25 research outputs found
Cellular signalling pathways mediating the pathogenesis of chronic inflammatory respiratory diseases: an update
Respiratory disorders, especially non-communicable, chronic inflammatory diseases, are amongst the leading causes of mortality and morbidity worldwide. Respiratory diseases involve multiple pulmonary components, including airways and lungs that lead to their abnormal physiological functioning. Several signaling pathways have been reported to play an important role in the pathophysiology of respiratory diseases. These pathways, in addition, become the compounding factors contributing to the clinical outcomes in respiratory diseases. A range of signaling components such as Notch, Hedgehog, Wingless/Wnt, bone morphogenetic proteins, epidermal growth factor and fibroblast growth factor is primarily employed by these pathways in the eventual cascade of events. The different aberrations in such cell-signaling processes trigger the onset of respiratory diseases making the conventional therapeutic modalities ineffective. These challenges have prompted us to explore novel and effective approaches for the prevention and/or treatment of respiratory diseases. In this review, we have attempted to deliberate on the current literature describing the role of major cell signaling pathways in the pathogenesis of pulmonary diseases and discuss promising advances in the field of therapeutics that could lead to novel clinical therapies capable of preventing or reversing pulmonary vascular pathology in such patients
Estimation of the poly (ε-caprolactone) [PCL] and α-cyclodextrin [α-CD] stoichiometric ratios in their inclusion complexes [ICs], and evaluation of porosity and fiber alignment in PCL nanofibers containing these ICs
This paper describes the utilization of Proton-Nuclear Magnetic Resonance spectroscopy (1H NMR) to quantify the stoichiometric ratios between poly (ε-caprolactone) [PCL] and α-cyclodextrin (α-CD) present in their non-stoichiometric inclusion complexes [(n-s)-ICs]. This paper further describes the porosity and fiber alignment of PCL nanofibers nucleated by the [(n-s)-ICs] during electrospinning. 1H NMR indicated that the two non-stoichiometric inclusion complexes utilized in this study had differing stoichiometric ratios that were closely similar to those of the starting ratios used to make them. Studies on porosity and fiber alignments were conducted on the scanning electron microscope images using ImageJ. The data indicates that both fiber alignment as well as porosity values remain almost the same over all the samples. Thus we can conclude the improvement in mechanical properties was due only to the loading of the ICs, and their subsequent interaction with bulk unthreaded PCL
Buffers more than buffering agent: introducing a new class of stabilizers for the protein BSA
In this study, we have analyzed the influence of four biological buffers on the thermal stability of bovine serum albumin (BSA) using dynamic light scattering (DLS). The investigated buffers include 4-(2-hydroxyethyl) piperazine-1-ethanesulfonic acid (HEPES), 4-(2-hydroxyethyl)-1-piperazine-propanesulfonic acid (EPPS), 4-(2-hydroxyethyl) piperazine-1-ethanesulfonic acid sodium salt (HEPES-Na), and 4-morpholine-propanesulfonic acid sodium salt (MOPS-Na). These buffers behave as a potential stabilizer for the native structure of BSA against thermal denaturation. The stabilization tendency follows the order of MOPS-Na > HEPES-Na > HEPES >> EPPS. To obtain an insight into the role of hydration layers and peptide backbone in the stabilization of BSA by these buffers, we have also explored the phase transition of a thermoresponsive polymer, poly(N-isopropylacrylamide (PNIPAM)), a model compound for protein, in aqueous solutions of HEPES, EPPS, HEPES-Na, and MOPS-Na buffers at different concentrations. It was found that the lower critical solution temperatures (LCST) of PNIPAM in the aqueous buffer solutions substantially decrease with increase in buffer concentration. The mechanism of interactions between these buffers and protein BSA was probed by various techniques, including UV-visible, fluorescence, and FTIR. The results of this series of studies reveal that the interactions are mainly governed by the influence of the buffers on the hydration layers surrounding the protein. We have also explored the possible binding sites of BSA with these buffers using a molecular docking technique. Moreover, the activities of an industrially important enzyme alpha-chymotrypsin (alpha-CT) in 0.05 M, 0.5 M, and 1.0 M of HEPES, EPPS, HEPES-Na, and MOPS-Na buffer solutions were analyzed at pH = 8.0 and T = 25 degrees C. Interestingly, the activities of alpha-CT were found to be enhanced in the aqueous solutions of these investigated buffers. Based upon the Jones-Dole viscosity parameters, the kosmotropic or chaotropic behaviors of the investigated buffers at 25 degrees C have been examined
Treatment of Coffee Husk with Ammonium-Based Ionic Liquids: Lignin Extraction, Degradation, and Characterization
Four ammonium-based
ionic liquids were synthesized for the selective
extraction and degradation of lignin from coffee husk. The extracted
lignin samples were characterized by Fourier transform infrared, gel
permeation chromatography, gas chromatography–mass spectrometry,
UV–vis, <sup>1</sup>H and <sup>13</sup>C NMR, heteronuclear
single-quantum coherence-NMR, thermogravimetric analysis, X-ray diffraction,
and field emission scanning electron microscopy analyses. The analyzed
results confirmed that these ionic liquids are able to effectively
extract and decompose the lignin to smaller molecules from the biomass.
Experimental results show that a significantly high yield, 71.2% of
the original lignin, has been achieved. This processing method is
an efficient, economical, and environmentally friendly green route
for producing high-added-value lignin from wasted coffee husk
Poly(ε-caprolactone) Nanowebs Functionalized with α- and γ‑Cyclodextrins
The
effects of alpha- and gamma-cyclodextrins (α- and γ-CDs)
on the thermal and crystal nucleation behavior of electrospun polyÂ(ε-caprolactone)
(PCL) nanofibers have been investigated. PCL/CD composite nanofibers
were obtained for the first time by electrospinning the mixture from
chloroform/<i>N,N</i>-dimethylformamide (60:40). Scanning
electron microscopy analyses indicated that neat PCL nanofibers have
an average diameter of 400 nm, which increases with the addition of
CDs. The presence of CDs on or in the electrospun PCL fibers in the
electrospun mats was investigated using Fourier transform infrared
spectroscopy, thermogravimetric analysis, and wide-angle X-ray diffraction
analysis. Differential scanning calorimetry showed that the PCL/CD
composite fibers exhibit higher crystallization temperatures and sharper
crystallization exotherms with increased CD loading, indicating the
ability of CDs to nucleate PCL crystallization. Water contact angle
(WCA) measurements indicate an inverse relationship between WCA and
α- or γ-CD concentration up to 30% loading. Phenolphthalein
absorption tests were performed to study the kinetics of their inclusion
complex (IC) formation with CDs. Unexpectedly, γ-CD-functionalized
nanowebs performed better than α-CD. This might be because at
elevated loadings some α-CDs may have threaded over PCL chains
and formed ICs, whereas γ-CD did not. With their encapsulation
capabilities and their lowered hydrophobicity, PCL/CD composite fibers
might have potential uses in medical applications, in particular as
wound odor absorbants in dressings, because it is well known that
CDs can form ICs with these odorants, thereby effectively removing
them
Aliphatic Polyester Nanofibers Functionalized with Cyclodextrins and Cyclodextrin-Guest Inclusion Complexes
The fabrication of nanofibers by electrospinning has gained popularity in the past two decades; however, only in this decade, have polymeric nanofibers been functionalized using cyclodextrins (CDs) or their inclusion complexes (ICs). By combining electrospinning of polymers with free CDs, nanofibers can be fabricated that are capable of capturing small molecules, such as wound odors or environmental toxins in water and air. Likewise, combining polymers with cyclodextrin-inclusion complexes (CD-ICs), has shown promise in enhancing or controlling the delivery of small molecule guests, by minor tweaking in the technique utilized in fabricating these nanofibers, for example, by forming core–shell or multilayered structures and conventional electrospinning, for controlled and rapid delivery, respectively. In addition to small molecule delivery, the thermomechanical properties of the polymers can be significantly improved, as our group has shown recently, by adding non-stoichiometric inclusion complexes to the polymeric nanofibers. We recently reported and thoroughly characterized the fabrication of polypseudorotaxane (PpR) nanofibers without a polymeric carrier. These PpR nanofibers show unusual rheological and thermomechanical properties, even when the coverage of those polymer chains is relatively sparse (~3%). A key advantage of these PpR nanofibers is the presence of relatively stable hydroxyl groups on the outer surface of the nanofibers, which can subsequently be taken advantage of for bioconjugation, making them suitable for biomedical applications. Although the number of studies in this area is limited, initial results suggest significant potential for bone tissue engineering, and with additional bioconjugation in other areas of tissue engineering. In addition, the behaviors and uses of aliphatic polyester nanofibers functionalized with CDs and CD-ICs are briefly described and summarized. Based on these observations, we attempt to draw conclusions for each of these combinations, and the relationships that exist between their presence and the functional behaviors of their nanofibers
Application of Buffer-Based Ionic Liquid in the Separation of 1,4-Dioxane from Its Azeotropic Aqueous Solution
We
have found that the ionic liquid (IL) [TMA]Â[EPPS] could induce
liquid–liquid phase splitting in the aqueous solution of 1,4-dioxane
at ambient conditions. This IL is composed of <i>tetra</i>methylammonium (TMA) as a cation and a biological buffer, 4-(2-hydroxyethyl)-1-piperazinepropanesulfonic
acid (EPPS), as an anion. The efficiency of this buffer-based IL for
separating 1,4-dioxane from its aqueous solution has been evaluated
on the basis of the liquid–liquid equilibrium (LLE) and solid–liquid–liquid
equilibrium (SLLE) data of 1,4-dioane + water + [TMA]Â[EPPS] at 298.15
K and under atmospheric pressure. The experimental LLE phase boundary
data were correlated with an empirical equation and the effective
excluded volume (EEV) model, respectively. The consistency of the
LLE tie-line data was confirmed by using the Othmer–Tobias
model. The binary interaction parameters of the NRTL model for each
pair were obtained by correlating the experimental LLE and SLLE tie-line
data. By using [TMA]Â[EPPS] as an auxiliary agent, the maximum concentrations
of 1,4-dioxane (97.8 wt %) in the organic-rich phase is greater than
the azeotropic compositions (87.82 wt %) of the corresponding aqueous
system. It clearly indicates that [TMA]Â[EPPS] can be served as a high
efficiency, noncorrosive, and biocompatible green agent for recovering
high purity of 1,4-dioxane from its aqueous solution
Fabrication and Characterization of Poly(ε-caprolactone)/α-Cyclodextrin Pseudorotaxane Nanofibers
Multifunctional scaffolds comprising
neat polyÂ(ε-caprolactone)
(PCL) and α-cyclodextrin pseudorotaxanated in α-cyclodextrin
form have been fabricated using a conventional electrospinning process.
Thorough in-depth characterizations were performed on the pseudorotaxane
nanofibers prepared from chloroform (CFM) and CFM/dimethylformamide
(DMF) utilizing scanning electron microscopy (SEM), transmission electron
microscopy (TEM), rheology, differential scanning calorimetry (DSC),
thermogravimetric analyses (TGA), wide-angle X-ray diffraction (WAXD),
and Instron tensile testing. The results indicate the nanofibers obtained
from chloroform retain the rotaxanated structure; while those obtained
from CFM/DMF had significantly dethreaded during electrospinning.
As a consequence, the nanowebs obtained from CFM showed higher moduli
and lower elongations at break compared to neat PCL nanowebs and PCL/α-CD
nanowebs electrospun from CFM/DMF