Study of wear resistance and nanostructure of tertiary Al2O3/Y2O3/CNT pulsed electrodeposited Ni-based nanocomposite

Electrodeposition of tertiary Alumina/Yitria/carbon nanotube (Al2O3/Y2O3/CNT) nanocomposite by using pulsed current has been studied. Coating process has been performed in nickel sulphate bath and nanostructure of the obtained compound layer was examined with high precision figure analysis of SEM nanographs. The effects of process variables, i.e. Y2O3 concentration, treatment time, current density and temperature of electrolyte have been experimentally studied. Statistical methods were used to achieve the minimum wear rate and average size of nanoparticles. Finally the contribution percentage of different effective factors was revealed and confirmation run showed the validity of the obtained results. Also it has been revealed that by changing the size of nanoparticles, wear properties of coatings will change significantly. Atomic force microscopy (AFM) and transmission electron microscope (TEM) analysis have confirmed smooth surface and average size of nanoparticles in the optimal coating.Вивчено електроосадження методом імпульсного струму потрійного композиту на основі вуглецевих нанотрубок, алюмінію та ітрію оксидів. Покриви наносили у нікелесульфатній ванні, а наноструктуру отриманого складного шару досліджували методом комп’ютерного аналізу знімків, одержаних на електронному мікроскопі. Вплив змінних параметрів процесу, зокрема, концентрації Y2O3, часу обробки, густини струму та температури електроліту вивчали експериментально. Для мінімізації впливу відхилень швидкості зношування та середнього розміру наночастинок на аналіз експериментальних даних використовували статистичні методи. Встановлено процентний вклад різних факторів і виконано підтверджувальний розрахунок, який показав достовірність одержаних результатів. Також виявлено, що зміна розміру наночастинок та зносотривкість покривів матиматимуть значною мірою однаковий тренд.Изучено электроосаждение методом импульсного тока тройного композита на основе углеродных нанотрубок, алюминия и иттрия оксидов. Покрытия наносили в никельсульфатной ванне, а наноструктуру полученного сложного слоя исследовали методом компьютерного анализа снимков, полученных на электронном микроскопе. Влияние изменяющихся параметров процесса, в частности, концентрации Y2O3, времени обработки, плотности тока и температуры электролита изучали экспериментально. Для минимизации влияния отклонений скорости изнашивания и среднего размера наночастиц на анализ экспериментальных данных использовали статистические методы. Установлен процентный вклад разных факторов и проведен подтверждающий расчет, который показал достоверность полученных результатов. Также установлено, что изменение размера наночастиц и износостойкость покрытий имеют в значительной степени одинаковый тренд

Rapid cell-surface prion protein conversion revealed using a novel cell system

Prion diseases are fatal neurodegenerative disorders with unique transmissible properties. The infectious and pathological agent is thought to be a misfolded conformer of the prion protein. Little is known about the initial events in prion infection because the infecting prion source has been immunologically indistinguishable from normal cellular prion protein (PrPC). Here we develop a unique cell system in which epitope-tagged PrPC is expressed in a PrP knockdown (KD) neuroblastoma cell line. The tagged PrPC, when expressed in our PrP-KD cells, supports prion replication with the production of bona fide epitope-tagged infectious misfolded PrP (PrPSc). Using this epitope-tagged PrPSc, we study the earliest events in cellular prion infection and PrP misfolding. We show that prion infection of cells is extremely rapid occurring within 1 min of prion exposure, and we demonstrate that the plasma membrane is the primary site of prion conversion

Preparation of substituted purinylpyrazolylacetamides as adenosine A2B receptor antagonists.

The title compds. I [R1, R2 = (un)substituted alkyl; R3 = H, halo; R4, R5 = H or alkyl; R6 = (un)substituted (hetero)aryl] which are adenosine A2B receptor antagonists and, thus, may be employed for the treatment of conditions and diseases mediated by the adenosine A2B receptor activity, were prepd. Such conditions and diseases include, but are not limited to, chronic and acute inflammatory diseases involving degranulation of mast cells, e.g., asthma, allergic rhinitis and allergic dermatitis; impaired sensitivity to insulin, e.g., type 2 diabetes, non-insulin dependent diabetes, pre-diabetic state, and impaired glucose tolerance; diseases in which angiogenesis is a key component of pathogenesis, e.g., solid tumors and angiogenic retinopathies; apnea of preterm infants; myocardial reperfusion injury; inflammatory bowel disease; autoimmune diseases, such as rheumatoid arthritis, multiple sclerosis, and lupus erythematosus; diseases involving microvascular abnormalities of the retina that are mediated by adenosine A2B receptors, e.g., retinopathy of prematurity, macular degeneration, and diabetic retinopathy; and cardiac diseases including hyperplasia consequent to hypertension, arteriosclerosis, and heart attack. E.g., a multi-step synthesis of II, starting from aniline, was described. Exemplified compds. I were tested in adenosine A2B receptor binding and functional assays (data given). Pharmaceutical compn. comprising the compd. I is disclosed

Self-organized TiO2 nanotube layer on Ti–6Al–7Nb for biomedical application

In the present study, a self-organized nanotube TiO2 layer on Ti–6Al–7Nb was fabricated. The influence of acidic electrolytes including glycerol (G) and ethylene glycol (EG) on the anodization, microstructural features and surface wettability was explored. The phase compositions and morphological characteristics were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM), respectively. According to the results, due to the intrinsic amorphous feature of ceramic oxide, the characteristic TiO2 peaks were not detected in the XRD profiles. After annealing in normal atmosphere at 600 °C for 2 h, TiO2 crystallized and consequently, nanotubular TiO2 arrays containing anatase and rutile phases formed. From a microstructural point of view, the average length and diameter of the nanotube array ranged from 2.23 to 4.22 μm and 160 to 170 nm, respectively. Besides, the type of acidic electrolyte and subsequent annealing noticeably affected the surface wettability of the products.University of Malaya, grant Nos.: UM TNC2/RC/261/1/1/RP021C-13AET and HIR UM.C/HIR/MOHE/ENG/2

Effect of microstructural evolution on wettability and tribological behavior of TiO2 nanotubular arrays coated on Ti–6Al–4V

Self-organized TiO2 nanotubular arrays were fabricated by electrochemical anodization of Ti–6Al–4V plates in an NH4F/H3PO4 electrolyte. The effect of microstructural evolutions on the wettability and tribological behavior of the TiO2 nanotubes was investigated. Based on the XRD profiles of the fabricated material, the characteristic TiO2 peaks were not recognized after anodization; however, highly crystalline TiO2 (anatase and rutile) was formed due to crystallization during annealing at 500 C for 1.5 h. The nanotube arrays were converted entirely to rutile at 700 C. From a microstructure point of view, a highly ordered nanotube structure was achieved when the specimen was annealed at 500 C, with a length of 0.72 μm and a pore diameter of 72 nm. Further increasing the annealing temperature to 700 C resulted in the complete collapse of the tubular structure. The results indicate that the improved wettability of the anodized specimens was due to the combination of the effects of both the surface oxide layer and the increased surface roughness achieved after anodization. Moreover, the wear resistance and wettability of the sample annealed 500 C were improved due to the high hardness (435 HV) and low coefficient of friction (0.133–168) of the highly crystalline structure of the TiO2 nanotubes.Ministry of Higher Education, Malaysia with the high impact research grant no. of M.C/HIR/MOHE/ENG/27 and partly sponsored by UM.TNC/IPPP/UPGP/638/PPP/PG121-2012B and UM.TNC2/RC/AET/261/1/1/RP017-2012

Vertically oriented ZrO2[sbnd]TiO2[sbnd]Nb2O5[sbnd]Al2O3 mixed nanopatterned bioceramics on Ti6Al7Nb implant assessed by laser spallation technique

Recently, reports on the fabrication of nonstructural configuration have generated scientific interest due to increased awareness of the oxide nanotubes in the biomedical implant field and other industrial approaches. Here, highly ordered ZrO2[sbnd]TiO2[sbnd]Nb2O5[sbnd]Al2O3 nanotube arrays were grown by physical vapor deposition (PVD) of a zirconium layer on titanium-niobium alloy implant (IMPTi67) and succeeding anodic oxidation at a constant voltage (60 V) with exposure times ranging from 30 to 300 min. To crystallize the resulting mixed oxide nanotubes, heat treatment was also applied. The nanotubes were placed in an atmospheric furnace at temperatures ranging from 450 to 800 °C for 2 h. This treatment provided a morphological evolution was strongly influenced by the anodization time, where highly aligned bamboo-shaped oxide nanotubes (161 ± 44 nm in inside diameter and ∼1 μm in length) were formed after 300 min of anodization. After annealing at temperature below 500 °C, the nano-array configuration remained stable and the average inner diameter decreased to around 40 nm. The effects of anodically fabrication time on the adhesion strength of four-phase multilayered mixed oxide nanotubes on anodized Zr/IMPTi67 surfaces assed by microscratch analysis. From the results, increasing the annealing temperature further to 800 °C fully destroyed the nanotubes and consequently the tubular arrangement was converted to a coarse grain structure. It was revealed that annealing at 450 °C for 2 h was the optimum conditions for stable nanotubular array generation, where the highest adhesion strength (shifted from 2595.59 to 2640.12 mN), microhardness (372 HV) and hydrophilicity (15 ± 1°) were recorded. It is notify that the adhesion strength of highly ordered mixed nanotubes was remarkably decreased after thermal treatment at 800 °C (1817.51 mN). Through the laser spallation analysis, the intrinsic adhesion strength of the Zr/IMPTi67 interface was found to be at 63 MPa, while the first stages of failure occurred at a stress state of 35 MPa. The adhesion of the film with the tubular structure proved to have a significantly larger adhesion strength of 246 MPa for the complete failure and 203 MPa for incipient stages of spallation. The considered surface modification can be an effective step in determining the interface strength between biomedical implants and the nanostructured coatings

Iran thalassemia in twenty years: The carrier rates and the births trend

<b>Background</b>\ud \ud - Iran is one of the countries located on “the thalassemia belt” with a significant annual number of thalassemia new births. Given the importance of thalassemia prevention, a program to this effect was approved in Iran in 1995. Screening of carrier couples and prenatal diagnosis were the two main elements of this program. In the present study, the authors have tried to address the impacts of prevention efforts in Iran (1989-2009) and also the status of new birth cases of thalassemia during the time period ranging from 1989 when the Iranian Thalassemia Society was established to 1995 when the prevention program started to run. \ud \ud <b>Materials and Method</b>\ud \ud - The data were obtained from the countrywide haemovigilance network. The data were then compared against the available information in the thalassemia treatment network of Iran and some other thalassemia associations. The available information had been collected through questionnaires and in some cases by phone calls and emails. \ud \ud <b>Results</b>\ud \ud - The findings show that the average thalassemia carrier prevalence rate in the country is about 4% and the thalassemia prevention in Iran has been successful with the number of new born thalassemic patients falling from 1087 cases in 1989 to 239 in 2009. The success rate of the program was evaluated to be 82.3% in 2009. \ud \ud <b>Conclusion</b>\ud \ud - The results show that the thalassemia prevention program has played an effective role in lowering thalassemia births in Iran. Nonetheless, the still high number of new thalassemia cases in the year 2009 is worth considering Keywords: Prevention of thalassemia, Iran, thalassemia, thalassemia carrier rate, success rate, screening, prenatal diagnosis