Negative Gibbs Free Energy Research Articles

A thermodynamic insight into viral infections: do viruses in a lytic cycle hijack cell metabolism due to their low Gibbs energy?

After adsorption and penetration, a virus hijacks a cell's metabolic machinery and uses it as a medium for its reproduction and growth through multiplication. Growth is competitive, since the same precursors and machinery are used by both the virus and its host cell. But what drives a virus to perform its life cycle more efficiently than its host? Gibbs energy represents the driving force for all chemical reactions in nature. Therefore, hypothetically Gibbs energy of growth can represent the driving force of viral lytic cycle. After chemical characterization of 17 viruses and their hosts, in this paper, growth reactions were suggested, and enthalpy, entropy and Gibbs free energy of both formation and growth were calculated. By comparing the Gibbs energy of growth of viruses and their hosts, it has been found that a virus always has a more negative Gibbs free energy of growth than its host implying that synthesis of viral components is more thermodynamically favorable. Thus, it seems that the physical laws explain observed biological phenomena - the hijack of host life machinery and high efficiency of virus growth.

활성탄에 의한 Direct Yellow 9 염료의 흡착 공정 파라미터 연구

In this study, the adsorption process parameters of direct yellow 9 (DY 9) dye by activated carbon in an aqueous solution were measured using adsorption variables that included adsorbent dose, pH, contact time, initial concentration and temperature. The adsorption equilibrium data were applied to the Langmuir, Freundlich, Temkin, and Halsey equations. The adsorption equilibrium data can be described well using the four isotherm models. The Langmuir separation coefficient (R_L=0.549~0.859) and the Freundlich constant (1/n=0.780~0.998) were evaluated to confirm that the adsorption of DY 9 by activated carbon was an effective treatment method. The Temkin constant (B_T=2.147~2.562 J/mol) and Dubinin-Radushkevich constant (E=0.211~0.255 kJ/mol) showed that this process was associated with physical adsorption. The kinetic experimental results showed that the adsorption process fits well to a pseudo-second-order model. Because the activation energy equals 30.97 kJ/mol and the reaction has a positive enthalpy (16.685 kJ/mol), the adsorption of DY 9 by activated carbon is a physisorption process and is also endothermic. The negative Gibbs free energy (ΔG= -5.316~-3.958 kJ/mol) indicates that the adsorption process is spontaneous.

Detection of Chemical Weapon Agents Using Spectroscopic Probes: A Computational Study

Organophosphorus compounds are organic compounds widely employed in agriculture as well as in chemical weapons. The use in agriculture is due to their insecticidal properties. However, in chemical warfare, the use of organophosphorus is associated with acetylcholinesterase inhibition, which promotes the cholinergic syndromes. In this line, the fast detection of this class of compound is crucial for the determination of environmental exposure. This improved detection will naturally allow for more prompt courses of treatment depending on the contaminant findings. In this perspective, the dipyrrinone oxime (1) was employed for the detection of organophosphorus compounds that are employed as nerve agents, such as cyclosarin, sarin, soman, diethyl chlorophosphate, diisopropylfluorophosphate, 2-(dimethylamino)ethyl N,N-dimethylphosphoramidofluoridate, O-ethyl-S-[2-(diethylamino)ethyl]methylphosphonothioate, O-ethyl-S-[2(diisopropylamino)ethyl] methylphosphonothioate, and O,O-diethyl-S-[2-(diethylamino)ethyl] phosphorothioate, through fluorescent emission. The thermodynamics and kinetic parameters as well as spectroscopic properties of the complexes formed for 1 and all organophosphorus compounds previously cited were investigated by means of theoretical calculations. From our findings, only the diethyl chlorophosphate, 2-(dimethylamino)ethyl N,N-dimethylphosphoramidofluoridate, and O,O-diethyl-S-[2-(diethylamino)ethyl] phosphorothioate emitted fluorescence in the hexane, toluene, chloroform, dichloromethane, methanol, acetonitrile, water, and dimethyl sulfoxide solvents. The study of the absorption wavelength with the most polar solvent showed higher values compared to apolar solvents. In the same solvent, for instance, soman in hexane showed the lowest absorption wavelength value, 324.5 nm, and DCP the highest value, 330.8 nm. This behavior was observed in other tested solvents. The thermodynamic parameters indicate negative Gibbs free energy (ΔG) values for the O-ethyl-S-[2(diisopropylamino)ethyl] methylphosphonothioate with 1 reaction. On the other hand, the sarin and cyclosarin revealed the lowest Gibbs free energy (ΔG‡) values, being kinetically favorable and presenting more reactivity.

PAMAM-halloysite Dunino hybrid as an effective adsorbent of ibuprofen and naproxen from aqueous solutions

The eco-friendly halloysite from Polish mine Dunino was grafted with polyamidoamine dendrimer to obtain the hybrid material for removal of two model drug pollutants – ibuprofen and naproxen – from aqueous solutions. The hybrid was characterized using several physicochemical methods – Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, and nitrogen sorptometry. The optimal adsorption conditions were achieved for pH 6 and 50 mg of the adsorbent dose. The adsorption capacities of ibuprofen and naproxen were 68.34 mg g−1 and 5.96 mg g−1 respectively. The adsorption of model drugs increased with increasing initial drug concentration and temperature. The mathematical models indicated the compatibility of the adsorption with pseudo-second-order kinetics and Langmuir isotherm. The calculated thermodynamic parameters – negative Gibbs free energy change and positive enthalpy and entropy change – showed spontaneous and endothermic nature of the process. Additionally, the hybrid studied was obtained using inexpensive and available raw material of significant natural resources, which should increase the possibility of its use for purification of aqueous solutions from pharmaceutical impurities.

Study of Electrochemical Redox Reaction of CuSO4 Salt with Amoxicillin at Different Temperatures Using Glassy Carbon Electrode

The redox behavior of copper sulfate in absence and presence of Amoxicillin was studied at two different temperatures (288.15 and 298.15)K. The redox behavior was studied in 0.1 M HCl electrolyte, potential range from (1.5 to -1.5)V. The copper ions concentration is small ones ranging from (3.3×10-4 to 1.67×10-3)M. Only one reduction and one oxidation peaks are obtained in our results indicating the reduction and oxidation of the divalent copper ions to the zero valent copper metal. All the solvation cyclic voltammetry parameters were evaluated at the two temperatures used and their values were discussed for cupric ions in presence and absence of Amoxicillin. Also, the thermodynamic parameters for the interaction of copper ions with Amoxicillin as stability constant, Gibbs free energies, enthalpies and entropies of interaction were calculated. The thermodynamic parameters indicate that the reaction between cupric ions and Amoxicillin is chemical reaction (high negative Gibbs free energies values), good spontaneous (positive entropies) and endothermic chemical reaction (valuable positive values). Energy values of interaction between Amx and 2hg6 which obtained by molecular docking calculations indicate that Amx has an anticancer activity for liver cancer treatment

Thermodynamic potential of a novel plasma-assisted sustainable process for co-production of ammonia and hydrogen with liquid metals

In the present article, the thermodynamic potential of a sustainable plasma-assisted nitrogen fixation process for co-production of ammonia and hydrogen is investigated. The developed process takes advantage of chemical looping system by using a liquid metal such as gallium to drive nitrogen fixation reaction using three reactors including reactor R1 to produce gallium nitride from gallium and nitrogen, reactor R2 to produce ammonia and hydrogen from gallium nitride, and plasma reactor R3 to convert gallium oxide to pure gallium. The results of the thermodynamic assessments showed that the proposed reactions are spontaneous and feasible to occur in the reactors. Likewise, the first two reactions are exothermic with ΔH=-230kJmol and ΔH=-239kJmol in the reactors R1 and R2, respectively with an equilibrium chemical conversion of 100%. The plasma reactor requires thermal energy to drive an endothermic reaction of gallium oxide dissociation withΔH=+870kJmol. Thermochemical equilibrium analysis showed that the molar ratio of steam to GaN, as well as the operating pressure and temperature of reactor R2 are the main operating parameters identifying the product composition in the reactor such that by increasing the temperature, the molar ratio of hydrogen to ammonia increases. However, by increasing the molar ratio of steam/GaN (φ value) from 0.1 to 1, the hydrogen content of the reactor increases from 45% to 70% at 400 °C. For φ > 1.0, the hydrogen content decreases while more hydrogen participate in the formation of NH3 thereby increasing the mole fraction of ammonia in the reactor. The equilibrium chemical conversion of all three reactors is expected to reach the completion point (χ = 100%) due to the highly negative Gibbs free energy of the liquid metal-based reactions together with a large thermal driving force supported by thermal plasma reactor. Finally, a scalability study points at a possible use of the new disruptive process design at small scale, and possible industrial transformation scenarios for a distributed production at a local site of consumption are depicted.

2-Methyltetrol sulfate ester-initiated nucleation mechanism enhanced by common nucleation precursors: A theory study

Aerosol samples from all over the word contained 2-methyltetrol sulfate ester (MTS). We investigated the role of MTS in new particle formation (NPF) with aerosol nucleation precursors, including sulfuric acid (SA), water (W), ammonia (N), methylamine (MA), dimethylamine (DMA), and trimethylamine (TMA). The analysis was performed using quantum chemical approach, kinetic calculation and molecular dynamics (MD) simulations. The results proved that the molecular interactions in the clusters were mainly H-bonds and electrostatic interaction. The negative Gibbs free energy changes for all the studied MTS-containing clusters indicated that the formation of these clusters was thermodynamically favorable. The stability of the clusters was evaluated according to the total evaporation rate. Here, (MTS)(SA) and (MTS)(W) were the most and least stable cluster, respectively. MD simulations were used for time and spatial analysis of the role of the MTS-SA system. The results indicated that MTS can self-aggregate or absorb SA molecules into clusters, larger than the size of the critical cluster (approximately 1 nm), suggesting that MTS can initiate NPF by itself or together with SA.

Efficient adsorbent derived from Haloxylon recurvum plant for the adsorption of acid brown dye: Kinetics, isotherm and thermodynamic optimization

The capacities, mechanisms, and potential of low-cost Haloxylon recurvum stem (HRS) biomass for sorption of acid brown 354 dye (AB354) from waters were studied. Fourier transformed infrared spectroscope (FTIR), scanning electron microscope (SEM), thermal analysis (TGA) and elemental analyzers were utilized for the characterization of biomass before and after sorption of dye. There was an enhancement in adsorption capacity with increasing the dye concentrations. With an increase in the initial dye concentration, the increase in the sorption capacity of the biomass was noticed (i.e. 2.846 mg/g – 10.011 mg/g). The extent of removal of dye decreased with the increase in temperature (i.e. 77.7% to 52.9%) and the particle size of the biomass (i.e. 81.3% to 36.6%). Ho's pseudo-second-order kinetic model (χ2 = 0.0679361), as well as Langmuir (χ2 = 1.05637 × 10–12) and Temkin sorption isotherms (χ2 = 1.36752 × 10–12), were well in line with the sorption data and best represented the equilibrium sorption of the dye. Negative Gibb's free energy value ∆G (-3.616–-0.333) and enthalpy ∆Ho (-24.826) values were the indication of spontaneous, as well as feasible and exothermic nature of the sorption process. The investigations demonstrated that HRS biomass was an attractive and potential material for removal of acidic dye from dyed effluents than many others reported in the literature.

Interaction of the synthesized anticancer compound of the methyl-glycine 1,10-phenanthroline platinum nitrate with human serum albumin and human hemoglobin proteins by spectroscopy methods and molecular docking

In the present study, the interaction of the novel synthesized platinum complex named methyl-glycine 1,10-phenanthroline platinum nitrate product with two most crucial blood carrier proteins of hemoglobin (Hb) and human serum albumin (HSA) has been investigated. Notably, structural alternation ability of the above anticancer compound was assessed at various temperatures through multispectroscopic techniques such as far-UV circular dichroism (CD) and fluorescence with the participation of the molecular docking targeting Hb and HSA in the systems of the medicine delivery. Fluctuations in the inherent fluorescence intensities of the proteins in consequence of the Pt(II) complex binding represented statics of the quenching system. It should be mentioned that thermodynamic and binding parameters have been calculated through the analysis of the outcomes of the quenching and outcomes of van’t Hoff equation for the two proteins. Theoretical and experimental findings pointed out that the leading force for the Pt(II) complex interaction was electrostatic for HSA and hydrophobic interactions for Hb. Moreover, fluorescence experiments discovered that one binding site would be available because of the Pt(II) complex binding in the two proteins accompanied by a negative Gibbs free energy value. Additionally, the far-UV CD outputs suggested that the Pt(II) complex would cause some variations in the regular secondary and tertiary structures of the HSA as the remarkable going down in the α helical contents of proteins structures at different temperatures equal to 25 °C and 37 °C; however, any noteworthy modifications have not been seen in the respective structures of Hb. However, the interaction between the newly made-up medicine (Pt(II) complex) and the two most crucial blood carrier proteins of the Hb and HSA made a notable shifting in the structures and conformations of the proteins via many fluctuations in the secondary and tertiary structures of the two proteins. Hence, such researches of designing the novel metal anticancer medicines may gather useful data for exploring the more suitable path in the face-off with severe disorders like various cancers through inventing and developing metal medical compounds that are more advantageous and have fewer consequences.

Interactions between type A carbohydrate binding modules and cellulose studied with a quartz crystal microbalance with dissipation monitoring

The specific interaction between carbohydrate binding modules (CBMs) and substrates is of utmost importance due to it affects the biological activity of the parent enzymes and determines the chemo-mechanical properties of protein-cellulose composites. In this investigation, a quartz crystal microbalance with dissipation monitoring was employed to study, in situ and in real-time, the adsorption behaviors, conformational changes and associated thermodynamics that define the specific interactions between type A CBMs (CBM1 and CBM3) and cellulose (crystalline, CNC and nanofibrillated, CNF). CBM1 and CBM3 specifically bind to CNC and CNF substrates, with the CBM3 forming more rigid adsorbed layers at 25 °C. Despite the wide variation in adsorption enthalpy (ΔH) and entropy (ΔS), depending on the experimental conditions, a negative Gibbs free energy (ΔG) was determined from the adsorption isotherms for both CBMs. Particularly, the ΔH and ΔS associated with CBM3 adsorbing on CNF exhibited significant greater values than others due to cellulose chain disorder when swelling. The results further our understandings on the interactions between type A CBMs and cellulose substrates.

Characterization and thermodynamic study of nanostructured Cu‐26Zn‐4Al (wt.%) shape memory alloy through mechanical alloying

AbstractIn the current study, nanostructured Cu−Zn−Al ternary alloy was synthesized via mechanical alloying. The structural evolutions were also measured using x‐ray diffraction and scanning electron microscope. The results showed an increase in lattice strain while the crystallite size decreased. Afterwards, thermodynamic analysis was carried out on Cu−Zn, Cu−Al and Zn−Al binary systems through Miedema's semi‐empirical model. It was found that in all binary systems, there is a driving force for solid solution formation over all compositions due to its negative Gibbs free energy changes in those compositions, whilst, this value is positive for the formation of amorphous phase over some compositions which can be attributed to the absence of driving force. Finally, the extended version of Miedema's semi‐empirical model was used and discussed in detail to determine the thermodynamic desirability of solid solution and amorphous phase formation for Cu−Zn−Al ternary system. It was concluded that in this ternary system, the minimum thermodynamic driving force for solid solution formation occurred for those compositions which were located in the corners of ternary diagram.

Measurement and correlation of phase equilibria in aqueous two-phase systems containing ionic liquid ([EOMiM]Br) and potassium citrate/ammonium citrate/potassium tartrate at different temperatures

An aqueous two-phase system (ATPS) containing an ionic liquid (1-(2-methoxyethyl)-3-methylimidazolium bromide) and three organic salts (K3C6H5O7, (NH4)3C6H5O7, and K2C4H4O6) at different temperatures was designed. Binodal data were correlated using two empirical equations, and tie-line data were fit with the utilization of Bancroft and Othmer-Tobias equations. In the systems investigated, three conclusions were drawn from the study of the phase-forming ability of salt through effective excluded volume, Gibbs free energy of ions, and the phase diagram. First, if the same cations of salt were present, the ability of salt to form phases increased with increasing valence of the anion. Second, the larger the effective excluded volume, the stronger the aforementioned ability of salt in forming phases. Third, salt had more ability to form phases if cations (or anions) contained in the salt possessed higher negative Gibbs free energy when the cation (anion) of the salt was the same. The effect of temperature on ATPSs was also investigated. It was found that it was easier to form ATPSs at lower temperature, and the tie-line slope showed growing absolute values as the temperature was decreased.

Geometrical Thermodynamic Investigation on Fe-Co-Ni(Mn-Si) <sub>x</sub> High Entropy Alloys And Correlation with Their Structural and Magnetic Properties

In the present study, different symmetrical and asymmetrical geometrical thermodynamic models such as Muggianu, Luck chou, Kohler, Colinet, Hillert, Toop, General solution model (GSM) were modelled by using the Redlich-Kister formalism for all the possible binary alloy system and then applied to FeCoNi(Mn-Si)x (x=0.0,0.1,0.25,0.5,0.75,1.0) HEAs at 1273 K (FCC phase). The results revealed that asymmetrical GSM model with a similarity coefficient ξ(ij)(k) of ~0.5 shows maximum negative excess Gibbs free energy (G1-2-E3-4-5) and associated activity coefficients (Υa) decreases with the elevation of excess energy as well as Mn-Si content. The Miedema semi-empirical model was also evaluated in order to confirm the G1-2-E3-4-5 and associated Υα greatly influenced by a high negative value of enthalpy of mixing (ΔΗmix) and melting temperature (Tm). These negative value of ΔΗmix and G1-2-3E-4-5 plays a significant role during the formation of the solid solution produced by non-equilibrium process i.e. mechanical alloying (MA). Therefore, an experimental approach has been carried out in the proposed alloy system on the basis of phase evolution, physical parameters such as lattice parameter (LP), crystallite size (Dcrystal), microstrain (es) and dislocation density (ρdis), microstructure and magnetic properties were performed at 300 K.

The coupling reaction of Fe2+ bio-oxidation and resulting Fe3+ hydrolysis drastically improve the formation of iron hydroxysulfate minerals in AMD

ABSTRACT The oxidation of Fe2+ by Acidithiobacillus ferrooxidans (A. ferrooxidans) in acid mine drainage (AMD) is often accompanied by formation of iron hydroxysulfate minerals, such as schwertmannite and jarosite. This study reported that 80 mmol L−1 of Fe2+ could be completely oxidized by A. ferrooxidans LX5 within 48 h, but only 27.7% of the resultant Fe3+ precipitated to form schwertmannite. However, the conversion efficiency to jarosite was much higher (54.5%). The formation of jarosite lasted 120 h, while only 24 h when conversed to schwertmannite. By constructing a cyclic process of ‘Cu-reducing coupled with bio-oxidization’, the total Fe in AMD could be fully converted into mineral precipitates. The resultant mineral specie could be regulated simply by control the K+ concentration. Thermodynamically, Fe3+ cannot hydrolyze spontaneously to form schwertmannite due to the positive Gibbs free energy ( = 6.63 kJ mol−1) of the reaction. However, if Fe2+ were biologically oxidized by A. ferrooxidans, the resultant Fe3+ could spontaneously form schwertmannite because the aforementioned coupling reaction has a negative Gibbs free energy ( = −34.12 kJ mol−1). Even though Fe3+ itself could hydrolyze to form jarosite spontaneously with = −22.20 kJ mol−1, the coupling reaction of Fe2+ bio-oxidation followed by Fe3+ hydrolysis in the presence of K+ could easily promote the formation of jarosite, which exhibited a great negative Gibbs energy ( = −67.45 kJ mol−1).

SORPTION OF NICKEL (II) IONS BY CHELATING RESIN WITH IMINODIACETATE FUNCTIONALITY

The regularities of sorption of nickel (II) ions from a monocomponent system on macroporous weakly acidic cationite Lewatit MonoPlus TP 207 were studied. Sorption isotherms were obtained. It is shown that the extraction process can be fairly reliably described by Langmuir and Freundlich equations. The static exchange capacity (SEC) of the resin was determined. The SEC dependencies at temperatures of 305 and 328 K during the sorption process were revealed. Integral kinetic curves were obtained. It is defined that the equilibrium concentration of nickel (II) ions is reached about 13 times faster with temperature increase from 305 to 328 K. The experimental data were processed using equations that take into account the influence of external, internal diffusion, "sorbent-sorbate" and "sorbate-sorbate" chemical interactions. It was found that the main limiting stage of sorption of nickel (II) ions is the internal diffusion. The values of external and internal diffusion rate constants at the indicated temperatures were determined. The kinetic curves were processed by pseudo first and pseudo second order models, which satisfactorily describe the experimental data. According to transition-state theory the thermodynamic characteristics of the activation process (activation energy, entropy, enthalpy, and Gibbs free energy) were calculated. Relatively low activation energy indicates the decisive contribution of diffusion in the process of sorption of nickel (II) ions. Positive entropy is the evidence of nickel hydration shells destruction during the sorption process. Positive enthalpy proves an endothermic nature of interaction of nickel (II) ions and ionogenic groups. Negative Gibbs free energy witnesses to spontaneous course of the reaction in the forward direction. For known values of stability constants the contents of nickel ionic forms and SEC’s were calculated in terms of pH value. Nickel extraction from solution increases with the appearance of singly-charged NiOH+ ions in the pH range from 8 to 9.

2-Phenylbutyric acid based organotin(IV) carboxylates; synthesis, spectroscopic characterization, antibacterial action against plant pathogens and in vitro hemolysis

Abstract 2-Phenylbutyric acid based four organotin (IV) complexes were prepared with general formula R3SnL/R2SnL2, where R = methyl (1), butyl (2), octyl (3) and L = 2-phenylbutyrate. The 2-phenyl butyrate coordinates to the tin atom via carboxylate group as evidenced by FT-IR and 13C NMR data. Moreover, skew-trapezoidal bipyramidal geometry was observed for complex 3 by single crystal X-ray diffraction data. The prepared complexes were evaluated for antibacterial action against four plant pathogens namely Xanthomonas vesicatoria, Erwinia carotovora, Ralstonia solanacearum and Xanthomonas oryzae. The results disclosed that filtered complexes have high biological action. In vitro hemolysis was performed using fresh human red blood cells (RBCs) with different concentrations of the complexes and data revealed these complexes can be screened for further assays and could be used as potential drugs. DNA binding potential of the complexes was investigated by using UV–Vis spectroscopy which suggests the intercalative binding mode. The conductometric measurements were done to explore the interaction of complexes with cetyl trimethyl ammonium bromide (CTAB) and the higher value of critical micelle concentration (CMC) while negative Gibbs free energy of micellization (ΔGm) indicates strong binding capacity of complexes with cetyl trimethyl ammonium bromide.

Highly Efficient Antimonate Removal from Water by Pyrite/Hematite Bi-Mineral: Performance and Mechanism Studies

Pyrite/hematite bi-mineral (FeS2/α-Fe2O3) was obtained by thermal modification of pyrite. FeS2/α-Fe2O3 was investigated and developed as a promising adsorbent for antimonate [Sb(V)] removal. The influence of initial concentration, temperature, initial pH, contact time, and coexisting anions on Sb(V) adsorption performance of FeS2/α-Fe2O3 was investigated. FeS2/α-Fe2O3 exhibited good adsorption performance and excellent removal efficiency. The results of the Langmuir isotherm model indicated that FeS2/α-Fe2O3 had a large adsorption capacity (347.2 mg/g) for Sb(V) removal from water. High removal efficiency by FeS2/α-Fe2O3 was achieved over a broad pH range (2.5–10.7). The coexisting anions had little influence on Sb(V) adsorption by FeS2/α-Fe2O3. The pseudo-second-order and Dubinin–Radushkevich model analyses (E = 12.62 kJ/mol) suggested that FeS2/α-Fe2O3’s Sb(V) removal process was chemisorption. The negative Gibbs free energy change and endothermic enthalpy change of 5.00 kJ/mol indicated that Sb(V) adso...

Investigation of drug-polymer miscibility, biorelevant dissolution, and bioavailability improvement of Dolutegravir-polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer solid dispersions

The aim of the current study was to prepare the efficacious amorphous solid dispersion of poorly water-soluble compound, Dolutegravir. After theoretical and experimental determination of drug-polymer miscibility, polyvinyl caprolactam-polyvinyl acetate-polyethylne glycol graft copolymer was chosen as a polymer. The solid dispersions of Dolutegravir were prepared by quench cooling and solvent evaporation method. Though quench cooling successfully stabilized the drug into amorphous form, solvent evaporation technique failed to render the drug completely amorphous. Owing to the negative Gibbs free energy at room temperature, the prepared dispersions were found stable at room temperature for 60 days. To resolve the overlapping contribution of micellar solubilization and amorphicity in improving the dissolution characteristics of Dolutegravir, the in vitro dissolution studies were performed in USP phosphate buffer as well as bio-relevant media. The dissolution advantage between prepared dispersions and pure drug in USP phosphate buffer was found bridged in the bio-relevant media. For this, the micellar solubilization driven dissolution of Dolutegravir in the presence of bile and lecithin micelles was thought as a contributing factor. Nevertheless, the dissolution advantage of dispersions prepared by quench cooling method was found endured in FeSSIF, which was thought to be due to its amorphicity leading to molecular level dissolution. Subsequently, the dissolution advantage was translated into the improved flux. Further, in vivo oral bioavailability was investigated for the dispersion prepared by quench cooling by using crystalline Dolutegravir as a control. The overall exposure of Dolutegravir was improved by 1.7 fold (AUC), while the maximum plasma concentration (Cmax) demonstrated 2 fold increase after comparing with crystalline Dolutegravir.

Preparation of novel aminated chitosan schiff’s base derivative for the removal of methyl orange dye from aqueous environment and its biological applications

A novel, eco-friendly aminated chitosan Schiff’s base (ACSSB@ZnO) was developed and utilized to remove MO from aqueous environment. The impact of different significant parameters, for example, pH (3–11), adsorbent dose (0.1–0.6 g), contact time (0–120 min), and temperature (303–323 K) have been explored by batch process. Kinetic data was illustrated by pseudo-second-order model and the isotherms fitted well with Langmuir isotherm model. The highest sorption capacity of ACSSB@ZnO was observed to be 111.11 mg/g at 323 K. Positive enthalpy and entropy values demonstrated that the MO adsorption procedure was an endothermic. Negative Gibbs free energy values implied the spontaneous nature of the adsorption system. Moreover, reusability experiments were studied and it can be regenerated by using NaOH as effluent.

PEI-Modified CMKGM/GO Porous Biocomposite for Superior Removal of Pb(II)

Using polyethylenimine-modified carboxylmethyl konjac glucomannan as a matrix and graphene oxide as nanofillers, a novel porous biocomposite named as PCGt was synthesized by a facile chemical cross-linking method. The structure of prepared PCGt was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, thermal gravimetric analysis, and X-ray photoelectron spectroscopy. Batch adsorption experiments was designed to exploit key factors on Pb(II) removal such as the pH, dose, contact time, initial concentration, and temperature. According to the data from pseudo-second-order kinetic and Freundlich isotherm models, the adsorption process was controlled by chemisorption and occurred on heterogeneous surfaces. The maximum adsorption capacity of PCGt on Pb(II) was up to 977 mg g–1 at 303.15 K. In thermodynamic analysis, positive enthalpy change and negative Gibbs free energy change exposed that the adsorption was endothermic and spontaneous at 308.15 K. The recyclability of PCGt w...