scholarly journals Occurrence of drug target residues within decantation tank sediments: a good clue to assess their historical excretion?

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Thomas Thiebault ◽  
Laëtitia Fougère ◽  
Anaëlle Simonneau ◽  
Emilie Destandau ◽  
Claude Le Milbeau ◽  
...  
Keyword(s):  
Drug Target ◽  
Chemical Properties ◽  
Deposition Process ◽  
Drug Consumption ◽  
Organic Layers ◽  
Sewer Systems ◽  
Physico Chemical ◽  
Deep Underground ◽  
Deposition Processes

AbstractThis study investigated the potential of sediments accumulated in sewer systems to record human activities through the occurrence of drug target residues (DTR). The installation studied is 17 m deep underground decantation tank that traps the coarse fractions of a unitary sewer system (northern part of Orléans, France), collecting both stormwater and wastewater. The sediments deposited in this tank could constitute a nonesuch opportunity to study the historical evolution of illicit and licit drug consumption in the catchment, however, the deposition processes and the record of DTRs remain largely unknown at present. Five cores were acquired from 2015 to 2017. One hundred fifty-two sediment samples were extracted using a mixture of ultra-pure water:methanol (1:1) prior to analysis of the extracts by high-pressure liquid chromatography coupled to tandem mass spectrometry. Several classical sedimentological analyses such as total organic carbon, facies description and granulometry were also performed on these samples, in order to understand the most important factors (e.g., physico-chemical properties of the DTRs, solid type, assumed load in wastewater) impacting their deposition.The key role of the speciation of DTRs was highlighted by the higher contents in neutral and anionic DTRs in organic layers, whereas only cationic DTRs were found in mineral layers. The considerable modifications in the sediments’ properties, generated by distinct origins (i.e., stormwater or wastewater), are therefore the most important drivers that must be taken into account when back-calculating the historical patterns of drug consumption from their DTR concentrations in decantation tank sediments. Further research remains necessary to fully understand the deposition process, but this study provides new clues explaining these temporal evolutions.

scholarly journals Impact of Quantum Dot Surface on Complex Formation with Chlorin e6 and Photodynamic Therapy

Nanomaterials ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 9 ◽  
Author(s):  
Artiom Skripka ◽  
Dominyka Dapkute ◽  
Jurga Valanciunaite ◽  
Vitalijus Karabanovas ◽  
Ricardas Rotomskis
Keyword(s):  
Photodynamic Therapy ◽  
Cancer Therapy ◽  
Complex Formation ◽  
Chemical Properties ◽  
Disease Diagnosis ◽  
Chlorin E6 ◽  
Deep Tissue ◽  
Physico Chemical

Nanomaterials have permeated various fields of scientific research, including that of biomedicine, as alternatives for disease diagnosis and therapy. Among different structures, quantum dots (QDs) have distinctive physico-chemical properties sought after in cancer research and eradication. Within the context of cancer therapy, QDs serve the role of transporters and energy donors to photodynamic therapy (PDT) drugs, extending the applicability and efficiency of classic PDT. In contrast to conventional PDT agents, QDs’ surface can be designed to promote cellular targeting and internalization, while their spectral properties enable better light harvesting and deep-tissue use. Here, we investigate the possibility of complex formation between different amphiphilic coating bearing QDs and photosensitizer chlorin e6 (Ce6). We show that complex formation dynamics are dependent on the type of coating—phospholipids or amphiphilic polymers—as well as on the surface charge of QDs. Förster’s resonant energy transfer occurred in every complex studied, confirming the possibility of indirect Ce6 excitation. Nonetheless, in vitro PDT activity was restricted only to negative charge bearing QD-Ce6 complexes, correlating with better accumulation in cancer cells. Overall, these findings help to better design such and similar complexes, as gained insights can be straightforwardly translated to other types of nanostructures—expanding the palette of possible therapeutic agents for cancer therapy.

scholarly journals Role of cationic lipids for the formulation of lipoplexes

2018 ◽  
Vol 1 (1) ◽  
pp. 1-8
Author(s):  
Varsha Singh ◽  
Pramod Kumar Sharma ◽  
Md. Aftab Alam
Keyword(s):  
Gene Therapy ◽  
Gene Transfer ◽  
Chemical Properties ◽  
Cationic Lipid ◽  
Cationic Lipids ◽  
Current Status ◽  
Viral Gene ◽  
Transfection Efficacy ◽  
Physico Chemical

Cationic lipids are widely used for their advantages over viral gene transfer as they are non-immunogenic and their production is easy. The formation of cationic liposomes to lipoplexes with the help of cationic lipids has been done. Cationic lipids are often used in combination with helper lipids such as DOPE or cholesterol for defining their structural properties. The mode of lipoplex formation has been described in this review. This review also focuses on the parameters that affects the physico-chemical properties of lipoplexes describing their use for the cationic lipid based on the gene therapy purposes. The current status and various prospects for the transfection efficacy of lipoplexes is also been described.

scholarly journals Physico-chemical properties of calcium phosphates

2012 ◽  
Vol 59 (1) ◽  
pp. 7-21 ◽  
Author(s):  
Vesna Babic-Ivancic ◽  
Maja Dutour-Sikiric
Keyword(s):  
Calcium Phosphates ◽  
Chemical Properties ◽  
Organic Matrix ◽  
Octacalcium Phosphate ◽  
Carbonate Apatite ◽  
Organic Additives ◽  
Biologically Relevant ◽  
Beta Tricalcium Phosphate ◽  
Physico Chemical

Calcium phosphates have important role in biological and pathological mineralization. While only one of calcium phosphates, carbonate apatite, represents the main mineral component of teeth and bones, octacalcium phosphate, calcium hydrogenphosphate dihydrate and beta-tricalcium phosphate occur in pathological deposits. From the stand-point of chemists, processes of biological and pathological mineralization could be considered as deposition of inorganic phase within organic matrix, i.e. formation of inorganic-organic composites. Although this approach is very simplified at first glance, it allows clarification of important issues related to biomineralization (e.g. what is the role of individual components of organic matrix in the emerging solid tissue), and design and preparation of new materials for hard tissue regeneration (e.g. process of transformation after implantation). The importance of investigation about calcium phosphates will be presented through the overview of basic physico-chemical reactions related to the formation and transformation of biologically relevant calcium phosphates and their interaction with various organic additives in the laboratory.

scholarly journals Tryptophan, an Amino-Acid Endowed with Unique Properties and Its Many Roles in Membrane Proteins

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1032
Author(s):  
Sonia Khemaissa ◽  
Sandrine Sagan ◽  
Astrid Walrant
Keyword(s):  
Amino Acid ◽  
Membrane Proteins ◽  
Hydrogen Bonds ◽  
Membrane Protein ◽  
Lipid Bilayers ◽  
Noncovalent Interactions ◽  
Chemical Properties ◽  
Protein Stabilization ◽  
Physico Chemical

Tryptophan is an aromatic amino acid with unique physico-chemical properties. It is often encountered in membrane proteins, especially at the level of the water/bilayer interface. It plays a role in membrane protein stabilization, anchoring and orientation in lipid bilayers. It has a hydrophobic character but can also engage in many types of interactions, such as π–cation or hydrogen bonds. In this review, we give an overview of the role of tryptophan in membrane proteins and a more detailed description of the underlying noncovalent interactions it can engage in with membrane partners.

On a deposition process on the circle with disorder

2004 ◽  
Vol 36 (04) ◽  
pp. 996-1020 ◽  
Author(s):  
Thierry Huillet
Keyword(s):  
Unit Circle ◽  
Thermodynamic Limit ◽  
Random Number ◽  
Deposition Process ◽  
Random Set ◽  
Number Of Clusters ◽  
One Dimensional ◽  
Deposition Processes ◽  
Occurrence Times

Throw n points sequentially and at random onto a unit circle and append a clockwise arc (or rod) of length s to each such point. The resulting random set (the free gas of rods) is a union of a random number of clusters with random sizes modelling a free deposition process on a one-dimensional substrate. A variant of this model is investigated in order to take into account the role of the disorder, θ > 0; this involves Dirichlet(θ) distributions. For such free deposition processes with disorder θ, we shall be interested in the occurrence times and probabilities, as n grows, of two specific types of configurations: those avoiding overlapping rods (the hard-rod gas) and those for which the largest gap is smaller than the rod length s (the packing gas). Special attention is paid to the thermodynamic limit when ns = ρ for some finite density ρ of points. The occurrence of parking configurations, those for which hard-rod and packing constraints are both fulfilled, is then studied. Finally, some aspects of these problems are investigated in the low-disorder limit θ ↓ 0 as n ↑ ∞ while nθ = γ > 0. Here, Poisson-Dirichlet(γ) partitions play some role.

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