Optical sensor for sulfur dioxide determination in wines

A method for the determination of free and total sulfur dioxide in wines, based on the use of an optical sensor that employs a dichlorobis(diphenylphosphino)methane dipalladium I complex [Pd(2)(dppm)(2)Cl(2)] immobilized in a PVC membrane plasticized with o-nitrophenyloctylether (o-NPOE) is described. A sensing membrane [4.2% Pd(2)(dppm)(2)Cl(2), 20.8% PVC, and 75% o-NPOE] was adapted to the tip of a bifurcated optical fiber bundle to perform reflectance measurements at 550 nm. The detection system consisted of two cells (40 mL), which hold the sample solution (plus reagents) and the optical sensor, respectively. For the determination of free SO(2), a wine sample was mixed with H(2)SO(4) solution in the sample cell, into which N(2) was bubbled, providing mixing of the solutions and conducting the SO(2) formed toward the detection cell. For determination of total SO(2), a KOH solution was mixed with the wine in the sample cell. Afterward, an H(2)SO(4) solution was added to the cell, and then N(2) was bubbled to conclude the measurement. Linear responses up to 50 and 150 mg L(-1) were obtained for free and total SO(2), with detection limits of 0.37 and 0.70 mg L(-1), respectively. The repeatability of the method was evaluated by carrying out 10 measurements using a single wine sample, providing relative standard deviation values of 2.2 and 2.5% for free and total SO(2), respectively. The sensing membrane prepared from 10 muL of the cocktail solution lasted for 80 measurements, whereas those prepared from 200 muL can be used for 250 measurements. The method was applied to free and total SO(2) determination in wines, and the results did not show significant difference from those obtained with the Ripper reference method at a confidence level of 95%.     

桃果实水孔蛋白cDNA的分离

使用逆转录聚合酶链失反应(RT-PCR)技术从桃果实的果皮组织中分离出来2个编码水孔蛋白部分cDNA克隆.比较结果表明,其推导的氨基酸序列与从其他一些植物体中分离出来的液泡膜内在蛋白有很高的同源性.数量PCR分析表明,编码水孔蛋白基因pWCl在果实发育早期表达,而pWC2在果实发育期间全过程均有表达.     

Demographic assessment of a stocking experiment in European Eels

Since the 1980s, the European eels’ stocks have dramatically decreased with no sign of recovery, resulting in their classification as Critically endangered on the IUCN red list of threatened species. The European Council Regulation 1100/2007 requires that 35% of glass eels caught annually by fishing be released in European waters for restocking. However, the efficiency of this measure on population viability has never been evaluated. Here, we estimated demographic parameters of a stocked population of French eels using a multistate capture–recapture model. Using these estimates, we then estimated population size and predicted the number of future genitors obtained by stocking. We found that the stage in which eels were stocked did not influence their future survival and that the maximal number of silver eels was quickly reached, after 3 years following stocking. We concluded that stocking experiments in the Mediterranean region are efficient for fast production of genitors. We suggest that further studies should assess the quality of these genitors.     

Polycyclic aromatic hydrocarbons and olive pomace oil

The occurrence of polycyclic aromatic hydrocarbons (PAHs) in five samples of olive pomace oil has been studied to determine the contamination degree of this type of oil and to evaluate if specific purification steps must be introduced during its manufacture. The PAHs present have been determined by gas chromatography-mass spectrometry. A high number of PAHs, with a wide range of molecular weights and in very high concentrations, have been found in four of the samples studied. A very high number of alkyl derivatives and, in many cases, in higher concentrations than their respective parent PAHs, have also been identified. One of the samples, however, presents a more reduced number of PAHs and in significantly lower concentrations than the others. These findings reveal that it is necessary to introduce adequate cleanup steps in the manufacturing process of olive pomace oil, which can give rise to oils with a relatively low content of PAHs. Some carcinogenic PAHs have also been identified, both unalkylated and alkylated.     

Characterization of Fuji apples from different harvest dates and storage conditions from measurements of volatiles by gas chromatography and electronic nose

Volatile compounds in Fuji apples harvested at two different maturities were measured at harvest and after 5 and 7 months of cold storage (1 degrees C) in four different atmospheres. When the samples were characterized by both chromatographic measurements of volatiles and responses of an electronic nose, the analyses showed a clear separation between fruits from different storage conditions (a normal cold atmosphere and three controlled atmospheres). During poststorage, the apples were left to ripen for 1, 5, and 10 days at 20 degrees C before analytical measurements were done involving headspace-gas chromatography methods and electronic nose type quartz crystal microbalances. Electronic nose responses registered by seven different sensors were used to classify the apples using principal component analysis. It was possible to identify the samples from different storage periods, days of shelf life, and harvest dates, but it was not possible to differentiate the fruits corresponding to different cold storage atmospheres.     

The impact of introduced predators, light-induced mortality of fledglings and poaching on the dynamics of the Cory’s shearwater (Calonectris diomedea) population from the Azores, northeastern subtropical Atlantic

Cory’s shearwater (Calonectris diomedea) is a procellariiform seabird which breeds in the Mediterranean and the north-eastern subtropical Atlantic, and which is considered “Vulnerable” in Europe due to recent declines at some localities. In the Azores archipelago (Atlantic), the introduction of mammalian predators by man has led to petrels being extirpated from the main islands, except for Cory’s shearwater. Currently, the Azorean population of Cory’s shearwaters represents 65% of the species’ world population. However, its dynamics remains unknown, although: (1) numbers might have declined by 43% between 1996 and 2001, (2) on the main islands, the young suffer mortality from introduced mammals, poachers, and urban lights upon fledging, and (3) at sea, the level of fishery mortality remains unknown.To fill this gap, we conducted a 7-year demographic survey on a mammal-free islet in the Azores to determine adult survival rate using capture-mark-recapture of the breeders and to estimate fecundity. We also assessed urban mortality using the data from the rescue campaigns annually conducted in the archipelago. Urban mortality concerned about 6% of fledglings, but its importance greatly varied among islands. When rescue campaigns occur, the rate might drop below 0.5%. Overall, our simulations concerning the next 100 years do not allow excluding a decrease in Cory’s shearwater numbers in the Azores without rescue campaigns (by 87% under the least favourable scenario). Rescue campaigns should only slow down the decline unless, simultaneously, lower competition for nests compared to Vila islet allows adults to breed almost every year on the main islands and juvenile survival exceeds a threshold value. Since adult survival rate was high (>0.93), an eventual decline of the Azorean population of Cory’s shearwaters would probably not result from fishery mortality of adults, but rather from poor fledgling productivity and perhaps also from low survival during the first year at sea.     

Maggot-therapy in veterinary medicine

Maggot-therapy is the application of disinfected fly larvae to chronic wounds to debride the wound bed of necrotic tissue, reduce bacterial contamination and enhance the formation of healthy granulation tissue. Interest in the use of maggot-therapy in human medicine is growing as a result of the prevalence of antibiotic resistant bacteria. Maggot therapy, however, is used relatively little in veterinary medicine. Nevertheless, concern over antibiotic resistance and the increase in demand for organic husbandry and residue-free meat and milk, suggest that it is an option which merits further consideration.