Tribo-Corrosion behaviour of TiCxOy thin films in bio fluids

In recent years, the development of thin film systems for decorative applications has attracted significant attention in scientific research. These decorative coatings require, not only an attractive appearance for market applications, but also an ability to protect the surface underneath. Because of this, corrosion, wear and their combined effects (termed tribo-corrosion) are particularly important for lifetime prediction. The tribo-corrosion behaviour of a range of single layered titanium oxycarbide, TiCxOy,coatings, produced by DC reactive magnetron sputtering, has been studied and reported as a function of electrode potential (-0.9 V, -0.5 V, 0.0 V and +0.5 V) and applied load (3, 6 and 9 N). The study was conducted in a reciprocating sliding tribosystem (Plint TE 67/E) in a bio fluid (an artificial perspiration solution) at room temperature. During the wear tests, both the open-circuit potential and the corrosion current were monitored. The results showed that electrode potential and load have a significant influence on the total material loss. The variations in Rp (polarization resistance) and Cf(capacitance) before and after sliding, obtained by Electrochemical Impedance Spectroscopy (EIS) were evaluated in order to provide an understanding of the resistance of the film in such conditions. Tribo-corrosion maps were generated, based on the results, indicating the change in mechanisms of the tribological and corrosion parameters for such coatings

Properties and occurrence rates of KeplerKepler exoplanet candidates as a function of host star metallicity from the DR25 catalog

Correlations between the occurrence rate of exoplanets and their host star properties provide important clues about the planet formation processes. We studied the dependence of the observed properties of exoplanets (radius, mass, and orbital period) as a function of their host star metallicity. We analyzed the planetary radii and orbital periods of over 2800 $Kepler$ candidates from the latest $Kepler$ data release DR25 (Q1-Q17) with revised planetary radii based on $Gaia$~DR2 as a function of host star metallicity (from the Q1-Q17 (DR25) stellar and planet catalog). With a much larger sample and improved radius measurements, we are able to reconfirm previous results in the literature. We show that the average metallicity of the host star increases as the radius of the planet increases. We demonstrate this by first calculating the average host star metallicity for different radius bins and then supplementing these results by calculating the occurrence rate as a function of planetary radius and host star metallicity. We find a similar trend between host star metallicity and planet mass: the average host star metallicity increases with increasing planet mass. This trend, however, reverses for masses $> 4.0\, M_\mathrm{J}$: host star metallicity drops with increasing planetary mass. We further examined the correlation between the host star metallicity and the orbital period of the planet. We find that for planets with orbital periods less than 10 days, the average metallicity of the host star is higher than that for planets with periods greater than 10 days.Comment: 14 pages, 13 Figures, Accepted for publication in The Astronomical Journa

Impact of migration on Kerala's economy and society

This research is first of its kind for Kerala, being the first migration study that covers the entire state and encompasses both measurement as well as analysis of the various types and facets of migration. Migration has been the single-most dynamic factor in the otherwise dreary development scenario of Kerala in the last quarter of the twentieth century. Kerala is approaching the end of the millennium with a little cheer in many people's homes, a major contributing factor for which has been migration. Migration has contributed more to poverty alleviation in Kerala than any other factor, including agrarian reforms, trade union activities and social welfare legislation. The study shows that nearly 1.5 million Keralites now live outside India. They send home more than Rs.4,000 million a year by way of remittances. Three-quarters of a million former emigrants have come back. They live mostly on savings, work experience, and skills brought with them from abroad. More than a million families depend on internal migrants'earnings for subsistence, children's education and other economic requirements. Whereas the educationally backward Muslims from the Thrissur-Malappuram region provide the backbone of emigration, it is the educationally forward Ezhawas, Nairs and Syrian Christians from the former Travancore-Cochin State who form the core of internal migration. The paper also analyses the determinants and consequences of internal and external migration. It offers suggestions for policy formulation for the optimum utilization of remittances sent home by the emigrants and the expertise brought back by the return migrants. Migration in Kerala began with demographic expansion, but it won't end with demographic contraction. Kerala has still time to develop itself into an internally self-sustaining economy. The prevailing cultural milieu of Kerala in which its people believe that anything can be achieved through agitation and any rule can be circumvented with proper political connections, must change and be replaced by a liberalised open economy with strict and definite rules of the game. JEL Classification: J21, J2

Tumor suppressor in lung cancer 1 (TSLC1) alters tumorigenic growth properties and gene expression

BACKGROUND: Introduction of cDNA or genomic clones of the tumor suppressor in lung cancer 1 (TSLC1) gene into the non-small cell lung cancer line, A549, reverses tumorigenic growth properties of these cells. These results and the observation that TSLC1 is down-regulated in a number of tumors suggest that TSLC1 functions as a critical switch mediating repression of tumorigenesis. RESULTS: To investigate this mechanism, we compared growth properties of A549 with the TSLC1-containing derivative. We found a G1/S phase transition delay in 12.2. Subtractive hybridization, quantitative PCR, and TranSignal Protein/DNA arrays were used to identify genes whose expression changed when TSLC1 was up-regulated. Members of common G1/S phase regulatory pathways such as TP53, MYC, RB1 and HRAS were not differentially expressed, indicating that TSLC1 may function through an alternative pathway(s). A number of genes involved in cell proliferation and tumorigenesis were differentially expressed, notably genes in the Ras-induced senescence pathway. We examined expression of several of these key genes in human tumors and normal lung tissue, and found similar changes in expression, validating the physiological relevance of the A549 and 12.2 cell lines. CONCLUSION: Gene expression and cell cycle differences provide insights into potential downstream pathways of TSLC1 that mediate the suppression of tumor properties in A549 cells

More than just hormones: H295R cells as predictors of reproductive toxicity

AbstractMany of the commonly observed reproductive toxicities associated with therapeutic compounds can be traced to a disruption of the steroidogenic pathway. We sought to develop an in vitro assay that would predict reproductive toxicity and be high throughput in nature. H295R cells, previously validated as having an intact and functional steroidogenic pathway, were treated with 83 known-positive and 79 known-negative proprietary and public-domain compounds. The assay measured the expression of the key enzymes STAR, 3βHSD2, CYP17A1, CYP11B2, CYP19A1, CYP21A2, and CYP11A1 and the hormones DHEA, progesterone, testosterone, and cortisol. We found that a Random Forest model yielded a receiver operating characteristic area under the curve (ROC AUC) of 0.845, with sensitivity of 0.724 and specificity of 0.758 for predicting in vivo reproductive toxicity with this in vitro assay system

Study of candidate Be stars in the Magellanic Clouds using near-infrared photometry and optical spectroscopy

Mennickent et al. and Sabogal et al. identified a large number of classical Be (CBe) candidates (∼3500) in the Large and Small Magellanic Clouds (LMC and SMC) based on their photometric variability using the OGLE II data base. They classified these stars into four different groups based on the appearance of their variability. In order to refine and understand the nature of this large number of stars, we studied the infrared properties of the sample and the spectroscopic properties of a subsample. We cross‐correlated the optical sample with the IRSF‐MCPS catalogue to obtain the J, H, Ks magnitudes of all the four types of stars (∼2500) in the LMC and SMC. Spectra of 120 stars belonging to the types 1, 2 and 3 were analysed to study their spectral properties. Among the four types, the type 4 stars are the dominant group, with ∼60 and ∼65 per cent of the total sample in the LMC and SMC, respectively. The near‐infrared (NIR) colour–colour diagrams suggest that the type 4 stars in the LMC have a subclass, which is not found in our Galaxy or in the SMC. This subclass is ∼18 per cent of the type 4 sample. The main type 4 sample which is ∼49 per cent of the total sample has NIR properties similar to the Galactic CBe stars and the SMC type 4 stars. Though the new subclass of type 4 stars have high E(B−V) ∼ 0.75, they are not located close to regions with high reddening. The type 3 stars (∼6 per cent and 7.3 per cent in the LMC and SMC) are found to have large Hα equivalent width (EW) in the SMC and some are found to have large NIR excess. This small fraction of stars are unlikely to be CBe stars. Three stars among the type 3 stars in the LMC are found to be double periodic variables. The type 2 stars are found in larger fraction in the SMC (∼14.5 per cent), when compared to the LMC (∼6 per cent). The spectroscopic and the NIR properties suggest that these could be CBe stars. The type 1 stars are relatively more in the LMC (∼24 per cent) when compared to the SMC (∼13 per cent). The SMC type 1 stars have relatively large Hα EW and this class has properties similar to CBe stars. The spectroscopic sample of type 1 stars which show Hα in emission and are confirmed as CBe stars are more abundant in the SMC by a factor of 2.6. If the effect of metallicity is to cause more CBe stars in the SMC, when compared to the LMC, then type 1, type 2 and type 4 stars follow this rule, with an enhancement of 2.6, 2.4 and 1.3, respectively

A New Field Protocol for Monitoring Forest Degradation

Forest degradation leads to the gradual reduction of forest carbon stocks, function, and biodiversity following anthropogenic disturbance. Whilst tropical degradation is a widespread problem, it is currently very under-studied and its magnitude and extent are largely unknown. This is due, at least in part, to the lack of developed and tested methods for monitoring degradation. Due to the relatively subtle and ongoing changes associated with degradation, which can include the removal of small trees for fuelwood or understory clearance for agricultural production, it is very hard to detect using Earth Observation. Furthermore, degrading activities are normally spatially heterogeneous and stochastic, and therefore conventional forest inventory plots distributed across a landscape do not act as suitable indicators: at best only a small proportion of plots (often zero) will actually be degraded in a landscape undergoing active degradation. This problem is compounded because the metal tree tags used in permanent forest inventory plots likely deter tree clearance, biasing inventories toward under-reporting change. We have therefore developed a new forest plot protocol designed to monitor forest degradation. This involves a plot that can be set up quickly, so a large number can be established across a landscape, and easily remeasured, even though it does not use tree tags or other obvious markers. We present data from a demonstration plot network set up in Jalisco, Mexico, which were measured twice between 2017 and 2018. The protocol was successful, with one plot detecting degradation under our definition (losing greater than 10% AGB but remaining forest), and a further plot being deforested for Avocado (Persea americana) production. Live AGB ranged from 8.4 Mg ha–1 to 140.8 Mg ha–1 in Census 1, and from 0 Mg ha–1 to 144.2 Mg ha–1 Census 2, with four of ten plots losing AGB, and the remainder staying stable or showing slight increases. We suggest this protocol has great potential for underpinning appropriate forest plot networks for degradation monitoring, potentially in combination with Earth Observation analysis, but also in isolation

An effective sensor for tool wear monitoring in face milling : acoustic emmision

Acoustic Emission (AE) has been widely used for monitoring manufacturing processes particularly those involving metal cutting. Monitoring the condition of the cutting tool in the machining process is very important since tool condition will affect the part size, quality and an unexpected tool failure may damage the tool, work-piece and sometimes the machine tool itself. AE can be effectively used for tool condition monitoring applications because the emissions from process changes like tool wear, chip formation i.e. plastic deformation, etc. can be directly related to the mechanics of the process. Also AE can very effectively respond to changes like tool fracture, tool chipping, etc. when compared to cutting force and since the frequency range is much higher than that of machine vibrations and environmental noises, a relatively uncontaminated signal can be obtained. AE signal analysis was applied for sensing tool wear in face milling operations. Cutting tests were carried out on a vertical milling machine. Tests were carried out for a given cutting condition, using single insert, two inserts (adjacent and opposite) and three inserts in the cutter. AE signal parameters like ring down count and rms voltage were measured and were correlated with flank wear values (VB max). The results of this investigation indicate that AE can be effectively used for monitoring tool wear in face milling operations.Fundação para a Ciência e a Tecnologia (FCT

Tribological and corrosion behaviors of warm- and hot-rolled Ti-13Nb-13Zr alloys in simulated body fluid conditions

Development of submicrocrystalline structure in biomedical alloy such as Ti-13Nb-13Zr (in wt%) through warm-rolling process has been found to enhance mechanical properties compared to conventional thermomechanical processing routes including hot-rolling process. The present study investigated the tribological and corrosion behaviors of warm-rolled (WR) and hot-rolled Ti-13Nb-13Zr alloys which have not been studied to date. Both tribological and corrosion experiments were carried out in simulated body fluid conditions (Hank's solution at 37 degrees C) based on the fact that the investigated alloys would be used in a human body as orthopedic implants. The WR Ti-13Nb-13Zr demonstrated a submicrocrystalline structure that provided a significant enhancement in hardness, strength, and corrosion resistance. Meanwhile, there was no notable difference in wear resistance between the WR and hot-rolled samples despite the different microstructure and hardness. The present study confirmed the enormous potential of WR Ti-13Nb-13Zr with not only great mechanical properties but also high corrosion resistance in the simulated body fluid.111Ysciescopu

Mathematics of random growing interfaces

We establish a thermodynamic limit and Gaussian fluctuations for the height and surface width of the random interface formed by the deposition of particles on surfaces. The results hold for the standard ballistic deposition model as well as the surface relaxation model in the off-lattice setting. The results are proved with the aid of general limit theorems for stabilizing functionals of marked Poisson point processes.Comment: 12 page