DMF Concentration Research Articles

The Influence of N,N-Dimethylformamide on Dispersion of Multi-Walled Carbon Nanotubes

Preparation of highly homogeneous disperse ions multi-walled carbon nanotubes (MWCNTs) has vital effect on their applications. In this research, the ultrasonication and heat treatment were used to prepare suspensions of MWCNTs using N,N-dimethylformamide (DMF) as dispersant innovatively. The suspensions were characterized by UV–Vis absorbance spectroscopy, adsorption isotherm, transmission electron microscopy, atomic force microscope and fourier transform infrared. The experimental results showed that the optimum concentration of DMF was 0.9 g/L, the best sonication time was 30 min and the optimum temperature was 50°C; The TEM and AFM images showed that the agglomeration of bundles was broken up, and the thickness of MWCNTs decreased because of the incorporation of DMF. In addition, the dispersing mechanism is that molecules of DMF get into the space of MWCNTs bundles to break up the aggregation, and amide groups of DMF easily form intermolecular hydrogen bonds to decrease surface tension. Using DMF to disperse MWCNTs had a remarkable effect, dispersed MWCNTs may be added into cement-based materials or other composite materials to improve their performance.

The structure of water-DMF binary mixtures probed by linear and nonlinear vibrational spectroscopy.

Attenuated total reflectance Fourier transform infrared spectroscopy and sum frequency generation (SFG) vibrational spectroscopy have been employed to probe the molecular structure of N,N-dimethylformamide (DMF) and water mixture by varying the concentration of DMF. From the bulk studies, we observed a gradual decrease in the intensity with a continuous blue shift in the OH-stretch region with the increase in the DMF concentration. In contrast, no significant blue shift in the OH-stretch region is noticed from the SFG spectra collected from the air-aqueous binary mixture interface as a function of DMF concentration. However, the impact of DMF is found to be disruptive in nature toward the existing hydrogen bonding network of the pristine water at the interfacial region. Interestingly, in the CH-stretch region, the vibrational signatures of the DMF molecule show blue shifts, as proposed in earlier studies. We have calculated the molecular tilt angle of the methyl group of the DMF molecule as a function of DMF concentration. For the case of neat DMF, the observed tilt angle is ∼17.7° with respect to the surface normal. The value of tilt angle decreases with the decrease in DMF concentration and reaches a value of ∼1.7° for a mole fraction of 0.5, and it further increases with the decrease in DMF concentration. It achieves a value of ∼20° for the dilute DMF mole fraction of 0.05 in the binary mixture. This indicates that DMF molecules at the air-binary mixture interface are placing their methyl groups more toward the normal for the intermediate DMF concentrations.

New insights into the cultivation of N, N-dimethylformamide-degrading methanogenic consortium: A long-term investigation on the variation of prokaryotic community inoculated with activated sludge

The cultivation of the N, N-dimethylformamide (DMF)-degrading methanogenic consortium is considered difficult. In this study, an up-flow anaerobic sludge blanket (UASB) was inoculated with activated sludge in order to culture the DMF-degrading anaerobic sludge under a constant DMF concentration of approximately 2000 mg L−1. While the UASB realized a nearly 100% degradation of DMF and a high methane production of 1.03 L d−1 for the first two months, both the removal efficiency and methane production continued to decrease until the end. The characterization of the prokaryotic community reveals that those DMF-hydrolyzing bacteria (DHB) originating from the activated sludge were responsible for the effective degradation of DMF. However, even when fed with a constant concentration of DMF, the DHB kept decreasing all the time while methane-producing archaea were rapidly cultivated. The variation of prokaryotic community suggests that the DHB could not proliferate anaerobically without utilizing the intermediate products from the hydrolysis of DMF, resulting in an unstable DMF-degrading consortium. The cultivation of DHB under the anaerobic condition of the UASB was therefore difficult. The reason it was not possible to culture a DMF-degrading methanogenic consortium in this study is that the DHB are denitrifying bacteria which require nitrate for their cell growth under the anaerobic condition. The solution to maintain the abundance of these DHB is to add doses of nitrate into the system. Nitrate is likely to help these DHB recapture intermediates from methanogens, enabling them to perform a heterotrophic denitrification by using a small proportion of DMF as the carbon source while simultaneously maintaining the cell growth of DHB.

Synthesis, characterization, and investigation of photochemical properties of tetra-substituted zinc phthalocyanines bearing 4-(3,5-dimethyl-1H-pyrazol-1-yl)phenyl moiety with different linker heteroatoms

A novel 4-((3,5-dimethyl-1H-pyrazol-1-yl)phenylthio)phthalonitrile 3 and corresponding zinc phthalocyanine 5 has been synthesized and characterized. There has been investigated the effect of nature of the linker heteroatom (S or O) on spectroscopic, photophysical and photochemical properties of zinc phthalocyanine 5 and zinc phthalocyanine 6, containing 4-(3,5-dimethyl-1H-pyrazol-1-yl)phenoxy moiety. The zinc phthalocyanines 5 and 6 are highly soluble in common organic solvents. The solvatochromic effects were evaluated by changes in UV–Vis spectra. A correlation between the Q band frequency and the refractive index of 20 organic solvents was examined. The aggregation behavior and photochemical properties (quantum yields singlet oxygen generation and photodegradation) of zinc phthalocyanines were investigated at different concentrations in DMSO, DMF, THF and water-organic solvents mixtures. The water content in the mixture has a crucial effect on the aggregation behavior and the generation of singlet oxygen. In DMSO aggregation of 5 takes place with the addition of any amount of water, whereas for 6 the formation of dimers is observed at a water concentration of more than 10%. However, in THF the formation of aggregates is observed at a water concentration above 30% for 5 and 50% for 6. The synthesized novel phthalocyanines have high quantum yield of singlet oxygen (ΦΔ) values (the range of 0.50–0.70) and can be considered as potential photosensitizers for photodynamic therapy. The highest ΦΔ values were obtained for zinc phthalocyanine 6 containing oxygen linker heteroatom in all solvents.

Surface and optical characteristics of polycrystalline GaN layer with different pores profile of porous GaAs/GaAs substrate

This work investigated the influence of pores profile of a porous GaAs/GaAs substrate on surface and optical characteristics of an over-deposited GaN layer. Different pores profile of the porous GaAs/GaAs substrate was introduced by varying the DMF concentration of 50%, 75% and 90%. The pores distribution is more uniform, while the pores size is bigger with higher DMF concentration. In contrast, the pores depth is less deep when the DMF concentration was higher than 75%. Next, the GaN layer was deposited onto the porous GaAs/GaAs substrate using an e-beam evaporator system, followed by thermal annealing in ammonia ambient. It was found that the porous GaAs/GaAs substrate, etched by the DMF concentration above 75% gave lower surface roughness to the polycrystalline GaN layer although the surface morphology showed no significant changes. XRD measurement showed on non-porous substrate favoured hexagonal growth in the polycrystalline GaN layer. Instead, the porous GaAs/GaAs substrate favoured the cubic growth, especially the porous GaAs/GaAs substrate etched by 75% DMF concentration. Moreover, the GaN layer on the porous GaAs/GaAs substrate etched by 75% DMF concentration showed the smallest FWHM of NBE peak emission, while exhibited a relaxation level closer to a reported stress-free bulk GaN, as compared to other samples. After all, the porous GaAs/GaAs substrate, etched by 75% DMF concentration has improved the surface and optical characteristics of the layer due to its better porosity.

Ultrabright fluorescent microsphere and its novel application for improving the sensitivity of immunochromatographic assay

Fluorescent microsphere (FM) is widely used as probe in immunochromatographic assay (ICA). However, the performance of conventional FM is limited because of the aggregation-caused quenching effect. Herein, we compared a kind of conventional FM (DMFFM, loading DMF) with novel aggregation-induced emission FM (AIEFM, loading TCBPE). The fluorescence intensity of DMFFM initially increased and then decreased as the concentrations of the loading DMF increased. The fluorescence intensity of AIEFM increased as the concentrations of the loading TCBPE increased and retained a high value. AIEFM was compared with two commercial FMs purchased from Ocean (OFM) and Merk (MFM). The maximum fluorescence intensity and relative quantum yield of AIEFM was approximately 5 and 4.5 times higher than those of two commercial FMs. We used the novel AIEFM as a probe to improve the sensitivity of ICA. When Escherichia coli O157:H7 was detected as the target, the limit of detection of ICA based on AIEFM, OFM and MFM were 3.98 × 103 CFU/mL, 4.48 × 104 and 2.78 × 104 CFU/mL, respectively. The ICA of AIEFM had 11 and 7 times improvement in sensitivity compared with that of OFM and MFM. Our results could be used as a basis for novel probes in practical ICA applications.

Solvent‐Induced Control over Breathing Behavior in Flexible Metal–Organic Frameworks for Natural‐Gas Delivery

AbstractFinding appropriate stimuli for controlling the breathing behavior of flexible metal–organic frameworks (MOFs) is highly challenging. Herein, we report the solvent‐induced changes in the particle size and stability of different breathing phases of the MIL‐53 series, a group of flexible MOFs. A water/dimethylformamide (DMF) ratio is tuned to synthesize members of the MIL‐53 series which have different behaviors. The breathing is explored by high‐pressure methane sorption tests. Increasing DMF concentration decreases MOF particle size and increases the stability of the porous phases, boosting the 5.8–65 bar sorption difference of methane, which is required for natural‐gas delivery.

Solvent-Induced Control over Breathing Behavior in Flexible Metal-Organic Frameworks for Natural-Gas Delivery.

Finding appropriate stimuli for controlling the breathing behavior of flexible metal-organic frameworks (MOFs) is highly challenging. Herein, we report the solvent-induced changes in the particle size and stability of different breathing phases of the MIL-53 series, a group of flexible MOFs. A water/dimethylformamide (DMF) ratio is tuned to synthesize members of the MIL-53 series which have different behaviors. The breathing is explored by high-pressure methane sorption tests. Increasing DMF concentration decreases MOF particle size and increases the stability of the porous phases, boosting the 5.8-65 bar sorption difference of methane, which is required for natural-gas delivery.

Anaerobic treatment of N,N-dimethylformamide-containing high-strength wastewater by submerged anaerobic membrane bioreactor with a co-cultured inoculum

The anaerobic treatment of wastewater containing approximately 2000 mg L−1N,N-dimethylformamide (DMF) was conducted by a lab-scale submerged anaerobic membrane bioreactor (SAnMBR). The inoculum consisted of aerobic DMF-hydrolyzing activated sludge (DAS) and anaerobic digested sludge (ADS). A rapid start-up was achieved with thorough DMF methanogenic degradation on the first day. The results of a 250-day long-term experiment demonstrated that under a low organic loading rate (OLR) of 3.14–4.16 g COD L−1 d−1, SAnMBR maintained excellent DMF removal efficiency along with high methane conversion. However, the elevation of OLR significantly limited DMF hydrolysis. When OLR exceeded 6.54 g COD L−1 d−1, both removal efficiency and methane production dramatically dropped. The DMF-hydrolyzing bacteria originating from the DAS gradually decayed under the anaerobic condition, resulting in the weak hydrolysis of DMF. The shortening of hydraulic retention time (HRT) is not recommended for the SAnMBR because severe membrane fouling occurred when HRT was shortened to 8 h. To handle high OLRs, an appropriate solution is to maintain a low F/M ratio by increasing both the influent DMF concentration and sludge concentration. The high CH4 content in the biogas, exceeding 85%, was shown to be the reason for the suitability of anaerobic treatment to DMF. Some improvements which would help to maintain the effective hydrolysis are proposed: a side-stream system to replenish DAS to the SAnMBR is helpful; slight dosage of nitrate could also help to enrich the DMF-hydrolyzing bacteria; and the co-digestion of DMF and other organics might be convenient to establish a stable DMF-degrading consortium.

The Synthesis of Fiber Membranes from High-Impact Polystyrene (HIPS) Waste using Needleless Electrospinning as Air Filtration Media

The production and characterization of air filter membranes from HIPS waste are presented. The HIPS membranes were synthesized using needleless electrospinning. The HIPS precursor solutions were made by dissolving the HIPS waste in the d-limonene:DMF solvent mixing ratio of 3:1, 1:1, and 1:3. The different mixing ratio led to different viscosity, surface tension, and fiber morphology. Beaded to fine fiber morphology were obtained by increasing the DMF concentration in the mixing solvent. The filtration test using PM2.5 as test particles demonstrated the good performance of the HIPS membrane as an air filter media (filtration efficiency up to 98.75%).

Facile Method for the Controllable Synthesis of Cs xPb yBr z-Based Perovskites.

We report a facile method to realize the selective synthesis of Cs xPb yBr z-based perovskites, including CsPbBr3, Cs4PbBr6 and CsPb2Br5. The use of an appropriate amount of N, N-dimethylformamide (DMF) solvent is experimentally determined to play a critical role in the controlled formation of various perovskite products. With continuously increasing DMF concentration, first CsPbBr3 nanocrystals with tunable size can be achieved, and then the production of Cs4PbBr6 and CsPb2Br5 perovskite analogues is successively realized. Our findings present a novel path for the controlled synthesis of other perovskite analogues for specific applications.

Validity of different biomonitoring parameters for the assessment of occupational exposure to N,N-dimethylformamide (DMF).

This study was performed to assess the relation between occupational exposure to N,N-dimethylformamide after an 8h work shift in the acrylic fibre industry and its three biological markers N-methylformamide (NMFtotal), N-acetyl-S-(N-methylcarbamoyl)cysteine (AMCC), and N-methylcarbamoyl adduct at haemoglobin (MCVal). External DMF exposure of 220 workers was determined during the whole shift. A standardised questionnaire was used to obtain information about the worker's general health status, medical treatment, smoking habits, protective measures, and possible symptoms caused by DMF exposure. NMF and AMCC were analysed in post-shift urine samples and MCVal in blood. For longitudinal assessment the average AMCC concentration was determined over a period of 4weeks (weekly sampling) in a sub-collective of 89 workers. The median of DMF concentration in air was 3.19mg/m3 (range < 0.15-46.9mg/m3). The biological markers showed a median of 4.80mg/L (range 0.20-50.6mg/L) for NMFtotal, 4.75mg/g creatinine (range 0.06-49.6mg/g creatinine) for AMCC, and 57.5nmol/g globin (range 0.5-414nmol/g) for MCVal. A significant linear relationship was observed between DMF in air and NMF as well as between DMF in air and AMCC in post-shift urine samples. The mean AMCC values measured weekly over a period of 4weeks correlated significantly with MCVal adducts too. Excluding workers who had been using breathing masks on the day of the study led to even tighter correlations. The results of the present study demonstrate the applicability of the DMF biomonitoring parameters NMFtotal in post-shift urine for the present-day exposure assessment, AMCC in the post-shift urine after several shifts for assessment of the cumulative exposure of the previous working days, and MCVal for assessment of long-term exposure during previous weeks and months. The data of the present study enable now the estimation of valid equivalents of these biomonitoring parameters to the external DMF exposure. From the risk assessment point of view, the exposure limit values for AMCC and MCVal, which are directly linked to the presumed toxic intermediate MIC, exhibit a significant advance.

Health risk assessment of volatile organic compounds exposure near Daegu dyeing industrial complex in South Korea

BackgroundStudying human health in areas with industrial contamination is a serious and complex issue. In recent years, attention has increasingly focused on the health implications of large industrial complexes. A variety of potential toxic chemicals have been produced during manufacturing processes and activities in industrial complexes in South Korea. A large number of dyeing industries gathered together in Daegu dyeing industrial complex. The residents near the industrial complex could be often exposed to volatile organic compounds. This study aimed to evaluate VOCs levels in the ambient air of DDIC, to assess the impact on human health risks, and to find more convincing evidences to prove these VOCs emitted from DDIC.MethodsAccording to deterministic risk assessment, inhalation was the most important route. Residential indoor, outdoor and personal exposure air VOCs were measured by passive samplers in exposed area and controlled area in different seasons. Satisfaction with ambient environments and self-reported diseases were also obtained by questionnaire survey. The VOCs concentrations in exposed area and controlled area was compared by t-test. The relationships among every VOC were tested by correlation. The values of hazard quotient (HQ) and life cancer risk were estimated.ResultsThe concentrations of measured VOCs were presented, moreover, the variety of concentrations according the distances from the residential settings to the industrial complex site in exposed area. The residential indoor, outdoor, and personal exposure concentrations of toluene, DMF and chloroform in exposed area were significantly higher than the corresponding concentrations in controlled area both in summer and autumn. Toluene, DMF, chloroform and MEK had significantly positive correlations with each other in indoor and outdoor, and even in personal exposure. The HQ for DMF exceeded 1, and the life cancer risk of chloroform was greater than 10− 4 in exposed area. The prevalence of respiratory diseases, anaphylactic diseases and cardiovascular diseases in exposed area were significantly higher than in controlled area.ConclusionsThis study showed that adverse cancer and non-cancer health effects may occur by VOCs emitted from DDIC, and some risk managements are needed. Moreover, this study provides a convenient preliminarily method for pollutants source characteristics.

Microbial degradation of N,N-dimethylformamide by Paracoccus sp. strain DMF-3 from activated sludge

N,N-dimethylformamide (DMF) was a typical toxic chemical and existed extensively in industrial wastewater. In this study, a strain of the high-efficient DMF degrading bacteria DMF-3 belonging to Paracoccus sp. was enriched and isolated from activated sludge. The removal rate of DMF by DMF-3 was up to 100% while 1000 mg/L DMF was used as the sole carbon and nitrogen source. Growth kinetics model of DMF-3 was thus established, and the kinetic constants were determined with maximum specific growth rate μmax = 0.22 (h−1), saturation constant Ks = 0.41 (g/L) and inhibition constant Ki = 25.93 (g/L). Based on the analysis of the intermediate products, it was found that DMF was firstly converted into dimethylamine and formic acid, and these intermediates were finally degraded to ammonia and carbon dioxide following the typical metabolic pathway of methylotrophs. In addition, to enhance the degrading capacity of DMF-3 in high DMF concentration, ultraviolet mutagenesis process was applied. Compared with the usage of the original strain of DMF-3, the degradation rate was increased by 14.8% with the usage of obtained mutant strain with applied initial DMF concentration 10,000 mg/L.

DESIGN, SYNTHESIS OF BIOLOGICALLY ACTIVE HETEROCYCLES CONTAINING INDOL- THIAZOLYL- THIAZOLIDINONE DERIVATIVES

Objective: The present study envisage a novel series of thiazole, indole and thiazolidine derivatives, namely, N-((5-Substituted-2-phenyl-1 H-indol-3-yl)methylene)-4,5,6,7-tetrahydro-5,7,-dimethylbenzo [d]thiazole-2-amine (4a-c), 2-(5-substituted-2-phenyl-1H-indol-3-yl)-3-(4,5,6,7- trimethylbenzo[d]thiazol-2-yl)-thiazolidin-4-one (5a-c) and 5-benzylidine-2-(5-substituted-2phenyl-1H-indol-3yl)-3-(4,5,6,7-tetrahydro-5,5,7- trimethylbenzo[d]thiazol-2-yl) thiazolidin-4-one (6a-c).Methods: All the newly synthesized compounds were characterized by infrared, 1H, 13C nuclear magnetic resonance and mass spectral data and elemental analysis and evaluated for in vitro antimicrobial activity.Results: Novel compounds N-((5-Substituted-2-phenyl-1H-indol-3-yl)methylene)-4,5,6,7-tetrahydro-5,7,-dimethylbenzo [d]thiazole-2-amine (4a-c), 2-(5-substituted-2-phenyl-1H-indol-3-yl)-3-(4,5,6,7-trimethylbenzo[d]thiazol-2-yl)-thiazolidin-4-one (5a-c) and 5-benzylidine-2-(5-substituted- 2phenyl-1H-indol-3yl)-3-(4,5,6,7-tetrahydro-5,5,7-trimethyl benzo[d]thiazol-2-yl)thiazolidin-4-one (6a-c) have been made and characterized using spectral and analytical data. The results of antibacterial and antifungal activities showed that some of the synthesized compounds exhibited promising activities.Conclusion: All the newly synthesized compounds were carried out by the broth microdilution method (NCCLS. 2002) in a DMF concentration of 500, 250, 125, and 62.5 μg/ml. Gentamycin and fluconazole are used as reference standards for antibacterial and antifungal activity, respectively. The final results revealed that compounds 4b, 5b, and 6b exhibited potent antimicrobial activity when compared to the standard drugs.

Bio-Engineered Graphene-Based Cage for Efficient Local Enrichment and Biodegradation of Aqueous Organic Wastes

Microorganism immobilization has attracted great attention as a traditional method to overcome aqueous organic wastes containing N, N-dimethylformamide (DMF). In this approach, graphene oxide was modified with functional polymer firstly to obtain micro-composites material (PGO), and then the prepared composites were deposited on the surface of copper mesh (CM) to block the meshes and CM@PGO was achieved. Moreover, cage-shaped model was designed based on CM@PGO and P. denitrificans was packed inside the cage for batch experiments. This strategy could enrich the local concentration of DMF due to the formation of hydrogen bonds with the oxygen-containing groups from PGO and the character of bacteria in captivity could also contribute to the process of degradation. Results showed that the approach could remove DMF more efficiently about 15% compared with free microorganism and presented excellent cycling performance. Meantime, physical adsorption and chemical adsorption were both contributed to the process of PGO adsorption, and the adsorption isotherm fits Langmuir model well, furthermore, the theoretical maximum of adsorption ability calculated through Langmuir model is 95 mg/g. In other words, this cage-shaped CM@PGO provided a facile platform for treating various wastewaters by altering the species of packed microorganisms, which exhibited considerable prospects for wastewater treatment.

Influence of the dissolution solvent on the cytotoxicity of octahedral cationic Ir(III) hydride complexes

The stability of a compound in the solvent in which it is dissolved is a fundamental parameter in medicinal chemistry. In this article, we report on the results of our investigations on the stability of five Ir(III) complexes in DMF and DMSO. Importantly, we demonstrate that the rate of ligand exchange/decomposition of these compounds has an influence on their in vitro anticancer properties. The compounds were generally found to be less toxic to cancer cells after having been dissolved for longer time (24 h) in DMSO compared to short incubation time (1 h) in the same solvent. On the contrary, only minor differences in cytotoxicity were observed when the compounds were dissolved in DMF, emphasizing that this solvent should be employed instead of DMSO when unstable compounds are investigated, provided that the concentration of DMF is kept at a low concentration level.

SYNTHESIS, CHARACTERIZATION, IN VITRO ANTIMICROBIAL, ANTHELMINTIC AND DOCKING STUDIES OF NEW 2-[(E)-{[4-(1H-1,2,4-TRIAZOL-1 YLMETHYL)PHENYL]IMINO} METHYL]PHENOL, AND THEIR COMPLEXES WITH 3D METAL IONS

&lt;p&gt;&lt;strong&gt;Objective: &lt;/strong&gt;The main objectives of this research work is the synthesis and characterization of biologically potential triazole ring containing the Schiff base legend and their transition metal complexes, followed by screenings of their antimicrobial and anthelmintic activity the results of antimicrobial activity were compared with docking scores.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods: &lt;/strong&gt;The&lt;strong&gt; &lt;/strong&gt;coordination complexes of Co(II), Cu(II), Fe(III) and Zn(II) with Schiff base derived ligand 4-(1&lt;em&gt;H&lt;/em&gt;-1,2,4-triazol-1-ylmethyl) aniline and substituted aldehydes have been synthesized. The complexes are characterized by elemental analysis, conductivity measurements, electronic, IR, and &lt;sup&gt;1&lt;/sup&gt;H NMR spectral data. The synthesized compounds were also screened &lt;em&gt;In vitro&lt;/em&gt; antimicrobial activity was carried out according to diffusion method by using agar and potato dextrose agar at 100, 500 and 700 mg/ml concentrations in DMF.&lt;strong&gt; &lt;/strong&gt;HEX 8.0&lt;strong&gt; &lt;/strong&gt;programmers were used to perform the docking experiments on &lt;em&gt;nucleotide &lt;/em&gt;of &lt;em&gt;S. typhi &lt;/em&gt;&lt;em&gt;at&lt;/em&gt; as ligand [PDB: 3B6O].&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;Schiff base ligand and their transition metal complexes were studied for antimicrobial activity as well as docking. The results of both studies concluded that 4a, 4c and 4d compounds are more active in minimum inhibition concentration (30μg/ml) against &lt;em&gt;Staphylococcus aureus&lt;/em&gt; (&lt;em&gt;S. aureus), Salmonella typhi (S. typlei)&lt;/em&gt; bacteria and &lt;em&gt;Penicillium chrysogenum&lt;/em&gt; (&lt;em&gt;P. Crysogenum) &lt;/em&gt;fungi. The compounds showed highest docking score (-257.47,-275.61 and-280.17 respectively) with the secondary structure of the alpha-amylase with a nucleotide from &lt;em&gt;s. typhi&lt;/em&gt; in the solid model. In the study of anthelmintic activity among these three compounds, 4d compound exhibits more activity compared with the standard.&lt;/p&gt;&lt;strong&gt;Conclusion: &lt;/strong&gt;The compounds 4a, 4c and 4d were found to be more promising pharmacological activity this observation may promote a further development of this triazole group of compounds which may lead to better pharmacological profile than standard drugs. &lt;p&gt; &lt;/p&gt;

An Eco-tank system containing microbes and different aquatic plant species for the bioremediation of N,N-dimethylformamide polluted river waters

An Eco-tank system of 10m was designed to simulate the natural river. It consisted of five tanks sequentially connected containing microbes, biofilm carriers and four species of floating aquatic plants. The purification performance of the system for N,N-dimethylformamide (DMF) polluted river water was evaluated by operating in continuous mode. DMF was completely removed in Tanks 1 and 2 at influent DMF concentrations between 75.42 and 161.05mg⿿L⿿1. The NH4+-N concentration increased in Tank 1, followed by a gradual decrease in Tanks 2⿿5. Removal of NH4+-N was enhanced by aeration. The average effluent NH4+-N concentration of Tank 5 decreased to a minimum of 0.89mg⿿L⿿1, corresponding to a decrease of 84.8% when compared with that before aeration. TN concentration did not decrease significantly as expected after inoculation with denitrifying bacteria. The average effluent TN concentration of the system was determined to be 4.58mg⿿L⿿1, still unable to satisfy the Class V standard for surface water environmental quality. The results of this study demonstrated that the Eco-tank system is an efficient process in removing DMF, TOC, and NH4+-N from DMF polluted river water. However, if possible, alternative technologies should be adopted for controlling the effluent TN concentration.

Apparent Molar Heat Capacities of n-Alcohols (C2 to C4) and Symmetric Tetraalkylammonium Bromides (C2 to C5) in Water–N,N-Dimethylformamide Mixtures: Methylene Group Contribution and Hydrophobic Hydration

The apparent molar heat capacities, ϕ C p , of ethanol, n-propanol, n-butanol, and tetraethylammonium, tetra-n-propylammonium, tetra-n-butylammonium and tetra-n-pentylammonium bromides have been measured measured using a Picker flow calorimeter (Sodev, Canada, Model CP-Cpr) at 298.15 K in water–N,N-dimethylformamide (DMF) mixtures. The contribution of the CH2 moiety, ϕ C p (CH2), was estimated from these data as the change in ϕ C p per additional CH2 unit. The values of ϕ C p (CH2) in water (ca. 100 J·K−1·mol−1) are two to three times those in neat organic solvents (ca. 30–40 J·K−1·mol−1), consistent with a substantial contribution from hydrophobic solvation in water. In water-rich aqueous DMF solutions, ϕ C p (CH2) decreases monotonically with increasing DMF concentration, the decrease being more rapid for the n-alcohols. This trend differs significantly from that reported in the literature for highly aqueous mixtures of t-butanol, where ϕ C p (CH2) passes through a maximum.