Benzoylgermanium Derivatives as Novel Visible‐Light Photoinitiators for Dental Composites

New dibenzoylgermanium derivatives are synthesized starting from various dithioacetal protected benzaldehydes by a coupling reaction with different dialkyldichlorogermanes and subsequent oxidative cleavage of the protecting group. The synthesized germanium compounds show a significantly stronger blue light absorption than camphorquinone. During irradiation, the dibenzoylgermanium derivatives undergo photodecomposition under formation of radicals. Therefore, the different dibenzoylgermanium derivatives are used as amine‐free visible‐light photoinitiators for dental cements and composites. Composites based on the different dibenzoylgermanes are storage‐stable and show a significantly improved bleaching behavior over composites with CQ/amine photoinitiators.

     

Polymerization of Cyclic Monomers, 12

Summary: The radical polymerization of different substituted methyl 2‐(bicyclo[3.1.0]hex‐1‐yl) acrylates, 1a – f , was initiated by 2,2′‐azoisobutyronitrile (AIBN) at 65 °C in chlorobenzene. The radical homopolymerization of 1a – f occurred through the opening of the cyclopropane ring, and lead to polymers with number‐average molecular weights of 13 000 to 434 400 g · mol^?1 and glass transition temperatures between 77 and 121 °C. The monomers 1a – f showed a similar reactivity to MMA (in the copolymerization with MMA). Selected monomers were determined to be diluent monomers for dental filling composites and enable the preparation of composites that show a significantly reduced polymerization shrinkage, compared to composites based on dimethacrylate diluents.

     

Listeria innocua and Lactobacillus delbrueckii subsp. bulgaricus employ different strategies to cope with acid stress

Responses of Listeria innocua and Lactobacillus delbrueckii subsp. bulgaricus to a rapid change in extracellular pH (pHex) from pHex 6 to a range of concentrations down to pHex 3.0 were examined, using HCl and lactic acid (LA) as acidulants. A new fluorescent probe 5-(and-6)-carboxy-2', 7'-dichlorofluorescein diacetate succinimidyl ester (CDCFDA-SE) was employed that enabled reliable measurements of intracellular pH (pHi) to a minimum pHi of 4.0. Changes in pHi and H+ fluxes from immobilised bacteria were measured using fluorescence ratio imaging microscopy (FRIM) and a non-invasive ion flux measuring technique (MIFE), respectively. L. innocua maintained a relatively constant pHi of 5.5-6.1 at pHex 4 and 5 via H+ extrusion. In contrast, L. delbrueckii subsp. bulgaricus progressively lowered pHi towards pHex over the entire pHex range examined. The type of acidulant used influenced pH regulation with both pHi and H+ -fluxes being more severely affected by LA compared to HCl. Overall, our data demonstrated different adaptive strategies in these two bacteria. While L. innocua expels protons to maintain a constant pHi, L. delbrueckii subsp. bulgaricus allows proton entry after acidic treatment so that pHi follows pHex.     

Democratic design experiments in urban planning – navigational practices and compositionist design

In the field of urban planning, public participation and inclusion of citizens have been practised and researched for many years. However, a focus on co-creative urban planning practices seems to have gained more focus over the last decade and calls for new urban planning practices, which allow experimentation and imagination, and at the same time take its outset in the existing networks in the city (such as visions, strategies, regulations and practices) when planning for the future. In this article, we investigate how a compositionist design programme can be translated into the practices of urban planners. We find that the notion of ‘democratic design experiments’ in many ways meet the demands of the increasingly complex field of urban planning and set out to explore how such a design programme can be applied in practice. We suggest ‘navigational practice’ as a way of describing how urban planners deal with ‘drawing things together’ in urban space and introduce ‘sensitivity’, ‘staging’ and ‘mobilization’ as interconnected elements of this practice. We exemplify the significance of these navigational practices by analysing two democratic design experiments in the area of urban waste management in Copenhagen. The article concludes that compositionist design is a powerful contribution to the framing of urban planning projects and that navigational practice can be a productive way of operationalising democratic design experiments in the urban context.     

Metabolite production by different Ulocladium species

Ulocladium, which is phylogenetically related to Alternaria, contains species that are food spoilers and plant pathogens, but also species that have potential as enzyme producers and bio-control agents. Ulocladium spp. are often found on dead vegetation, in soil, air and dust, but also on food and feedstuffs and on water-damaged building materials. The aim was to study the morphological and chemical diversity within the genus Ulocladium. Cultures of 52 Ulocladium strains were identified morphologically, and then extracted and analyzed using automated Chemical Image Analysis. Production of individual metabolites was correlated to species identity and source of isolation (substratum). Chemical analyses corroborated the morphological identifications and showed the existence of several species species-specific metabolites, of which most were known compounds. The production of curvularins was specific to Ulocladium atrum, while most species produced infectopyrones and derivatives of altertoxin I. None of the 52 Ulocladium strains produced alternariols, tenuazonic acid, altersolanols or macrosporin, which are common in species of Alternaria.     

Impact of dietary FA and energy restriction on plasma leptin and ob gene expression in mice

The aim of the present study was to elucidate whether the qualitative compositiion of dietary fat influences plasma leptin and adipose tissue ob gene expression differentially. Two high-fat diets and a diet rich in carbohydrate were each administered both ad libitum and with a 25% energy restriction. The high-fat diets contained 58 energy percent as either monounsaturated FA (MUFA) or saturated FA (SAFA), whereas the carbohydrate-rich diet (CH) contained 7 energy percent as fat. We aimed at obtaining the same final weight for the animals in the ad libitum group as in the energy-restricted groups. This goal was reached at he same time (days 22–24) for all groups except for the ad libitum animals fed on saturated fat (day 36). The plasma leptin concentrations on ad libitum CH and MUFA diets did not differ significantly (24.3 ± 2.1 and 34.7 ± 6.7 ng/mL, respectively) whereas the saturated fat diet caused a lower concentration (13.9 ± 1.9 ng/mL; P < 0.05). Interestingly, no differences in plasma leptin levels between groups were seen in the energy-restricted groups (mean 8.0 + 1.0 ng/mL). The type of diet did not alter the ob gene expression in intraabdominal white adipose tissue; however, a lower expression level was found in the energy-restricted groups. The percentage of body fat in the three ad libitum fed groups did not differ (23 ± 1%). Thus, short-term administration of a diet rich in SAFA suppresses circulating leptin levels without altering the adipose tissue ob gene expression. This indicates that saturated fat may alter protein handling by adipose tissue or the whole body clearance of leptin.     

Effect of pre-slaughter physiological conditions on the oxidative stability of colour and lipid during chill storage of sliced, retail packed roast ham

Pre-slaughter physiological conditions (A serving as control, B subjected to treadmill exercise immediately prior to stunning, C epinephrine injection 15 h prior to slaughter, and D epinephrine injection 15 h prior to slaughter and subjected to treadmill exercise immediately before stunning) were found to significantly affect colour and lipid oxidation of sliced, retail packed roast ham, produced from nitrite-cured (78 ppm nitrite) M. Longissimus dorsi. The pre-slaughter treatment resulted in variations in the level of glycogen, lactate, ATP and IMP and pH development as monitored in Longissimus dorsi muscles, with the lowest ultimate pH (pH(u)) in muscles from non-epinephrine treated pigs (treatments A and B). The initial tristimulus L(?)-value and the L(?)-value during chill storage of sliced roast ham packed in laminates with low or with very low oxygen transmission rate (OTR=40 and <0.5 cm(3)/m(2)/atm/24 h, respectively) were significantly affected by treatment, although the effect of the treatments was different during storage for 28 days (interaction between treatment and storage time). Roast ham from treatments A and B generally had a paler appearance (higher L(?)-values) than from treatments C and D. No differences in the initial tristimulus a(?)-values (redness) were found. During chill storage, a pronounced colour fading (decrease in a(?)-values) was seen for laminate with low OTR, with a tendency of better colour stability for treatment C than A, but with no differences for the other treatments. For laminates with very low OTR, the cured meat pigment was stable with no decreases in a(?)-values during storage. Lipid oxidation (thiobarbituric acid reactive substances, TBARS) in products in laminates with low OTR increased during storage and was significantly higher for roast ham from non-epinephrine treated pigs (A and B) than for ham from epinephrine-treated pigs (C and D). Statistical analysis relating pH and the level of glycogen, lactate, creatine phosphate, ATP and IMP in the individual pigs to the product quality parameters revealed that the ultimate level of lactate was the most important single parameter affecting product quality. After 28 days of chill storage, roast ham from pigs subjected to treatments C and D were more likely to support bacterial growth than from treatments A and B. In conclusion, the results show that pre-slaughter physiological conditions are of importance for chemical as well as for microbiological changes in retail stored roast ham.     

Effects of proanthocyanidins,dehulling and removal of pericarp on digestion of barley grain by ruminal micro‐organisms

The effects of proanthocyanidins (PA), dehulling, and removal of the pericarp on the rate and extent of barley digestion by ruminal micro‐organisms were studied using a control barley (cv Harrington) and three PA‐free barley lines (Caminant, Ca504316 and Ca802711). Each barley was studied in five preparations: whole grain (W); dehulled kernels (DH); kernels with pericarp removed (DP); dry‐rolled grain (DR), and the pericarp‐testa fraction (PT) produced during preparation of DP. Vanillin‐HCl staining and chemical analysis confirmed that PA were present only in the Harrington barley, and localised in the pericarp‐testa layer. Whole kernels, DH and DP were incubated with diluted ruminal fluid in vitro, and all five preparations were incubated in situ (nylon bag technique). Harrington DR and all four PT fractions were also incubated in vitro in the presence (0.074% w/v) and absence of polyethylene glycol (PEG), which specifically binds PA. The four barleys did not differ in in vitro dry matter disappearance (DMD) or gas production from W, DH or DP preparations, nor in in situ DMD rates from W, DH or DP (P > 0.05). In vitro DMD and gas production among PT fractions from the four barleys were also similar (P > 0.05), as were in vitro DMD from PEG‐present and PEG‐absent DR Harrington. With Harrington PT, in vitro ammonia concentrations were higher (P < 0.05) with PEG than without. For each barley line, in vitro DMD rates were highest (P < 0.01) with DP, followed by DH, and then by W (P < 0.01). In in situ incubations also, DMD rates and effective degradabilities of DR samples exceeded (P < 0.05) those of DH samples. It was concluded that the presence of proanthocyanidins did not affect ruminal digestion of barley grain, and that abrasive milling to breach the hull and pericarp may be a promising method by which to regulate the rate of barley digestion in the rumen. © Minister of Public Works and Government Services Canada 1999     

Leuconostoc carnosum 4010 has the potential for use as a protective culture for vacuum-packed meats: culture isolation,bacteriocin identification,and meat application experiments

A new culture, Leuconostoc carnosum 4010, for biopreservation of vacuum-packed meats is described. The culture originated from bacteriocin-producing lactic acid bacteria (LAB) naturally present in vacuum-packed meat products. Approximately, 72,000 colonies were isolated from 48 different vacuum-packed meat products and examined for antibacterial activity. Bacteriocin-producing colonies were isolated from 46% of the packages examined. Leuc. carnosum was the predominant bacteriocin-producing strain and Leuc. carnosum 4010 was selected for further experiments because it showed strong antilisterial activity without producing any undesirable flavour components in meat products. For identification of the bacteriocins produced, partial purification was carried out by ammonium sulphate precipitation, dialysis, and cation exchange chromatography. SDS-PAGE analysis revealed two bands with inhibitory activity corresponding to molecular sizes of 4.6 and 5.3 kDa. N-terminal amino acid sequencing showed that Leuc. carnosum 4010 produced two bacteriocins highly similar or identical to leucocin A and leucocin C. Application experiments showed that the addition of 10(7) cfu/g Leuc. carnosum 4010 to a vacuum-packaged meat sausage immediately reduced the number of viable Listeria monocytogenes cells to a level below the detection limit and no increase of L. monocytogenes was observed during storage at 5 degrees C for 21 days. The results presented demonstrate that Leuc. carnosum 4010 is suitable as a new protective culture for cold-stored, cooked, sliced, and vacuum-packed meat products.     

Amino acid transamination in permeabilised cells of Lactobacillus helveticus, Lb. paracasei and Lb. danicus

Aminotransferase (AT) activity against 18 amino acids was studied in ten strains of three species of Lactobacillus. A method for permeabilisation of cells was developed using toluene and ethanol combined with mechanical treatment. It was found that the AT activities in the washed permeabilised cells (W-PC) corresponded well to that in cell-free extracts (CFE). The AT specificity pattern was species as well as strain dependant. Strains of Lb. helveticus had high specificity for aromatic amino acids (ArAA) and lower activity against branched-chain amino acids (BcAA) and Asp, while strains of Lb. paracasei subsp. paracasei degraded BcAA and Asp, but had a lower and variable specificity against ArAA. One of the Lb. paracasei strains was characterised by having very high AT activity against all three BcAA (Ile, Leu, Val) compared with any of the other Lb. paracasei strains tested. Strains of Lb. danicus, which is a newly discovered Lactobacillus species isolated from cheese, had up to about 20 times higher AT activity against Leu than Lb. paracasei and Lb. helveticus. The permeabilised cells of Lb. danicus had also considerably higher AT activity against ArAA than Lb. paracasei and Lb. helveticus strains, and also higher AT activity against Asp. All Lactobacillus strains tested had AT activity against Met, but at a much lower rate than against other amino acids. Results of this study also demonstrated a chemical reaction between alpha-ketoglutaric acid and Asp that was catalysed by pyridoxal-5-phosphate without any AT present.