15 research outputs found
White rot fungi can be a promising tool for removal of bisphenol A, bisphenol S, and nonylphenol from wastewate
Endocrine-disrupting chemicals (EDC) are a wide group of chemicals that interfere with the endocrine system. Their similarity to natural steroid hormones makes them able to attach to hormone receptors, thereby causing unfavorable health effects. Among EDC, bisphenol A (BPA), bisphenol S (BPS), and nonylphenol (NP) seem to be particularly harmful. As the industry is experiencing rapid expansion, BPA, BPS, and NP are being produced in growing amounts, generating considerable environmental pollution. White rot fungi (WRF) are an conomical, ecologically friendly, and socially acceptable way to remove EDC contamination from ecosystems. WRF secrete extracellular ligninolytic enzymes such as laccase, manganese peroxidase, lignin peroxidase, and versatile peroxidase, involved in lignin deterioration. Owing to the broad substrate specificity of these enzymes,
they are able to remove numerous xenobiotics, including EDC. Therefore, WRF seem to be a promising tool in the abovementioned EDC elimination during wastewater treatment processes. Here, we review WRF application for this EDC removal from wastewater and indicate several strengths and limitations of such methods
Supramolecular Structure of Phenyl Derivatives of Butanol Isomers
Wide-angle X-ray scattering patterns were recorded
for a series of aliphatic butanol isomers (n-, iso-, sec-, tert-butanol)
and their phenyl derivatives (4-phenyl-1-butanol, 2-methyl-3-
phenyl-1-propanol, 4-phenyl-2-butanol, and 2-methyl-1-phenyl-2-
propanol, respectively) to determine their atomic-scale structure
with particular emphasis on the formation of supramolecular
clusters. In addition, molecular dynamics simulations were carried
out and yielded good agreement with experimental data. The
combination of experimental and theoretical results allowed
clarification of the origin of the pre-peak appearing at low
scattering angles for the aliphatic butanols and its absence for their
phenyl counterparts. It was demonstrated that the location of the
hydroxyl group in the molecule of alkyl butanol, its geometry, and
rigidity determine the morphology of the supramolecular clusters, while the addition of the aromatic moiety causes more disordered
organization of molecules. The phenyl group significantly decreases the number of hydrogen bonds and size of the supramolecular
clusters formed via the O−H···O scheme. The lower association ability of phenyl alcohols via H-bonds is additionally attenuated by
the appearance of competing π−π configurations evidenced by the structural models
Simple rules for complex near-glass-transition phenomena in medium-sized Schiff bases
Glass-forming ability is one of the most desired properties of organic compounds dedicated to optoelectronic applications. Therefore, finding general structure–property relationships and other rules governing vitrification and related near-glass-transition phenomena is a burning issue for numerous compound families, such as Schiff bases. Hence, we employ differential scanning calorimetry, broadband dielectric spectroscopy, X-ray diffraction and quantum density functional theory calculations to investigate near-glass-transition phenomena, as well as ambient-and high-pressure molecular dynamics for two structurally related Schiff bases belonging to the family of glycine imino esters. Firstly, the surprising great stability of the supercooled liquid phase is shown for these compounds, also under high-pressure conditions. Secondly, atypical self-organization via bifurcated hydrogen bonds into lasting centrosymmetric dimers is proven. Finally, by comparing the obtained results with the previous report, some general rules that govern ambient-and high-pressure molecular dynamics and near-glass transition phenomena are derived for the family of glycine imino esters. Particularly, we derive a mathematical formula to predict and tune their glass transition temperature (Tg) and its pressure coefficient (dTg / dp). We also show that, surprisingly, despite the presence of intra-and intermolecular hydrogen bonds, van der Waals and dipole–dipole interactions are the main forces governing molecular dynamics and dielectric properties of glycine imino ester
Phenyl Ring: A Steric Hindrance or a Source of Different Hydrogen Bonding Patterns in Self-Organizing Systems?
A series of five alcohols (3-methyl-2-butanol, 1-cyclopropylethanol, 1-cyclopentylethanol, 1-cyclohexylethanol, and 1-phenylethanol) was used to study the impact of the size of steric hindrance and its aromaticity on self-assembling phenomena in the liquid phase. In this Letter, we have explicitly shown that the phenyl ring exerts a much stronger effect on the self-organization of molecules via the O–H···O scheme than any other type of steric hindrance, leading to a significant decline in the size and concentration of the H-bonded clusters. Given the combination of calorimetric, dielectric, infrared, and diffraction studies, this phenomenon was ascribed to its additional proton-acceptor function for the competitive intermolecular O–H···π interactions. The consequence of this is a different packing of molecules on the short- and medium-range scale
Systematic studies on the dynamics, intermolecular interactions and local structure in the alkyl and phenyl substituted butanol isomers
In this paper, we have studied local structure, interactions scheme and molecular dynamics of series of
aliphatic butanol (AB) isomers: n-butanol, iso-butanol, sec-butanol, and their phenyl counterparts
(PhB): 4-phenyl-1-butanol, 2-methyl-3-phenyl-1-propanol, and 4-phenyl-2-butanol by means of X-ray
diffraction (XRD), Fourier transform infrared (FTIR), and broadband dielectric spectroscopy (BDS) methods.
XRD demonstrated that aside from the main peak related to the nearest-neighbour intermolecular
correlations, there is a strong pre-peak at low scattering vector range for ABs, while for PhBs, this diffraction
feature was weakly visible or not detected at all. At first sight, it suggests that molecules in aliphatic
alcohols tend to associate and form medium-range order, while PhBs can be considered as disordered,
simple liquids. However, further thorough FTIR and BDS spectroscopy investigations have shown that
the phenyl moiety affects only slightly the degree of association and does not influence the strength of
H-bonds in aromatic alcohols. What is more, PhBs are characterized by a similar Kirkwood factor (gk
1) to the ABs. 4-phenyl-2-butanol is characterized by the greatest gk ~ 3.7 among all studied herein
alcohols, indicating a strong correlation between dipole moments and the formation of nanoassociates
of chain-like topology in its structure. Combining results obtained from different experimental techniques,
we pointed out that there are clear differences in dynamic and static properties between primary
and secondary alcohols, including medium- and short-range order, variation in the strength of H-bonds
and distribution of these types of interactions, the enthalpy of dissociation process, the glass transition
temperature, and Kirkwood factor, irrespective of the presence of steric hindrance posed by the phenyl
moiety. Results discussed in this paper clearly demonstrated that a superficial analysis of standard
diffraction patterns, which are often the first step to probe the structure of materials, may lead to wrong
conclusions. That is why complementary techniques must be applied together to understand the structure
and behavior of assembling liquids
Anormal thermal history effect on the structural dynamics of probucol infiltrated into porous alumina
Herein, broadband dielectric (BDS) and Fourier transform infrared spectroscopy (FTIR), together with differential scanning calorimetry (DSC) and X-ray diffraction (XRD), were applied to study the molecular dynamics, molecular interactions as well as physical stability of an amorphous Active Pharmaceutical Ingredient (API)-probucol (PRO)-infiltrated into anodic aluminum oxide (AAO) membranes of pore size, d ~ 10-160 nm. Interestingly, the behavior of examined substance strongly depends on the applied thermal protocol.
Remarkably, for the first time, we observed that the structural dynamics of the slowly cooled PRO under confinement is significantly enhanced when compared to thatofthe quenched material. This unusual behavior
was interpreted as a result of surface-induced effects (including the formation of well-resolved interfacial H-bonded layer and adsorption-desorption processes near the interface) that are magnified by the extremely high sensitivity to density fluctuation of studied PRO, reflected in the enormous pressure coefficient of the glass transition temperature dTg/dp = 427 K/GPa. In fact, FTIR investigations revealed that PRO tends to self-associate under confinement and forms a strongly bonded interfacial layer, which controls the variation in the structural dynamics of core molecules. Finally, we observed that the tendency to crystallize of confined API is
reduced with respect to the bulk, even though the critical size of PRO nuclei (rc ~ 3 nm) is significantly lower than the smallest examined pore size. Nevertheless, after few weeks of storage, the investigated substance crystallized in larger pores, while it remained stable in the nanochannels of d = 10 nm. A combination of XRD and DSC measurements indicated that the infiltrated PRO forms two polymorphs, the stable form I (dominating in bulk) and unstable form II (prevailing under confinement). That means that porous matrices might be used to obtain and maintain prolonged stability of unstable polymorphic forms of API
Aromaticity Effect on Supramolecular Aggregation. Aromatic vs. Cyclic Monohydroxy Alcohols
In this paper, the steric hindrance effect related to the presence of either an aromatic or cyclic
ring on the self-association process in the series of monohydroxy alcohols (MAs), from
cyclohexanemethanol to 4-cyclohexyl-1-butanol and from benzyl alcohol to 4-phenyl-1-
butanol, was studied using X-Ray Diffraction (XRD), Differential Scanning Calorimetry
(DSC), Fourier Transform Infrared (FTIR) spectroscopy, Broadband Dielectric Spectroscopy
(BDS) and the Pendant Drop (PD) methods. Based on FTIR results, it was shown that phenyl
alcohol (PhA) and cyclohexyl alcohol (CA) derivatives reveal substantial differences in the
association degree, the activation energy of dissociation, and the homogeneous distribution of
supramolecular nanoassociates suggesting that the phenyl ring exerts a stronger steric impact
on the self-assembling of molecules than cyclohexyl one. Additionally, XRD data revealed
that phenyl moiety introduces more heterogeneity in the organization of molecules compared
to the cyclic one. The changes in the self-association process of alcohols were also reflected
in differences in the molecular dynamics of the H-bonded aggregates, as well as in the
Kirkwood factor, defining the long-range correlation between dipoles, which were slightly
higher for CAs with respect to those determined for PhAs. Unexpectedly it was also found
that the surface layers of PhAs were more organized than those formed by CAs. Thus, these
findings provided insight into the impact of aromaticity on the self–assembly process, Hbonding
pattern, supramolecular structure, and intermolecular dynamics of the studied
alcohols
Synthetic strategy matters : the study of a different kind of PVP as micellar vehicles of metronidazole
Poly(1-vinyl-2-pyrrolidone) (Povidone, PVP) is one of the most interesting and versatile synthetic polymers utilised in the pharmaceutical and cosmetic industries. Its large-scale commercial production offers an assortment of products in a wide range of molecular weights but poorly-controlled (macro)structural parameters (i.e., dispersity, functionality) limiting the efficiency of PVP-based drug delivery systems (DDS). In this work, synthesised linear and star-shaped PVPs with a strictly defined structure and functionality were compared with the linear, commercially-supplied product and explored as potential vehicles for physical entrapment of metronidazole (MTZ). Here, a question is addressed how differences in their macromolecular properties affect the amorphisation of MTZ, drug encapsulation, the stability of drug-loaded micellar structures and their in vitro release from the carrier. The X-ray diffraction studies and calorimetric measurements revealed that MTZ crystallises in all investigated herein systems reducing the glass transition temperature of the binary mixture significantly. Transmission electron microscopy and dynamic light scattering analysis revealed that MTZ-loaded DDS are able to form ultrasmall regular nanocarriers with an increasing effect of regularity and sphericity from star-shaped DDS to linear-based ones. We founded that synthesised linear-based DDS is the most effective for MTZ entrapment (PVP:MTZ = 1:1 weight ratio) due to their smallest hydrodynamic radius dh = 14.7 nm, the highest stability of micellar structures −2.37 mV, and the highest values of loaded drug 76.5%. Moreover, all applied PVP-based DDS revealed an initial burst release effect of MTZ (pH = 7.4) reaching up to 60% of drug released within the first 5 h (the first-order release model fits). The marked efficiency of MTZ-loaded DDS of strictly defined structural parameters indicates the great importance of polymer preparation strategy in the targeted therapy
Kuramoto model with repulsive interactions
Model Kuramoto opisuje wiele zjawisk w przyrodzie, gdzie układ można przedstawić za pomocą sprzężonych oscylatorów. Dla oddziaływań przyciągających i odpowiednio dużej stałej sprzężenia oscylatory synchronizują się. W przypadku jednowymiarowego modelu, synchronizacja zachodzi dla dowolnej stałej sprzężenia. W pracy zbadano jednowymiarowy model oscylatorów z oddziaływaniami odpychającymi. Przyciągające, sinusoidalne sprzężenia zastąpiono kosinusoidalnymi. W tak zdefiniowanym układzie synchronizacja w czasie zachodzi tylko dla określonej liczby oscylatorów i przy zadanych warunkach początkowych. Przykładowe układy synchronizujące się i ich stabilność obliczono teoretyczne. Następnie wykonano symulacje komputerowe, które potwierdziły ich istnienie.The Kuramoto model describes many phenomena in natural science, where a system can be represented by coupled oscillators. For attractive interactions and strong enough coupling, oscillators synchronize. In one-dimensional model, synchronization occurs for any coupling. Within thesis the one-dimensional model with repulsive interactions was studied. Attractive, sinusoidal coupling was substituted with cosinusoidal one. In such defined system, synchronization in time occurs only for certain number of oscillators and for given initial conditions. Exemplary synchronizing systems and their stability were calculated theoretically. Next, computer simulations were performed which confirmed their existence
Supramolecular structures of self-assembled oligomers under confinement
We study the molecular origin of a prepeak (PP) observed at low q values in the structure factors
of three oligomers in a bulk (poly(mercaptopropyl)methylsiloxane, PMMS, poly(methylmercaptopropyl)-
grafted-hexylmethacrylate, PMMS-g-HMA, and poly(methylphenyl)siloxane, PMPS) in order to
understand the lowering of the PP intensity detected for oligomers confined in cylindrical pores with
low diameter. For this purpose, we use a combination of X-ray diffraction measurements and coarsegrained
bead-spring molecular dynamics simulations. Our molecular modelling demonstrated that the
planarity of the pendant groups triggers the self-association of oligomers into nanoaggregates.
However, the formation of oligomeric nanodomains is not sufficient for building-up the PP. The latter
requires spatial disturbance in the arrangement of the side groups of oligomers within clusters.
Importantly, our numerical analysis revealed that the increasing degree of the confinement of oligomers
limits their aggregation and consequently lowers the amplitude of the PP observed in the
experimental data