scholarly journals Antimicrobial Photodynamic Activity of Phthalocyanine Derivatives

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Samuel N. Nyamu ◽  
Lucy Ombaka ◽  
Eric Masika ◽  
Margaret Ng’ang’a
Keyword(s):  
Microbial Pathogens ◽  
Quantum Yields ◽  
Promising Alternative ◽  
The Public ◽  
Gram Positive Bacteria ◽  
Photodynamic Activity ◽  
Alternative Approaches ◽  
Therapeutic Properties ◽  
Photochemical Properties ◽  
Bacteria Resistance

Microbial pathogens have increasingly shown multidrug resistance posing a serious threat to the public health. Advances in technology are opening novel avenues for discovery of compounds that will mitigate the ever-increasing drug-resistant microbes. Use of photodynamic photosensitizer is one of the promising alternative approaches since they offer low risk of bacteria resistance as they use generated reactive oxygen species to kill the microbes. Phthalocyanine (Pc) is one such photosensitizer which has already shown promising antimicrobial photodynamic therapeutic properties. Previous studies have shown effectiveness of the Pc against Gram-positive bacteria. However, its effectiveness toward Gram-negative bacteria is limited by the impermeability of the bacteria’s outer membrane which is made up of lipopolysaccharides layer. The effectiveness of this photosensitizer is determined by its photophysical and photochemical properties such as singlet/triplet lifetimes, singlet oxygen quantum yields, and fluorescence quantum yield. Therefore, this review focuses on the recent significance advances on designing Pc that have this improved property by either conjugating with nanoparticles, quantum dots, functional groups in peripheral position, considering effect of cationic charge, and its position on the macrocycle.

scholarly journals Red and Near-Infrared Absorbing Dicyanomethylene Squaraine Cyanine Dyes: Photophysicochemical Properties and Anti-Tumor Photosensitizing Effects

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2083
Author(s):  
Tiago D. Martins ◽  
Eurico Lima ◽  
Renato E. Boto ◽  
Diana Ferreira ◽  
José R. Fernandes ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Near Infrared ◽  
Cyanine Dyes ◽  
Quantum Yields ◽  
Squaraine Dyes ◽  
Photodynamic Activity ◽  
Photochemical Properties ◽  
Radiation Treatments ◽  
Species Production

Photodynamic therapy is a medical modality developed for the treatment of several diseases of oncological and non-oncological etiology that requires the presence of a photosensitizer, light and molecular oxygen, which combined will trigger physicochemical reactions responsible for reactive oxygen species production. Given the scarcity of photosensitizers that exhibit desirable characteristics for its potential application in this therapeutic strategy, the main aims of this work were the study of the photophysical and photochemical properties and the photobiological activity of several dicyanomethylene squaraine cyanine dyes. Thus, herein, the study of their aggregation character, photobleaching and singlet oxygen production ability, and the further application of the previously synthesized dyes in Caco-2 and HepG2 cancer cell lines, to evaluate their phototherapeutic effects, are described. Dicyanomethylene squaraine dyes exhibited moderate light-stability and, despite the low singlet oxygen quantum yields, were a core of dyes that exhibited relevant in vitro photodynamic activity, as there was an evident increase in the toxicity of some of the tested dyes exclusive to radiation treatments.

The public-private partnership valuation paradox

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Stephen Gray ◽  
Jason Hall ◽  
Grant Pollard ◽  
Damien Cannavan
Keyword(s):  
Mathematical Proof ◽  
Systematic Risk ◽  
Cash Flows ◽  
Current Theory ◽  
Apparent Paradox ◽  
Content Type ◽  
The Public ◽  
The Past ◽  
Alternative Approaches ◽  
Practical Implications

Purpose In the context of public-private partnerships (PPPs), it has been argued that the standard valuation framework produces a paradox whereby government appears to be made better off by taking on more systematic risk. This has led to a range of approaches being applied in practice, none of which are consistent with the standard valuation approach. The purpose of this paper is to demonstrate that these approaches are flawed and unnecessary. Design/methodology/approach The authors step through the proposed alternative valuation approaches and demonstrate their inconsistencies and illogical outcomes, using theory, logic and mathematical proof. Findings In this paper, the authors demonstrate that the proposed (alternative) approaches suffer from internal inconsistencies and produce illogical outcomes in some cases. The authors also show that there is no problem with the current accepted theory and that the apparent paradox is not the result of a deficiency in the current theory but is rather caused by its misapplication in practice. In particular, the authors show that the systematic risk of cash flows is frequently mis-estimated, and the correction of this error solves the apparent paradox. Practical implications Over the past 20 years, PPP activity around the globe amounts to many billions of dollars. Decisions on major infrastructure funding are of enormous social and economic importance. Originality/value To the best of the authors’ knowledge, this study is the first to demonstrate the flaws and internal inconsistencies with proposed valuation framework alternatives for the purposes of evaluating PPPs.

New soluble 4-(4-formyl-2,6-dimethoxyphenoxy) substituted phthalocyanines: Synthesis, characterization, photophysical and photochemical properties

2021 ◽  
pp. 1-10
Author(s):  
Ibrahim Erden ◽  
Betül Karadoğan ◽  
Fatma Aytan Kılıçarslan ◽  
Göknur Yaşa Atmaca ◽  
Ali Erdoğmuş
Keyword(s):  
Quantum Yield ◽  
Singlet Oxygen ◽  
Fluorescence Quantum Yield ◽  
Metal Ion ◽  
Mass Spectra ◽  
Quantum Yields ◽  
Therapeutic Outcomes ◽  
Ft Ir ◽  
Photochemical Properties ◽  
New Compounds

This work describes the synthesis, spectral and fluorescence properties of bis 4-(4-formyl-2,6-dimethoxyphenoxy) substituted zinc (ZnPc) and magnesium (MgPc) phthalocyanines. The new compounds have been characterized by elemental analysis, UV-Vis, FT-IR, 1H-NMR and mass spectra. Afterward, the effects of including metal ion on the photophysicochemical properties of the complexes were studied in biocompatible solvent DMSO to analyze their potential to use as a photosensitizer in photodynamic therapy (PDT). The fluorescence and singlet oxygen quantum yields were calculated as 0.04–0.15 and 0.70–0.52 for ZnPc and MgPc, respectively. According to the results, MgPc has higher fluorescence quantum yield than ZnPc, while ZnPc has higher singlet oxygen quantum yield than MgPc. The results show that the synthesized complexes can have therapeutic outcomes for cancer treatment.

scholarly journals Designing Public Library of Binjai City by Metaphorical Architecture

2019 ◽  
Vol 3 (2) ◽  
pp. 232-240
Author(s):  
Imam Faisal Pane ◽  
Febrina
Keyword(s):  
Public Library ◽  
Building Construction ◽  
Library Services ◽  
Concept Design ◽  
Visual Form ◽  
The Public ◽  
Physical Form ◽  
Alternative Approaches ◽  
Reading Interest

The lack of public reading interest makes people rarely come to visit the public library. The public library of The Binjai city as a media to increase people's knowledge, in fact, that still using traditional planning and structuring and has a less comfortable atmosphere. The Binjai city public library requires to improve its facilities and infrastructures related to the standards of a public library, so that possible to increase people's interest in visiting the library. The designer can make several alternative approaches to design an object, one of that is a metaphorical approach. Choosing of metaphor theme is a theme approachment by taking the book as a visual form that applicated to an element of the building. The strong Malay culture of Binjai city as a local heritage can be applicated in designing the public library of Binjai City. The concept design of the Binjai City Public Library is applied to accommodate library services and activities. By taking a representation physical form of the book as part of the building construction, giving all facilities and services can be functioned to attract more people's attention to visit the library.

The Role of Management Accounting Systems in Public Hospitals and the Construction of Budgets

2016 ◽  
pp. 366-389
Author(s):  
Carla Marina Pereira de Campos ◽  
Lúcia Lima Rodrigues ◽  
Susana Margarida Faustino Jorge
Keyword(s):  
Management Accounting ◽  
Health Sector ◽  
Public Hospitals ◽  
Public Funds ◽  
Accounting Systems ◽  
The Public ◽  
Management Accounting Systems ◽  
Alternative Approaches ◽  
Traditional Approaches

The role of management accounting systems (MAS) in the construction of budgets in the public health sector has been one of the least studied topics in the international literature. Furthermore, several studies have confirmed the loss of relevance of traditional approaches to budgeting due to the need to implement techniques that are more performance-oriented. Since public hospitals are organisations that depend significantly on public funds, with substantial impacts on governments' budgets, the pressure for reducing expenditures is strong, causing increased difficulties in hospital management. In order to analyse the role of MAS in the preparation of hospital budgets, this chapter presents a literature review on this topic. This review allows to understand the loss of relevance of traditional budgeting techniques and to present alternative approaches. In this process, the implementation of different kinds of budgeting is heavily influenced by governments and professionals. Nevertheless, the research on this topic is still very scarce, evidencing the need to continue studying it.

New peripherally substituted lutetium mono and bis phthalocyanines: Synthesis and comparative photophysical and photochemical properties

2019 ◽  
Vol 23 (11n12) ◽  
pp. 1542-1550
Author(s):  
Nagihan Kocaağa ◽  
Öznur Dülger Kutlu ◽  
Ali Erdoğmuş
Keyword(s):  
Mass Spectrometry ◽  
Photodynamic Therapy ◽  
Singlet Oxygen ◽  
Photophysical Properties ◽  
Quantum Yields ◽  
Synthesis And Characterization ◽  
Type Ii ◽  
H Nmr ◽  
Photochemical Properties

In this study, the synthesis and characterization of mono-(phthalocyaninato) lutetium(III) (1-Cl and 1-F) [Lu[Formula: see text](AcO)(Pc)] (Pc [Formula: see text] phthalocyaninato, AcO [Formula: see text] acetate) and bis-(phthalocyaninato) lutetium(III) (2-Cl and 2-Br) [Lu[Formula: see text]Pc[Formula: see text]] bearing halogenated (F, Cl and Br) phenoxy–phenoxy groups are described and verified by IR, [Formula: see text]H-NMR, UV-vis and mass spectrometry. Photochemical and photophysical properties of 1-F, 1-Cl 2-Cl and 2-Br in DMSO are also presented. A comparison between photophysical and photochemical parameters of mono and bis derivatives showed that mono phthalocyanines are better photosensitizers than bis phthalocyanines. Photophysical and photochemical properties of phthalocyanines are very useful for photodynamic therapy applications. Singlet oxygen quantum yields [Formula: see text] give an indication of the potential of the complexes as photosensitizers in photodynamic therapy applications. The chloro, fluoro, bromo-phenoxy–phenoxy substituted mono-(phthalocyaninato) lutetium(III) complexes (1-Cl and 1-F) gave good singlet oxygen quantum yields (from 0.86 to 0.80) in DMSO. Thus, these complexes show potential as Type II photosensitizers for PDT of cancer.

scholarly journals Lantibiotics: A Candidate for Future Generation of Antibiotics

1970 ◽  
Vol 1 (1) ◽  
pp. 1-12 ◽  
Author(s):  
SM Asaduzzaman ◽  
Abdullah Al-Mahin ◽  
Tanvir Bashar ◽  
Rashed Noor
Keyword(s):  
Future Generation ◽  
Food Preservation ◽  
Natural Resistance ◽  
Resistant Bacteria ◽  
Peptide Antibiotic ◽  
Safe Alternative ◽  
Promising Alternative ◽  
Chemical Reagents ◽  
Gram Positive Bacteria ◽  
Modes Of Action

Emergence of multi-resistant pathogens has urged the exploration of antibiotic repertoires. The long reliability on the glycopeptide antibiotic vancomycin against fatal diseases caused by Gram-positive bacteria is also in wrecked to insist on finding more promising alternative antibiotics. The peptide antibiotic nisin is effective against vancomycin resistant bacteria. Nisin is the first lantibiotic that was discovered before penicillin and has been widely used as a safe alternative for chemical reagents in food preservation in around 50 countries for over 40 years without natural resistance development. Therefore, lantibiotics are one of the most promising alternative candidate for future antibiotics that maintain their antibacterial efficacy by many modes of action. Till now, more than 60 lantibiotics have been isolated, identified and characterized. We explained various aspects of biosynthesis, grouping, mutagenesis, activities and modes of action of lantibiotics in this review. DOI: http://dx.doi.org/10.3329/sjm.v1i1.9096 Stamford Journal of Microbiology, Vol.1(1), July 2011, p.1-12

Synthesis and characterization of novel 7-oxy-3-ethyl-6-hexyl-4-methylcoumarin substituted metallo phthalocyanines and investigation of their photophysical and photochemical properties

2019 ◽  
Vol 48 (34) ◽  
pp. 13046-13056 ◽  
Author(s):  
Mücahit Özdemir ◽  
Begümhan Karapınar ◽  
Bahattin Yalçın ◽  
Ümit Salan ◽  
Mahmut Durmuş ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Quantum Yields ◽  
Synthesis And Characterization ◽  
Photochemical Properties ◽  
Lipophilic Groups

Coumarin functionalized metallo phthalocyanines shows increased singlet oxygen quantum yields when included lipophilic groups.

scholarly journals Potent Antibacterial Prenylated Acetophenones from the Australian Endemic Plant Acronychia crassipetala

Antibiotics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 487 ◽  
Author(s):  
Trong D. Tran ◽  
Malin A. Olsson ◽  
David J. McMillan ◽  
Jason K. Cullen ◽  
Peter G. Parsons ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Secondary Metabolites ◽  
First Record ◽  
Endemic Plant ◽  
Structural Characterisation ◽  
Gram Positive Bacteria ◽  
Spectroscopic Analyses ◽  
Therapeutic Properties ◽  
Endemic Plant Species

Acronychia crassipetala is an endemic plant species in Australia. Its phytochemistry and therapeutic properties are underexplored. The hexane extract of the fruit A. crassipetala T. G. Hartley was found to inhibit the growth of the Gram-positive bacteria Staphylococcus aureus. Following bio-activity guided fractionation, two prenylated acetophenones, crassipetalonol A (1) and crassipetalone A (2), were isolated. Their structures were determined mainly by NMR and MS spectroscopic analyses. This is the first record of the isolation and structural characterisation of secondary metabolites from the species A. crassipetala. Their antibacterial and cytotoxic assessments indicated that the known compound (2) had more potent antibacterial activity than the antibiotic chloramphenicol, while the new compound (1) showed moderate cytotoxicity.

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