Artificial Neural Network prediction of Cu–Al2O3 composite properties prepared by powder metallurgy method

AbstractArtificial Neural Networks (ANNs) are excellent tools for prediction of complex processes that have many variables and complex interactions. In the present study, the properties of copper based composite prepared from sintering of mechanically alloyed powders, were predicted using Artificial Neural Network (ANN) approach. In order to prepare copper based composites, copper powder with four different amounts of Al2O3 reinforcement (1, 1.5, 2, 2.5wt%) were mechanically alloyed and the consolidated compacts of prepared powders were sintered in five different temperatures of 725–925°C at seven several sintering times of 15–180min. Hardness and electrical conductivity measurements were performed to evaluate the properties of these composites. Then, for modeling and prediction of hardness and electrical conductivity, a multi layer perceptron back propagation feed forward neural network was constructed to evaluate and compare the experimental calculated data to predicted values. It was found that, in a given sintering temperature of 875°C, the electrical conductivity increases as the sintering time increases and the amount of Al2O3 reinforcement decreases. Also, increasing of reinforcement amount and sintering time in a given sintering temperature of 875°C leads to a decrease in hardness. Furthermore, electrical conductivity and hardness of specimens have shown a consistency with predicted results of ANN. These trained values had an average error of 3% and 5% for electrical conductivity and hardness values, respectively

High-Risk and Low-Risk Human Papillomavirus in Esophageal Squamous Cell Carcinoma at Mazandaran, Northern Iran

Cancers are the second most common cause of nonaccidental deaths in Iran, following cardiovascular deaths. Mazandaran, near the Caspian Littoral at north of Iran have identified as a several-high incidence area for Esophageal Squamous Cell Carcinoma (ESCC) in the world. Several associated risk factors, such as dietary and cultural habits, infectious agents, nutritional deficiencies, too much use of tobacco and alcohol and infection to certain DNA tumor viruses (HPVs), including environmental and genetic factors are attributed to this disease. To explore this issue, we analyzed HPV DNA prevalence and HPV types together in relation to tumor sites a high-incidence population. Archived tissue blocks from 46, 69 and 62 upper, middle and lower third of esophagus, respectively from ESCC patients were evaluated for the presence of HPV DNA by PCR using the degenerate HPV L1 consensus primer pairs MY09/MY11. The positive specimens were evaluated by Real-time PCR to determine HPV genotypes. From the 49 HPV positive cases, of ESCC patients, 5 (23.1%), 11 (55 %) and 9 (56.3 %) of upper, middle and lower third of ESCC specimens, respectively were positive by at least one high and one low-risk HPV genotypes. In general, HPV45 and HPV11 were the most common high- risk and low-risk HPV genotypes in HPV L1 positive cases, respectively, followed by HPV6, HPV52 and HPV39. Therefore, the high prevalence of HPV DNA in different anatomical sites of ESCC patients from the Mazandaran region in North of Iran provides more evidence for a role of HPV in this cancer

Open flow hot isostatic pressing assisted synthesis of highly porous materials and catalysts

Open-flow hot isostatic pressing (OFHIP) technique is applied for synthesizing molecular sieves and highly porous catalytic materials. First, the isostatic pressure is applied to the starting material/catalyst precursor, and then heat is applied. Under this condition, as the organic components gradually decompose and leave the material, the voids left behind are immediately filled/replaced by the gas (pressure medium) in flow. This substitution warrants the preservation as well as the uniformity of the voids/pores. The result is a very porous material with very uniform pore size distribution. Another advantage is the production of the catalyst directly from the precursor, in the absence of solvent (neat), rendering the process simpler and less costly than previous processes. The entire process takes place under flow of the gas that is used as medium to develop the isostatic pressure. Consequently, the entire process, as well as the final product produced, is devoid of any undesirable residues. This endeavor also introduces a viable technique for mass-producing porous materials/catalysts. The resulting materials are termed “amorphous sulfide sieves” to reflect their unique properties that include high surface area, narrow pore size distribution and high activity. The catalysts are potentially licensable to all petroleum and petroleum chemical companies for a wide variety of environmental and product improvement purposes. The results obtained on unpromoted samples synthesized at 300°C indicate that as the synthesis pressure is increased, both surface area and catalytic activity of the materials produced increase. The increase in activity k value from 3 to 6 × 10−7 mol/g.s corresponds to increase in pressure from 100 to 800 psi, respectively. The N2 gas used as pressure medium results in highly porous materials but low activity. H 2 seems to be the ideal gas for both pressure medium and reducing agent. Co-promoted catalysts synthesized at 1400 psi and 300°C show catalytic activity as high as 47 mol/g.s. Based on the activity values obtained at all pressures tested, the projected activity values if tested at 2000 psi by polynomial and exponential curve fittings would be 98 × 10−7 mol/g.s, and 142 × 10−7, respectively. This manuscript contains two parts. Part One consists of eight chapters. Chapters 1 and 2 review supported/unsupported catalysts and the importance of catalysis. Chapters 3–8 provide an exhaustive overview of the existing industrial techniques for the precursor preparation and catalyst synthesis. Part Two of this manuscript covers the OFHIP technique. A separate chapter (Chapter 11) is dedicated to reviewing the Small Angle X-ray Scattering (SAXS) technique for its importance and relevance to this work. Objective. The objective of this work was to synthesize catalyst(s) from the desired precursor(s) using a minimum number of processing steps. Attempts were made to transform the desired catalyst precursor to the final catalytic material in one single step. By minimizing the number of processing steps, the cost of catalyst production would be minimized, rendering a process for mass-producing catalysts desirable for industrial applications. To achieve this objective, open-flow hot isostatic pressing (OFHIP) method has been applied to transform the desired precursor(s) to the final catalyst(s). The objective set forth was achieved for catalysts with activity as high as 47 mol/g.s. has been produced by this newly developed technique

SpoofKiller: You Can Teach People How to Pay, but Not How to Pay Attention

We describe a novel approach to reduce the impact of spoofing by a subtle change in the login process. At the heart of our contribution is the understanding that current anti-spoof technologies fail largely as a result of the difficulties to communicate security and risk to typical users. Accordingly, our solution is oblivious to whether the user was tricked by a fraudster or not. We achieve that by modifying the user login process, and letting the browser or operating system cause different results of user login requests, based on whether the site is trusted or not. Experimental results indicate that our new approach, which we dub “SpoofKiller”, will address approximately 80% of spoofing attempts. Free licenses to the technology are offered by the organization owning it, and serious discussions with a major OS vendor have been initiated, with the goal of protecting payments made from apps running on their platform.

Effect of zinc-doped hydroxyapatite/graphene nanocomposite on the physicochemical properties and osteogenesis differentiation of 3D-printed polycaprolactone scaffolds for bone tissue engineering

Processing and composition can significantly affect the mechanobiology, biodegradability, and cellular behavior of polymer-based bone scaffolds to replace damaged bone tissue. In this research, hydroxyapatite (HA), zinc-doped HA (ZnHA), and ZnHA-graphene (ZnHA-rGO) nanoparticles are composed in a polycaprolactone (PCL) matrix. After compositing PCL with nanoparticles, 3D bone scaffolds were built by a custom-built 3D printing system. The characterization of nanoparticles was extensively investigated by TEM, EDX-MAP, XRD, and ATR-FTIR. Simultaneously, 3D-printed scaffolds with different compositions were studied in terms of structure, morphology, thermogravimetry, biodegradability, and mechanical behaviors. The FE-SEM images of the scaffolds showed a highly regular structure and good printability of the developed material system. Moreover, the stiffness modulus of the samples increased due to the presence of the nanoparticles, especially in the ZnHA-rGO nanocomposite. In vitro cell assessment of 3D bone scaffolds was investigated by cell viability tests, cell attachment, and alizarin red staining via mesenchymal stem cells (MSCs). For differentiation capacity of the developed scaffolds, stem cell osteogenesis differentiation was studied by RT-PCR to analyze the ALP, RUNX2, BMP2, TGFβ, and OCN genes. The cellular assessments revealed an increase in PCL scaffold's cell osteogenesis due to the HA nanoparticles in the scaffold matrix. Zinc doping in the HA nanoparticles and rGO addition significantly increased the osteogenesis of MSCs. In particular, the nanocomposite of ZnHA-rGO in PCL scaffold matrix significantly improved the osteogenic differentiation and, thus, it is a viable option for effective regeneration of damaged bone tissue

Methodology of the Comprehensive Program on Prevention and Control of Overweight and Obesity in Iranian Children and Adolescents : The IRAN-Ending Childhood Obesity (IRAN-ECHO) Program

Background: The World Health Organization program on Ending Childhood Obesity (WHO-ECHO) has developed a comprehensive and integrated package of recommendations to address childhood obesity. The present study, entitled IRAN-ECHO, was designed and implemented in the framework of the WHO-ECHO program. Methods: The IRAN-ECHO program is implementing multicomponent interventions by considering life course dimensions. The program has two parts: a population approach and an individual approach. The population approach considers different periods in life, including prenatal, infancy, childhood, and adolescence, as well as family and society. The individual approach targets those children or adolescents with overweight or obesity; this part is conducted as a referral system that is now integrated in the current national health system. As part of the population approach, a quasi-experimental study was conducted in six provinces to compare the status before and after implementing parts of the interventions. By intersectoral collaboration with different organizations, multicomponent interventions are conducted for different age groups. Results: The IRAN-ECHO program is being conducted in six provinces, and will be considered in all provinces in the near future. Its main effects could be assessed in future years. Part of this program that was conducted as a quasi-experimental survey comprised 7149 students and showed that a high percentage of students had acceptable knowledge about adverse health effects of overweight and obesity. However, the knowledge about the low nutritional value of unhealthy snacks such as potato chips, puffs, industrial juices, and carbonated drinks was not appropriate. Many participants had the undesirable attitude of skipping one of the main meals when attempting to lose weight. Conclusions: The IRAN-ECHO program is presenting the feasibility of conducting the WHO-ECHO recommendations in Iran. The scope of potential policy recommendations to decrease childhood obesity is extensive and includes various elements. This program considers multisectoral interventions through population and individual approaches. The multicomponent interventions of this program address the obesogenic environment by considering the life course dimensions. It is expected that, by its life course interventions, it could help in primordial and primary prevention of noncommunicable diseases.Funded by the Iranian Ministry of Health and Medical Education</p