Asymmetry in effective fields of spin-orbit torques in Pt/Co/Pt stacks

Measurements of switching via spin-orbit coupling (SOC) mechanisms are discussed for a pair of inverted Pt/Co/Pt stacks with asymmetrical Pt thicknesses. Taking into account the planar Hall effect contribution, effective fields of spin-orbit torques (SOT) are evaluated using lock-in measurements of the first and second harmonics of the Hall voltage. Reversing the stack structure leads to significant asymmetries in the switching behavior, including clear evidence of a nonlinear current dependence of the transverse effective field. Our results demonstrate potentially complex interplay in devices with all-metallic interfaces utilizing SOT

Penilaian Kelakuan Hasil Kimpalan Geseran Untuk Logam Kep Ada Logam (Cu-Keluli Dan Al-Keluli) Dan Seramik Kepada Logam (Ab03-A1)

Penyambungan seramik kepada logam penting untuk menggabungkan kekuatan suhu tinggi, rintangan haus dan kakisan, serta sifat seramik yang ringan dengan keliatan dan kebolehrnesinan komponen logam. Sebagai proses penyambungan keadaan pepejal, kimpalan geseran sangat sesuai untuk penyambungan bahan dengan sifat terma dan mekanikal yang jauh berbeza, seperti logam dan seramik. Objektif tesis ini adalah menilai kimpalan geseran logam kepada logam dan seramik kepada logam. Kajian dimulakan dengan penilaian hasil kimpalan geseran antara tembaga dengan keluli (Cu- St) serta aluminium dengan keluli (Al-St) sebelum diteruskan dengan kimpalan geseran aluminium kepada alumina. Sambungan-sambungan disediakan menggunakan kelajuan putaran dan tekanan tempaan yang berbeza. Kelajuan putaran yang digunakan ialah 900 rpm, 1250 rpm dan 1800 rpm, sementara tekanan tempaan yang digunakan dalam julat, 50 MPa sehingga 110 MPa, bergantung kepada bahan yang disambung. Sambungan Cu- St menunjukkan kekuatan tegangan bertambah dengan peningkatan kelajuan putaran. Joining metals to ceramics is important because it allows the supenor high temperature properties, wear and corrosion resistance, as well as the low weight of ceramics to be combined with tough, easy-to-machine metal parts. As a solid state joining process, friction welding is well suited for joining materials with very different thermal and mechanical properties, such as metals to ceramics. The objective of this thesis was to evaluate friction joints between dissimilar-. metals as well as between metals and ceramics. This study started with a look at the effects of different process parameters on the properties of copper to steel (Cu-St) and aluminum to steel (Al-St) friction joints before moving on to aluminum to alumina (AI-Ah03) friction joints. Friction joints were prepared using different forging pressures and rotational speeds

Effect of Fish Proteins, Salt, Sugar and Monosodium Glutamate on the Microstructural, Rheological and Physico-Chemical Properties of Fish Cracker ('Keropok')

Fish cracker or more commonly known as 'keropok' in Malaysia is a popular snack food among countries in the ASEAN region. This work examines factors affecting 'keropok' quality such as the effect of fish proteins, salt. sugar, monosodium glutamate (MSG) on the gelatinisation of tapioca and sago st arches. Microstructural studies of 'keropok' during different stages of processing were al so observed and correlated to rheological behaviour. Results from differential scanning calorimetry (DSC) showed that with increasing fish content the conclusion gelatinisation temperature (Tc) of the mixture remained relatively constant while the range of gelatinisation temperature decreased. There were hardly any effect due to the addition of 1% sugar and 0.4% MSG. on the onset (To) and peak(Tp) gelatinisation temperatures of sago and tapioca starches. The addition of 2% salt had the greatest effect on gelatinisation temperature of 'keropok' mixture, linear expansion of fried'keropok',and small and large deformations of 'keropok' gel. The technology of producing a good expanded 'k that fresh fish, sufficient amount of salt (2% of the total weight of wet fish and starch), proper sequence of mixing of the 'keropok' mixture to form evenly distributed fiexpansion, full gelatinisation of fish-starch gel, and elastic fish-starch gel formation. At high fish contents (60-70%) the formation of fish protein network in the matrix caused a drop in expansion. There was, however, a sharp increase in the compressive strength of the 'keropok' gel. This result is complemented by the higher storage modulus (G') and lower loss tangent (tan ᵟ) values obtained, indicative of the existence of a strong elastic network. Such conditions were observed when the microstructure of the fish muscle fibres appeared to be well crosslinked. The findings in this study revealed that in order to produce better expanded 'keropok' and a more elastic and fully gelatinised 'keropok' gel, superior interms of appearance, shape and linear expansion, several important factors that ensure even distribution of fish proteins in the fish-starch gel must be taken into account. In conclusion, fresh fish, sufficient amount of salt (2% of the weight of wet fish and starch) and the proper sequence of adding ingredients in mixing are recommended to produce high quality ' keropok'

Chemical Constituents and Biological Activities From Garcinia Maingayi and Garcinia Parvifolia

In this present study, the stem bark of Garcinia maingayi and Garcinia parvifolia were investigated and resulted in the isolation of nine compounds. There are no previous reports on chemical components and biological activities from Garcinia maingayi. The structures of these compounds were elucidated by using spectroscopic experiments namely NMR, MS, IR and UV. Being the first report on Garcinia maingayi, detailed chemical studies have afforded two triterpenoids, stigmasterol and sitosterol, two xanthones, 1,3,7-trihydroxy-2-(3- methylbut-2-enyl)-xanthone and 1,3,6,8-tetrahydroxyxanthone, one benzophenone, isoxanthochymol, and one benzoic acid derivative methyl 3,4-dihydroxybenzoate. The findings are significant as it contributes to the knowledge of the chemotaxonomy on Garcinia species and all these compounds are new to the species. iii Meanwhile investigations on Garcinia parvifolia have afforded one triterpenoid, α- amyrin and two xanthones, cowanin and rubraxanthone. Acetylation reaction was carried out on rubraxanthone to yield triacetate rubraxanthone. This is also the first report on cytotoxic and larvicidal activities of Garcinia maingayi, Garcinia parvifolia and rubraxanthone. Cytotoxic tests were performed using HL-60 and CEM-SS cell lines. The crude hexane and chloroform extracts of Garcinia maingayi were active against HL-60 cell line with IC50 values of less than 30 μg/ml. The crude hexane and acetone extracts of Garcinia parvifolia were found to be active against CEM-SS cell line with IC50 values of less than 30 μg/ml meanwhile, the crude chloroform extract gave a significant activity with an IC50 value of 6.5 μg/ml. The antimicrobial assay was carried out against four pathogenic bacteria, Methicillin resistant Staphylococcus aures, Pseudomonas aeruginosa, Staphylococcus typhimurium and Bacillus subtilis. Most of the crude extracts tested against these microbes gave only moderate or weak activity. The antifungal activity testing of the plant extracts were carried out against the fungi Candida albican, Aspergillus ochraceaus, Sacchoromyces cerevisiae and Candida lypolytica. No activity was observed for all the crude extracts The larvicidal test was carried out towards the larvae of Aedes aegypti. All the crude extracts of Garcinia maingayi were weakly active against the larvae with LC50 values of more than 150 μg/ml. The crude extracts of Garcinia parvifolia showed moderate activities against the larvae by giving LC50 values of less than 100 μg/ml. The pure iv rubraxanthone showed a strong activity against the larvae with a LC50 value of 15.49 μg/ml

Characterization Of Malaysian Isolates Of Bovine Herpes Virus I Of Buffalo Origin

This research was carried out to investigate two isolates of bovine herpes virus I (BHV -l) isolated from buffaloes at Universiti Pertanian Malaysia , Serdang , Selangor Darul Ehsan, and compare them to a reference cattle strain of BHV- l ( Cooper strain) . The cytopathogenic and serologic properties of the three virus isolated (Buffalo respiratory , Buffalo genital , and the Cooper strain) were first studied. The cytopathogenicity of the three BHV-1 isolates was investigated using Acridine Orange staining (to compare localization of DNA) , Hematoxylin and Eosin staining (to compare morphologic changes induced in cell culture), the indirect Immunoperoxidase ( lIP) staining method ( to compare localization o f the virus antigen ) , plaque assay, and Negative Contrast Electron Microscopy

Effects of nitrogen substitution in amorphous carbon films on electronic structure and surface reactivity studied with x-ray and ultra-violet photoelectron spectroscopies

We investigated the effects of incorporating a very low percentage of nitrogen on the local and the electronic structure of amorphous carbon (a-C) using X-ray pho- toelectron spectroscopy (XPS) and ultra-violet photoelectron spectroscopy (UPS). Nitrogen-doped amorphous carbon films (a-CNx) with varying nitrogen content, were prepared by a thermal decomposition method using a mixture of CH4 + NH3 under atmosphere. A slight shift of the C 1s core-level spectrum toward the higher binding energy (BE) side was detected in a-CNx as a function of nitrogen content. This was interpreted as a charge transfer between carbon and nitrogen atoms rather than as a shift of the Fermi level (EF). The C 1s peak shifts can be explained by the presence of two kinds of C{N local structures and the charge transferred bulk C{C compo- nents by nitrogen atoms. The two kinds of deconvoluted C 1s components could be well correlated with the two N 1s components. Two localized states were detected below the EF in UPS spectra of a-CNx, which could be assigned to defect bands. These defects played a significant role in the surface reactivity, and were stabilized in a-CNx. The adsorption and reaction of NO were carried out on a-CNx as well as a-C films. It was found that both defect sites and O2- species were responsible on a-C, while O2- species were selectively active for NO adsorption on a-CNx. We concluded that nitrogen doping reduces defect density to stabilize the surface of a-C, while at the same time inducing the selective adsorption capability of NO

Colesevelam for type 2 diabetes mellitus (Protocol).

Colesevelam was originally approved for the treatment of hyperlipidaemia (high blood lipids) in the 2000s but has been shown to improve blood sugar as well. Therefore, we investigated its role in the management of type 2 diabetes mellitus. A total of 1450 patients took part in six studies investigating colesevelam. These studies lasted 8 to 26 weeks. Only one small study compared colesevelam directly to placebo, the other five studies investigated a combination of colesevelam with other antidiabetic agents versus a combination of placebo with other antidiabetic agents. There were no two studies with the same intervention and comparison group. When added to other antidiabetic agents colesevelam showed improvements in the control of blood glucose and blood lipids. However, it is difficult to disentangle the effects of colesevelam from the other antidiabetic agents used because only one study compared colesevelam to placebo. The same is true for adverse effects: three studies reported on just a few non-severe hypoglycaemic episodes, no other serious side effects were observed. No study investigated mortality; complications of type 2 diabetes such as eye disease, kidney disease, heart attack and stroke; health-related quality of life; functional outcomes and costs of treatment. Therefore, long-term data on the efficacy and safety of colesevelam are necessary

Momordica charantia for type 2 diabetes mellitus.

Momordica charantia (bitter gourd) is not only a nutritious vegetable but it is also used in traditional medical practices to treat type 2 diabetes mellitus. Experimental studies with animals and humans suggested that the vegetable has a possible role in glycaemic control. To assess the effects of mormodica charantia for type 2 diabetes mellitus. Several electronic databases were searched, among these were The Cochrane Library (Issue 1, 2012), MEDLINE, EMBASE, CINAHL, SIGLE and LILACS (all up to February 2012), combined with handsearches. No language restriction was used. We included randomised controlled trials (RCTs) that compared momordica charantia with placebo or a control intervention, with or without pharmacological or non-pharmacological interventions. Two authors independently extracted data. Risk of bias of the trials was evaluated using the parameters of randomisation, allocation concealment, blinding, completeness of outcome data, selective reporting and other potential sources of bias. A meta-analysis was not performed given the quality of data and the variability of preparations of momordica charantia used in the interventions (no similar preparation was tested twice). Four randomised controlled trials with up to three months duration and investigating 479 participants met the inclusion criteria. Risk of bias of these trials (only two studies were published as a full peer-reviewed publication) was generally high. Two RCTs compared the effects of preparations from different parts of the momordica charantia plant with placebo on glycaemic control in type 2 diabetes mellitus. There was no statistically significant difference in the glycaemic control with momordica charantia preparations compared to placebo. When momordica charantia was compared to metformin or glibenclamide, there was also no significant change in reliable parameters of glycaemic control. No serious adverse effects were reported in any trial. No trial investigated death from any cause, morbidity, health-related quality of life or costs. There is insufficient evidence on the effects of momordica charantia for type 2 diabetes mellitus. Further studies are therefore required to address the issues of standardization and the quality control of preparations. For medical nutritional therapy, further observational trials evaluating the effects of momordica charantia are needed before RCTs are established to guide any recommendations in clinical practice

Sensory optimization of crackers developed from high-quality cassava flour, starch, and prawn powder

Crackers produced from high-quality cassava flour (HQCF), cassava starch, and prawn powder were optimized based on sensory preference testing. Ten different formulations of crackers were produced using mixture design. These were subjected to sensory evaluation using attributes such as taste, crispiness, puffiness, and acceptability on a 7-point hedonic scale. A mean score of 4.7, 5.6, 5.2, and 5.2 was obtained correspondingly for taste, crispiness, puffiness, and acceptability. Scores for these attributes indicated that the crackers were acceptable. Mixture regression models were used to generate contour plots for the sensory attributes and these were superimposed to obtain an optimal region, from where an optimum formulation was chosen. Verification of the optimal formulation with acceptability studies confirmed that the newly developed snack had a likeness score of 6.3 and was highly acceptable to consumers. The study demonstrates the suitability of HQCF in processing value added snack products

Secondary metabolites from two garcinia species and their biological activities.

Detail chemical studies on Garcinia maingayi have yielded one xanthone, 1,3,7-trihydroxy-2-(3-methylbut-2-enyl)xanthone, one benzophenone, isoxanthochymol, one benzoic acid derivative 3,4-dihydroxy-methylbenzoate and two triterpenoids, stigmasterol and sitosterol. Meanwhile, investigations on Garcinia parvifolia have afforded one triterpenoid, α-amyrin and two xanthones, cowanin and rubraxanthone. Their structures were derived based on spectroscopic evidence, mainly 1D and 2D NMR spectroscopy. Acetylation reaction was carried out on rubraxanthone to yield triacetate rubraxanthone. It was found that the pure rubraxanthone was strongly active against the larvae of Aedes aegypti with LC50 value of 15.49 μg/mL and HL-60 cell line with an IC50 value of 7.5 μg/mL