Microstructure and corrosion behaviour of NiTiCo shape memory alloys under various aging conditions

In this study the microstructure evolution and corrosion resistance of NiTiCo and Co-free NiTi shape memory alloys (smart alloys) were investigated under various aging conditions. Cobalt NiTi alloy contains 4 at% in addition to 52 at% Nickel and 44 at% Titanium, while in Co- free alloy Titanium content increased to 48 at%. Optical and scanning electron microscopes were used to investigate the microstructure evolution of NiTi alloys. Potentiodynamic polarization measurements were used to study the corrosion behavior of the tested alloys in 1.0 M HCl solution at 25 °C. The results show that martensite phase, B19’, is predominant phase in the aged microstructures of the investigated alloys. Moreover, there is an intermetallic compound phase, Ti2Ni, that precipitated in various densities and sizes in microstructures depending on the aging heat treatment conditions. Polarization measurements show that the corrosion rate of the NiTi alloys increases as the aging temperature increase. Also, potentiodynamic polarization shows that the addition of 4% of cobalt as alloying element decreases the corrosion rate

Electrochemical investigation and modeling of corrosion inhibition of aluminum in molar nitric acid using some sulphur-containing amines,” Corros

a b s t r a c t Chemical and electrochemical measurements incorporated with quantum chemical calculations and molecular dynamics simulations were used to study the corrosion inhibition characteristics of some thiosemicarbazone derivatives on the inhibition of aluminum corrosion in 1.0 M HNO 3 . Polarization curves demonstrated that the thiosemicarbazone derivatives were of mixed-type inhibitors. EIS plots indicated that the addition of thiosemicarbazone derivatives increases the charge-transfer resistance of the corrosion process, and hence the inhibition performance. The molecular dynamics simulation results show that the three thiosemicarbazone derivatives can adsorb on the A 2 O 3 (1 1 1) surface through the sulphur and nitrogen atoms as well as p-electrons in the pyridyl structure

Creation and use of an iBook as well as chemistry videos to improve student learning experiences in general chemistry Laboratory

Digital books have revolutionized the way student accesses books and information. An alternative to a static e-book, is an interactive textbook designed with iBooks Author, a free Apple software program. This technology allows teachers to develop textbooks based on the needs of their students. In this study a digital interactive book—iBook (for use on the Apple iPad and iPhone)—was created to teach general chemistry laboratory for first year collage. In this study the flipped classroom is a form of hybrid instructions in which active form of engagement inside as well as outside the classroom are made possible by designing an iBook for general chemistry laboratory supported by a set of video lectures. This study documents the implementation of partially flipped class over one semester and presents results of students’ perception toward flipped learning and using the iBook. It is found that students respond positively to flipped learning and they are excited to use this technology (iBook) to introduce general chemistry laborator

Safety of Transcatheter Aortic Valve Replacement in Patients with Aortic Aneurysm: A Propensity-Matched Analysis

Introduction There is a paucity of data regarding the outcomes of transcatheter aortic valve replacement (TAVR) among patients with thoracic or abdominal aortic aneurysms (AA). Using the Nationwide Inpatient Sample (NIS) database, we explored the safety of TAVR among patients with a diagnosis of AA. Methods We queried the National Inpatient Sample database (2012–2017) for hospitalized patients undergoing TAVR, using ICD-9 and ICD-10 codes for endovascular TAVR. Reports show that \u3e 95% of endovascular TAVR in the US is via transfemoral access, so our population are mostly patients undergoing transfemoral TAVR. Using propensity score matching, we compared the trends and outcomes of TAVR procedures among patients with versus without AA. Results From a total sample of 29,517 individuals who had TAVR procedures between January 2012 and December 2017, 910 had a diagnosis of AA. In 774 matched-pair analysis, all-cause in-hospital mortality was similar in patients with and without AA OR 0.63 [(95% CI 0.28–1.43), p = 0.20]. The median length of stay was higher in patients with AA: 4 days (IQR 2.0–7.0) versus 3 days (IQR 2.0–6.0) p = 0.01. Risk of AKI [OR 1.01 (0.73–1.39), p = 0.87], heart block requiring pacemaker placement [OR 1.17 (0.81–1.69), p = 0.40], aortic dissection [OR 2.38 (0.41–13.75), p = 0.25], acute limb ischemia [OR 0.46 (0.18–1.16), p = 0.09], vascular complications [OR 0.80 (0.34–1.89), p = 0.53], post-op bleeding [OR 1.12 (0.81–1.57), p = 0.42], blood transfusion [OR 1.20 (0.84–1.70), p = 0.26], and stroke [OR 0.58 (0.24–1.39), p = 0.25] were similar in those with and without AA. Conclusions Data from a large nationwide database demonstrated that patients with AA undergoing TAVR are associated with similar in-hospital outcomes compared with patients without AA. Key Summary Points Patients with a diagnosis aortic aneurysm (thoracic or abdominal) undergoing transcatheter aortic valve replacement (TAVR) have same risk of periprocedural complications as those without a diagnosis of aortic aneurysms (AA). Patients with a diagnosis of aortic aneurysm had a longer length of hospital stay. Further studies are needed to determine how specific features of aortic aneurysm such as size, shape, thrombus burden, or calcifications affect the safety of TAVR

PHYTOCHEMICAL ANALYSIS, ASSESSMENT OF ANTIPROLIFERATIVE AND FREE RADICAL SCAVENGING ACTIVITY OF MORUS ALBA AND MORUS RUBRA FRUITS

Objective: Mulberry is a nontoxic commonly eaten plant, belongs to the Morus and used in folk medicine in the remedy of dysentery, antiphlogistic, diuretic, expectorant, and antidiabetic. The purpose of this study is to evaluate the antiproliferative and radical scavenging activity of the total alcoholic and successive fractions thereof of Morus alba and Morus rubra fruits. In addition, the chemical composition of the bioactive fractions of each species was investigated.Methods: The antiproliferative potential of 8 extracts on 4 human cancer cell lines, hepatocellular carcinoma (HepG2), Caucasian breast adenocarcinoma (MCF7), prostate (PC3), and colon carcinoma (HCT116) in addition to one normal cell line namely human normal immortalized skin fibroblast cells (BJ1) were carried out. Cell viability was determined using MTT assay. The potency was compared with the reference drug doxorubicin. These extracts were also assayed for 1,1-diphenyl-2-hydrazyl free radical scavenging activities. After saponification of the n-hexane fraction, unsaponifiable matter and fatty acid methyl esters were analyzed by gas liquid chromatography (GLC). The chemical composition of the bioactive fractions was investigated using gas chromatography/mass spectrometry (GC/MS) analysis.Results: All the extracts showed significant free radical scavenging activity dose-dependently. The n-hexane and dichloromethane (DCM) fractions of M. rubra exhibited potent cytotoxic activity on almost cancer cell lines. In the same pattern, ethyl acetate (EtOAc) of M. rubra has moderate cytotoxic activity against all cell lines except HepG2. DCM fraction of M. alba possessed both radical scavenging and high potential antiproliferated activities against HCT116 and MCF7 with inhibitory concentration of 43.9 and 32.3 μg/ml, respectively, while it showed no cytotoxic effect on BJ1. GLC analysis showed the major hydrocarbons in M. alba and M. rubra were heptacosane and docosane, respectively. Sterols were similar in both species but with different ratios and cholesterol was the major one. Palmitic and margaric were the major saturated fatty acid while arachidonic was the major unsaturated fatty acid in both species. GC/MS analysis showed the main compound in DCM fraction of each Morus species was palmitic acid. Furthermore, 1,11-bis-(methoxycarbonyl-ethenyl)-10,2-dihydroxy-cycloeicosane and linolelaidic acid, methyl ester were the main compounds in the EtOAc fraction of each Morus species. Whereas, the main compounds in alcoholic extract of M. alba and M. rubra were methyl-14-methyl-pentadecanoate and 1,2-O-isopropylyidene-4-nonene-1,2,3-triol, respectively.Conclusions: The results observed remarkable biological activity of the successive fractions of M. rubra more than those of M. alba and confirmed its importance as a natural bioactive source. Morus species are good candidates to be promising as possible sources for future antitumor and antioxidants in food and pharmaceutical formulations. The strong activity partly explains the potential effects of Morus species for the treatment of cancer and degenerative diseases caused by free radicals

Nano-Yttrium Titanate Coated 304 Stainless Steel: Preparation, Characterization and Corrosion Protection Application

A protective coating of nano-yttrium titanate was developed for 304 stainless steel under acidic conditions (1.0 M HCl). The nano-yttrium titanate (Y2Ti2O7) was thoroughly characterized using various surface analysis tools, such as X-ray diffraction analysis (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDS). In addition, electrochemical techniques, including Tafel polarization (dc), electrochemical frequency modulation (EFM), and electrochemical impedance spectroscopy (EIS) were employed. The findings demonstrate that the nano-yttrium titanate coating significantly improves the protection efficiency of 304 stainless steel by enhancing its hydrophobic propertie

Ambient particulate pollution and the world-wide prevalence of asthma, rhinoconjunctivitis and eczema in children: Phase One of the International Study of Asthma and Allergies in Childhood (ISAAC)

Objectives: To investigate the effect of ambient particulate matter on variation in childhood prevalence of asthma, rhinoconjunctivitis and eczema. Methods: Prevalences of asthma, rhinoconjunctivitis and eczema obtained in Phase One of the International Study of Asthma and Allergies in Childhood (ISAAC) were matched with city-level estimates of residential PM10 obtained from a World Bank model. Associations were investigated using binomial regression adjusting for GNP per capita and for clustering within country. For countries with more than one centre, a two stage meta-analysis was carried out. The results were compared with a meta-analysis of published multi-centre studies. Results: Annual concentrations of PM₁₀ at city level were obtained for 105 ISAAC centres in 51 countries. After controlling for GNP per capita, there was a weak negative association between PM₁₀ and various outcomes. For severe wheeze in 13-14-year-olds, the OR for a 10 μg/m³ increase in PM₁₀ was 0.92 (95 CI 0.84 to 1.00). In 24 countries with more than one centre, most summary estimates for within-country associations were weakly positive. For severe wheeze in 13-14-year-olds, the summary OR for a 10 μg/m³ increase in PM₁₀ was 1.01 (0.92 to 1.10). This result was close to a summary OR of 0.99 (0.91 to 1.06) obtained from published multi-centre studies. Conclusions: Modelled estimates of particulate matter at city level are imprecise and incomplete estimates of personal exposure to ambient air pollutants. Nevertheless, our results together with those of previous multi-centre studies, suggest that urban background PM₁₀ has little or no association with the prevalence of childhood asthma, rhinoconjunctivitis or eczema either within or between countries

Far-infrared study of the Jahn-Teller distorted C60 monoanion in C60 tetraphenylphosphoniumiodide

We report high-resolution far-infrared transmission measurements on C(60)-tetraphenylphosphoniumiodide as a function of temperature. In the spectral region investigated (20-650 cm(-1)), we assign intramolecular modes of the C(60) monoanion and identify low-frequency combination modes. The well-known F(1u)(1) and F(1u)(2) modes are split into doublers at room temperature, indicating a D(5d) or D(3d) distorted ball. This result is consistent with a dynamic Jahn-Teller effect in the strong-coupling limit or with a static distortion stabilized by low-symmetry perturbations. The appearance of silent odd modes is in keeping with symmetry reduction of the hall, while activation of even modes is attributed to interband electron-phonon coupling and orientational disorder in the fulleride salt. Temperature dependences reveal a weak transition in the region 125-150 K in both C(60)(-) and counterion modes, indicating a bulk, rather than solely molecular, effect. Anomalous softening (with decreasing temperature) in several modes may correlate with the radial character of those vibrations. [S0163-1829(98)03245-7]