-
Advanced Science (Weinheim,... Jun 2024Individual differences in size, experience, and task specialization in natural swarms often result in heterogeneity and hierarchy, facilitating efficient and coordinated...
Individual differences in size, experience, and task specialization in natural swarms often result in heterogeneity and hierarchy, facilitating efficient and coordinated task accomplishment. Drawing inspiration from this phenomenon, a general strategy is proposed for organizing magnetic micro/nanorobots (MNRs) with apparent differences in size, shape, and properties into cohesive microswarms with tunable heterogeneity, controlled spatial hierarchy, and collaborative tasking capability. In this strategy, disparate magnetic MNRs can be manipulated to show reversible transitions between synchronization and desynchronization by elaborately regulating parameter sets of the rotating magnetic field. Utilizing these transitions, alongside local robust hydrodynamic interactions, diverse heterospecific pairings of disparate magnetic MNRs can be organized into heterogeneous microswarms, and their spatial organization can be dynamically adjusted from egalitarian to leader-follower-like hierarchies on the fly, both in open space and complex microchannels. Furthermore, when specializing the disparate MNRs with distinct functions ("division of labor") such as sensing and drug carrying, they can execute precise drug delivery targeting unknown sites in a collaborative sensing-navigating-cargo dropping sequence, demonstrating significant potential for precise tumor treatment. These findings highlight the critical roles of attribute differences and hierarchical organization in designing efficient swarming micro/nanorobots for biomedical applications.
PubMed: 38868929
DOI: 10.1002/advs.202401711 -
ChemSusChem Jun 2024The sulfoxide moiety is one of the most commonly utilized groups in pharmaceutical and industrial chemistry. The need for sustainability and easy accessibility to...
The sulfoxide moiety is one of the most commonly utilized groups in pharmaceutical and industrial chemistry. The need for sustainability and easy accessibility to sulfoxide moieties is deemed necessary, due to its ubiquity in natural products and potentially pharmaceutically active compounds. In this context, we report herein a sustainable, aerobic and environmentally friendly photochemical protocol based on the use of a benzothioxathene imide as the photocatalyst to selectively oxidise sulfides under mild irradiation (456 nm), in very low catalyst loading (0.01 mol%) and on water. In addition, to demonstrate the compatibility of our protocol with wide scope of substrates, the latter was successfully applied to the synthesis of the biologically-active Sulforaphane and Modafinil.
PubMed: 38867402
DOI: 10.1002/cssc.202400903 -
Environmental Science & Technology Jun 2024Hydrogen peroxide (HO) plays a crucial role as an oxidizing agent within the tropospheric environment, making a substantial contribution to sulfate formation in hydrated...
Hydrogen peroxide (HO) plays a crucial role as an oxidizing agent within the tropospheric environment, making a substantial contribution to sulfate formation in hydrated aerosols and cloud and fog droplets. Field observations show that high levels of HO are often observed in heavy haze events and polluted air. However, the source of HO remains unclear. Here, using the droplets formed by the deliquescence of hygroscopic compounds under a high relative humidity (RH), the formation of HO by the photochemistry of imidazole-2-carbaldehyde (2-IC) under ultraviolet irradiation was explored. The results indicate that 2-IC produces IM-C-OH and IM-C═O radicals via H transfer itself to its excited triplet state and generates HO and organic peroxides in the presence of O, which has an evident oxidizing effect on SO, suggesting the potential involvement of this pathway in the formation of atmospheric sulfate. HO formation is limited in acidic droplets or droplets containing ammonium ions, and no HO is detected in droplets containing nitrate, whereas droplets containing citric acid have an obvious promotion effect on HO formation. These findings provide valuable insights into the behaviors of atmospheric photosensitizers, the source of HO, and the formation of sulfate in atmospheric droplets.
Topics: Hydrogen Peroxide; Oxidation-Reduction; Imidazoles; Photochemistry; Sulfur Dioxide; Air Pollutants; Ultraviolet Rays
PubMed: 38865480
DOI: 10.1021/acs.est.3c11113 -
Journal of the American Chemical Society Jun 2024Titanium-oxo clusters can undergo photochemical reactions under UV light, resulting in the reduction of the titanium-oxo core and oxidation of surface ligands. This is...
Titanium-oxo clusters can undergo photochemical reactions under UV light, resulting in the reduction of the titanium-oxo core and oxidation of surface ligands. This is an important step in photocatalytic processes in light-absorbing Ti/O-based clusters, metal-organic frameworks, and (nano)material surfaces; however, studying the direct outcome of this photochemical process is challenging due to the fragility of the immediate photoproducts. In this report, titanium-oxo clusters [TiO(OPr)(L)] ( = 4, L = OPPh, or = 6, L = OCCHBu) undergo a two-electron photoredox reaction in the single-crystal state via an irreversible single-crystal to single-crystal (SC-SC) transformation initiated by a UV laser. The process is monitored by single crystal X-ray diffraction revealing the photoreduction of the cluster with coproduction of an (oxidized) acetone ligand, which is retained in the structure as a ligand to Ti(3+). The results demonstrate that photochemistry of inorganic molecules can be studied in the single crystal phase, allowing characterization of photoproducts which are unstable in the solution phase.
PubMed: 38865257
DOI: 10.1021/jacs.4c04068 -
The Journal of Physical Chemistry. C,... Jun 2024We present an optical study of the spontaneous emission of lead sulfide (PbS) nanocrystal quantum dots in 3D photonic band gap crystals made from silicon. The...
We present an optical study of the spontaneous emission of lead sulfide (PbS) nanocrystal quantum dots in 3D photonic band gap crystals made from silicon. The nanocrystals emit in the near-infrared range to be compatible with 3D silicon nanophotonics. The nanocrystals are covalently bound to polymer brush layers that are grafted from the Si-air interfaces inside the nanostructure by using surface-initiated atom transfer radical polymerization. The presence and position of the quantum dots were previously characterized by synchrotron X-ray fluorescence tomography. We report both continuous wave emission spectra and time-resolved, time-correlated single photon counting. In time-resolved measurements, we observe that the total emission rate greatly increases when the quantum dots are transferred from suspension to the silicon nanostructures, likely due to quenching (or increased nonradiative decay) that is tentatively attributed to the presence of Cu catalysts during the synthesis. In this regime, continuous wave emission spectra are known to be proportional to the radiative rate and thus to the local density of states. In spectra normalized to those taken on flat silicon outside the crystals, we observe a broad and deep stop band that we attribute to a 3D photonic band gap with a relative bandwidth of up to 26%. The shapes of the relative emission spectra match well with the theoretical density of states spectra calculated with plane-wave expansion. The observed inhibition is 4-30 times, similar to previously reported record inhibitions, yet for coincidental reasons. Our results are relevant to applications in photochemistry, sensing, photovoltaics, and efficient miniature light sources.
PubMed: 38864002
DOI: 10.1021/acs.jpcc.4c01541 -
Frontiers in Plant Science 2024In the Near East and North Africa (NENA) region, crop production is being affected by various abiotic factors, including freshwater scarcity, climate, and soil salinity....
INTRODUCTION
In the Near East and North Africa (NENA) region, crop production is being affected by various abiotic factors, including freshwater scarcity, climate, and soil salinity. As a result, farmers in this region are in search of salt-tolerant crops that can thrive in these harsh environments, using poor-quality groundwater. The main staple food crop for most of the countries in this region, Tunisia included, is barley.
METHODS
The present study was designed to investigate the sensitivity and tolerance of six distinct barley genotypes to aridity and salinity stresses in five different natural field environments by measuring their photosynthetic activity.
RESULTS AND DISCUSSION
The results revealed that tolerant genotypes were significantly less affected by these stress factors than sensitive genotypes. The genotypes that were more susceptible to salinity and aridity stress exhibited a significant decline in their photosynthetic activity. Additionally, the fluorescence yields in growth phases J, I, and P declined significantly in the order of humid environment (BEJ), semi-arid site (KAI), and arid environment (MED) and became more significant when salt stress was added through the use of saline water for irrigation. The stress adversely affected the quantum yield of primary photochemistry (φP0), the quantum yield of electron transport (φE0), and the efficiency by trapped excitation (ψ0) in the vulnerable barley genotypes. Moreover, the performance index (PI) of the photosystem II (PSII) was found to be the most distinguishing parameter among the genotypes tested. The PI of sensitive genotypes was adversely affected by aridity and salinity. The PI of ICARDA20 and Konouz decreased by approximately 18% and 33%, respectively, when irrigated with non-saline water. The reduction was even greater, reaching 39%, for both genotypes when irrigated with saline water. However, tolerant genotypes Souihli and Batini 100/1B were less impacted by these stress factors.The fluorescence study provided insights into the photosynthetic apparatus of barley genotypes under stress. It enabled reliable salinity tolerance screening. Furthermore, the study confirmed that the chlorophyll a fluorescence induction curve had an inflection point (step K) even before the onset of visible signs of stress, indicating physiological disturbances, making chlorophyll fluorescence an effective tool for identifying salinity tolerance in barley.
PubMed: 38863544
DOI: 10.3389/fpls.2024.1324388 -
Nature Reviews. Chemistry Jun 2024Electronic waste (e-waste) recycling is becoming a global concern owing to its immense quantity, hazardous character and the potential loss of valuable metals. The many... (Review)
Review
Electronic waste (e-waste) recycling is becoming a global concern owing to its immense quantity, hazardous character and the potential loss of valuable metals. The many processes involved in e-waste recycling stem from a mixture of physicochemical reactions, and understanding the principles of these reactions can lead to more efficient recycling methods. In this Review, we discuss the principles behind photochemistry, thermochemistry, mechanochemistry, electrochemistry and sonochemistry for metal recovery, polymer decomposition and pollutant elimination from e-waste. We also discuss how these processes induce or improve reaction rates, selectivity and controllability of e-waste recycling based on thermodynamics and kinetics, free radicals, chemical bond energy, electrical potential regulation and more. Lastly, key factors, limitations and suggestions for improvements of these physicochemical reactions for e-waste recycling are highlighted, wherein we also indicate possible research directions for the future.
PubMed: 38862738
DOI: 10.1038/s41570-024-00616-z -
Journal of Hazardous Materials Aug 2024Photochemical transformation is an important attenuation process for the non-steroidal anti-inflammatory drug naproxen (NPX) in both engineered and natural waters....
Photochemical transformation is an important attenuation process for the non-steroidal anti-inflammatory drug naproxen (NPX) in both engineered and natural waters. Herein, we investigated the photolysis of NPX in aqueous solution exposed to both ultraviolet (UV, 254 nm) and natural sunlight irradiation. Results show that N purging significantly promoted NPX photolysis under UV irradiation, suggesting the formation of excited triplet state (NPX*) as a critical transient. This inference was supported by benzophenone photosensitization and transient absorption spectra. Sunlight quantum yield of NPX was only one fourteenth of that under UV irradiation, suggesting the wavelength-dependence of NPX photochemistry. NPX* formed upon irradiation of NPX underwent photodecarboxylation leading to the formation of 2-(1-hydroxyethyl)-6-methoxynaphthalene (2HE6MN), 2-(1-hydroperoxyethyl)-6-methoxynaphthalene (2HPE6MN), and 2-acetyl-6-methoxynaphthalene (2A6MN). Notably, the conjugation and spin-orbit coupling effects of carbonyl make 2A6MN a potent triplet sensitizer, therefore promoting the photodegradation of the parent NPX. In hospital wastewater, the photolysis of NPX was influenced because the photoproduct 2A6MN and wastewater components could competitively absorb photons. Bioluminescence inhibition assay demonstrated that photoproducts of NPX exhibited higher toxicity than the parent compound. Results of this study provide new insights into the photochemical behaviors of NPX during UV treatment and in sunlit surface waters.
Topics: Naproxen; Photolysis; Ultraviolet Rays; Sunlight; Water Pollutants, Chemical; Anti-Inflammatory Agents, Non-Steroidal; Benzophenones; Photosensitizing Agents
PubMed: 38852251
DOI: 10.1016/j.jhazmat.2024.134841 -
Advanced Science (Weinheim,... Jun 2024The wavelength-by-wavelength resolved photoreactivity of two photo-caged carboxylic acids, i. e. 7-(diethylamino)-coumarin- and 3-perylene-modified substrates, is...
The wavelength-by-wavelength resolved photoreactivity of two photo-caged carboxylic acids, i. e. 7-(diethylamino)-coumarin- and 3-perylene-modified substrates, is investigated via photochemical action plots. The observed wavelength-dependent reactivity of the chromophores is contrasted with their absorption profile. The photochemical action plots reveal a remarkable mismatch between the maximum reactivity and the absorbance. Through the action plot data, the study is able to uncover photochemical reactivity maxima at longer and shorter wavelengths, where the molar absorptivity of the chromophores is strongly reduced. Finally, the laser experiments are translated to light emitting diode (LED) irradiation and show efficient visible-light-induced release in a near fully wavelength-orthogonal, sequence-independent fashion (λ = 405 nm, λ = 505 nm) with both chromophores in the same reaction solution. The herein pioneered wavelength orthogonal release systems open an avenue for releasing two different molecular cargos with visible light in a fully orthogonal fashion.
PubMed: 38852174
DOI: 10.1002/advs.202402011 -
Ecotoxicology and Environmental Safety Jul 2024Isoprenoid metabolism and its derivatives took part in photosynthesis, growth regulation, signal transduction, and plant defense to biotic and abiotic stresses. However,...
Isoprenoid metabolism and its derivatives took part in photosynthesis, growth regulation, signal transduction, and plant defense to biotic and abiotic stresses. However, how aluminum (Al) stress affects the isoprenoid metabolism and whether isoprenoid metabolism plays a vital role in the Citrus plants in coping with Al stress remain unclear. In this study, we reported that Al-treatment-induced alternation in the volatilization rate of monoterpenes (α-pinene, β-pinene, limonene, α-terpinene, γ-terpinene and 3-carene) and isoprene were different between Citrus sinensis (Al-tolerant) and C. grandis (Al-sensitive) leaves. The Al-induced decrease of CO assimilation, maximum quantum yield of primary PSII photochemistry (F/F), the lower contents of glucose and starch, and the lowered activities of enzymes involved in the mevalonic acid (MVA) pathway and 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway might account for the different volatilization rate of isoprenoids. Furthermore, the altered transcript levels of genes related to isoprenoid precursors and/or derivatives metabolism, such as geranyl diphosphate (GPP) synthase (GPPS) in GPP biosynthesis, geranylgeranyl diphosphate synthase (GGPPS), chlorophyll synthase (CHS) and GGPP reductase (GGPPR) in chlorophyll biosynthesis, limonene synthase (LS) and α-pinene synthase (APS) in limonene and α-pinene synthesis, respectively, might be responsible for the different contents of corresponding products in C. grandis and C. sinensis. Our data suggested that isoprenoid metabolism was involved in Al tolerance response in Citrus, and the alternation of some branches of isoprenoid metabolism could confer different Al-tolerance to Citrus species.
Topics: Aluminum; Terpenes; Citrus; Limonene; Photosynthesis; Bicyclic Monoterpenes; Plant Leaves; Stress, Physiological; Monoterpenes; Hemiterpenes; Cyclohexenes; Sugar Phosphates; Butadienes; Erythritol; Mevalonic Acid; Cyclohexane Monoterpenes; Citrus sinensis; Chlorophyll; Alkyl and Aryl Transferases; Volatilization
PubMed: 38850709
DOI: 10.1016/j.ecoenv.2024.116545