57 resultados para crosslink by oxidation with sodium periodate

em Deakin Research Online - Australia


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When aqueous sodium borohydride (50 mM) is added to a solution of potassium permanganate (1mM, in sodium hexametaphosphate) at acidic pH, bright red-orange emission is easily visible in a darkened room. This chemiluminescence emission is due to an excited state of manganese (II) that undergoes solution phase phosphorescence and provides an excellent opportunity for students to explore the relationship between the initial oxidation state of the manganese and the likelihood of luminescence. Not surprisingly Mn(VII), Mn(IV) and Mn(III) all give rise to chemiluminescence where as Mn(II) fails to react.

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This data was obtained from an experiment, where polycarbonate (PC) membranes were used to filter two types of organic foulants, including protein and sodium alginate, from suspension in a dead-end filtration cell. These model foulants were stained with fluorescent dyes before filtration. Consequently, a stack of images were captured from the fouling layers on the PC membrane surface using confocal laser scanning microscope (CLSM). This data collection contains 105 2D images of polycarbonate (PC) membranes fouling layer. This data collection would be useful to investigate membrane fouling mechanism by membrane materials researchers and water researchers.

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Yeast cells begin to bud and enter S phase when growth conditions are favourable during G1 phase. When subjected to some oxidative stresses, cells delay entry at G1 allowing repair of cellular damage. Hence, oxidative stress sensing is coordinated with the regulation of cell cycle. We identified a novel function of the cell-cycle regulator of Saccharomyces cerevisiae, Swi6p, as a redox sensor through its cysteine residue at position 404. When alanine was substituted at this position, the resultant mutant, C404A, was sensitive to several reactive oxygen species and oxidants including linoleic acid hydroperoxide, the superoxide anion and diamide. This mutant lost the ability to arrest in G1 phase upon treatment with lipid hydroperoxide. The Cys404 residue of Swi6p in wild-type cells was oxidised to a sulfenic acid when cells were subjected to linoleic acid hydroperoxide. Mutation of Cys404 to Ala abolished the down-regulation of expression of the G1 cyclin genes CLN1, CLN2, PCL1 and PCL2 that occurred when cells of the wild type were exposed to the lipid hydroperoxide. In conclusion, oxidative stress signaling for cell-cycle regulation occurs through oxidation of the G1/S-speicific transcription factor Swi6p and consequently leads to suppression of the expression of G1-cyclins and delay in cells entering the cell cycle.

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This collection is the result of an investigation into the backwashing efficiency of polycarbonate (PC) membrane fouled by two types of organic foulants, protein and sodium alginate. In this experiement, polycarbonate (PC) membrane was used to filter those organic foulants from suspensions in a dead-end stirred cell. The organic foulants were stained with fluorescent dyes before filtration. After filtration, the PC membrane was backwashed. Consequently, a stack of images were captured from the fouling layers on the PC membrane surface using confocal laser scanning microscope (CLSM) and its associated image acquisition software. It contains image data of polycarbonate (PC) membranes' fouling layer when two types of organic foulants (protein and sodium alginate) are present. By comparing with the same membrane without backwashing, the efficiency of backwashing was computed. This data collection would be useful to researchers evaluating the backwashing efficiency of PC membrane in order to optimize frequency and operational conditions of backwashing by membrane materials researchers and by water..

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This collection is the result of an investigation into the backwashing efficiency of poly(vinylidene fluoride) (PVDF) membrane fouled by yeast and sodium alginate. In this experiement, poly(vinylidene fluoride) (PVDF) membrane was used to filter two types of organic foulants from suspensions in a dead-end stirred cell. The organic foulants including yeast and sodium alginate were stained with fluorescent dyes before filtration. After filtration, the PC membrane was backwashed. Consequently, a stack of images were captured from the fouling layers on the PVDF membrane surface using confocal laser scanning microscope (CLSM) and its associated image acquisition software. The data collection contains image data of poly(vinylidene fluoride) (PVDF) membranes' fouling layer when two types of organic foulants (yeast and sodium alginate) are present. By comparing with the same membrane without backwashing, the efficiency of backwashing was computed. The collection would be useful to researchers evaluating the backwashing efficiency of poly(vinylidene fluoride) (PVDF) membrane in order to optimize frequency and operational conditions of backwashing by membrane materials and by water.

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This sub-collection is the result of an investigation into the mechanism of organic fouling in membrane filtration processes. In this experiment, poly(vinylidene fluoride) (PVDF) membranes were used to filter two types of organic foulants, protein and sodium alginate with a concentration of 50mg/l and 40 mg/l, respectively, from suspension in a dead-end filtration cell. These model foulants were stained with fluorescent dyes before filtration. This dataset contains a stack of images of the fouling layer on the PVDF membrane surface captured by a confocal laser scanning microscope (CLSM) and its associated acquisition software. This dataset would be useful to researchers who are investigating the membrane organic fouling mechanism so that new membrane materials and new anti-fouling surface treatment technologies can be developed for water and wastewater industry in the future.

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In this study, shell powder was modified by sodium stearate surface modifier for improving the compatibility of SP with polymer materials. The surface modifiers influence on the physical and chemical properties of SP were studied by scanning electron microscope(SEM), fourier infrared spectrum(FT-IR), surface contact angle meter, XRD diffraction analysis meter and other modern instruments and analysis method. The results showed that the surface modifier was successfully coupled to the shell powder surface. After surface modifier modification, the interfacial compatibility of the shell powder with polymer materials was effectively improved. The contact angle of shell powder surface increased from 73.5 ° to 110.8 °, along with the dosage of sodium stearate surface modifier was 4.0%. All results suggested that modified shell powder is promising for using as a reinforcement filler in polymer materials. © (2014) Trans Tech Publications, Switzerland.

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Zwitterions with a cyano group on the side chain (CZ) were synthesized. Although the addition of CZ caused a slightly negative effect on viscosity, ionic conductivity, limiting current density, and lithium transference number, the oxidation limit of PEGDME/lithium bis(trifluoromethylsulfonyl)amide (LiTFSA) composites was improved to over 5 V. For charge/discharge testing using Li|electrolyte|LiCoO2 cells, the cycle stability of PEGDME/LiTFSA with CZ in the voltage range of 3.0-4.6 V was much higher than that of PEGDME/LiTFSA. Incorporating a small mole fraction of CZ into PEGDME-based electrolytes prevented an increase in the interface resistance between the electrolyte and cathode with increasing numbers of the cycle.

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This study compared the rate of self-reported alcohol and other drug use in a sample of 30 young adults with mild intellectual disability whose offending behaviour had resulted in involvement in the criminal justice system, with a matched comparison group of 30 non-offenders. Performance on an alcohol and other drug knowledge test was also compared. The results indicated that many individuals with mild intellectual disability regularly consumed alcohol and used illicit drugs. Furthermore, the data suggest a possible link between substance abuse and offending behaviour in this population. Individuals who had offended reported greater use of both legal and illicit drugs than their non-offending counterparts and many reported that they had been under the influence of alcohol or illicit drugs at the time of committing the offence that had resulted in their current placement within the criminal justice system. Although deficits in knowledge were apparent in both groups, the offenders demonstrated greater overall knowledge about alcohol and other drugs.

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Objective: To explore medication knowledge and self management practices of people with type 2 diabetes.

Design: A one-shot cross sectional study using in-depth interviews and participant observation.

Setting: Diabetes outpatient education centre of a university teaching hospital.

Subjects:
People with type 2 diabetes, n=30, 17 males and 13 females, age range 33-84, from a range of ethnic groups.

Outcome measures: Ability to state name, main actions and when to take medicines. Performance of specific medication-related tasks; opening bottles and packs, breaking tablets in half, administering insulin, and testing blood glucose.

Results: Average medication use > or = 10 years. Respondents were taking 86 different medicines, mean 7 +/- 2.97 SD. Dose frequency included two, three and four times per day. All respondents had > or = 2 diabetic complications +/- other comorbidities. The majority (93%) were informed about how and when to take their medicines, but only 37% were given information about side effects and 17% were given all possible seven items of information. Younger respondents received more information than older respondents. Older respondents had difficulty opening bottles and breaking tablets in half. Twenty per cent regularly forgot to take their medicines. Increasing medication costs was one reason for stopping medicines or reducing the dose or dose interval. The majority tested their blood glucose but did not control test their meters and 33% placed used sharps directly into the rubbish.

Conclusion:
Polypharmacy was common. Medication knowledge and self management were inadequate and could lead to adverse events.

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Human telomerase reverse transcriptase (hTERT) underlies cancer cell immortalization, and the expression of hTERT is regulated strictly at the gene transcription. Here, we report that transcription factor Ets2 is required for hTERT gene expression and breast cancer cell proliferation. Silencing Ets2 induces a decrease of hTERT gene expression and increase in human breast cancer cell death. Reconstitution with recombinant hTERT rescues the apoptosis induced by Ets2 depression. In vitro and in vivo analyses show that Ets2 binds to the EtsA and EtsB DNA motifs on the hTERT gene promoter. Mutation of either Ets2 binding site reduces the hTERT promoter transcriptional activity. Moreover, Ets2 forms a complex with c-Myc as demonstrated by co-immunoprecipitation and glutathione S-transferase pulldown assays. Immunological depletion of Ets2, or mutation of the EtsA DNA motif, disables c-Myc binding to the E-box, whereas removal of c-Myc or mutation of the E-box also compromises Ets2 binding to EtsA. Thus, hTERT gene expression is maintained by a mechanism involving Ets2 interactions with the c-Myc transcription factor and the hTERT gene promoter, a protein-DNA complex critical for hTERT gene expression and breast cancer cell proliferation.

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This study investigates the capacity of individuals with an intellectual disability to make accurate discriminations of computer-generated displays and also to reproduce the characteristics of those displays. The findings suggest that the learning of everyday motor skills in this population may be hampered by difficulties in visually perceiving important characteristics of the demonstration. Procedures, employed for teaching these skills to intellectually disabled, are being reassessed in the light of these findings.

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Objective
Glucosamine has been previously shown to suppress cartilage aggrecan catabolism in explant cultures. We determined the effect of glucosamine on ADAMTS5 (a disintegrin-like and metalloprotease domain (reprolysin type) with thrombospondin type-1 motifs 5), a major aggrecanase in osteoarthritis, and investigated a potential mechanism underlying the observed effects.

Design
HEK293F and CHO-K1 cells transiently transfected with ADAMTS5 cDNA were treated with glucosamine or the related hexosamine mannosamine. Glucosamine effects on FURIN transcription were determined by quantitative RT-PCR. Effects on furin-mediated processing of ADAMTS5 zymogen, and aggrecan processing by glucosamine-treated cells, were determined by western blotting. Post-translational modification of furin and N-glycan deficient furin mutants generated by site-directed mutagenesis was analyzed by western blotting, and the mutants were evaluated for their ADAMTS5 processing ability in furin-deficient CHO-RPE.40 cells.

Results

Ten mM glucosamine and 5–10 mM mannosamine reduced excision of the ADAMTS5 propeptide, indicating interference with the propeptide excision mechanism, although mannosamine compromised cell viability at these doses. Although glucosamine had no effect on furin mRNA levels, western blot of furin from glucosamine-treated cells suggested altered post-translational modification. Glucosamine treatment led to decreased glycosylation of cellular furin, with reduced furin autoactivation as the consequence. Recombinant furin treated with peptide N-glycanase F had reduced activity against a synthetic peptide substrate. Indeed, site-directed mutagenesis of two furin N-glycosylation sites, Asn387 and Asn440, abrogated furin activation and this mutant was unable to rescue ADAMTS5 processing in furin-deficient cells.

Conclusions
Ten mM glucosamine reduces excision of the ADAMTS5 propeptide via interference with post-translational modification of furin and leads to reduced aggrecanase activity of ADAMTS5.