGaN multi‐quantum wells (MQWs) and n‐GaN layer. This study signifies the role of prestrained layers on the piezoelectric polarization of LED nanowires, for enhanced luminescence. When compared with the conventional one, the EBL free LED nanowire with prestrained layer shows an enhancement of ~2.897% efficiency, which occurs due to the reduction of polarization field in the active region. The LED with 15% indium in the prestrained layer obtains a maximum efficiency of 85.21% along with a minimum efficiency droop of 3.848% at 40 mA injected current. The proposed III‐nitride LED nanostructure allows for achieving superior optical power across the output spectral range. 

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4. Carbon isotope trends across a century of herbarium specimens suggest CO ₂ fertilization of C ₄ grasses

   https://doi.org/10.1111/nph.19868  

   del_Toro, Isa; Case, Madelon_F; Tyler_Karp, A.; Slingsby, Jasper_A; Staver, A_Carla (May 2024, New Phytologist)

   Summary Increasing atmospheric CO₂is changing the dynamics of tropical savanna vegetation. C₃trees and grasses are known to experience CO₂fertilization, whereas responses to CO₂by C₄grasses are more ambiguous.Here, we sample stable carbon isotope trends in herbarium collections of South African C₄and C₃grasses to reconstruct¹³C discrimination.We found that C₃grasses showed no trends in¹³C discrimination over the past century but that C₄grasses increased their¹³C discrimination through time, especially since 1950. These changes were most strongly linked to changes in atmospheric CO₂rather than to trends in rainfall climatology or temperature.Combined with previously published evidence that grass biomass has increased in C₄‐dominated savannas, these trends suggest that increasing water‐use efficiency due to CO₂fertilization may be changing C₄plant–water relations. CO₂fertilization of C₄grasses may thus be a neglected pathway for anthropogenic global change in tropical savanna ecosystems. 

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5. Polysaccharide‐based H₂S donors: Thiol‐ene functionalization of amylopectin with H₂S ‐releasing N ‐thiocarboxyanhydrides

   https://doi.org/10.1002/pol.20240262  

   Chinn, Abigail F; Williams, Noah R; Miller, Kevin M; Matson, John B (September 2024, Journal of Polymer Science)

   Abstract Polymeric donors of gasotransmitters, gaseous signaling molecules such as hydrogen sulfide, nitric oxide, and carbon monoxide, hold potential for localized and extended delivery of these reactive gases. Examples of gasotransmitter donors based on polysaccharides are limited despite the availability and generally low toxicity of this broad class of polymers. In this work, we sought to create a polysaccharide H₂S donor by covalently attachingN‐thiocarboxyanhydrides (NTAs) to amylopectin, the major component of starch. To accomplish this, we added an allyl group to an NTA, which can spontaneously hydrolyze to release carbonyl sulfide and ultimately H₂S via the ubiquitous enzyme carbonic anhydrase, and then coupled it to thiol‐functionalized amylopectin of three different molecular weights (MWs) through thiol‐ene “click” photochemistry. We also varied the degree of substitution (DS) of the NTA along the amylopectin backbone. H₂S release studies on the six samples, termed amyl‐NTAs, with variable MWs (three) and DS values (two), revealed that lower MW and higher DS led to faster release. Finally, dynamic light scattering experiments suggested that aggregation increased with MW, which may also have affected H₂S release rates. Collectively, these studies present a new synthetic method to produce polysaccharide H₂S donors for applications in the biomedical field. 

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