Continuous time trading of a small investor in a limit order market

We provide a mathematical framework to model continuous time trading of a small investor in limit order markets. We show how elementary strategies can be extended in a suitable way to general continuous time strategies containing orders with infinitely many different limit prices. The general limit buy order strategies are predictable processes with values in the set of nonincreasing demand functions. It turns out that our strategy set of limit and market orders is closed, but limit orders can turn into market orders when passing to the limit, and any element can be approximated by a sequence of elementary strategies.     

Use of bacterial cellulose in the textile industry and the wettability challenge—a review

Bacterial cellulose (BC) has been studied as an alternative material in several segments of the food, pharmaceutical, materials and textile industries. The importance of BC is linked to sustainability goals, since it is an easily degradable biomaterial of low toxicity to the environment and is a renewable raw material. For use in the textile area, bacterial cellulose has attracted great interest from researchers, but it presents some challenges notably to its hydrophilic structure. This integrative review article brings together studies and methods related to minimizing the hydrophilicity of bacterial cellulose, in order to expand its applicability in the textile industry in its dry state. The databases consulted were Scopus, ScienceDirect, ProQuest and Web of Science, the documents investigated were scientific articles and the time period investigated was between 2015 and 2021. The results showed that although there are methods to make the BC membrane more hydrophobic, future studies in this regard and on other properties must continue so that bacterial cellulose can be commercially introduced in the textile sector.

     

Disposable and Flexible Electrochemical Paper-based Analytical Devices Using Low-cost Conductive Ink

In this work, a simple procedure for construction of disposable electrochemical paper-based analytical devices (ePADs) by screen-printing using low-cost materials and a home craft electronic printer is proposed. The devices were constructed using liner paper as a substrate and carbon ink prepared with graphite powder and wood glue. The ePAD was evaluated as an electrochemical sensor and biosensor. The proposed conductive carbon-based ink can be easily prepared and is an eco-friendly and non-toxic material. The developed ePAD was simple to produce and can be used as a low-cost electrochemical sensor, at less than US $0.20 per device.     

The metal-rich palladium chalcogenides Pd2MCh2 (M=Fe, Co, Ni; Ch=Se, Te): Crystal structure and topology of the electron density

Crystals of Pd₂MCh₂ (M=Fe, Co, Ni; Ch=Se, Te) were synthesized by heating the elements at 823-1323 K in silica ampoules under argon atmosphere. Their structures were determined by single-crystal X-ray diffraction at room temperature. The metallic compounds crystallize in a variant of the K₂ZnO₂ type (Ibam, Z=4, Pd₂CoSe₂: a=5.993(1), b=10.493(2), c=5.003(1) Å; Pd₂FeSe₂: a=5.960(1), b=10.576(2), c=5.078(1) Å; Pd₂CoTe₂: a=6.305(1), b=11.100(2), c=5.234(1) Å; Pd₂NiTe₂: a=6.286(1), b=11.194(2), c=5.157(1) Å). One-dimensional tetrahedra chains with remarkably short M—M bonds run along [001], separated by [Pd₂] dumbbells with palladium in fivefold coordination of selenium or tellurium atoms. The structure may also be described as a filled variant of the SiS₂ type. M atoms occupy of the tetrahedral voids and the Pd atoms fill all octahedral voids in a distorted ccp motif of chalcogen atoms. Even though the Pd₂MCh₂ compounds are isotypic to K₂ZnO₂ from the crystallographic viewpoint, we find a different bonding situation with additional homo- and heteronuclear metal-metal bonds between the Pd and Co atoms. The electronic structures and topologies of the electron densities of Pd₂CoSe₂ and isotypic Na₂CoSe₂ are analyzed and compared by using Bader's AIM theory. Different values of topological charge transfer and electron density flatness indices uncover striking quantitative differences in the nature of chemical bonding between the metallic compound Pd₂CoSe₂ and nonmetallic Na₂CoSe₂.     

Automated sub-ppm mass accuracy on an ESI-TOF for use with drug discovery compound libraries

An automated, routine method to obtain sub-ppm accurate mass data on a benchtop electrospray ionization time-of-flight (ESI-TOF) mass spectrometer is described. Standards in the mass range 114 to 734 Da were analyzed over a 5-day period to demonstrate intra- and interday precision and mean mass accuracy less than 1 ppm. One hundred drug discovery pharmaceutical compounds were used to demonstrate an absolute average mass accuracy of 0.47 +/- 0.31 ppm. This is in contrast to previous reports of accurate mass analysis using time-of-flight mass spectrometry (TOFMS) technology that operates within 3 to 5 ppm. The same 100 samples were also analyzed using Fourier transform mass spectrometry (FTMS) technology and yielded comparable results to the TOFMS analysis.     

Spiroiminodihydantoin nucleoside formation from 2'-deoxyguanosine oxidation by [(18)O-labeled] singlet molecular oxygen in aqueous solution

The main singlet molecular oxygen ((1)O(2)) oxidation products of free 2'-deoxyguanosine (dGuo) in aqueous solution were identified as a pair of diastereomeric spiroiminodihydantoin 2'-deoxyribonucleosides (dSp) together with 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo). In the present work, evidence is provided from (18)[(1)O(2)] and H(2) (18)O labeling experiments, using HPLC-ESI-MS/MS, that the formation of dSp is explained by the addition of water to a reactive quinonoid intermediate, and a second reaction pathway leading to dSp involves (1)O(2) oxidation of initially generated 8-oxodGuo.     

Ethanol/water pulps from sugar cane straw and their biobleaching with xylanase from Bacillus pumilus

The influence of independent variables (temperature and time) on the cooking of sugar cane straw with ethanol/water mixtures was studied to determine operating conditions that obtain pulp with high cellulose contents and a low lignin content. An experimental 2(2) design was applied for temperatures of 185 and 215 degrees C, and time of 1 and 2.5 h with the ethanol/water mixture concentration and constant straw-to-solvent ratio. The system was scaled-up at 200 degrees C cooking temperature for 2 h with 50% ethanol-water concentration, and 1:10 (w/v) straw-to-solvent ratio to obtain a pulp with 3.14 cP viscosity, 58.09 kappa-number, and the chemical composition of the pulps were 3.2% pentosan and 31.5% lignin. Xylanase from Bacillus pumilus was then applied at a loading of 5-150 IU/g dry pulp in the sugar cane straw ethanol/water pulp at 50 degrees C for 2 and 20 h. To ethanol/water pulps, the best enzyme dosage was found to be 20 IU/g dry pulp at 20 h, and a high enzyme dosage of 150 IU/g dry pulp did not decrease the kappa-number of the pulp.     

Biodegradable poly(ethylene carbonate) nanoparticles as a promising drug delivery system with "stealth" potential

The goal of this study was to investigate the suitability of poly(ethylene carbonate) (PEC) nanoparticles as a novel drug delivery system, fulfilling the requirements for a long circulation time. Particles were obtained with a narrow size distribution and nearly neutral zeta potential. Adsorption studies with human plasma proteins revealed that PEC nanoparticles bind much less proteins in comparison to polystyrene (PS) nanoparticles. Cell experiments with fluorescently labeled PEC showed no uptake of the nanoparticles by macrophages. These novel PEC nanospheres with their unique surface properties are a promising candidate for long circulating drug delivery systems in vivo.     

Chemical composition and antioxidant, antimicrobial, and larvicidal activities of the essential oils of Annona salzmannii and A. pickelii (Annonaceae)

The essential oils from the leaves of Annona salzmannii and A. pickelii (Annonaceae) growing in Sergipe, northeastern region of Brazil, were obtained by hydrodistillation using a Clevenger-type apparatus, and analyzed by GC/MS and GC/FID. Thirty-four compounds were identified in the essential oil of A. salzmannii and twenty-seven in that of A. pickelii; sesquiterpenes predominated in both essential oils. Bicyclogermacrene (20.3%), (E)-caryophyllene (19.9%), delta-cadinene (15.3%), alpha-copaene (10.0%), and allo-aromadendrene (5.7%) were the main components of A. salzmannii, and bicyclogermacrene (45.4%), (E)-caryophyllene (14.6%), and alpha-copaene (10.6%) of A. pickelii. The essential oils showed significant antioxidant capacity in the ORAC(FL) and DPPH assays. The antimicrobial activity of these essential oils was also evaluated against bacteria and fungi, as well as the larvicidal activity against Aedes aegypti larvae.