CHRONOAMPEROMETRIC STUDIES ON MIGRATION AND DIFFUSION OF COUNTERION IN POLY(3-METHYLTHIOPHENE)

Small amplitude potential step experiments were carried out to study the counterion transfer process in oxidized poly(3-methylthiophene) (PMT) film. The results demonstrate that anion transfer process in PMT film is migration rather than diffusion. A porous metal electrode model-single hole model, which takes into account both the ionic resistance of the film and the uncompensated solution resistance, was found suitable to describe the potential step experiments. According to this model, the ionic resistivity of oxidized PMT film was calculated to be 5.0 x 10(4) OMEGA.cm, and, in turn, the diffusion coefficent of ClO4- ion in PMT film 3.7 x 10(-9) cm2/s.

XPS STUDIES ON RADIATION-INDUCED STRUCTURAL-CHANGES IN THE COPOLYMER OF TETRAFLUOROETHYLENE AND ETHYLENE

In this work, the radiation-induced structural changes in the copolymer of tetrafluoroethylene and ethylene (F-40) were studied by X-ray photoelectron spectroscopy (XPS). During irradiation, some CF2 groups in the polymer were found to have been converted into carbon structures that bonded indirectly with fluorine atoms.

NMR-STUDIES ON THE COORDINATION OF RARE-EARTHS WITH GLYCYL-DL-VALINE AND THE CONFORMATION OF THEIR COMPLEX IN AQUEOUS-SOLUTION

In this paper lanthanide-induced shifts have been measured for C-13 and H-1 nuclei of glycyl-DL-valine in the presence of three lanthanide cations (La3+, Ho3+ and Yb3+) in aqueous solution. The stability constants of the coordination compounds of rare earths (Ho, Yb) with glycyl-DL-valine have been calculated. The coordination of rare earths with the ligand has been discussed. The simulation for conformation of lanthanide coordination compounds with glycyl-DL-valine shows that the ligand is coordinated to lanthanide ion through oxygen atoms of carboxyl group and the bond length of Ln-O is 0.226 nm. In the coordination compounds glycyl-DL-valine is in extended state with minimal steric hindrance.

STUDIES ON THE ELECTRICAL AND MAGNETIC-PROPERTIES FOR LASR2-XCAXV3O9+/-Y

The electrical and magnetical properties of LaSr(2-x)Ca(x)V3O9 +/- y have been investigated. The compounds are antiferromagnetic. They show a metallic conduction other than semiconductivity. The trivalent and tetravalent vanadium ions coexist in the system. The magnetic susceptibility increases and the resistivity decreases at room temperature with the increase of x value. It is shown that the change of the valency state of vanadium obviously influences the electrical and magnetical properties of the system.

Studies on hybridization effects of different geographic populations of Chlamys farreri - II. The medium-term growth and development of Chlamys farreri populations from China and Russia and their reciprocal crosses

Based on the research of juvenile (2, 3, 4 months) growth and survival of three populations of two different geographic areas in Chlamys farreri from Russian and China and their F, hybrids derived from Chinese cultural population (CC) female x Russian population (RW) male, Chinese wild population (CW) female x Russian population (RW) male, Russian population (RW) female x Chinese wild population (CW) the study of the medium-term (6, 8, 10, 12 months) growth and development of Chlamys farreri was carried out. The four determined results indicated that there existed different extent heterosis (3% similar to 52 %) for the growth in three types of F-1 hybrids, and the offspring derived from CC female X Rmale had a stronger heterosis among the crosses at the medium-term; the uptrend among traits are wet weight > shell width > shell length > shell height, Chinese cultural population could be recognized as excellent parent, and seasonal variations influence very much on the daily increment and growth rate of each trait of Chlamys farreri and it is only able to survive and could barely grow in winter (6 similar to 8 months), but grows fast in temperate season (10similar to12 months).

Studies on growth rate and grazing mortality rate by microzooplankton of size-fractionated phytoplankton in spring and summer in the Jiaozhou Bay, China

Dilution experiments were performed to examine the growth rate and grazing mortality rate of size-fractionated phytoplankton at three typical stations, inside and outside the bay, in the spring and summer of 2003 in the Jiaozhou Bay, China. in spring, the phytoplankton community structure was similar among the three stations, and was mainly composed of nanophytoplankton, such as, Skeletonema costatum and Cylindrotheca closterium. The structure became significantly different for the three stations in summer, when the dominant species at Stas A, B and C were Chaetoceros curvisetus, Pseudo-nitzschia delicatissima, C. affinis, C. debilis, Coscinodiscus oculus-iridis and Paralia sulcata respectively. Tintinnopsis beroidea and T. tsingtaoensis were the dominant species in spring, whereas the microzooplankton was apparently dominated by Strombidium sp. in summer. Pico- and nanophytoplankton had a relatively greater growth rate than microzooplankton both in spring and summer. The growth rate and grazing mortality rate were 0.18 similar to 0.44 and 0.12 similar to 1.47 d(-1) for the total phytoplankton and 0.20 similar to 0.55 and 0.21 similar to 0.37 d-1 for nanophytoplankton in spring respectively. In summer, the growth rate and grazing mortality rate were 0.38 similar to 0.71 and 0.27 similar to 0.60 d-1 for the total phytoplankton and 0.11 similar to 1.18 and 0.41 similar to 0.72 d(-1) for nano- and microphytoplankton respectively. The carbon flux consumed by microzooplankton per day was 7.68 similar to 39.81 mg/m(3) in spring and 12.03 similar to 138.22 mg/m(3) in summer respectively. Microzooplankton ingested 17.56%similar to 92.19% of the phytoplankton standing stocks and 31.77%similar to 467.88% of the potential primary productivity in spring; in contrast, they ingested 34.60%similar to 83.04% of the phytoplankton standing stocks and 71.28%similar to 98.80% of the potential primary productivity in summer. Pico- and nanophytoplankton appeared to have relatively greater rates of growth and grazing mortality than microphytoplankton during the experimental period. The grazing rate of microzooplankton in summer was a little bit greater than that in spring because of the relatively higher incubation temperature and different dominant microzooplankton species. Microzooplankton preferred ingesting nanophytoplankton to microphytoplankton in spring, while they preferred ingesting picophytoplankton to nanophytoplankton and microphytoplankton in summer. Compared with the results of dilution experiments performed in various waters worldwide, the results are in the middle range.

Studies on the transmission of WSSV (white spot syndrome virus) in juvenile Marsupenaeus japonicus via marine microalgae

We studied the possible role that marine microalgae may play during the outbreaks of WSS (white spot syndrome). In order to elucidate the possibility of marine microalgae carrying WSSV (white spot syndrome virus), six marine microallgae (Isochr.vsis galbana, Skeletonema costatum, Chlorella sp., Heterosigma akashiwo, Scrippsiella trochoidea, Dunaliella salina) were co-cultured with adult Marsupenaeus japollicus infected with WSSV and were assayed daily by nested-PCR to study whether they could carry WSSV. Further experiments were conducted to investigate whether the virus carried by microalgae could re-infect juvenile M. japonicus. Results showed that all of the experimental microalgae, except H. akashiwo could carry WSSV, and among them, Chlorella sp. and S. trochoidea had the strongest WSSV-carrying ability. Unlike other invertebrate carriers of WSSV, the WSSV detections in microalgae, which were positive after I and 3 days, were negative after 10 days of incubation. WSSV detection results in juvenile M. japonicus showed that the juvenile shrimp were re-infected by co-cultured Chlorella sp., although the juvenile M. japonicus carried so small an amount of WSSV that it could only be detected by nested-PCR. The results of this experiment suggest that microalgae might be one possible horizontal transmission pathway for WSSV. Further research, however, is required to better understand the factors behind the different carrying abilities and virus-carrying mechanisms of different microalgae. (c) 2007 Elsevier Inc. All rights reserved.

Studies on nitric oxide synthase activity in haemocytes of shrimps Fenneropenaeus chinensis and Marsupenaeus japonicus after white spot syndrome virus infection

The nitric oxide synthase (NOS) activity in the haemocytes of shrimps Fenneropenaeus chinensis (Osbeck) and Marsupenaeus japonicus (Bate) was Studied after white spot syndrome virus (WSSV) infection to determine its characteristics in response to virus infection. First, the NOS activity in haemocytes of shrimps was determined by the means of NBT reduction and changes in cell conformation. And the variations of NOS activity in shrimps after challenge with WSSV intramuscularly were evaluated through the analysis Of L-citrulline and total nitrite/nitrate (both as NO derivates) concentrations. The result showed that NOS activity in the haemocytes of F chinensis increased slightly from 0 to 12 h postchallenge, indicated by the variations Of L-Citrulline (from 11.15 +/- 0.10 to 12.08 +/- 0.64 mu M) and total nitrite/nitrate concentrations (from 10.45 +/- 0.65 to 12.67 +/- 0.52 mu M). Then it decreased sharply till the end of the experiment (84 h postchallenge), the concentrations Of L-Citrulline and total nitrite/nitrate at 84 It were 1.58 +/- 0.24 and 2.69 +/- 0.70 mu M, respectively. The LPS-stimulated NOS activity kept constant during the experiment. However, in M. japonicus, the NOS activity kept increasing during the first 72 It postchallenge, the concentrations Of L-Citrulline and total nitrite/nitrate increased from 7.82 +/- 0.77 at 0 h to 10.79 +/- 0.50 mu M at 72 h, and from 8.98 +/- 0.43 at 0 h to 11.20 +/- 0.37 mu M at 72 h, respectively. Then it decreased till the end of the experiment (216 h postchallenge), and the concentrations of L-Citrulline and total nitrite/nitrate at 216 h were 5.66 +/- 0.27 and 4.68 +/- 0.16 mu M, respectively. More importantly, an apparent increase of I-PS-stimulated NOS activity was observed in M japonicus at 48 h postchallenge, which was about 4 times higher than that in the control group of health shrimps. In correspondence with the difference of NOS activity between the two species of shrimps, the Cumulative mortalities of the shrimps were also different. All shrimps of F. chinensis in the mortality experiment died in 66 h, much more quickly than M. japonicus, Whose accumulative mortality reached 100% after 240 h. Data here reported let us hypothesize that NOS activity in the haemocytes of shrimps F chinensis and M. japonicus responses to WSSV infection differently, and this might be one of the reasons for the different susceptibility of F chinensis and M. japonicus to WSSV infection. (c) 2005 Elsevier Inc. All rights reserved.

Studies on factors relating to the development of defects in commercial cheese

Defects in commercial cheese result in a downgrading of the final cheese and a consequential economic loss to the cheese producer. Developments of defects in cheese are often not fully understood and therefore not controllable by the producer. This research investigated the underlying factors in the development of split and secondary fermentation defect and of pinking defects in commercial Irish cheeses. Split defect in Swiss-type cheese is a common defect associated with eye formation and manifests as slits and cracks visible in the cut cheese loaf (Reinbold, 1972; Daly et al., 2010). No consensus exists as to the definitive causes of the defect and possible factors which may contribute to the defect were reviewed. Models were derived to describe the relationship between moisture, pH, and salt levels and the distance from sample location to the closest external block surface during cheese ripening. Significant gradients within the cheese blocks were observed for all measured parameters in cheeses at 7 day post/after manufacture. No significant pH gradient was found within the blocks on exit from hot-room ripening and at three months post exit from the hot-room. Moisture content reached equilibrium within the blocks between exit from hot-room and 3 months after exit from hot-room while salt and salt-to-moisture levels had not reached equilibrium within the cheese blocks even at three months after exit from hot-room ripening. A characterisation of Swiss-type cheeses produced from a seasonal milk supply was undertaken. Cheeses were sampled on two days per month of the production year, at three different times during the manufacturing day, at internal and external regions of the cheese block and at four ripening time points (7 days post manufacture, post hot-room, 14 days post hot-room and 3 months in a cold room after exit from hot-room). Compositional, biochemical and microbial indices were determined, and the results were analysed as a splitplot with a factorial arrangement of treatments (season, time of day, area) on the main plot and ripening time on the sub-plot. Season (and interactions) had a significant effect on pH and salt-in-moisture levels (SM), mean viable counts of L. helveticus, propionic acid and non-starter lactic acid bacteria, levels of primary and secondary proteolysis and cheese firmness. Levels of proteolysis increased significantly during hot-room ripening but also during cold room storage, signifying continued development of cheese ripening during cold storage (> 8°C). Rheological parameters (e.g. springiness and cohesiveness) were significantly affected by interactions between ripening and location within cheese blocks. Time of day of manufacture significantly affected mean cheese calcium levels at 7 days post manufacture and mean levels of arginine and mean viable counts of NSLAB. Cheeses produced during the middle of the production day had the best grading scores and were more consistent compared to cheeses produced early or late during day of manufacture. Cheeses with low levels of S/M and low values of resilience were associated with poor grades at 7 days post manufacture. Chesses which had high elastic index values and low values of springiness in the external areas after exit from hot-room ripening also obtained good commercial grades. Development of a pink colour defect is an intermittent defect in ripened cheese which may or may not contain an added colourant, e.g., annatto. Factors associated with the defect were reviewed. Attempts at extraction and identification of the pink discolouration were unsuccessful. The pink colour partitioned with the water insoluble protein fraction. No significant difference was observed between ripened control and defect cheese for oxygen levels and redox potential or for the results of elemental analysis. A possible relationship between starter activity and defect development was established in cheeses with added coulourant, as lower levels of residual galactose and lactose were observed in defective cheese compared to control cheese free of the defect. Swiss-type cheese without added colourant had significantly higher levels of arginine and significantly lower lactate levels. Flow cell cytometry indicated that levels of bacterial cell viability and metabolic state differed between control and defect cheeses (without added colourant). Pyrosequencing analysis of cheese samples with and without the defect detected the previously unreported bacteria in cheese, Deinococcus thermus (a potential carotenoid producer). Defective Swiss-type cheeses had elevated levels of Deinococcus thermus compared to control cheeses, however the direct cause of pink was not linked to this bacterium alone. Overall, research was undertaken on underlying factors associated with the development of specific defects in commercial cheese, but also characterised the dynamic changes in key microbial and physicochemical parameters during cheese ripening and storage. This will enable the development of processing technologies to enable seasonal manipulation of manufacture protocols to minimise compositional and biochemical variability and to reduce and inhibit the occurrence of specific quality defects.

Studies on the texture, functionality, rheology and sensory properties of Cheddar and Mozzarella cheeses

The effect of fortification of skim milk powder and sodium caseinate on Cheddar cheeses was investigated. SMP fortification led to decreased moisture, increased yield, higher numbers of NSLAB and reduced proteolysis. The functional and texture properties were also affected by SMP addition and formed a harder, less meltable cheese than the control. NaCn fortification led to increased moisture, increased yield, decreased proteolysis and higher numbers of NSLAB. The functional and textural properties were affected by fortification with NaCn and formed a softer cheese that had similar or less melt than the control. Reducing the lactose:casein ratio of Mozzarella cheese by using ultrafiltration led to higher pH, lower insoluble calcium, lower lactose, galactose and lactic acid levels in the cheese. The texture and functional properties of the cheese was affected by varying the lactose:casein ratio and formed a harder cheese that had similar melt to the control later in ripening. The flavour and bake properties were also affected by decreased lactose:casein ratio; the cheeses had lower acid flavour and blister colour than the control cheese. Varying the ratio of αs1:β-casein in Cheddar cheese affected the texture and functionality of the cheese but did not affect insoluble calcium, proteolysis or pH. Increasing the ratio of αs1:β-casein led to cheese with lower meltability and higher hardness without adverse effects on flavour. Using camel chymosin in Mozzarella cheese instead of calf chymosin resulted in cheese with lower proteolysis, higher softening point, higher hardness and lower blister quantity. The texture and functional properties that determine the shelf life of Mozzarella were maintained for a longer ripening period than when using calf chymosin therefore increasing the window of functionality of Mozzarella. In summary, the results of the trials in this thesis show means of altering the texture, functional, rheology and sensory properties of Mozzarella and Cheddar cheeses.

Studies on Understanding Individual Willingness to Disclose Genetic Information to Public and Private Stakeholders

While technologies for genetic sequencing have increased the promise of personalized medicine, they simultaneously pose threats to personal privacy. The public’s desire to protect itself from unauthorized access to information may limit the uses of this valuable resource. To date, there is limited understanding about the public’s attitudes toward the regulation and sharing of such information. We sought to understand the drivers of individuals’ decisions to disclose genetic information to a third party in a setting where disclosure potentially creates both private and social benefits, but also carries the risk of potential misuse of private information. We conducted two separate but related studies. First, we administered surveys to college students and parents, to determine individual attitudes toward and inter-generational influences on the disclosure decision. Second, we conducted a game-theory based experiment that assessed how participants’ decisions to disclose genetic information are influenced by societal and health factors. Key survey findings indicate that concerns about genetic information privacy negatively impact the likelihood of disclosure while the perceived benefits of disclosure and trust in the institution receiving the information have a positive influence. The experiment results also show that the risk of discrimination negatively affects the likelihood of disclosure, while the positive impact that disclosure has on the probability of finding a cure and the presence of a monetary incentive to disclose, increase the likelihood. We also study the determinants of individuals’ decision to be informed of findings about their health, and how information about health status is used for financial decisions.

Preliminary studies on the effect of the increased biodiversity on the population dynamics of Caliroa cerasi L. (Hymenoptera: Tenthredinidae), and its natural enemy Trichogramma minutum R. (Hymenoptera: Trichogrammatidae) in a sweet cherry (Prunus avium L.) orchard in Virch (Southern Patagonia Argentina)

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Preliminary studies on the effect of the increased biodiversity on the population dynamics of Caliroa cerasi L. (Hymenoptera: Tenthredinidae), and its natural enemy Trichogramma minutum R. (Hymenoptera: Trichogrammatidae) in a sweet cherry (Prunus avium L.) orchard in Virch (Southern Patagonia Argentina)

p.25-36