Experimental and DFT studies of porous carbon covalently functionalized by polyaniline as a corrosion inhibition barrier on nickel-based alloys in acidic media

In acidic medium, nickel alloys severely suffer from long term corrosion problems as a result of the breakdown of their passivating oxide. The present study considers polyaniline functionalized fish-scale graphitic carbon as an anticorrosion coating on the nickel alloy surface. The fish-scale porous carbon materials are characterized by XRD, ATR-FITR, UV, Raman, TGA, SS NMR, FESEM, and TEM methods. The surface of the alloy is covalently bound with a polyaniline long chain protonated polymer so that the polyaniline functionalized honeycomb fish-scale carbon structure can exchange electrons with the metal surface. The corrosion inhibition efficiency has been investigated in different acid media like sulfuric acid and hydrochloric acid by electrochemical methods. Polyaniline functionalized porous carbon showed in 1 M H₂SO₄ inhibition efficiency around 64% and in 1 M HCl inhibition efficiency was around 74%. The inhibition efficiency was higher in HCl because chloride ions were not able to penetrate the graphitic sheet. The novelty of this coating is in the fact that the polyaniline functionalized porous carbon has high conductivity and is electrochemically stable in acidic medium. It is able to donate electrons to the polarized metal surface.

Polyaniline functionalized fish scale carbon chemisorption on 111 nickel alloy surface by polyaniline polaron nitrogen free electron.     

Experimental and computational studies of graphene oxide covalently functionalized by octylamine: electrochemical stability,hydrogen evolution,and corrosion inhibition of the AZ13 Mg alloy in 3.5% NaCl

Recently, carbon allotropes were shown to play a key role in energy harvesting and as hydrophobic coatings on metal alloys. We have designed octylamine-functionalized graphene oxide materials for energy harvesting and as an anti-corrosion coating for metal alloy protection in a 3.5% NaCl medium. The material has been characterized by different techniques to confirm the structure and composition of the modified graphene oxide sheet: FTIR spectroscopy, XRD, Raman spectroscopy, FESEM and TEM. The electrochemical stability and corrosion inhibition efficiency were studied by electrochemical methods. The electrochemical stability increased with an increase in the applied voltage up to 500 mV, and the corrosion inhibition efficiency was shown to be 73%. The coating stability studies showed a long stability time in the corrosion medium.

Octylamine-functionalized graphene oxide chemisorbed onto a Mg alloy surface by non-bonding electron.     

Stability of di-butyl-dichalcogenide-capped gold nanoparticles: experimental data and theoretical insights

Metals capped with organochalcogenides have attracted considerable interest due to their practical applications, which include catalysis, sensing, and biosensing, due to their optical, magnetic, electrochemical, adhesive, lubrication, and antibacterial properties. There are numerous reports of metals capped with organothiol molecules; however, there are few studies on metals capped with organoselenium or organotellurium. Thus, there is a gap to be filled regarding the properties of organochalcogenide systems which can be improved by replacing sulfur with selenium or tellurium. In the last decade, there has been significant development in the synthesis of selenium and tellurium compounds; however, it is difficult to find commercial applications of these compounds because there are few studies showing the feasibility of their synthesis and their advantages compared to organothiol compounds. Stability against oxidation by molecular oxygen under ambient conditions is one of the properties which can be improved by choosing the correct organochalcogenide; this can confer important advantages for many more suitable applications. This paper reports the successful synthesis and characterization of gold nanoparticles functionalized with organochalcogenide molecules (dibutyl-disulfide, dibutyl-diselenide and dibutyl-ditelluride) and evaluates the oxidation stability of the organochalcogenides. Spherical gold nanoparticles with diameters of 24 nm were capped with organochalcogenides and were investigated using X-ray photoelectron spectroscopy (XPS) to show the improved stability of organoselenium compared with organothiol and organotellurium. The results suggest that the organoselenium is a promising candidate to replace organothiol because of its enhanced stability towards oxidation by molecular oxygen under ambient conditions and its slow oxidation rate. The observed difference in the oxidation processes, as discussed, is also in agreement with theoretical calculations.

This study presents the improved stability against oxidation by molecular oxygen under ambient conditions of organoselenium compared with organothiol, and organotellurium.     

Pharmacokinetics and Biodistribution of Anastrozole in a Polymer-Containing Formulation

Pharmaceutical Chemistry Journal - A polymer-containing anastrozole formulation (PAF) in the form of micronized particles based on a copolymer of lactic and glycolic acids with a terminal carboxyl...     

Surgical delivery of drug releasing poly(lactic-co-glycolic acid)/poly(ethylene glycol) paste with in vivo effects against glioblastoma

Introduction

The median survival of patients with glioblastoma multiforme (astrocytoma grade 4) remains less than 18 months despite radical surgery, radiotherapy and systemic chemotherapy. Surgical implantation of chemotherapy eluting wafers into the resection cavity has been shown to improve length of survival but the current licensed therapy has several drawbacks. This paper investigates in vivo efficacy of a novel drug eluting paste in glioblastoma.

Methods

Poly(lactic-co-glycolic acid)/poly(ethylene glycol) (PLGA/PEG) self-sintering paste was loaded with the chemotherapeutic agent etoposide and delivered surgically into partially resected tumours in a flank murine glioblastoma xenograft model.

Results

Surgical delivery of the paste was successful and practical, with no toxicity or surgical morbidity to the animals. The paste was retained in the tumour cavity, and preliminary results suggest a useful antitumour and antiangiogenic effect, particularly at higher doses. Bioluminescent imaging was not affected significantly by the presence of the paste in the tumour.

Conclusions

Chemotherapy loaded PLGA/PEG paste seems to be a promising technology capable of delivering active drugs into partially resected tumours. The preliminary results of this study suggest efficacy with no toxicity and will lead to larger scale efficacy studies in orthotopic glioblastoma models.     

Congestive Heart Failure: A Case of Protein Misfolding

This article describes an interesting case of a patient presenting with congestive heart failure found to have restrictive cardiomyopathy with initial laboratory evaluation showing hypogammaglobuminemia without a monoclonal band on serum and urine electrophoresis. This case highlights the clinically significant cardiac manifestation caused by protein misfolding, a defect in protein homeostasis. In addition, the utility of a relatively newer laboratory test, serum free light chains as well as the importance of clinical and pathophysiologic correlation is also discussed. We present a relatively uncommon cause of heart disease, cardiac amyloidosis in a patient with a systemic plasma cell dyscrasia, and multiple myeloma.     

Risk factors for tuberculosis in older children and adolescents: a matched case–control study in Recife,Brazil

Background

Tuberculosis is a major disease worldwide and most research focus on risk factors for adults, although there is a marked adolescent peak in incidence. The objective of this study was to identify risk factors for tuberculosis in children aged 7 to 19.

Methods

A case control study matched by age with 169 cases and 477 controls. The study population consisted of adolescents and older children from Recife, Brazil. Cases were individuals diagnosed with tuberculosis in the control programme and controls were selected in the neighborhood of cases. Conditional logistic regression was used to identify risk factors.

Results

Cigarette smoking increased by 50% the risk of tuberculosis but that this was not statistically significant (OR?=?1.6). Other risk factors were sleeping in the same house as a case of tuberculosis (OR?=?31.6), living in a house with no piped water (OR?=?7.7) (probably as a proxy for bad living conditions), illiteracy (OR?=?3.7) and male sex (OR?=?1.8). The increase in risk with living in houses with no piped water was much more marked in males. The proportion of cases of tuberculosis attributed to contact with someone with TB was 38% and to illiteracy, lack of piped water and smoking, 20%.

Conclusion

Household contact with tuberculosis, social factors and male sex play the biggest role in determining risk of TB disease among children and adolescents in the study. We recommend further research on the relationship of cigarette smoking on tuberculosis in adolescents, and on whether the sex differentials are more marked in bad living conditions. Separate studies should be conducted in older children and in adolescents.

     

Differential coupling of CC chemokine receptors to multiple heterotrimeric G proteins in human interleukin-2-activated natural killer cells

Using two different approaches, we have investigated the types of G proteins coupled to CC chemokine receptors. First, permeabilization of interleukin-2-activated natural killer (IANK) cells with streptolysin-O and introduction of anti-G protein antibodies inside these cells resulted in the following. (1) Anti-G(s), anti-G(o), and anti-G(z) inhibited the migration of IANK cells in response to macrophage- inflammatory protein-1 alpha (MIP-1 alpha), monocyte chemoattractant protein-1 (MCP-1), or regulated on activation normal T cell expressed and secreted (RANTES). (2) Anti-Gi inhibited their migration in response to MCP-1 or RANTES but not in response to MIP-1 alpha. Second, incubation of IANK cell membranes with anti-G protein antibodies before incubating with (gamma-35S) GTP or (gamma-32P) GTP, resulted in the following. (1) Anti-G(s), anti-G(o), or anti-G(z) inhibited GTP binding and GTPase activity in the presence of MIP-1 alpha, or RANTES. (2) Anti- G(i) inhibited GTP binding and GTPase activity in the presence of MCP-1 or RANTES but not in the presence of MIP-1 alpha. The inhibitory effect of anti-G protein antibodies was reversed upon incubating these antibodies with their respective synthetic peptides before addition to IANK cell membranes. These results suggest that MCP-1 and RANTES receptors are promiscuously coupled to multiple G proteins in IANK cell membranes and that this coupling is different from MIP-1 alpha receptors, which seem to be coupled to G(s), G(o), and G(z) but not to G(i).     

Pre-B acute lymphoblastic leukemia cells may induce T-cell anergy to alloantigen

Even if neoplastic cells express tumor associated antigens they still may fail to function as antigen presenting cells (APC) if they lack expression of one or more molecules critical for the induction of productive immunity. These cellular defects can be repaired by physiologic activation, transfection, or fusion of tumor cells with professional APC. Although such defects can be repaired, antitumor specific T cells may still fail to respond in vivo if they may have been tolerized. Here, human pre-B cell acute lymphoblastic leukemia (pre-B ALL) was used as a model to determine if primary human tumor cells can function as alloantigen presenting cells (alloAPC) or alternatively whether they induce anergy. In the present report, we show that pre-B cell ALL express alloantigen and adhesion molecules but uniformly lack B7-1 (CD80) and only a subset express B7-2 (CD86). Pre-B ALL cells are inefficient or ineffective alloAPC and those cases that lack expression of B7-1 and B7-2 also induce alloantigen specific T- cell unresponsiveness. Under these circumstances, T-cell unresponsiveness could be prevented by physiologic activation of tumor cells via CD40, cross-linking CD28, or signaling through the common gamma chain of the interleukin-2 receptor on T cells. Taken together, these results suggest that pre-B ALL may be incapable of inducing clinically significant T-cell-mediated antileukemia responses. This defect may be not only due to their inability to function as APC, but also due to their potential to induce tolerance. Attempts to induce clinically significant antitumor immune responses may then require not only mechanisms to repair the antigen presenting capacity of the tumor cells, but also reversal of tolerance.