Inhibitive and adsorption behaviour of carboxymethyl cellulose on mild steel corrosion in sulphuric acid solution

Chemical methods were used to assess the inhibitive and adsorption behaviour of carboxymethyl cellulose (CMC) for mild steel in H₂SO₄ solution at 30-60 °C. Results obtained show that CMC act as inhibitor for mild steel in H₂SO₄. The inhibition efficiency was found to increase with increase in CMC concentration but decreased with rise in temperature, which is suggestive of physical adsorption mechanism. The adsorption of the CMC onto the mild steel surface was found to follow Langmuir and Dubinin-Radushkevich adsorption isotherm models. The inhibition mechanism was further corroborated by the values of activation parameters obtained from the experimental data.     

Synthesis,Characterization, and Spectroscopic Analysis of NdxY1−xTiNbO6 Microwave Ceramics

Solid solutions of Nd_xY_1−xTiNbO₆ ceramics were prepared through the solid-state ceramic route. The materials were calcined at 1250°C and sintered in the range 1400–1550°C. The structure of the system was analyzed using the X-ray diffraction and vibrational spectroscopic analysis. The morphology and the sintering behavior of the samples were analyzed using scanning electron microscopy. The dielectric constant (ɛ_r), temperature coefficient of resonant frequency (τ_f), and the unloaded quality factor (Q_u) were measured in the microwave frequency region using the cavity resonator method. The ɛ_r and τ_f increased with an increase in the concentration of Nd in the solid solutions. Nearly zero temperature coefficient of resonant frequency was obtained for the Nd_0.6Y_0.4TiNbO₆ ceramic. Samples are of high quality factor and are useful for microwave applications.     

Synthesis and Evaluation of Voltage-Gated Sodium Channel Blocking Pyrroline Derivatives Endowed with Both Antiarrhythmic and Antioxidant Activities

Under the hypothesis that cardioprotective agents might benefit from synergism between antiarrhythmic activity and antioxidant properties, a small series of mexiletine analogues were coupled with the 2,2,5,5-tetramethylpyrroline moiety, known for its antioxidant effect, in order to obtain dual-acting drugs potentially useful in the protection of the heart against post-ischemic reperfusion injury. The pyrroline derivatives reported herein were found to be more potent as antiarrhythmic agents than mexiletine and displayed antioxidant activity. The most interesting tetramethylpyrroline congener, a tert-butyl-substituted analogue, was at least 100 times more active as an antiarrhythmic than mexiletine.     

Characterization of the structure and properties of processed alumina-graphene and alumina-zirconia composites

The onset of hybrid alumina-based composites, which combines two or more nano-particles within the alumina matrix has already shown promising improvements in the matrix material. However, variations in mechanical properties including the optimum compositions that give improved properties faced with the development of alumina-based composites require further studies to understand the underlying mechanisms and synergistic effects of the nano-particle additions on the alumina matrix. In the current study, the structure and properties of Al?O?-graphene (0.5 wt%) and Al?O?–ZrO? (4 wt% and 10 wt%) composites fabricated via hot-pressing was studied as a baseline for multiple combinations. Even though the addition of 10 wt%ZrO? resulted in a 23% reduction in the grain size of the alumina matrix, the 4 wt%ZrO? addition resulted in a 14% increase in grain size as compared to the parent alumina matrix. X-ray diffraction analysis revealed that there was approximately 85% monoclinic (m-ZrO₂) vs. 15% tetragonal (t-ZrO₂) crystal structures in the A4ZrO? sample whilst the A₁₀ZrO? had approximately 93% m-ZrO₂ vs. 7% t-ZrO₂. The high-volume fraction of the monoclinic crystal structures in the A₁₀ZrO? accounts for the induced microcracks in the sample since the transition from the ductile-tetragonal to brittle-monoclinic is associated with the exertion of compressive stresses on the alumina matrix by the associated elastic volume expansion of m-ZrO₂. Also, the addition of 0.5 wt%graphene resulted in about 37% reduction in the grain size of the alumina matrix, and approximately 10% increase in hardness as a result of the distribution of graphene along the grain boundaries of the parent alumina matrix, which restricts grain coalescence and growth during processing. Furthermore, an increase up to 115% and 164% were observed in the fracture toughness (K_IC) with the inclusion of 0.5 wt%graphene and 10 wt%ZrO? respectively, which was primarily ascribed to the fine-grained microstructures and toughening mechanisms of the intergranular graphene and ZrO? particles.     

Effect of irrigation method on transmission to and persistence of Escherichia coli O157:H7 on lettuce

In this study, the transmission of Escherichia coli O157:H7 to lettuce plants through spray and surface irrigation was demonstrated. For all treatments combined, the number of plants testing positive following a single exposure to E. coli O157: H7 through spray irrigation (29 of 32 plants) was larger than the number testing positive following surface irrigation (6 of 32 plants). E. coli O157:H7 persisted on 9 of 11 plants for 20 days following spray irrigation with contaminated water. Immersion of harvested lettuce heads for 1 min in a 200 ppm chlorine solution did not eliminate all E. coli O157:H7 cells. The results of this study suggest that regardless of the irrigation method used, crops can become contaminated; therefore, the irrigation of food crops with water of unknown microbial quality should be avoided.     

Record-keeping practices of clinical and counseling psychologists: A survey of practitioners.

Record keeping by psychologists was examined with survey data. Results indicate substantial variability in policies and practices. Implications of the results are discussed, and it is recommended that more specific guidelines for practitioners be developed in order to reduce the variability in record keeping. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tarasoff: 10 years later.

This article reviews the Tarasoff case and other cases decided since the California Supreme Court issued its decision. The changing interpretation of the decision, the broadening of its applicability, and legislative reactions are also discussed. Recommendations for psychotherapists who may have to make decisions about potentially violent clients are noted. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Disruption of vitamin D receptor-retinoid X receptor heterodimer formation following ras transformation of human keratinocytes

A partial resistance to the growth inhibitory influence of 1, 25-dihydroxyvitamin D3 is apparent when immortalized keratinocytes are transformed by the ras oncogene. The vitamin D receptor (VDR) was isolated, analyzed, and found to be identical in normal, immortalized, and ras-transformed keratinocytes. Subsequently, nuclear extracts from immortalized and ras-transformed keratinocytes were analyzed in gel mobility shift assays utilizing labeled vitamin D response elements or thyroid hormone response elements. A specific protein.DNA complex that was shown to contain VDR using an anti-VDR antibody was identified in both types of extracts; however, the addition of an anti-retinoid X receptor (RXR) antibody identified RXR in the complex of both normal and immortalized keratinocyte cell extracts, but not in ras-transformed keratinocytes. Furthermore, transfection of ras-transformed keratinocytes with wild-type human RXRalpha rescued VDR.RXR and thyroid hormone receptor.RXR complexes as demonstrated by a supershift in the presence of the anti-RXR antibody. Both cell lines were found to express RXRalpha message in equal amounts. Western blot analysis revealed that RXRalpha protein from ras-transformed keratinocytes was indistinguishable from that from immortalized keratinocytes and from control cells. These results suggest a causal relationship between resistance to the growth inhibitory influences of 1,25-dihydroxyvitamin D3 and disruption of the VDR.RXR complex in malignant keratinocytes.