Building Blocks and COFs Formed in Concert—Three-Component Synthesis of Pyrene-Fused Azaacene Covalent Organic Framework in the Bulk and as Films

A three-component synthesis methodology is described for the formation of covalent organic frameworks (COFs) containing extended aromatics. Notably, this approach enables synthesis of the building blocks and COF along parallel reaction landscapes, on a similar timeframe. The use of fragmental building block components, namely pyrene dione diboronic acid as aggregation-inducing COF precursor and the diamines o-phenylenediamine (Ph), 2,3-diaminonaphthalene (Naph), or (1R,2R)-(+)-1,2-diphenylethylenediamine (2Ph) as extending functionalization units in conjunction with 2,3,6,7,10,11-hexahydroxytriphenylene, resulted in the formation of the corresponding pyrene-fused azaacene, i.e., Aza-COF series with full conversion of the dione moiety, long-range order, and high surface area. In addition, the novel three-component synthesis was successfully applied to produce highly crystalline, oriented thin films of the Aza-COFs with nanostructured surfaces on various substrates. The Aza-COFs exhibit light absorption maxima in the blue spectral region, and each Aza-COF presents a distinct photoluminescence profile. Transient absorption measurements of Aza-Ph- and Aza-Naph-COFs suggest ultrafast relaxation dynamics of excited-states within these COFs.     

Spleen SORT LNP Generated in situ CAR T Cells Extend Survival in a Mouse Model of Lymphoreplete B Cell Lymphoma

Chimeric Antigen Receptor (CAR) T cell immunotherapy is revolutionizing treatment for patients suffering from B-cell lymphoma (BL). However, the current method of CAR T cell production is complicated and expensive, requiring collection of patient blood to enrich the T cell population, ex vivo engineering/activation, and quality assessment before the patient can receive the treatment. Herein we leverage Spleen Selective ORgan Targeted (SORT) Lipid Nanoparticles (LNPs) to produce CAR T cells in situ and bypass the extensive and laborious process currently used. Optimized Spleen SORT LNPs containing 10 % 18 : 1 PA transfected CD3+, CD8+, and CD4+ T cells in wild-type mice. Spleen SORT LNPs delivered Cre recombinase mRNA and CAR encoding mRNA to T cells in reporter mice and in a lymphoreplete B cell lymphoma model (respectively) after intravenous injection without the need for active targeting ligands. Moreover, in situ CAR T cells increased the overall survival of mice with a less aggressive form of B cell lymphoma. In addition, in situ transfected CAR T cells reduced tumor metastasis to the liver by increasing tumor infiltrating lymphocytes. Overall, these results offer a promising alternative method for CAR T cell production with pre-clinical potential to treat hematological malignancies.     

Sensitive and Selective Voltammetric Determination of Ciprofloxacin Using Screen-printed Electrodes Modified with Carbon Black and Magnetic-molecularly Imprinted Polymer

This work reports the construction of screen-printed electrode (SPE) modified with carbon black (CB) and magnetic Fe₃O₄ nanoparticles coated with molecularly imprinted polymer (mag@MIP) based on an alternative low-cost approach. The proposed device was used for the sensitive and selective voltammetric determination of the antibiotic ciprofloxacin. The results obtained from cyclic voltammetry pointed to the improvement of the SPE response toward the irreversible oxidation of ciprofloxacin after the modification of the electrode surface with CB-based film and the magnetic preconcentration of mag@MIP containing adsorbed ciprofloxacin molecules. Compared to the non-molecularly imprinted sensor (mag@NIP), the presence of cavities selective for ciprofloxacin recognition in the mag@MIP nanoparticles accounted for the improvement in analytical signal of the molecularly imprinted sensor. The application of differential pulse voltammetry for ciprofloxacin determination yielded a linear response in the concentration range of 0.5 to 7.0 μmol L⁻¹. The repeatability and interference tests results showed that the proposed electrochemical sensor has good measurement accuracy and selectivity. The proposed device was applied for the voltammetric determination of ciprofloxacin in river water and synthetic urine samples, where recovery rates close to 100 % were recorded for all the samples. The quantification data obtained from the application of the proposed voltammetric method were quite consistent with those of the HPLC reference method.     

Challenges in distinguishing superexchange and hopping mechanisms of intramolecular charge transfer through fluorene oligomers

The temperature dependence of intramolecular charge separation in a series of donor-bridge-acceptor molecules having phenothiazine (PTZ) donors, 2,7-oligofluorene FL(n) (n = 1-4) bridges, and perylene-3,4:9,10-bis(dicarboximide) (PDI) acceptors was studied. Photoexcitation of PDI to its lowest excited singlet state results in oxidation of PTZ via the FL(n) bridge. In toluene, the temperature dependence of the charge separation rate constants for PTZ-FL(n)-PDI, (n = 1-4) is relatively weak and is successfully described by the semiclassical Marcus equation. The activation energies for charge separation suggest that bridge charge carrier injection is not the rate limiting step. The difficulty of using temperature and length dependence to differentiate hopping and superexchange is discussed, with difficulties in the latter topic explored via an extension of a kinetic model proposed by Bixon and Jortner.     

Phenol removal from aqueous solution by carbon xerogel

Carbon xerogel (CX) was used for phenol adsorption from aqueous solution. CX was synthesized by sol?Cgel polycondensation of resorcinol with formaldehyde using sodium carbonate (Na₂CO₃) as catalyst. Then, it was dried by convective drying technique and pyrolyzed under inert atmosphere. Phenol adsorption kinetics was very fast, what was attributed to the presence of open pore structure. The kinetic studies showed that the adsorption process could be fitted to a pseudo-second-order model and the particle diffusion process is the rate-limiting step of the adsorption. The phenol removal was maximum and unaffected by pH changes when the initial pH of the phenol solution was in the range of 3?C8. The optimum adsorbent dose obtained for phenol adsorption onto CX was 0.075?g/50?cm³ solution. The Langmuir model described the adsorption process better than the Freundlich isotherm model and the monolayer adsorption capacity is 32?mg?g^?1. Among the desorbing solutions used in this study, the most efficient desorbent was EtOH (100?%) which released about 87?% of phenol bound with the CX.     

A new massively parallel version of CRYSTAL for large systems on high performance computing architectures

Fully ab initio treatment of complex solid systems needs computational software which is able to efficiently take advantage of the growing power of high performance computing (HPC) architectures. Recent improvements in CRYSTAL, a periodic ab initio code that uses a Gaussian basis set, allows treatment of very large unit cells for crystalline systems on HPC architectures with high parallel efficiency in terms of running time and memory requirements. The latter is a crucial point, due to the trend toward architectures relying on a very high number of cores with associated relatively low memory availability. An exhaustive performance analysis shows that density functional calculations, based on a hybrid functional, of low‐symmetry systems containing up to 100,000 atomic orbitals and 8000 atoms are feasible on the most advanced HPC architectures available to European researchers today, using thousands of processors. © 2012 Wiley Periodicals, Inc.     

Static and dynamic coupled perturbed Hartree-Fock vibrational (hyper)polarizabilities of polyacetylene calculated by the finite field nuclear relaxation method

The vibrational contribution to static and dynamic (hyper)polarizability tensors of polyacetylene are theoretically investigated. Calculations were carried out by the finite field nuclear relaxation (FF-NR) method for periodic systems, newly implemented in the CRYSTAL code, using the coupled perturbed Hartree-Fock scheme for the required electronic properties. The effect of the basis set is also explored, being particularly important for the non-periodic direction perpendicular to the polymer plane. Components requiring a finite (static) field in the longitudinal direction for evaluation by the FF-NR method were not evaluated. The extension to that case is currently being pursued. Whereas the effect on polarizabilities is relatively small, in most cases the vibrational hyperpolarizability tensor component is comparable to, or larger than the corresponding static electronic contribution.     

Coherent quasiclassical dynamics of a persistent current qubit

A new regime of coherent quantum dynamics of a qubit is realized at low driving frequencies in the strong driving limit. Coherent transitions between qubit states occur via the Landau-Zener process when the system is swept through an energy-level avoided crossing. The quantum interference mediated by repeated transitions gives rise to an oscillatory dependence of the qubit population on the driving-field amplitude and flux detuning. These interference fringes, which at high frequencies consist of individual multiphoton resonances, persist even for driving frequencies smaller than the decoherence rate, where individual resonances are no longer distinguishable. A theoretical model that incorporates dephasing agrees well with the observations.     

Flow-injection turbidimetric determination of homatropine methylbromide in pharmaceutical formulations using silicotungstic acid as precipitant reagent

A flow-injection turbidimetric procedure exploiting merging zones is proposed for determining homatropine methylbromide (HMB) in pharmaceutical preparations. The determination is based on the precipitation reaction of homatropine methylbromide with silicotungstic acid in acidic medium to form a precipitate, which was measured at 410 nm. The analytical curve was linear in the HMB concentration range from 8.1 × 10⁻⁵ to 2.2 × 10⁻⁴ mol l⁻¹, with a detection limit of 5.0 × 10⁻⁶ mol l⁻¹. The recoveries ranged from 96 to 103%, the sampling frequency was 70 determinations per hour and relative standard deviations were less than 1.5% (n = 10). The results obtained for commercial formulations using the FIA procedure were in good agreement with those obtained by using a comparative method.     

Determination of the chemical oxygen demand (COD) using a copper electrode: a clean alternative method

A clean alternative method for the determination of chemical oxygen demand (COD) was developed using a copper electrode as an electrocatalytic sensor. The measuring principle is based on oxidation current of organic compounds in the wastewater. The effects of important experimental conditions, such as electrolytic solution concentration and potential scan rate, on analytical performance have been investigated. Analytical linear range of 53.0–2,801.4 mg l⁻¹ COD with detection limit of 20.3 mg l⁻¹ COD was achieved. The procedure was successfully applied to the COD determination in wastewater from soft industries. The results obtained using the proposed method were in good agreement with those obtained using the conventional (i.e., dichromate) COD method. In this fashion, the COD value of a sample can be determined in a simple, rapid, accurate manner, and the end products do not contain toxic metals.