Synthesis, Characterization, and BSA Binding Properties of Carboxylated Merocyanine-Based Fluorophores.

This study describes the synthesis of new carboxylated merocyanine dyes by Knoevenagel condensation between 4-carboxybenzaldehyde and indolium/benzoindolium- and benzothiazolium-based coupling compounds. The condensations were performed in the presence of ammonium acetate, and the products were obtained in good yields after simple purification. These merocyanines exhibit UV-A-to-blue absorption and blue-to-green fluorescence emission, characterized by relatively large Stokes shift values (∼5000 cm).

Revealing the ESIPT process in benzoxazole fluorophores within polymeric matrices through theory and experiment.

The impact of the polymeric matrix on the photophysical characteristics of monomeric dyes responsive to excited-state intramolecular proton transfer (ESIPT) was investigated through UV-Vis absorption as well as steady-state and time-resolved emission spectroscopies. For this purpose, two benzoxazole monomers (M1 and M2) with acryloyl groups at different positions in their molecular structures were employed to facilitate covalent bonding within a styrene chain. Our findings reveal significant variations in their excited-state properties due to the proximity of the acryloyl groups, which affects the energy barrier of the ESIPT reaction, the emission wavelength, and the balance between the normal and tautomeric forms.

Label-Free Immunosensor Based on Liquid Crystal and Gold Nanoparticles for Cardiac Troponin I Detection.

According to the World Health Organization (WHO), cardiovascular diseases (CVDs) are the leading cause of mortality and morbidity worldwide. The development of electrochemical biosensors for CVD markers detection, such as cardiac troponin I (cTnI), becomes an important diagnostic strategy. Thus, a glassy carbon electrode (GCE) was modified with columnar liquid crystal (LC) and gold nanoparticles stabilized in polyallylamine hydrochloride (AuNPs-PAH), and the surface was employed to evaluate the interaction of the cTnI antibody (anti-cTnI) and cTnI for detection in blood plasma.

ESIPT-based benzazole-pyromellitic diimide derivatives. A thermal, electrochemical, and photochemical investigation.

This study describes the synthesis of new pyromellitic diimide (PMDI) derivatives obtained in good yields from the reaction between pyromellitic dianhydride and aminobenzazoles reactive to proton-transfer in the excited state (ESIPT). In this investigation, a non-ESIPT PMDI was also prepared for comparison. These compounds presented absorption maxima in the ultraviolet region attributed to the allowed π-π* electronic transitions.

Synthesis and investigation of the trypanocidal potential of novel 1,2,3-triazole-selenide hybrids.

Chagas Disease is caused by the protozoan Trypanosoma cruzi and is considered a tropical neglected disease by the World Health Organization (WHO). The main drugs used in the therapy of the disease are obsolete and, as a result, it still kills millions of people every year. Therefore, the development of new drugs is urgent, as is the research reported in this article, in which new triazole selenides were synthesized through a simple methodology and to evaluate their potential against T.

Carajurin Induces Apoptosis in Promastigotes through Reactive Oxygen Species Production and Mitochondrial Dysfunction.

Carajurin is the main constituent of species with reported anti- activity. However, its mechanism of action has not been described. This study investigated the mechanisms of action of carajurin against promastigote forms of .

Polyphenol oxidase-based electrochemical biosensors: A review.

The detection of phenolic compounds is relevant not only for their possible benefits to human health but also for their role as chemical pollutants, including as endocrine disruptors. The required monitoring of such compounds on-site or in field analysis can be performed with electrochemical biosensors made with polyphenol oxidases (PPO). In this review, we describe biosensors containing the oxidases tyrosinase and laccase, in addition to crude extracts and tissues from plants as enzyme sources.

Synthesis of 2,1,3-Benzoxadiazole Derivatives as New Fluorophores-Combined Experimental, Optical, Electro, and Theoretical Study.

Herein, we report the synthesis and characterization of fluorophores containing a 2,1,3-benzoxadiazole unit associated with a π-conjugated system (D-π-A-π-D). These new fluorophores in solution exhibited an absorption maximum at around ~419 nm (visible region), as expected for electronic transitions of the π-π type (ε ~2.7 × 10 L mol cm), and strong solvent-dependent fluorescence emission (Φ ~0.

Selenylated-oxadiazoles as promising DNA intercalators: Synthesis, electronic structure, DNA interaction and cleavage.

A series of selenylated-oxadiazoles were prepared and their interaction with DNA was investigated. The photophysical studies showed that all the selenylated compounds presented absorption between 270 and 329 nm, assigned to combined n→π* and π→π* transitions, and an intense blue emission (325-380 nm) with quantum yield in the range of  = 0.1-0.

Molecular Docking and Quantum Studies of Lawsone Dimers Derivatives: New Investigation of Antioxidant Behavior and Antifungal Activity.

Background: In general, fungal species are characterized by their opportunistic character and can trigger various infections in immunocompromised hosts. The emergence of infections associated with high mortality rates is due to the resistance mechanisms that these species develop.

Methods: This phenomenon of resistance denotes the need for the development of new and effective therapeutic approaches.

Troponin T immunosensor based on liquid crystal and silsesquioxane-supported gold nanoparticles.

A nanostructured immunosensor based on the liquid crystal (E)-1-decyl-4-[(4-decyloxyphenyl)diazenyl]pyridinium bromide (Br-Py) and gold nanoparticles supported by the water-soluble hybrid material 3-n-propyl-4-picolinium silsesquioxane chloride (AuNP-Si4Pic(+)Cl(-)) was built for the detection of troponin T (cTnT), a cardiac marker for acute myocardial infarction (AMI). The functionalized nanostructured surface was used to bind anti-cTnT monoclonal antibodies through electrostatic interaction. The immunosensor (ab-cTnT/AuNP-Si4Pic(+)Cl(-)/Br-Py/GCE) surface was characterized by microscopy techniques.

Liquid crystal and gold nanoparticles applied to electrochemical immunosensor for cardiac biomarker.

A label-free electrochemical immunosensor based on the ionic liquid crystal (E)-1-decyl-4-[(4-decyloxyphenyl)diazenyl]pyridinium bromide (Br-Py) coated on a glassy carbon electrode (GCE) for the quantitative detection of myoglobin (Mb), a cardiac marker for acute myocardial infarction, is reported herein for the first time. The monoclonal anti-myoglobin antibody (ab-Mb) was covalently immobilized using glyoxal on a film of polyethyleneimine-coated gold nanoparticles (AuNP-PEI). The proposed method for Mb detection is based on voltammetric suppression of the Br-Py signal when the immunosensor was incubated with Mb antigen.

A bio-inspired sensor based on surfactant film and Pd nanoparticles.

A bio-inspired complex, [(bpbpmp)Fe(III)(m-OAc)(2)Cu(II)](ClO(4)), was combined with a zwitterionic surfactant (ImS3-14) stabilizing pre-formed palladium nanoparticles and coated on a glassy carbon electrode (GCE). This bio-inspired surfactant film was capable of catalyzing redox reactions of dihydroxybenzenes, thus allowing the simultaneous electrochemical quantification of CC and HQ in cigarette residue samples by square-wave voltammetry (SWV). The best experimental conditions were obtained using phosphate buffer solution (0.

Gold nanoparticles in an ionic liquid phase supported in a biopolymeric matrix applied in the development of a rosmarinic acid biosensor.

Gold nanoparticles dispersed in 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid (Au-BMI·PF(6)) were supported in chitin (CTN) chemically crosslinked with glyoxal and epichlorohydrin to obtain a new supported ionic liquid phase (SILP) catalyst with high catalytic activity, and providing an excellent environment for enzyme immobilization. This modified biopolymer matrix (Au-BMI·PF(6)-CTN) was used as a support for the immobilization of the enzyme peroxidase (PER) from pea (Pisum sativum), and employed to develop a new biosensor for rosmarinic acid (RA) determination in pharmaceutical samples by square-wave voltammetry. In the presence of hydrogen peroxide, the PER catalyzes the oxidation of RA to the corresponding o-quinone, which is electrochemically reduced at a potential of +0.

Tungsten allylimido complexes Cl4(RCN)W(NC3H5) as single-source CVD precursors for WNxCy thin films. Correlation of precursor fragmentation to film properties.

A mixture of the tungsten allylimido complexes Cl(4)(RCN)W(NC(3)H(5)) (3a, R = CH(3) and 3b, R = Ph) was tested as a single-source precursor for growth of tungsten nitride (WN(x)) or carbonitride (WN(x)C(y)) thin films. Films deposited from 3a,b below 550 degrees C contained amorphous beta-WN(x)C(y), while those deposited at higher temperatures were polycrystalline. Film growth rates from 3a,b ranged from 5 to 10 A/min over a temperature range of 450-650 degrees C, and the apparent activation energy for film growth was 0.

Interplanetary crew doses and dose equivalents: variations among different bone marrow and skin sites.

Previously, calculations of bone marrow dose from the large solar particle event (SPE) of July 2000 were carried out using the BRYNTRN space radiation transport code and the computerized anatomical man (CAM) model. Results indicated that the dose for a bone marrow site in the mid-thigh might be twice as large as the dose for a site in the pelvis. These large variations may be significant for space radiation protection purposes, which traditionally use an average of many (typically 33) sites throughout the body.

Space radiation protection: comparison of effective dose to bone marrow dose equivalent.

In many instances, bone marrow dose equivalents averaged over the entire body have been used as a surrogate for whole-body dose equivalents in space radiation protection studies. However, career radiation limits for space missions are expressed as effective doses. This study compares calculations of effective doses to average bone marrow dose equivalents for several large solar particle events (SPEs) and annual galactic cosmic ray (GCR) spectra, in order to examine the suitability of substituting bone marrow dose equivalents for effective doses.

Solar particle event organ doses and dose equivalents for interplanetary crews: variations due to body size.

Proper assessments of spacecraft shielding requirements and concomitant estimates of risk to critical body organs of spacecraft crews from energetic space radiation require accurate, quantitative methods of characterizing the compositional changes in these radiation fields as they pass through the spacecraft and overlying tissue. When estimating astronaut radiation organ doses and dose equivalents it is customary to use the Computerized Anatomical Man (CAM) model of human geometry to account for body self-shielding. Usually, the distribution for the 50th percentile man (175 cm height; 70 kg mass) is used.

Visual assessment of the radiation distribution in the ISS Lab module: visualization in the human body.

The US Lab module of the International Space Station (ISS) is a primary working area where the crewmembers are expected to spend majority of their time. Because of the directionality of radiation fields caused by the Earth shadow, trapped radiation pitch angle distribution, and inherent variations in the ISS shielding, a model is needed to account for these local variations in the radiation distribution. We present the calculated radiation dose (rem/yr) values for over 3,000 different points in the working area of the Lab module and estimated radiation dose values for over 25,000 different points in the human body for a given ambient radiation environment.

Solar particle event dose and dose-rate distributions: parameterization of dose-time profiles, with subsequent dose-rate analysis.

Calculations of total dose and equivalent dose as functions of time, as well as dose-rate and equivalent dose rate since event start are presented for fifteen of the larger solar particle events that occurred during the period between November 1987 and August 1991. The doses, dose-equivalents, and rates presented are for exposures to the skin, ocular lens, and bone marrow behind a thickness of aluminum shielding which provides protection comparable to that of a thin spacecraft. The calculated dose vs time profiles are parameterized using a Weibull cumulative distribution as the fitting function.

Dose uncertainties for large solar particle events: input spectra variability and human geometry approximations.

The true uncertainties in estimates of body organ absorbed dose and dose equivalent, from exposures of interplanetary astronauts to large solar particle events (SPEs), are essentially unknown. Variations in models used to parameterize SPE proton spectra for input into space radiation transport and shielding computer codes can result in uncertainty about the reliability of dose predictions for these events. Also, different radiation transport codes and their input databases can yield significant differences in dose predictions, even for the same input spectra.

Solar particle event dose distributions: parameterization of dose-time profiles.

Calculations of total dose and dose equivalent as a function of time since the start of the event are presented for four of the major solar particle events that occurred during the period from August to December 1989. Results are presented for exposures to the skin, ocular lens and bone marrow shielded by a nominal thickness of aluminum shielding, comparable to that provided by a spacesuit. The calculated curves of organ dose and dose equivalent versus time are parameterized using a Weibull functional form for the fitting equation.