Synthesis, characterization and phenol adsorption of carbonyl-functionalized mesoporous silicas

Carbonyl-functionalized mesoporous silicas have been synthesized by co-condensation of tetraethoxysilane and varying contents of 3-(trimethoxysilyl)propyl methacrylate in acidic medium with the block copolymer Pluronic 123 as a structure directing agent. The functionalized materials were characterized by PXRD, TEM, SEM, IR, and N₂ adsorption?Cdesorption at 77?K. Adsorption of phenol in aqueous solution on the materials has been investigated. The experimental results showed that carbonyl-functionalized mesoporous silicas possess strong adsorption ability for phenol with interaction of O-H??O?=?C hydrogen bond. The adsorption data are fitted to Langmuir Isotherms and a maximum adsorption capacity calculated from the Langmuir equation can reach 0.87?mmol of phenol/g. The effect of the pH on phenol adsorption has been studied.     

Operations research at container terminals: a literature update

The current decade sees a considerable growth in worldwide container transportation and with it an indispensable need for optimization. Also the interest in and availability of academic literatures as well as case reports are almost exploding. With this paper an earlier survey which proved to be of utmost importance for the community is updated and extended to provide the current state of the art in container terminal operations and operations research.     

Protein degradation in bovine milk caused by Streptococcus agalactiae

Streptococcus (Str.) agalactiae is a contagious mastitis bacterium, often associated with cases of subclinical mastitis. Different mastitis bacteria have been evaluated previously from a diagnostic point of view, but there is a lack of knowledge concerning their effect on milk composition. Protein composition is important in achieving optimal yield and texture when milk is processed to fermented products, such as cheese and yoghurt, and is thus of great economic value. The aim of this in vitro study was to evaluate protein degradation mainly caused by exogenous proteases originating from naturally occurring Str. agalactiae. The samples were incubated at 37°C to imitate degradation caused by the bacteria in the udder. Protein degradation caused by different strains of Str. agalactiae was also investigated. Protein degradation was observed to occur when Str. agalactiae was added to milk, but there were variations between strains of the bacteria. Caseins, the most economically important proteins in milk, were degraded up to 75% in milk inoculated with Str. agalactiae in relation to sterile ultra-high temperature (UHT) milk, used as control milk. The major whey proteins, α-lactalbumin and β-lactoglobulin, were degraded up to 21% in relation to the sterile control milk. These results suggest that different mastitis bacteria but also different strains of mastitis bacteria should be evaluated from a milk quality perspective to gain knowledge about their ability to degrade the economically important proteins in milk.     

1,2,4-Triazole-3-Thione Analogues with a 2-Ethylbenzoic Acid at Position 4 as VIM-type Metallo-β-Lactamase Inhibitors

Metallo-β-lactamases (MBLs) are increasingly involved as a major mechanism of resistance to carbapenems in relevant opportunistic Gram-negative pathogens. Unfortunately, clinically efficient MBL inhibitors still represent an unmet medical need. We previously reported several series of compounds based on the 1,2,4-triazole-3-thione scaffold. In particular, Schiff bases formed between diversely 5-substituted-4-amino compounds and 2-carboxybenzaldehyde were broad-spectrum inhibitors of VIM-type, NDM-1 and IMP-1 MBLs. Unfortunately, these compounds were unable to restore antibiotic susceptibility of MBL-producing bacteria, probably because of poor penetration and/or susceptibility to hydrolysis. To improve their microbiological activity, we synthesized and characterized compounds where the hydrazone-like bond of the Schiff base analogues was replaced by a stable ethyl link. This small change resulted in a narrower inhibition spectrum, as all compounds were poorly or not inhibiting NDM-1 and IMP-1, but showed a significantly better activity on VIM-type enzymes, with K_i values in the μM to sub-μM range. The resolution of the crystallographic structure of VIM-2 in complex with one of the best inhibitors yielded valuable information about their binding mode. Interestingly, several compounds were shown to restore the β-lactam susceptibility of VIM-type-producing E. coli laboratory strains and also of K. pneumoniae clinical isolates. In addition, selected compounds were found to be devoid of toxicity toward human cancer cells at high concentration, thus showing promising safety.     

Selection of a drainage operation in obstruction of the common bile duct

Drainage operations were accomplished on extrahepatic bile ducts in 194 patients. It is the authors' opinion that in emergency surgery the operative procedure may be terminated by external drainage only in relative blockade of bile outflow in the duodenal lumen, while in unrelieved complete blockade of bile outflow such drainage seems to be permissible only in patients with an extremely high operative risk. Biliodigestive anastomoses were constructed in 96 patients. In persistant cholemia, cholangitis, signs of hepatic insufficiency the authors construct biliodigestive anastomoses and simultaneously accomplish provisional external drainage of bile ducts.     

Forced chemical mixing in immiscible alloys during severe plastic deformation at elevated temperatures

The forced chemical mixing of atoms in model immiscible alloys during severe plastic deformation (SPD) has been investigated as a function of temperature and the heat of mixing using molecular dynamics computer simulations. At low temperatures, A₇₅B₂₅ alloys form solid solutions during SPD for heats of mixing less than ～20 kJ mol^?1, but tend to phase separate at larger values. At high temperatures these alloys show more extensive precipitation, with the precipitate morphology dependent on the heat of mixing. Analysis of the high-temperature mixing kinetics reveals that the precipitation process involves two separate mechanisms. The first derives from long-range diffusion mediated by shear-induced vacancies, while the second is due to local rearrangements of atoms induced by the forced mixing of atoms.