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1. Synthesis of graded CdS _1−x Se _x nanoplatelet alloys and heterostructures from pairs of chalcogenoureas with tailored conversion reactivity

   https://doi.org/10.1039/D3SC03384H  

   Saenz, Natalie; Hamachi, Leslie S.; Wolock, Anna; Goodge, Berit H.; Kuntzmann, Alexis; Dubertret, Benoit; Billinge, Isabel; Kourkoutis, Lena F.; Muller, David A.; Crowther, Andrew C.; et al (November 2023, Chemical Science)

   A mixture ofN,N,N′-trisubstituted thiourea and cyclicN,N,N′,N′-tetrasubstituted selenourea precursors were used to synthesize three monolayer thick CdS_1−xSe_xnanoplatelets in a single synthetic step. 

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2. Ranked Document Retrieval in External Memory

   https://doi.org/10.1145/3559763  

   Shah, Rahul; Sheng, Cheng; Thankachan, Sharma; Vitter, Jeffrey (January 2023, ACM Transactions on Algorithms)

   The ranked (or top-k) document retrieval problem is defined as follows: preprocess a collection{T₁,T₂,… ,T_d}ofdstrings (called documents) of total lengthninto a data structure, such that for any given query(P,k), wherePis a string (called pattern) of lengthp ≥ 1andk ∈ [1,d]is an integer, the identifiers of thosekdocuments that are most relevant toPcan be reported, ideally in the sorted order of their relevance. The seminal work by Hon et al. [FOCS 2009 and Journal of the ACM 2014] presented anO(n)-space (in words) data structure withO(p+klogk)query time. The query time was later improved toO(p+k)[SODA 2012] and further toO(p/log_σn+k)[SIAM Journal on Computing 2017] by Navarro and Nekrich, whereσis the alphabet size. We revisit this problem in the external memory model and present three data structures. The first one takesO(n)-space and answer queries inO(p/B+ log_Bn + k/B+log^*(n/B)) I/Os, whereBis the block size. The second one takesO(nlog^*(n/B)) space and answer queries in optimalO(p/B+ log_Bn + k/B)I/Os. In both cases, the answers are reported in the unsorted order of relevance. To handle sorted top-kdocument retrieval, we present anO(nlog(d/B))space data structure with optimal query cost. 

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3. Solid Decolorization: Dismantling of an Orange‐Red Zwitterionic Cocrystal by Multicomponent Milling

   https://doi.org/10.1002/adom.202400889  

   Ezekiel, Charles_Izuchukwu; Ortiz‐de_León, Celymar; Reinheimer, Eric; MacGillivray, Leonard_R (May 2024, Advanced Optical Materials)

   Abstract An application of multi‐component milling is described to achieve a decolorization by dismantling the orange‐red zwitterionic cocrystal (PDA)∙(APAP) (wherePDA= 2,4‐pyridinedicarboxylic acid,APAP= acetaminophen) usingn,n′‐BPE(BPE=trans‐1,2‐bis(n‐pyridylethylene and forn=n′ = 3 or 4). Each ofn,n′‐BPEforms a colorless hydrogen‐bonded cocrystal withPDA. 

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4. Does resource exchange in ectomycorrhizal symbiosis vary with competitive context and nitrogen addition?

   https://doi.org/10.1111/nph.17871  

   Bogar, Laura M.; Tavasieff, Oceana S.; Raab, Ted K.; Peay, Kabir G. (December 2021, New Phytologist)

   Summary Ectomycorrhizal symbiosis is essential for the nutrition of most temperate forest trees and helps regulate the movement of carbon (C) and nitrogen (N) through forested ecosystems. The factors governing the exchange of plant C for fungal N, however, remain obscure.Because competition and soil resources may influence ectomycorrhizal resource movement, we performed a 10‐month split‐root microcosm study usingPinus muricataseedlings withThelephora terrestris,Suillus pungens, or no ectomycorrhizal fungus, under two N concentrations in artificial soil. Fungi competed directly with roots and indirectly with each other. We used stable isotope enrichment to track plant photosynthate and fungal N.ForT. terrestris, plants received N commensurate with the C given to their fungal partners.Thelephora terrestriswas a superior mutualist under high‐N conditions. ForS. pungens, plant C and fungal N exchange were not coupled. However, in low‐N conditions, plants preferentially allocated C toS. pungensrather thanT. terrestris.Our results suggest that ectomycorrhizal resource transfer depends on competitive and nutritional context. Plants can exchange C for fungal N, but coupling of these resources can depend on the fungal species and soil N. Understanding the diversity of fungal strategies, and how they change with environmental context, reveals mechanisms driving this important symbiosis. 

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5. Mono ‐ and Bis ‐Alkylated Lumazine Sensitizers: Synthetic, Molecular Orbital Theory, Nucleophilic Index and Photochemical Studies

   https://doi.org/10.1111/php.13310  

   Sosa, María José; Urrutia, María Noel; Schilardi, Patricia L.; Quindt, Matías I.; Bonesi, Sergio M.; Denburg, Dobrushe; Vignoni, Mariana; Greer, Alexander; Greer, Edyta M.; Thomas, Andrés H. (August 2020, Photochemistry and Photobiology)

   Abstract Mono‐ andbis‐decylated lumazines have been synthesized and characterized. Namely,mono‐decyl chain [1‐decylpteridine‐2,4(1,3H)‐dione]6aandbis‐decyl chain [1,3‐didecylpteridine‐2,4(1,3H)‐dione]7aconjugates were synthesized by nucleophilic substitution (S_N2) reactions of lumazine with 1‐iododecane inN,N‐dimethylformamide (DMF) solvent. Decyl chain coupling occurred at theN¹site and then theN³site in a sequential manner, without DMF condensation. Molecular orbital (MO) calculations show ap‐orbital atN¹but notN³, which along with a nucleophilicity parameter (N) analysis predict alkylation atN¹in lumazine. Only after the alkylation atN¹in6a, does ap‐orbital onN³emerge thereby reacting with a second equivalent of 1‐iododecane to reach the dialkylated product7a. Data from NMR (¹H,¹³C, HSQC, HMBC), HPLC, TLC, UV‐vis, fluorescence and density functional theory (DFT) provide evidence for the existence ofmono‐decyl chain6aandbis‐decyl chain7a. These results differ to pterinO‐alkylations (kinetic control), whereN‐alkylation of lumazine is preferred and then to dialkylation (thermodynamic control), with an avoidance of DMF solvent condensation. These findings add to the list of alkylation strategies for increasing sensitizer lipophilicity for use in photodynamic therapy. 

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