Effect of Post-Deposition Solution Treatment and Ageing on Improving Interfacial Adhesion Strength of Cold Sprayed Ti6Al4V Coatings

This study aims at investigating the effect of post-deposition solution treatment and ageing (STA) on improving the interfacial adhesion strength in cold spray (CS) Ti6Al4V coatings deposited on Ti6Al4V substrates, measured by the adhesive-free collar-pin pull-off (CPP) test. Solution treatment was performed at 940 °C for 1 h and ageing was carried out at 480 °C for 8 h. Investigations were carried out for specimens with three different pre-treatments of the substrate surface, namely grit-blasted, as-machined (faced on lathe machine), and ground. Additionally, the effect of post-deposition STA was studied in terms of phase analysis, microstructure, and porosity level. It was observed that STA led to complete interfacial mixing resulting in significantly improved adhesion strength (by more than 520%) with the maximum measured value of greater than 766 MPa for ground substrates, reaching 81% of the ultimate tensile strength of mill annealed Ti6Al4V.

Uji Aktivitas Antikolesterol Ekstrak Etanol Daun Jambu Air(Syzygium aqueum (Burm.f.)Alston) SecaraIn Vitro

Cholesterol is a natural substance that has physical properties similar to fat but has the formula steroids. Cholesterol belongs to the non-hydrolyzed lipid group and is the main sterol in body tissues. When cholesterol levels increase, it can cause blockages in blood vessels. Several studies have explained that one of the compounds that can reduce cholesterol is flavonoid compounds, one of the plants containing flavonoid compounds is guava leaf (Syzygium aqueum (Burm.f.) Alston). The purpose of this study was to determine the activity and percent reduction in cholesterol levels and the EC50 value of the ethanol extract of guava leaves (Syzygium aqueum (Burm.f.) Alston) in vitro using UV-Vis spectrophotometry with a wavelength of 665 nm. Anticholesterol activity analysis was carried out using Lieberman-Burchard reagent with a test solution series of 150; 300; 450; 600; and 750 ppm. The results showed that the greater the concentration, the lower the absorbance produced and the higher the percent reduction in cholesterol levels. At a concentration of 750 ppm cholesterol decreased by 58.74%. And the obtained EC50 value of 462 ppm, which means at that concentration the ethanol extract of guava leaves (Syzygium aqueum (Burm.f.) Alston) can reduce 50% of the initial cholesterol.Keywords:Cholesterol, Guava leaf, In Vitro, Spectrophotometry UV-Vis, Syzygium aqueum (Burm.f.)Alston. AbstrakKolesterol merupakan suatu zat alami yang memiliki sifat fisik hampir sama dengan lemak tetapi memiliki rumus steroida. Kolesterol adalah sterol utama yang ada pada jaringan tubuh dan termasuk dalam golongan lipid yang tidak terhidrolisis. Apabila kadar kolesterol mengalami kenaikan, dapat menyebabkan penyumbatan pada pembuluh darah. Dari beberapa penelitian dijelaskan bahwa salah satu senyawa yang dapat menurunkan kolesterol adalah flavonoid, salah satu tanaman yang mengandung senyawa flavonoid adalah daun jambu air (Syzygium aqueum (Burm.f.)Alston). Tujuan dari penelitian ini adalah untuk mengetahui aktivitas dan persen penurunan kadar kolesterol serta nilai EC50 dari ekstrak etanol daun jambu air (Syzygium aqueum (Burm.f.)Alston) secara in vitro menggunakan spektrofotometri UV-Vis dengan panjang gelombang 665 nm. Analisis aktivitas antikolesterol dilakukan dengan menggunakan pereaksi Lieberman-Burchard dengan seri larutan sampeli 150; 300; 450; 600; dan 750 ppm. Hasil penelitian menunjukkan semakin besar konsentrasi, absorbansi yang dihasilkan adalah semakin rendah dan persen penurunan kadar kolesterolnya semakin tinggi. Pada konsentrasi 750 ppm terjadi penurunan kolesterol sebesar 58,74%. Dan diperoleh nilai EC50 sebesar 462 ppm yang artinya pada konsentrasi tersebut ekstrak etanol daun jambu air (Syzygium aqueum (Burm.f.)Alston) dapat menurunkan 50% dari kolesterol awal.Kata kunci: Daun jambu air;Kolesterol;In Vitro;Spektrofotometri UV-Vis;Syzygium aqueum (Burm.f.)Alston

Effect of TrisEDTA and Chlorhexidine 0.12% on an In Vitro-Defined Biofilm Representing the Subgingival Plaque Biofilm of the Dog

This study was designed to investigate the effects of chlorhexidine 0.12%, TrisEDTA (tromethamine ethylenediamintetraacetic acid), and a combination of chlorhexidine 0.12% and TrisEDTA on an in vitro plaque biofilm model comprised of three bacterial species commonly found in canine subgingival plaque. Porphyromonas gulae, Actinomyces canis, and Neisseria canis were grown in a biofilm on polished hydroxyapatite coated titanium alloy pucks for 72 h prior to exposure to one of four test solutions: TrisEDTA, chlorhexidine 0.12%, a combination of TrisEDTA and chlorhexidine 0.12%, or sterile deionized water as a control. Following exposure to the test solution, a sample was collected of the biofilm either immediately or following 24 h of additional incubation in a broth medium. Lower numbers of CFU/mL of Porphyromonas gulae resulted when the biofilm was treated with a solution of chlorhexidine 0.12% and TrisEDTA compared to with chlorhexidine 0.12% alone, TrisEDTA alone, or the control and so this solution can be said to be synergistic against Porphyromonas gulae in this controlled in vitro model. Greater reductions in the numbers of CFU/mL of Actinomyces canis and Neisseria canis resulted from treatment with chlorhexidine 0.12% alone than if treated with the combination of TrisEDTA and chlorhexidine 0.12%. When treated biofilm samples were allowed 24 h of additional growth in fresh media, greater variance resulted and this variance highlights the complex dynamics involved in bacterial growth within a biofilm.

Quantitative Phase Imaging to Study the Effect of Sodium Dodecyl Surfactant on Adherent L929 Fibroblasts on Tissue Culture Plates

Decellularization is the process of removing cellular components from native tissues or organs to obtain an acellular, collagenous scaffold for use in tissue engineering and organ regeneration. Surfactants are widely used to produce acellular scaffolds for clinical applications. However, cell–surfactants interactions have not been studied in depth. Cell-surfactant interaction was studied in a time-lapsed manner using sodium dodecyl sulfate (SDS) solution (surfactant) on adherent L929 fibroblasts as a test solution, phosphate-buffered saline (PBS) solution as control solution (isotonic), and deionized water as positive test solution (hypotonic), respectively. The QPI results show changes in the relative height and cross-sectional area of the cells, with various test solutions and exposure times. In particular, it was observed that the removal of the cell with SDS involved the disruption of the cellular membrane and detachment of the cell contents from the adhering surface. This study demonstrated the feasibility of using the QPI technique to understand the decellularization process.

UJI EFEKTIVITAS MUKOLITIK EKSTRAK UMBI BAWANG DAYAK (Eleuherine bulbosa (Mill) Urb) SECARA IN VITRO PADA USUS SAPI

Dayak Onions are a typical Borneo plant that have been used by generations of Dayaks as herbal medicine. Empirically, tubers can be used as cough medicines. The purpose of this study was to determine the mucolytic effect of Dayak onion tuber extract by in vitro and the concentration range which gaves an equivalent effect with the effect of 0.1% acetylcysteine. This study conducted extraction using maceration and mucolytic effectiveness by in vitro to reduce the viscosity of cattle mucus. The test solution was made with a concentration of 0.5%, 1%, and 1.5% mixed with a mucus-phosphate buffer pH 7 20:80. The test solution was incubated for 30 minutes at 37oC. Further, positive control used was 0.1% acetylcysteine drug and the negative control was mucus solution without extract. Viscosity values obtained were analyzed using the One-way Anova statistical test with a confidence level of 99% (α 0.01). Based on the results, it was revealed that the extract of Dayak tuber with a concentration of 0.5%, 1%, and 1.5% showed a significant difference and a concentration of 0.5%. Mucolytic effectiveness was better than positive controls (acetylcysteine).

A cautionary tale on proper use of branch-site models to detect convergent positive selection

Comparative genomics has become a powerful tool to elucidate genotype-phenotype relationships, particularly through the study of convergently acquired phenotypes. By identifying genes under positive selection specifically on branches with the convergent phenotype we can potentially link genes to that phenotype. Such gene scans are often done using branch-site codon models. However, we have observed a recent troubling trend of misinterpretation of branch-site models in which phylogeny-wide positive selection is not distinguished from positive selection specific to convergent branches. Here, we use simulations and real data to demonstrate how failing to discern between these two cases leads to false inferences of positive selection associated with a convergent trait. We then present a "drop-out" test solution to distinguish the two cases and thereby truly capture positive selection events associated with convergent phenotypes, thus allowing for further insights into both genetic and phenotypic evolution.

A new screening test to evaluate the presence of oxidizable sulphide minerals in coarse aggregates

A simple screening test was proposed in order to test coarse aggregates for their potential to cause damage when used in concrete due to the oxidation of sulphide phases. The test involves submerging an aggregate sample in an oxidizing agent and measuring the mass loss. Samples with no known oxidizable sulphides showed a mass loss of <1.0% after one week of testing at room temperature. Samples of oxidizable sulphides showed a mass loss higher than 3.5% and changes in the colour of the test solution. It is proposed that aggregates which achieve a mass loss of less than 0.50% and no colour change in the test solution be accepted.

A new screening test to evaluate the presence of oxidizable sulphide minerals in coarse aggregates

A simple screening test was proposed in order to test coarse aggregates for their potential to cause damage when used in concrete due to the oxidation of sulphide phases. The test involves submerging an aggregate sample in an oxidizing agent and measuring the mass loss. Samples with no known oxidizable sulphides showed a mass loss of <1.0% after one week of testing at room temperature. Samples of oxidizable sulphides showed a mass loss higher than 3.5% and changes in the colour of the test solution. It is proposed that aggregates which achieve a mass loss of less than 0.50% and no colour change in the test solution be accepted.

A new screening test to evaluate the presence of oxidizable sulphide minerals in coarse aggregates

A simple screening test was proposed in order to test coarse aggregates for their potential to cause damage when used in concrete due to the oxidation of sulphide phases. The test involves submerging an aggregate sample in an oxidizing agent and measuring the mass loss. Samples with no known oxidizable sulphides showed a mass loss of <1.0% after one week of testing at room temperature. Samples of oxidizable sulphides showed a mass loss higher than 3.5% and changes in the colour of the test solution. It is proposed that aggregates which achieve a mass loss of less than 0.50% and no colour change in the test solution be accepted.