Surface functionalization of poly(lactic acid) film by UV‐photografting of N‐vinylpyrrolidone

The photoinitiated grafting of N‐vinylpyrrolidone (NVP) onto poly(lactic acid) (PLA) film with the use of benzophenone (BP) as the initiator, modified the natural hydrophobic PLA behavior to an hydrophilic film with desirable wettability. The surface photografting parameters‐percent conversion of monomer to overall photopolymerization (Cp), percent conversion of monomer to the photograft polymerization (Cg), and grafting efficiency (Eg) were calculated. The resulting film surface was analyzed using ATR‐FTIR and UV spectroscopy, derivative spectroscopy and water contact angle. Besides, we demonstrated that the grafted polyvinylpyrrolidone chains could easily react with iodine to form a complex as the homopolymer does with antibacterial activity. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Pressurised feeding systems

Pressurised feeding is by no means new. Whitworth patented a method for pressurising steel in refractory lined ingot moulds in the mid 1800s, while accounts of pressurising aluminium castings during solidification appeared in the 1930s, and the pressurisation of risers in steel and iron castings surfaced in the 1950s. It is appropriate to distinguish between cases where the whole casting and rigging has been pressurised and those where the feeder heads alone were pressurised. Generally speaking, pressurising the whole casting has not proved especially effective. Early experiments with aluminium involved top pouring of moulds contained in an autoclave. The considerable height through which the metal fell undoubtedly mitigated results. Furthermore, since the alloys were of a non-skin forming variety (i.e. long freezing range) the puncture of the partially solidified surface led to further property degradation.

Work of Watmough and Berry in the US in 1961, repeated by Irani and Kondic at Birmingham published eight years later, employed aluminium sand cast bars with pressurised feeder heads surrounded by stout insulating sleeves. The results of both sets of experiments with long-freezing range alloys, showed excellent promise in terms of reducing dispersed porosity. During the nineties Fischer-Disa picked up this concept and successfully implemented it on a production basis for both aluminium and ductile iron. Most recently MSU in collaboration with US metal casters has applied the technique to tilt-poured permanent moulding (gravity-die casting). The results of this recent work will be described in detail.     

Microtubule Destabilizing Sulfonamides as an Alternative to Taxane-Based Chemotherapy

Pan-Gyn cancers entail 1 in 5 cancer cases worldwide, breast cancer being the most commonly diagnosed and responsible for most cancer deaths in women. The high incidence and mortality of these malignancies, together with the handicaps of taxanes—first-line treatments—turn the development of alternative therapeutics into an urgency. Taxanes exhibit low water solubility that require formulations that involve side effects. These drugs are often associated with dose-limiting toxicities and with the appearance of multi-drug resistance (MDR). Here, we propose targeting tubulin with compounds directed to the colchicine site, as their smaller size offer pharmacokinetic advantages and make them less prone to MDR efflux. We have prepared 52 new Microtubule Destabilizing Sulfonamides (MDS) that mostly avoid MDR-mediated resistance and with improved aqueous solubility. The most potent compounds, N-methyl-N-(3,4,5-trimethoxyphenyl-4-methylaminobenzenesulfonamide 38, N-methyl-N-(3,4,5-trimethoxyphenyl-4-methoxy-3-aminobenzenesulfonamide 42, and N-benzyl-N-(3,4,5-trimethoxyphenyl-4-methoxy-3-aminobenzenesulfonamide 45 show nanomolar antiproliferative potencies against ovarian, breast, and cervix carcinoma cells, similar or even better than paclitaxel. Compounds behave as tubulin-binding agents, causing an evident disruption of the microtubule network, in vitro Tubulin Polymerization Inhibition (TPI), and mitotic catastrophe followed by apoptosis. Our results suggest that these novel MDS may be promising alternatives to taxane-based chemotherapy in chemoresistant Pan-Gyn cancers.     

Piezoelectric properties of PVDF-conjugated polymer nanofibers

This study presents the development and characterization of PVDF-conjugated polymer nanofiber-based systems. Five different conducting polymers (CPs) were synthesized successfully and used to create the nanofiber systems. The CPs used are polyaniline (PANI), polypyrrole (PPY), polyindole (PIN), polyanthranilic acid (PANA), and polycarbazole (PCZ). Nanofiber systems were produced utilizing the Forcespinning® technique. The nanofiber systems were developed by mechanical stretching. No electrical field or post-process poling was used in the nanofiber systems. The morphology, structure, electrochemical and piezoelectric performance was characterized. All of the nanofiber PVDF/CP systems displayed higher piezoelectric performance than the fine fiber PVDF systems. The PVDF/PPY nanofiber system displays the highest piezoelectric performance of 15.56 V. The piezoelectric performance of the PVDF/CP nanofiber systems favors potential for an attractive source of energy where highly flexible membranes could be used in power actuators, sensors and portable, and wireless devices to mention some.     

An International Collaborative Study on Trypsin Inhibitor Assay for Legumes,Cereals, and Related Products

For determining trypsin inhibitor activity (TIA) in soy products, the American Oil Chemists' Society (AOCS) Method Ba 12-75 has been used. It measures differences in absorbance at 410 nm of bovine trypsin activity toward a synthetic substrate (Nα-benzoyl-DL-arginine-p-nitroanilide) in the absence and presence of an inhibitor. Recently, a significantly improved method was developed (JAOCS, 2019, 96:635–645), featuring 5 mL of total assay volume, enzyme-last sequence, and single inhibitor level in duplicate. It is proposed as the AOCS Method Ba 12a-2020. As a part of the AOCS method approval process, a collaborative study involving 12 international laboratories was conducted to evaluate the performance of the proposed method. The study involved measuring TIA in 10 selected test samples plus a blind duplicate. They included soybeans, pulses, cereals, and their processed products (flours, concentrates, and isolates). After rigorous statistical treatment of the data, only three outliers were removed from the data of two samples. Repeatability relative standard deviations (RSDr) for the 11 samples ranged from 0.99% to 5.52%. Reproducibility RSD (RSD_R) ranged from 7.07% to 22.92%, with seven samples having RSD_R around 10% or less. The remaining four samples had very low TIA, and their RSD_R values ranged from 13.34% to 22.92%. The study has demonstrated reliable performance of the proposed AOCS method. Several collaborators carried out additional experiments addressing some aspects of the method, leading to further refinements. The proposed method is undergoing evaluation by the AOCS Uniform Methods Committee for adoption as an Official Method for measuring TIA in various legume and grain products.     

Excited States of Bromopyrimidines Probed by VUV Photoabsorption Spectroscopy and Theoretical Calculations

We report absolute photoabsorption cross sections for gas-phase 2- and 5-bromopyrimidine in the 3.7–10.8 eV energy range, in a joint theoretical and experimental study. The measurements were carried out using high-resolution vacuum ultraviolet synchrotron radiation, with quantum chemical calculations performed through the nuclear ensemble approach in combination with time-dependent density functional theory, along with additional Franck–Condon Herzberg–Teller calculations for the first absorption band (3.7–4.6 eV). The cross sections of both bromopyrimidines are very similar below 7.3 eV, deviating more substantially from each other at higher energies. In the 7.3–9.0 eV range where the maximum cross-section is found, a single and broad band is observed for 5-bromopyrimidine, while more discernible features appear in the case of 2-bromopyrimidine. Several π* ← π transitions account for the most intense bands, while weaker ones are assigned to transitions involving the nitrogen and bromine lone pairs, the antibonding σ*_Br orbital, and the lower-lying Rydberg states. A detailed comparison with the available photo-absorption data of bromobenzene is also reported. We have found significant differences regarding the main absorption band, which is more peaked in bromobenzene, becoming broader and shifting to higher energies in both bromopyrimidines. In addition, there is a significant suppression of vibrational structures and of Rydberg states in the pair of isomers, most noticeably for 2-bromopyrimidine.     

Dehydration kinetics of red pepper (Capsicum annuum L var Jaranda)

Shredded and whole red pepper samples were dehydrated in a laboratory drier with a through‐flow air velocity of 0.5 m s^?1 at 50, 55, 60 and 70 °C. Shredded peppers dried faster than whole peppers. The drying behaviour of whole samples was characterised by a constant‐ and a falling‐rate drying period, whilst that of shredded samples was characterised by a falling‐rate drying period only. The mass transfer coefficient for whole samples during the constant‐rate period was computed experimentally. The effect of temperature on the mass transfer coefficient was described by the Arrhenius model. The activation energy was 58 kJ mol^?1. In the falling‐rate period the mass transfer was described by a diffusional model, and the effective diffusion coefficient at each temperature was determined. Diffusion coefficients were estimated to lie between 4.38 × 10^?11 and 10.99 × 10^?11 m² s^?1 for whole peppers and between 37.23 × 10^?11 and 99.61 × 10^?11 m² s^?1 for shredded peppers. The effect of temperature on the effective diffusion coefficient was described by the Arrhenius equation, with an activation energy of 44 kJ mol^?1 for whole peppers and 56 kJ mol^?1 for shredded peppers. © 2003 Society of Chemical Industry     

Geographic evaluation of trigeneration systems in the tertiary sector. Effect of climatic and electricity supply conditions

The development of trigeneration systems is especially important in the buildings sector, where the thermal loads are imposed by the needs of heating, domestic hot water, and cooling. A strong seasonal character is indicated, since the demands depend totally on local climatic conditions and vary considerably throughout the year. Geographic locations were chosen so as to represent the climatic variety in Spain: Canary Islands, Mediterranean Coast, Atlantic Coast, and different locations in the interior of the Iberian Peninsula. The solution of a mixed integer linear programming model (MILP) that incorporated local economic/environmental conditions determined the optimal configuration of the different energy supply plants as well as the optimal operation modes throughout an entire representative year. From an economic point of view, the optimal configuration for all localities included cogeneration modules. From an environmental point of view, the optimal solution was strongly dependent on the origin of the electricity supplied by the grid.     

Comparison of water management between two bipolar plate flow-field geometries in proton exchange membrane fuel cells at low-density current range

This experimental research studies some aspects of water formation and management in polymer electrolyte membrane fuel cells (PEMFCs). To this end, two different single cells of 49 cm² active area have been tested, the first one with a serpentine-parallel geometry and the second with a cascade-type flow-field topology. In order to visualize the processes, flow-field channels have been machined on transparent plastic. Experiments have consisted in both image acquisition using a CCD camera, and simultaneous measurements of pressure drop in both hydrogen and oxygen gas flow paths. It has been observed that with the cascade-type flow-field geometry, water produced in the cathode does not flood the gas flow channels and, consequently, can be drained in an easy way. On the other hand, it has also been verified that saturated condition for the hydrogen gas flow at the anode side produces water condensation and channel flooding for the serpentine-parallel flow-field topology. Time fluctuations in the pressure drop of the gas flow have been detected and are associated to some transient process inherent to water formation and management.     

An algorithm for the recognition of levels of congestion in road traffic problems

Detection and recognition of the level of congestion at an intersection is a very important problem and a valuable source of information in traffic management. Although it is just one of all the aspects that make up a traffic management system, it seems to be a crucial point for gathering information. In this paper, we present a technique based on a k-means clustering algorithm for classification, which has been already successfully used in a number of pattern recognition problems, namely: as an algorithm for face recognition problems and in a number of medical diagnosis problems and it compares very well with the state of the art techniques.