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Advanced energetic composites possess promising properties and wide-ranging applications in explosives and propellants. Nonetheless, most metal-based energetic composites present significant challenges due to surface oxidation and low-pressure output. This study introduces a facile in situ method to develop energetic composites Cutztr@AP through the intermolecular assembly of nitrogen-rich energetic coordination polymers and high-energy oxidant ammonium perchlorate (AP). Morphological analysis reveals the unique structure of Cutztr@AP, where Cutztr is distributed throughout the interior and surface of the AP particles. The nonisothermal thermodynamic analysis reveals a heat release of 2378.2 J g -1 for Cutztr@AP 2 , outperforming the Cutztr/AP 2 achieved through ultrasonic mixing (2000 J g -1 ). Notably, Cutztr@AP 2 exhibits promising combustion and pressure output performances, including a significantly shorter duration, a larger flame area, and higher pressure values. This novel and facile preparation technique and microstructure design approach holds significant promise for high-performance propellants, gas generators, and other related applications.

The presence of the acidic and weak ionic conductor polystyrenesulfonate (PSS) in poly(3,4-ethylenedioxythiophene:PSS (PEDOT:PSS) leads to degradation and limits the charge transfer within quantum dot light-emitting diodes (QLEDs). Two-step solvent treatment resulted in a 40% reduction of PSS, which could be attributed to ethylene glycol (EG) attenuating the ionic interactions between PSS and PEDOT via interacting with PSS through hydrogen bonding. Methanol dissolved the predominant PSS and EG from the surface. The redshift of the peak representing the symmetrical vibration of Cα═Cβ in the Raman spectrum confirmed the conformation of benzoid structure to quinoid structure after the surface treatment. This conformation was attributed to the extension of the conjugation length and the reduction of the energy barrier within the PEDOT chain. This resulted in the improved conductivity and charge hopping of the PEDOT:PSS, which was also proven using density functional theory (DFT) calculations. Reducing the insulating and acidic PSS improved the electroluminescence performance and extended the operational lifetime of the QLEDs. The tris(dimethylamino)phosphine-based InP QLEDs exhibited an external quantum efficiency (EQE) of 6.4%, that value is comparable to those of tris(trimethylsilyl)phosphine-based QLEDs, and operational lifetime (T 50 ) of 125.6 h.

M 5 C 4 T x MXenes represent the most recently discovered and least studied subfamily of out-of-plane ordered double transition metal carbides with 11 atomic layers, probably the thickest of all 2D materials. Molybdenum (Mo) and vanadium (V) in Mo 4 VC 4 T x offer multiple oxidation states, making this MXene potentially attractive for electrochemical energy storage applications. Herein, we evaluated the electrochemical properties of Mo 4 VC 4 T x free-standing thin films in acidic, basic, and neutral aqueous electrolytes and observed the highest gravimetric capacitance of 219 F g -1 at 2 mV s -1 in a 3 M H 2 SO 4 . Further, we investigated the intercalation states of four different cations (H + , Li + , Na + , and K + ) in MXenes through ab initio molecular dynamics (AIMD) simulation and used density functional theory (DFT) calculations to assess the charge storage mechanisms in different electrolytes. These studies show hydrated Li + , Na + , and K + ions forming an electric double layer (EDL) at the MXene surface as the primary charge storage mechanism. This work shows the promise of Mo 4 VC 4 T x MXene for energy storage in aqueous electrolytes.

A single-step hydrothermal method was utilized to grow ZnMoS 4 (ZMS) nanorods uniformly. Initially, [MoS 4 ] 2- and Zn 2+ ions interacted to create active nucleation centers, which then led to the formation of primary particles. These particles then underwent spontaneous aggregation and self-assembly on the nickel foam (NF) substrate, which served as a superior 3D interconnecting network template. This aggregation occurred nearly perpendicular to the NF and promoted the uniform growth of ZMS nanorods. The nanorods structure ensures efficient and rapid electrolyte accessibility and ion diffusion, resulting in an increased specific capacitance (Cs) of 2,116 Fg 1- (846.4 C g -1 ) at 1 A g -1 and maintaining about 90% of their capacitance after 10,000 cycles of galvanic charge-discharge (GCD). In a hybrid supercapacitor configuration, ZMS@NF//AC@NF achieved a peak specific power of 7.2 kW.kg -1 and a specific energy of 40.3 Wh.kg -1 . Remarkably, it preserved 93% of its initial capacitance after more than 20,000 cycles. These findings affirm the potential of binder-free ZMS nanorods as effective positive electrodes in advanced hybrid supercapacitors.

Drought is an inevitable environmental stress that drastically hampers the growth, productivity, and quality of food crops. Exogenous sodium nitroprusside and spermidine have decisive functions in the growth enhancement of plants; nevertheless, their specific role in mediating stress responses to improve drought tolerance in sunflowers at the reproductive stage (terminal drought) remains largely unknown. In the present study, we explored the positive effects of sodium nitroprusside and spermidine on physiological responses to increase in sunflower yield during periods of terminal drought. Initially, various doses (50, 100, 150, 200, 400 μM) for each sodium nitroprusside or spermidine were foliar sprayed to improve water content, chlorophylls, and biomass accumulation in sunflower seedlings under control (100% FC) and drought (60% FC) conditions. Optimized rates (100 μM for sodium nitroprusside) and (100 μM for spermidine) were further tested alone and in combination to assess drought tolerance potential and their ultimate impact on yield under drought stress. Drought exposure caused a marked reduction in relative water content (26%) and chlorophyll a (31%) and b (35%) contents; however, sodium nitroprusside and spermidine at 100 μM significantly improved the growth of sunflower (13%). Furthermore, combined use of sodium nitroprusside and spermidine at 100 + 100 μM markedly improved the achenes per head (16%), 1000-achene weight (14%), and ultimately grain (28%) and oil (21%) yields of sunflowers under drought stress. A strong association was found between the 1000-achene weight and the achene yield of sunflower. Hence, combined sodium nitroprusside and spermidine upregulate water balance and chlorophyll contents to increase sunflower yield under terminal drought., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

The high photoelectric conversion efficiency and low cost of perovskite solar cells (PSCs) have further inspired people's determination to push this technology toward industrialization. The high-quality perovskite films and high-efficiency and stable PSCs are the crucial factors. Ionic liquids have been proven to be an effective strategy for regulating high-quality perovskite films and high-performance PSCs. However, the regulation mechanism between ionic liquids and perovskites still needs further clarification. In this study, a novel sulfonic acid-functionalized ionic liquid, 1-butyl-3-methylimidazolium trifluoromethanesulfonate (BSO 3 HMImOTf), was used as an effective additive to regulate high-quality perovskite films and high-performance devices. Microscopic mechanism studies revealed strong interactions between BSO 3 HMImOTf and Pb 2+ ions as well as halogens in the perovskite. The perovskite film is effectively passivated with the controlled crystal growth, suppressed ion migration, facilitating to the greatly improved photovoltaic performance, and superior long-term stability. This article reveals the regulatory mechanism of sulfonic acid type ionic liquids through testing characterization and mechanism analysis, providing a new approach for the preparation of high-quality perovskite devices.

By dry crystallization, concentrations of unsaturated fatty acids and bioactive compounds can be increased in olein and super-olein fractions in vegetable oils. Among all sources of vegetable oils, safflower oil (SO) possesses the maximum linoleic acid content. To boost the industrial applications of SO, two variants were produced by single- and two-stage crystallization. This study aimed to determine the fatty acid compositions, phenolic compounds, phytosterols, and oxidative stability of fractionated olein (OF) and double-fractionated olein (DFO) produced by dry crystallization. For this, SO was cooled to -45 °C and filtered, the filtrate was denoted as single-fractionated olein (OF), and 40% of this section was taken for analytical purposes, while the remaining 60% was again cooled to -70 °C and filtered, and the filtrate was denoted as double-fractionated olein (DFO). Unfractionated safflower (SO) was used as a control, filled in amber glass bottles, and stored at 20-25 °C for 90 days. Fatty acid compositions and phytosterols were determined by gas chromatography-mass spectrometry (GC-MS). Phenolic compounds and induction periods were determined by high-performance liquid chromatography (HPLC) and Rancimat. GC-MS analysis revealed that the C18:2 contents of SO, OF, and DFO were 77.63 ± 0.82, 81.57 ± 0.44, and 89.26 ± 0.48 mg/100 g ( p < 0.05), respectively. The C18:1 contents of SO, OF, and DFO were 6.38 ± 0.19, 7.36 ± 0.24, and 9.74 ± 0.32 mg/100 g ( p < 0.05), respectively. HPLC analysis showed that phenolic compounds were concentrated in the low-melting-point fractions. In DFO, concentrations of tyrosol, rutin, vanillin, ferulic acid, and sinapic acid were 57.36 ± 0.12, 129.45 ± 0.38, 165.11 ± 0.55, 183.61 ± 0.15, 65.94 ± 0.11, and 221.75 ± 0.29 mg/100 g, respectively. In SO, concentrations of tyrosol, rutin, vanillin, ferulic acid, and sinapic acid were 24.79 ± 0.08, 78.93 ± 0.25, 115.67 ± 0.41, 34.89 ± 0.51, and 137.26 ± 0.08 mg/100 g, respectively. In OF, concentrations of tyrosol, rutin, vanillin, ferulic acid, and sinapic acid were 35.96 ± 0.20, 98.69 ± 0.64, 149.14 ± 0.13, 57.53 ± 0.74, and 188.28 ± 0.82 mg/100 g, respectively. The highest concentrations of brassicasterol, campesterol, stigmasterol, β-sitosterol, avenasterol, stigmastenol, and avenasterol were noted in DFO followed by OF and SO. The total antioxidant capacities of SO, OF, and DFO were 54.78 ± 0.12, 71.36 ± 0.58, and 86.44 ± 0.28%, respectively. After the end of the storage time, the peroxide values (POVs) of SO, OF, and DFO stored for 3 months were 0.68, 0.85, and 1.16 mequiv O 2 /kg, respectively, with no difference in the free fatty acid content., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

The emergence of antimicrobial resistance is an alarming global health concern and has stimulated the development of novel functional nanomaterials to combat multi-drug-resistant (MDR) bacteria. In this work, we demonstrate for the first time the synthesis and application of surfactin-coated silver nanoparticles as an efficient antibacterial and antibiofilm agent against the drug-resistant bacteria Pseudomonas aeruginosa for safe dermal applications. Our in vivo studies showed no significant superficial dermal irritation, edema, and erythema, while microscopic analysis revealed that surfactin-coated silver nanoparticles caused no pathological alterations at the applied concentrations. These results support the potential use of surfactin-coated silver nanoparticles against drug-resistant bacterial biofilm infections and in skin wound dressing applications.

Even with healthy foods, there is still a need to protect the functionality during processing. The stabilization and enrichment of fish oil (FO) extracted from fish fillets using solvent extraction might make this healthy oil more available. FO was stabilized by mixing it with chia seed oil (CSO) at 50:50 at room temperature. The antioxidant properties of the blends were evaluated using the total phenolic content (TPC), free radical scavenging activity (DPPH), ferric reducing antioxidant potential (FRAP), and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) activities with FO and CSO as controls. The blends of FO and CSO increased the oxidative stability, while FO was the most susceptible to degradation. The stability and bioactivity of antioxidants against environmental factors were improved by using encapsulation. Response surface methodology (RSM) was used to optimize spray-drying operating conditions for spray-dried microcapsules (SDMs). The independent variables were the inlet air temperature (IAT), which varied from 125 to 185 °C; wall material (WM) concentration, which varied from 5 to 25%; pump speed (PS), which varied from 3 to 7 mL/min; and needle speed (NS), which varied from 3 to 11 s. The results indicated that the maximum antioxidant activity of SDM was obtained at 140 °C IAT, 10% WM, 4 mL/min PS, and 5 s NS, while the minimum value was obtained at 170 °C IAT, 20% WM, 6 mL/min PS, and 9 s NS. The IAT had a significant effect on the antioxidant activities, and the stability of SDMs was increased. These SDMs can be used in the formulation of food matrices due to their therapeutic and nutritional properties., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

Polyphosphazenes are an inorganic molecular hybrid family with multifunctional properties due to their wide range of organic substitutes. This review intends to propose the basics of the synthetic chemistry of polyphosphazene, describing for researchers outside the field the basic knowledge required to design and prepare polyphosphazenes with desired properties. A special emphasis is placed on recent advances in chemical synthesis, which allow not only the synthesis of polyphosphazenes with controlled molecular weights and polydispersities but also the synthesis of novel branched designs and block copolymers. We also investigated the synthesis of polyphosphazenes using various functional materials. This review aims to assist researchers in synthesizing their specific polyphosphazene material with unique property combinations, with the hope of stimulating further research and even more innovative applications for these highly interesting multifaceted materials., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

Not only are new and novel materials sought for electrode material development, but safe and nontoxic materials are also highly being intensively investigated. Herein, we prepare ZnNiBO 3 (OH) (ZNBH), a modified and Be-free KBe 2 BO 3 F 2 (KBBF) family member as an effective electrode material. The novel ZNBH resembles the KBBF structure but with reinforced structure and bonding, in addition to well-incorporated conductive metals benefiting supercapacitor applications. The enhanced electronic properties of ZNBH are further studied by means of density functional theory calculations. The as-prepared ZNBH electrode material exhibits a specific capacity of 746 C g -1 at a current density of 1 A g -1 . A hybrid supercapacitor (HSC) device is fabricated and successfully illuminated multiple color LEDs. Interestingly, even after being subjected to long charge-discharge for 10 000 cycles, the ZNBH//AC HSC device retains 97.2% of its maximum capacity, indicating the practicality of ZNBH as an electrode material.

We reported a study on the preparation of bimetallic Ag-Cu nanoparticles (NPs) impregnated on PZS poly(cyclotriphosphazene- co -4,4'-sulfonyldiphenol) nanotubes via a facile and efficient reduction method. Herein, PZS nanotubes consisting of enriched hydroxyl groups are fabricated through an in situ template method, and then, fluctuating the amount ratios of Cu and Ag precursors, bimetallic NPs can be fabricated on readily prepared PZS nanotubes using NaBH 4 as a reductant, which results in a series of bimetallic catalysts having tunable catalytic activity. The characterization investigations of scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and Fourier transform infrared spectroscopy results show that Ag-Cu bimetallic NPs are well-dispersed, ultrasmall in size, and well-anchored on the surface of PZS nanotubes. In addition, to examine the catalytic activity and reusability of these nanocomposites, reduction of 4-nitrophenol to 4-aminophenol is utilized as a prototype reaction. The optimized Ag-Cu NPs with a copper ratio of 0.3% are well-stabilized by the organic-inorganic poly(cyclotriphosphazene- co -4,4'-sulfonyldiphenol) nanotubes. The obtained results show that bimetallic NPs have remarkably higher catalytic ability than that of their monometallic counterparts with maximum catalytic activity. These results are even better than those of noble metal-based bimetallic catalysts and pave the avenue to utilize the polyphosphazene polymer as a substrate material for highly effective bimetallic catalysts., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

Emulsion template-guided strategy has been used to produce porous architectures with exquisite structure, tailored morphology, and exclusive features for ubiquitous applications. Notwithstanding, the practical water remediation is often marred by their transport-limited behavior and fragility. To circumvent these conundrums, we prepared hierarchically porous poly(acrylic acid)-alumina nanocomposite beads by solidifying the droplets of emulsions jointly stabilized by the organic surfactants and alumina nanoparticles. By virtue of their positive charge, the alumina nanoparticles got entrapped within the poly(acrylic acid) scaffolds that excluded the risk of secondary contamination typically observed with conventional nanocomposites. Being amenable to surface modification, the carboxyl moieties of the beaded polymer were further exploited to covalently tether branched polyethylenimine throughout the exterior and interior surface of the porous matrix via a grafting-to approach. The macropores expedite an active fluid flow and easier adsorbate transport throughout the functionalized nanocomposites whose overall higher density of positive charge over a certain pH range electrostatically attracts and effectively adsorbs the negatively charged Cr(VI) complexes and anionic congo red ions/molecules from water. This proof-of-concept synthetic approach and postsynthetic modification offer an improved mechanical robustness to these macrosized multifunctional nanocomposite beads for their easier processing, thereby paving the way for the point-of-use water purification technology development.

Oxygen evolution reaction (OER) is a bottleneck process in the water-splitting module for sustainable and clean energy production. Transition metal-based electrocatalysts can be effective as water-splitting catalytic materials because of their appropriate redox properties and natural abundance, but the slow kinetics because of strong adsorption and consequently slow desorption of intermediates on the active sites of catalysts severely hamper the dynamics of the released molecular oxygen and thus remains a formidable challenge. Herein, we report the development of structurally and surface-modified PA-Gd-Ni(OH) 2 Cl (partially alkylated gadolinium-doped nickel oxychloride) nanoclusters (NCs, size ≤ 3 nm) for enhanced and stable OER catalysis at low overpotential and high turnover frequency. The ameliorated catalytic performance was achieved by controlling the surface coverage of these NCs with hydrophobic ligands and through the incorporation of electronegative atoms to facilitate easy adsorption/desorption of intermediates on the catalyst surface, thus improving the liberation of O 2 . Such a surface and structural modification and uniform distribution at the nanoscale length are indeed worth considering to selectively tune the catalytic potential and further modernize the electrode materials for the challenging OER process.

We prepared novel flame retardants with concurrent excellent smoke-suppression properties based on lignin biomass modified by functional groups containing N and P. Each lignin-based flame retardant (Lig) was quantitatively added to a fixed amount of epoxy resin (EP), to make a Lig/EP composite. The best flame retardancy was achieved by a Lig-F/EP composite with elevated P content, achieving a V-0 rating of the UL-94 test and exhibiting excellent smoke suppression, with substantial reduction of total heat release and smoke production (by 46.6 and 53%, respectively). In this work, we characterized the flame retardants and the retardant/EP composites, evaluated their performances, and proposed the mechanisms of flame retardancy and smoke suppression. The charring layer of the combustion residual was analyzed using SEM and Raman spectroscopy to support the proposed mechanisms. Our work provides a feasible method for lignin modification and applications of new lignin-based flame retardants., Competing Interests: The authors declare no competing financial interest., (© 2020 American Chemical Society.)

Neisseria gonorrhoeae is among the most multidrug-resistant bacteria in circulation today, and new treatments are urgently needed. In this work, we demonstrate the ability of 5-mercapto-2-nitrobenzoic acid-coated silver nanoclusters (MNBA-AgNCs) to kill strains of Neisseria gonorrhoeae . Using an in vitro bactericidal assay, MNBA-AgNCs had been found to show significantly higher anti-gonococcal bioactivity than the antibiotics ceftriaxone and azithromycin and silver nitrate. These nanoclusters were effective against both planktonic bacteria and a gonococcal infection of human cell cultures in vitro. Treatment of human cells in vitro with MNBA-AgNCs did not induce significant release of lactate dehydrogenase, suggesting minimal cytotoxicity to eukaryotic cells. Our results suggest that MNBA-AgNCs hold great potential for topical treatment of localized gonorrhoeae.

Emulsion templating has emerged as a cutting-edge technique to prepare a wide array of porous polymer-metal nanocomposites with intriguing properties. Using this strategy, we set out to prepare novel hierarchically porous poly(vinylsulfonic acid) beads, which were then used for the in situ production of silver nanoparticles to obtain poly(vinylsulfonic acid)-Ag nanocomposite beads via a facile approach. Owing to their multimodal macro-meso-/microporosity that accounts for their decent BET surface areas (170.75-197.74 m 2 /g) and easier mass diffusion and transport together with the synergistic benefits of very small silver nanoparticles (down to ∼3.77 nm), the nanocomposite beads are found effective to remove Hg(II) and RhB and to kill Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria. The adsorption capacities (167.98-190.58 mg/g) of these materials for Hg(II) surpass some recently reported benchmark materials. The larger size (1.56 ± 0.20-1.50 ± 0.14 mm) of the beads that helps favor the handling and subsequent recovery for recycling is also very useful to further broaden the horizons of these materials to develop decentralized water treatment systems.

Tainting of waterbodies with noxious industrial waste is the gravest environmental concern of the day that continues to wreak inevitable havoc on human health. To cleanup these hard-to-remove life-threatening water contaminants, we have prepared hierarchically porous poly(acrylic acid) beads by emulsion templating. These emulsion-templated macroporous polymer beads not only mediate the synthesis of Fe 3 O 4 nanoparticles inside their porous network using a coprecipitation approach but, in turn, create diverse anchoring sites to immobilize an additional poly(acrylic acid) active layer onto the nanocomposite beads. These post-synthetically modified nanocomposite beads with macropores and abundant acrylic acid moieties offer the ready mass transfer and fair advantage of relatively higher overall negative charge to efficiently adsorb lead [Pb(II)] and crystal violet with impressive performance-even superior to many of the materials explored in this regard so far. Furthermore, the strong entanglement of nanoparticles in the porous polymeric scaffolds tackles the curb of trade-off between all-round effective remediation and secondary pollution and the millimeter size eases their processing and recovery during the adsorption tests, thereby making these materials practically worthwhile.

Bacterial multidrug resistance (MDR) is a serious healthcare issue caused by the long-term subtherapeutic clinical treatment of infectious diseases. Nanoscale engineering of metal nanoparticles has great potential to address this issue by tuning the nano-bio interface to target bacteria. Herein, we report the use of branched polyethylenimine-functionalized silver nanoclusters (bPEI-Ag NCs) to selectively kill MDR pathogenic bacteria by combining the antimicrobial activity of silver with the selective toxicity of bPEI toward bacteria. The minimum inhibitory concentration of bPEI-Ag NCs was determined against 12 uropathogenic MDR strains and found to be 10- to 15-fold lower than that of PEI and 2- to 3-fold lower than that of AgNO 3 alone. Cell viability and hemolysis assays demonstrated the biocompatibility of bPEI-Ag NCs with human fibroblasts and red blood cells, with selective toxicity against MDR bacteria., Competing Interests: The authors declare no competing financial interest.

Water, the driver of nature, has always been polluted by the blind hurling of highly toxic contaminants, but human-friendly science has continuously been presenting better avenues to help solve these challenging issues. In this connection, the present study introduces novel nanocomposites composed of emulsion-templated hierarchically porous poly(1-vinylimidazole) beads loaded with the silver nanoparticles generated via an in situ approach. These nanocomposites have been thoroughly characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, Brunauer-Emmett-Teller, and field emission scanning electron microscopy. The appropriate surface chemistry, good thermal stability, swelling behavior, porosity, and nanodimensions contributed to achieve very good performance in water treatment. Owing to their easier handling and separation, these novel nanocomposites are highly efficient to remove arsenic and eriochrome black T with decent adsorption capacities in addition to the inactivation and killing of Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria.

Groundwater is the major source of drinking water for people living in rural areas of India. Pollutants such as fluoride in groundwater may be present in much higher concentration than the permissible limit. Fluoride does not give any visible coloration to water, and hence, no effort is made to remove or reduce the concentration of this chemical present in drinking water. This may lead to a serious health hazard for those people taking groundwater as their primary source of drinking water. Sophisticated laboratory grade tools such as ion selective electrodes (ISE) and portable spectrophotometers are commercially available for in-field detection of fluoride level in drinking water. However, such tools are generally expensive and require expertise to handle. In this paper, we demonstrate the working of a low cost, robust, and field portable smartphone platform fluoride sensor that can detect and analyze fluoride concentration level in drinking water. For development of the proposed sensor, we utilize the ambient light sensor (ALS) of the smartphone as light intensity detector and its LED flash light as an optical source. An android application "FSense" has been developed which can detect and analyze the fluoride concentration level in water samples. The custom developed application can be used for sharing of in-field sensing data from any remote location to the central water quality monitoring station. We envision that the proposed sensing technique could be useful for initiating a fluoride removal program undertaken by governmental and nongovernmental organizations here in India.

Subtle changes in the monolayer structure of nanoparticles (NPs) influence the interfacial behavior of both NPs and NP-protein conjugates. In this study, we use a series of monolayer-protected gold NPs to explore the role of particle hydrophobicity on their dynamic behavior at the toluene-water interface. Using dynamic surface tension measurements, we observed a linear decrease in the meso-equilibrium surface tension (γ) and faster dynamics as the hydrophobicity of the ligands increases. Further modulation of γ is observed for the corresponding NP-protein complexes at the charge-neutralization point., (© 2011 American Chemical Society)

Homeobox gene HOXB9 is a critical player in development of mammary gland and sternum and in regulation of renin which is closely linked with blood pressure control. Our studies demonstrated that HOXB9 gene is transcriptionally regulated by estrogen (E2). HOXB9 promoter contains several estrogen-response elements (ERE). Reporter assay based experiments demonstrated that HOXB9 promoter EREs are estrogen responsive. Estrogen receptors ERα and ERβ are essential for E2-mediated transcriptional activation of HOXB9. Chromatin immunoprecipitation assay demonstrated that ERs bind to HOXB9 EREs as a function of E2. Similarly, histone methylases MLL1 and MLL3 also bind to HOXB9 EREs and play a critical role in E2-mediated transcriptional activation of HOXB9. Overall, our studies demonstrated that HOXB9 is an E2-responsive gene and ERs coordinate with MLL1 and MLL3 in E2-mediated transcriptional regulation of HOXB9.

Functionalized diarylcarbenes are excellent reactive intermediates suitable for the direct surface modification of organic polymers, and these may be used to introduce urea and thiourea functions onto polystyrene at loading levels of up to 2.3 x 10(13) molecules/cm(2). These functions are capable of the reversible binding and release of peroxide at loading levels of up to 0.6 mmol/g and give polymers that display biocidal activity against a spectrum of gram-positive and gram-negative bacteria.

Keto-enol tautomerization of 3-formylacetylacetone has been studied by NMR spectroscopy, ab initio, and DFT calculations in the gas phase and continuum solvation. By employing very low temperatures in a freonic solvent, tautomeric and conformational equilibria in the slow exchange regime were analyzed in detail. The beta-tricarbonyl compound always adopts a structure with an enolized keto group irrespective of an increasing dielectric constant of the solvent when lowering the temperature of the Freon mixture. This experimentally observed tautomeric distribution of 3-formylacetylacetone is correctly reproduced by continuum solvated DFT calculations.

The solution-phase assembly of 15 nm gold particles into relatively linear chains of fairly controllable length of up to 1 mum is achieved by molecularly linking nanoparticles with alkanedithiols. This step-growth process can be controlled to prepare dimers, oligomers, and polymer-like gold nanoparticle chains by varying the ratio of alkanedithiols to nanoparticles. These size-controlled, relatively linear aggregates remain suspended in ethanol solution without precipitation for several weeks to months depending on the chain length. The resulting soluble nanoparticle assemblies were characterized by a variety of techniques including cryogenic transmission electron microscopy. The surface plasmon coupling of regularly spaced gold nanoparticles in these chains could be of interest in the fabrication of optical waveguide and nanoelectronic systems.

BACE-1 inhibition has the potential to provide a disease-modifying therapy for the treatment of Alzheimer's disease. Optimization of a first generation of BACE-1 inhibitors led to the discovery of novel hydroxyethylamines (HEAs) bearing a tricyclic nonprime side. These derivatives have nanomolar cell potency and are orally bioavailable.

Functionalized dibenzo[b,d]pyran-6-ones were prepared by formal [3 + 3] cyclization of 1,3-bis(silyl enol ethers) with 3-silyloxy-2-en-1-ones or 1,1-diacetylcyclopropane to give functionalized salicylates, Suzuki cross-coupling reactions of the corresponding triflates, and subsequent BBr3-mediated lactonization. A second approach to dibenzo[b,d]pyran-6-ones relies on the [3 + 3] cyclization of 1,3-bis(silyl enol ethers) with 1-(2-methoxyphenyl)-1-(trimethylsilyloxy)alk-1-en-3-ones and subsequent BBr3-mediated lactonization.

A new methodology is described for the one-step aqueous preparation of highly monodisperse gold nanoparticles with diameters below 5 nm using thioether- and thiol-functionalized polymer ligands. The particle size and size distribution was controlled by subtle variation of the polymer structure. It was shown that poly(acrylic acid) (PAA) and poly(methacrylic acid) (PMAA) were the most effective stabilizing polymers in the group studied and that relatively low molar mass ligands (approximately 2500 g/mol) gave rise to the narrowest particle size distributions. Particle uniformity and colloidal stability to changes in ionic strength and pH were strongly affected by the hydrophobicity of the ligand end group. "Multidentate" thiol-terminated ligands were produced by employing dithiols and tetrathiols as chain-transfer agents, and these ligands gave rise to particles with unprecedented control over particle size and enhanced colloidal stability. It was found throughout that dynamic light scattering (DLS) is a very useful corroboratory technique for characterization of these gold nanoparticles in addition to optical spectroscopy and TEM.

Stable suspensions of size-uniform spherical assemblies of 5-8 nm gold colloids in toluene are readily obtained by cross linking the colloidal particles using alkanedithiols within a defined range of gold-dithiol molar ratios. The assemblies are very stable and remain suspended in toluene for several months without significant aggregation. These porous gold spheres can be further organized into hierarchically assembled relatively linear chains by the addition of ethanol.

We report here a simple one-step protocol for the preparation of near-monodisperse gold hydrosols in the small size regime (<5 nm). The particle size can be controlled by varying the concentration of the stabilizing polymer, which can be readily displaced by thiol ligands to yield monolayer protected clusters of the usual type.

Based on protein folding considerations, a pentapeptide ligand, CALNN, which converts citrate-stabilized gold nanoparticles into extremely stable, water-soluble gold nanoparticles with some chemical properties analogous to those of proteins, has been designed. These peptide-capped gold nanoparticles can be freeze-dried and stored as powders that can be subsequently redissolved to yield stable aqueous dispersions. Filtration, size-exclusion chromatography, ion-exchange chromatography, electrophoresis, and centrifugation can be applied to these particles. The effect of 58 different peptide sequences on the electrolyte-induced aggregation of the nanoparticles was studied. The stabilities conferred by these peptide ligands depended on their length, hydrophobicity, and charge and in some cases resulted in further improved stability compared with CALNN, yielding detailed design criteria for peptide capping ligands. A simple strategy for the introduction of recognition groups is proposed and demonstrated with biotin and Strep-tag II.

A highly functionalized four-carbon unit, 4-hydroxyalk-2-en-1-one functionality [R2CH(OH)CH=CHCOR1], was conveniently prepared by a reaction of an aldehyde (R2CH2CHO) with a 1-(arylsulfinyl)alkan-2-one [ArS(O)CH2COR1] in the presence of diethylamine (Knoevenagel condition). Other functional groups, such as carbonyl and hydroxy groups, in both of the alkyl chains (R1, R2) did not prevent this reaction. This reaction was used to conveniently prepare (+/-)-(11E)-13-hydroxy-10-oxooctadec-11-enoic acid (14), having cytotoxic activity, and its analogues from undec-10-enoic acid in good yield.

An investigation into the anion dependence of the network-forming ability of metal complexes of hexamethylenebis(acetamide), CH3CONH(CH2)6NHCOCH3 (HMBA), has resulted in the X-ray characterization of the compounds [Co(HMBA)3][Co(NCS)4], 1, [Nd(HMBA)3][Nd(NO3)6].2CHCl3, 2, [Co(HMBA)3][HgCl4], 3, and [Mn(HMBA)3][HgBr4].3CHCl3, 4. The structures of compounds 1, 3, and 4 each comprise cationic frameworks formed by the bridging action of HMBA ligands binding octahedrally to the cobalt or manganese centers and, in the cases of 3 and 4, the formation of tetrahedral HgX4(2-) anions by transfer of the respective halide ions from Co or Mn to Hg. Complete anion (NO3-) transfer between Nd centers is also a key factor in the structure of 2, which forms a cationic 3-D network of HMBA-bridged octahedrally coordinated Nd centers with occluded [Nd(NO3)6]3- anions. These types of inter-metal-anion transfer, with consequent complex counteranion formation, appear to facilitate the network-forming ability of the metal-HMBA cationic arrays.

The amyloid precursor protein (APP) is proteolytically processed predominantly by alpha-secretase to release the ectodomain (sAPPalpha). In this study, we have addressed the cellular location of the constitutive alpha-secretase cleavage of endogenous APP in a neuronal cell line. Incubation of the neuroblastoma cell line IMR32 at 20 degrees C prevented the secretion into the medium of soluble wild-type APP cleaved by alpha-secretase as revealed by both immunoelectrophoretic blot analysis with a site-specific antibody and immunoprecipitation following metabolic labeling of the cells. No sAPPalpha was detected in the cell lysates following incubation of the cells at 20 degrees C, indicating that alpha-secretase does not cleave APP in the secretory pathway prior to or within the trans-Golgi network. Parallel studies using an antibody that recognizes specifically the neoepitope revealed on soluble APP cleaved by beta-secretase indicated that this enzyme was acting intracellularly. alpha-Secretase is a zinc metalloproteinase susceptible to inhibition by hydroxamate-based compounds such as batimastat [Parvathy, S., et al. (1998) Biochemistry 37, 1680-1685]. Incubation of the cells with a cell-impermeant, biotinylated hydroxamate inhibitor inhibited the release of sAPPalpha by >92%, indicating that alpha-secretase is cleaving APP almost exclusively at the cell surface. The observation that alpha-secretase cleaves APP at the cell surface, while beta-secretase can act earlier in the secretory pathway within the neuronal cell line indicates that there must be strict control mechanisms in place to ensure that APP is normally cleaved primarily by alpha-secretase in the nonamyloidogenic pathway to produce the neuroprotective sAPPalpha.

Bis(amides) of the type CH(3)CONH(CH(2))(n)()NHCOCH(3) (n = 2, 4, or 6) react with a range of manganese(II) and cobalt(II) salts to produce polymeric "framework" arrays, five of which have been studied by X-ray crystallography. Hexamethylenebis(acetamide) (HMBA) forms the compound [Co(HMBA)(3)](CoCl(4)).2EtOH in which the HMBA molecules bridge the metal centers, binding octahedrally via the oxygen atoms of the amide groups and forming cationic arrays of large rhomboidal "boxes" containing tetrahedral CoCl(4)(2-) ions. The butylenebis(acetamide) (BBA) complex [Co(BBA)(3)]Br(2) forms a sheet cationic network, but in this case, the counteranions are simple bromide ions. The ethylenebis(acetamide) (EBA) complex [Co(EBA)(2)(H(2)O)(2)]Br(2) comprises trans-octahedral [Co(O-amide)(4)(H(2)O)(2)](2+) units interlinked by the bridging action of the EBA ligands to form sheet arrays, with simple bromide counterions. From the reaction of HMBA with manganese(II) bromide two crystalline forms were obtained, [Mn(HMBA)(3)](MnBr(4)).2EtOH, with a structure similar to [Co(HMBA)(3)](CoCl(4)).2EtOH, and a solvent-free form, [Mn(HMBA)(3)](MnBr(4)), comprising a cationic sheet array. The preparations of several other transition-metal complexes with these ligands are reported together with relevant spectroscopic data.

The 4 kDa beta-amyloid peptide that forms the amyloid fibrils in the brain parenchyma of Alzheimer's disease patients is derived from the larger integral membrane protein, the amyloid precursor protein. In the nonamyloidogenic pathway, alpha-secretase cleaves the amyloid precursor protein within the beta-amyloid domain, releasing an extracellular portion and thereby preventing deposition of the intact amyloidogenic peptide. The release of the amyloid precursor protein from both SH-SY5Y and IMR-32 neuronal cells by alpha-secretase was blocked by batimastat and other related synthetic hydroxamic acid-based zinc metalloprotease inhibitors, but not by the structurally unrelated zinc metalloprotease inhibitors enalaprilat and phosphoramidon. Batimastat inhibited the release of the amyloid precursor protein from both cell lines with an I50 value of 3 microM. Removal of the thienothiomethyl substituent adjacent to the hydroxamic acid moiety or the substitution of the P2' substituent decreased the inhibitory potency of batimastat toward alpha-secretase. In the SH-SY5Y cells, both the basal and the carbachol-stimulated release of the amyloid precursor protein were blocked by batimastat. In contrast, neither the level of full-length amyloid precursor protein nor its cleavage by beta-secretase were inhibited by any of the zinc metalloprotease inhibitors examined. In transfected IMR-32 cells, the release of both the amyloid precursor protein and angiotensin converting enzyme was inhibited by batimastat, marimastat, and BB2116 with I50 values in the low micromolar range, while batimastat and BB2116 inhibited the release of both proteins from HUVECs. The profile of inhibition of alpha-secretase by batimastat and structurally related compounds is identical with that observed with the angiotensin converting enzyme secretase suggesting that the two are closely related zinc metalloproteases.