Preparation and Characterization of Nanostructured CaCu2.90 Zn0.10 Ti4O12 Ceramic

Nanostructure CaCu2.90Zn0.10Ti4O12 (CCZTO) electronic ceramic was synthesized by semi‐wet route. The objective of this route is to enable the calcination and sintering processes to go for completion in shorter time and at lower temperature.The samples were characterized by XRD, TEM, SEM and EDX analyses. The crystallite size of the CCZTO ceramic, obtained by XRD using Debye Scherrer formula, range from 38‐74nm which is in good agreement with the particle size observed by TEM analysis. It was observed clearly that the grain size significantly increased with an increase in sintering duration. Dielectric measurements were carried out by LCR meter in the temperature range, 300‐  500K, at few selected frequencies. It was also observed that the dielectric constant and dielectric loss of CCZTO are temperature independent in higher frequency whereas temperature dependent in low frequency region. The ceramics exhibit high dielectric constant of 1.35 x 10 4 at 1 kHz

Oxy-Ti(IV) Dicarboxylates

208-20

Using multi-valued decision diagram to solve the expected hop count problem

The Expected Hop Count (EHC) of a computer communication network has so far been computed for network models that consider only device or link failure, but not both. We introduce an Augmented Ordered Multi-valued Decision Diagram (OMDD-A) to obtain the EHC of a network in which both devices and links may fail. The OMDD-A approach can compute the EHC of a 2100 grid network with 299 paths, which is unsolvable using existing techniques. We show that OMDD-A generates significantly fewer nodes than the corresponding ordered binary decision diagram, leading to large reductions in processing time

Heap Reference Analysis Using Access Graphs

Despite significant progress in the theory and practice of program analysis, analysing properties of heap data has not reached the same level of maturity as the analysis of static and stack data. The spatial and temporal structure of stack and static data is well understood while that of heap data seems arbitrary and is unbounded. We devise bounded representations which summarize properties of the heap data. This summarization is based on the structure of the program which manipulates the heap. The resulting summary representations are certain kinds of graphs called access graphs. The boundedness of these representations and the monotonicity of the operations to manipulate them make it possible to compute them through data flow analysis. An important application which benefits from heap reference analysis is garbage collection, where currently liveness is conservatively approximated by reachability from program variables. As a consequence, current garbage collectors leave a lot of garbage uncollected, a fact which has been confirmed by several empirical studies. We propose the first ever end-to-end static analysis to distinguish live objects from reachable objects. We use this information to make dead objects unreachable by modifying the program. This application is interesting because it requires discovering data flow information representing complex semantics. In particular, we discover four properties of heap data: liveness, aliasing, availability, and anticipability. Together, they cover all combinations of directions of analysis (i.e. forward and backward) and confluence of information (i.e. union and intersection). Our analysis can also be used for plugging memory leaks in C/C++ languages.Comment: Accepted for printing by ACM TOPLAS. This version incorporates referees' comment

Dissociative Autoionization in (1+2)-photon Above Threshold Excitation of H2 Molecules

We have theoretically studied the effect of dissociative autoionization on the photoelectron energy spectrum in (1+2)-photon above threshold ionization(ATI) of H2 molecules. We have considered excitation from the ground state X-singlet-Sigma-g+(v=0,j) to the doubly excited autoionizing states of singlet-Sigma-u+ and singlet-Pi-u+ symmetry, via the intermediate resonant B-singlet-Sigma-u+(v=5,j) states. We have shown that the photoelectron energy spectrum is oscillatory in nature and shows three distinct peaks above the photoelectron energy 0.7 eV. This feature has been observed in a recent experiment by Rottke et al, J. Phys. B, Vol. 30, p-4049 (1997).Comment: 11 pages and 4 figure

Communicating with older people about physical activity

Objective: Little is known about how to effectively encourage higher levels of activity among older people. This study tested the effectiveness of a public service advertisement designed according to recommendations for communicating with older audiences and featuring five types of moderate-to-vigorous physical activity: tennis, line dancing, cycling, swimming and jogging. Methods: A survey administered to 1,200 Australians aged 50+ years assessed effects of the public service advertisement on: motivation (intrinsic and extrinsic); perceived believability, relevance, and effectiveness; and feelings elicited (e.g. interest, hope, guilt). Open-ended questions enabled respondents to describe aspects of the ad they considered to be most and least effective. Results: Moderate to high scores were obtained on the motivation measures and the ad evaluation criteria of perceived effectiveness, likeability, believability and personal relevance. Mean scores for the feelings measures were generally low, with the exception of the positive feelings of being interested, inspired, hopeful and determined. Conclusions: The results suggest physical activity promotion ads can be motivating across age and socioeconomic subgroups of older people. Implications for public health: Ads aiming to encourage older people to be more physically active may be accepted and effective if they depict everyday older people enjoying a range of relevant activities

Preparation, Characterization & Solubility of Arsenic Hydroxylapatite

1014-101

The measurement of primary productivity in a high-rate oxidation pond (HROP)

A high-rate oxidation pond is studied as a model system for comparing 14C and oxygen evolution methods as tools for measuring primary productivity in hypertrophic aquatic systems. Our results indicate that at very dense algal populations (up to 5 mg chl. a l−1) and high photosynthetic rates, 14C based results may severely underestimate primary productivity, unless a way is found to keep incubation times very short. Results obtained with our oxygen electrode were almost an order of magnitude higher than those obtained by all 14C procedures. These higher values correspond fairly well with a field-tested computer-simulation model, as well as with direct harvest data obtained at the same pond when operated under similar conditions. The examination of the size-fractionation of the photosynthetic activity underscored the important contribution of nannoplanktonic algae to the total production of the syste

Testing campaign slogans designed to motivate older people to be more physically active

Objectives and importance of study: Being physically active is critical for healthy ageing, yet many older people do not meet physical activity guidelines. The aim of this study was to test the relative effectiveness of five previously identified campaign slogans designed to encourage older people to be more physically active: ‘Be active 30–60 minutes a day to stay fit and well’; ‘Move more, live longer’; ‘Stay fit to stay functional’; ‘This is your time – enjoy being strong and active’; and ‘Use it or lose it’. Study type: Online experiment Methods: A total of 1200 Australians aged 50 years and older (50% female, mean age 65 years) were recruited to complete an online survey, with respondents randomised to answer a series of questions on a video featuring one of the five slogan conditions. One-way ANOVAs with Tukey’s post-hoc tests were used to identify differences in outcomes between slogans. Results: Overall, the slogans were assessed favourably, suggesting older adults may be receptive to messages about increasing their physical activity. ‘Use it or lose it ‘performed best across the outcome measures of internal and external motivation, perceived effectiveness, liking, believability, and personal relevance. Conclusion: Efforts to encourage physical activity among older Australians could use the slogan ‘Use it or lose it’ as an evidence-based tagline. © 2023 Pettigrew et al

Extended-release formulations of somatostatin for ocular application and their effect on vascular endothelial growth factor as a biomarker of diabetic retinopathy

The International Diabetes Federation reports 642 million adults globally will be living with diabetes by 2040. Approximately one third will go on to develop some extent of diabetic retinopathy (DR), with ca. 93 million current sufferers. Current therapeutic options for DR target the late stages of the disease when vision is already significantly degraded. These treatments aim to prevent haemorrhaging using laser therapy or intraocular injections of corticosteroids and therapeutic anti-vascular endothelial growth factor (VEGF) antibodies. However, efficacy is low or variable with frequent injections required and associated with serious ocular side-effects. Moreover, all result in some degree of tissue destruction. New therapies to prevent the onset or arrest the progression of the disease before overt microvascular pathologies are therefore essential. Somatostatin (SST) has been reported to have neuroprotective, antiangiogenic effects in addition to the regulation of water and ion transport in the retina. It is postulated that SST could attenuate key pathological changes in DR. However, studies with SST analogues such as octreotide demonstrated that systemic administration resulted in the drug reaching the retina only when there is a breakdown of the blood retinal barrier. SST is produced by the retina and there is downregulation of SST levels in the retina of diabetic patients, correlated to retinal neurodegeneration. SST eye drops show some promise (EUROCONDOR). The purpose of this thesis was to develop a modified-release formulation of SST enhancing the treatment of diabetic retinopathy. The physicochemical characterization of SST self-assembled hydrogels was performed to investigate the rheological and morphological properties of the self-assembled hydrogels and their influence on the mechanism and rate of SST release in vitro. This study demonstrated that the SST hydrogels were shear-thinning, did not exhibit thermogelation and exhibited a higher degree of structure with higher somatostatin concentration and in the presence of electrolytes. Transmission electron micrographs demonstrated the presence of nanofibrils that were narrower and denser in appearance in the presence of electrolytes. This corresponds to the higher G' (storage modulus) of the SST hydrogels in electrolytes and at a higher SST concentration. In the presence of electrolytes SST hydrogels released a lower cumulative percentage of SST monomers at 48 hours compared to those in water. The release kinetics of the SST monomers demonstrated concurrent first-order and zero-order mechanisms. However the limited release at 48 hours in vitro precludes these selfassembled hydrogels as depots for SST delivery. Two formulation candidates of SST were produced and characterized. The first candidate was SST 2.5% w/w microparticles encapsulated in a triblock polymer of polycaprolactone-polyethylene glycol-polycaprolactone (PCL-PEG-PCL) prepared by the double emulsion method. Encapsulation efficiency of SST ranged from 19% to 43% of which 1.4% -4% was released over 16-24 days. Scanning electron microscopy of the microparticles showed spherical aggregates which averaged 32 µm in size. The release kinetics of somatostatin from the microparticles demonstrated first-order decay to a plateau with good mean R2 value of 0.979. The second formulation candidate consisted of somatostatin 5% w/w entrapped in hydroxypropyl methylcellulose (HPMC) 3% w/w or 6% w/w hydrogel. The SST in HPMC hydrogels were subjected to rheological studies and FTIR characterization, transmission electron microscopy and release studies. Rheological tests demonstrated that inclusion of SST at a concentration of 5% w/w did not alter the characteristic properties of HPMC matrices. FTIR data showed transition of SST structure from random conformations to structured organisations upon exposure to simulated lachrymal fluid (SLF). These transitions were hindered in the HPMC hydrogels compared to SST 5% w/w in water, consistent with the hypothesis that the entanglement network of HPMC acts a barrier to the interaction of the electrolytes in SLF with SST. This was supported by the TEM images. Release studies demonstrated an extended release of SST monomers from the SST/HPMC hydrogels compared to SST 5% w/w in water. The SST 5% w/w solution reached a 100% release at 6 hours. The SST 5% w/w in HPMC 3% w/w gels released a total of 45.6% incorporated SST at 96 hours whereas the SST 5% w/w in HPMC 6% w/w gels continued to release a total of 37.6% at 10 days. The release kinetics of SST 5% w/w in HPMC 3% w/w and HPMC 6% w/w hydrogels were fitted to a hybrid model of release with R2 values of 0.998 and 0.997 respectively. Mass spectrometry confirmed the structural integrity of the SST released from hydrogels. SST 5% w/w in HPMC 6% w/w hydrogels are the most promising candidate in terms of SST delivery, with delayed SST nanofibril formation and extended duration of release in comparison to SST 5% w/w aqueous dispersions. The safety and efficacy of SST solutions at different concentrations and that from hydrogel formulations were tested on immortalized human retinal pigment epithelium cells (ARPE-19). MTT cell viability assay was conducted to assess the effect of the release samples from SST/HPMC hydrogels and SST 10-7M and 10-6 M on the viability of the ARPE-19 cells. The results of the MTT assay demonstrated a significant decrease in cell viability only by the Release Day 1 samples compared to control. It is postulated that the combination of the viscosity of the Release Day 1 sample with the higher concentration of SST present at 24 hours may have additive effects on the viability of the cells. The markers for assessment for efficacy were expression of vascular endothelial growth factor receptor-2 (VEGF-R2) and secretion of VEGF by the ARPE-19 cells. Immunofluorescence was used to assess the effect of SST concentrations (10-8 M to 10-5 M) on the expression of VEGF-R2 levels. The results of the first study showed that SST 10-7 M produced significant downregulation of VEGF-R2 expression in high glucose (25 mM) conditions compared to normal glucose (5 mM) conditions. The quantitative analysis of VEGF secretion in the same conditions performed by ELISA did not show any significant effect by the treatments applied in the same conditions. In conclusion, two formulations of somatostatin for ocular delivery were developed and characterised. The microparticle formulation showed reasonable encapsulation and duration of release, however, the more promising candidate consisted of somatostatin entrapped in a HPMC network and demonstrated modified release of somatostatin over 10 days. This work has introduced HPMC as a suitable candidate for modifying the release rate of peptides. The current work also evidenced the downregulation of the VEGF receptor 2 (VEGF-R2) by somatostatin at a concentration of 10-7 M in high glucose (25 mM) conditions. Although further studies are warranted on other retinal cell lines and animal models with additional markers, the identification of a new polymeric carrier for the delivery of somatostatin adds to the current body of work in the search for a noninvasive treatment for diabetic retinopathy