Photochemically-Driven CO2 Release Using a Metastable-State Photoacid for Energy Efficient Direct Air Capture

One of the grand challenges underlying current direct air capture (DAC) technologies relates to the intensive energy cost for sorbent regeneration and CO₂ release, making the massive scale (GtCO₂/year) deployment required to have a positive impact on climate change economically unfeasible. This challenge underscores the critical need to develop new DAC processes with substantially reduced regeneration energies. Here, we report a photochemically-driven approach for CO₂ release by exploiting the unique properties of an indazole metastable-state photoacid (mPAH). Our measurements on simulated and amino acid-based DAC systems revealed the potential of mPAH to be used for CO₂ release cycles by regulating pH changes and associated isomers driven by light. Upon irradiating with moderate intensity light, a ≈55 % and ≈68 % to ≈78 % conversion of total inorganic carbon to CO₂ was found for the simulated and amino acid-based DAC systems, respectively. Our results confirm the feasibility of on-demand CO₂ release under ambient conditions using light instead of heat, thereby providing an energy efficient pathway for the regeneration of DAC sorbents.     

A Conductive polylactic acid/polyaniline porous scaffold via freeze extraction for potential biomedical applications

This paper reports for the first time a simple yet effective method for fabricating a conductive and highly porous scaffold material made up of polylactic acid (PLA) and conducting polyaniline (PANI). The electrical percolation state was successfully obtained at 3 wt% of PANI inclusions and reached a conductivity level of useable tissue engineering applications at 4 wt%. In addition, preliminary bioactivity test results indicated that the protonating agent could form a chelate at the scaffold surface leading to good in-vitro apatite forming ability during biomimetic immersion. This new conductive scaffold has potential as a suitable biomedical material that requires electrical conductivity.     

Simultaneous lipidomic analysis of three families of bioactive lipid mediators leukotrienes, resolvins, protectins and related hydroxy-fatty acids by liquid chromatography/electrospray ionisation tandem mass spectrometry

Bioactive lipid mediators derived from polyunsaturated fatty acids (PUFA) exhibit a range of tissue- and cell-specific activities in many physiological and pathological processes. Electrospray ionisation tandem mass spectrometry coupled to liquid chromatography (LC/ESI-MS/MS) is a sensitive, versatile analytical methodology for the qualitative and quantitative analysis of lipid mediators. Here we present an LC/ESI-MS/MS assay for the simultaneous analysis of twenty mono- and poly-hydroxy-fatty acid derivatives of linoleic, arachidonic, eicosapentaenoic and docosahexaenoic acids. The assay was linear over the concentration range 1-100 pg/microL, whilst the limits of detection and quantitation were 10-20 and 20-50 pg, respectively. The recovery of the extraction methodology varied from 76-122% depending on the metabolite. This system is useful for profiling a range of biochemically related potent mediators including the newly discovered resolvins and protectins, and their precursor hydroxyeicosapentaenoic and hydroxydocosahexaenoic acids, and, consequently, advance our understanding of the role of PUFA in health and disease.     

Alternating iodonium-mediated reaction cascades giving indole- and quinoline-containing polycycles

A simple two-step convergent protocol gives direct access to synthetic intermediate A from ortho-iodoanilines. Intermediate A can be treated with NIS in CH2Cl2 to induce novel iodonium mediated domino reaction cascade, which provides direct access to ring-fused indole compounds B. Simply by changing the reaction conditions, this protocol can be directed down an alternative domino reaction cascade to give various ring fused quinoline compounds C.     

Renal replacement lipomatosis: MR findings in one case

Replacement lipomatosis of the kidney is the result of severe atrophy or destruction of the renal parenchyma, often caused by calculous disease with secondary marked proliferation of renal sinus, renal hilus, and perirenal fatty tissue. Different diagnostic tools have been used to define this entity, with ultrasonography (US), i.v. pyelography (IVP) and computed tomography (CT) used most commonly. We report MR urography and MR appearance of replacement lipomatosis in a 38-year-old man. We think that it combines the advantages of IVP, US and CT.     

AFM substantiation of the fracture behavior and mechanical properties of sol–gel derived silica packed epoxy networks

Silica packed epoxy networks are prepared in two steps via in situ, solvent free sol–gel processing of tetraethoxysilane in liquid epoxy monomer and curing the mixture with a flexible diamine afterwards. The influence of filler content and processing conditions on the mechanical properties and the fracture behavior is studied by means of the static mechanical analysis and AFM characterization of the pristine and the fractured polymer surfaces, and a mechanism to enhance polymer strength and toughness is proposed. The in–situ evolution and packing of silica nanostructures into epoxy networks influences the overall morphology and performance of polymers under high stress. It is found that smaller silica domains distributed at the molecular level cause efficient crack distribution by absorbing energy and thus improve the strength and toughness of silica packed epoxy polymers.     

Micelle directed synthesis of (C19H42N)4H3(PW11O39) nanoparticles and their catalytic efficiency for oxidative degradation of azo dye

The nanoparticles of monovacant lacunary keggin-type polyoxometalate (C₁₉H₄₂N)₄H₃(PW₁₁O₃₉) has been successfully synthesized by Micelle Directed Method using hexadecyltrimthyl ammonium bromide (CTAB) as a template. Non-ionic copolymer Pluronic F127 was used as a capping agent that helps in formation of nanoparticles by preventing the aggregation during the coating of H₃(PW₁₁O₃₉)^4- onto the counter ion (C₁₉H₄₂N)⁺. The synthesized material was characterized by Scanning electron microscope (SEM), TGA, DSC and FT-IR techniques. SEM images indicated that (C₁₉H₄₂N)₄H₃(PW₁₁O₃₉) nanoparticles possess spherical structure. FTIR results revealed that the structural integrity of monovacant lacunary keggin-type polyoxometalates (POM) was not affected when reducing the size. TGA–DSC results showed that the material was thermally stable (with 37 % weight loss) and POM encapsulates CTAB. The efficiency of synthesized material was checked by applying it as a catalyst for the oxidation of toxic mordant yellow dye i.e., potentially hazardous and non-biodegradable azo dye. The (C₁₉H₄₂N)₄H₃(PW₁₁O₃₉) nanoparticles gave 96 % dye degradation in 60 min at 60 °C temperature. Moreover, on recycling POM nanoparticles demonstrate 92 % oxidative degradation of mordant yellow dye.     

Pulsed supersonic beams with nucleobases

The dissolution of the primary nucleobases in supercritical fluids has been investigated using pulsed molecular beam mass spectrometry. Due to the low critical temperatures of ethylene and carbon dioxide, their adiabatic jet expansion permits transferring thermally sensitive solutes into the gas phase. This feature is particularly attractive for pharmaceutical and biomedical applications. In this study, adenine, guanine, cytosine, thymine, and uracil have been dissolved in supercritical ethylene with a few percent of ethanol as cosolvent. At source temperatures of 313?K, these solutions have been expanded from supercritical pressures into high vacuum using a customized pulsed nozzle. A mass spectrometer was used to monitor the relative amounts of solute, solvent, and cosolvent in the supersonic beam. The results suggest a paramount influence of the cosolvent.     

Repeated dose 28-days oral toxicity study of Carica papaya L. leaf extract in Sprague Dawley rats

Carica papaya L. leaves have been used in ethnomedicine for the treatment of fevers and cancers. Despite its benefits, very few studies on their potential toxicity have been described. The aim of the present study was to characterize the chemical composition of the leaf extract from 'Sekaki' C. papaya cultivar by UPLC-TripleTOF-ESI-MS and to investigate the sub-acute oral toxicity in Sprague Dawley rats at doses of 0.01, 0.14 and 2 g/kg by examining the general behavior, clinical signs, hematological parameters, serum biochemistry and histopathology changes. A total of twelve compounds consisting of one piperidine alkaloid, two organic acids, six malic acid derivatives, and four flavonol glycosides were characterized or tentatively identified in the C. papaya leaf extract. In the sub-acute study, the C. papaya extract did not cause mortality nor were treatment-related changes in body weight, food intake, water level, and hematological parameters observed between treatment and control groups. Some biochemical parameters such as the total protein, HDL-cholesterol, AST, ALT and ALP were elevated in a non-dose dependent manner. Histopathological examination of all organs including liver did not reveal morphological alteration. Other parameters showed non-significant differences between treatment and control groups. The present results suggest that C. papaya leaf extract at a dose up to fourteen times the levels employed in practical use in traditional medicine in Malaysia could be considered safe as a medicinal agent.