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Quaternary ammonium salt polymers, a kind of polyelectrolyte with a quaternary ammonium group, are widely used in traditional and emerging industries due to their good water-solubility, adjustable cationicity and molecular weight, high efficiency and nontoxicity. In this paper, firstly, the properties and several synthesis methods of typical quaternary ammonium salt monomers were introduced. Secondly, the research progress on the synthesis of polymers was summarized from the perspective of obtaining products with high molecular weight, narrow molecular weight distribution and high monomer conversion, and special functional polymers. Thirdly, the relationships between the structures and properties of the polymer were analyzed from the perspectives of molecular weight, charge density, structural stability, and microstructural regulation of the polymer chain unit. Fourthly, typical examples of quaternary ammonium salt polymers in the application fields of water treatment, daily chemicals, petroleum exploitation, papermaking, and textile printing and dyeing were listed. Finally, constructive suggestions were put forward on developing quaternary ammonium salt polymers with high molecular weights, strengthening the research on the relationships between the structures and their properties and pinpointing relevant application fields.

Background There has been a great interest in developing strategies for enhancing antigen delivery to the mucosal immune system as well as identifying mucosal active immunostimulating agents. To elevate the potential of O -2ʹ-Hydroxypropyl trimethyl ammonium chloride chitosan (O-2ʹ-HACC) as an adjuvant and mucosal immune delivery carrier for DNA vaccine, we prepared the O-2ʹ-HACC loaded with Newcastle disease virus (NDV) F gene plasmid DNA and C3d6 molecular adjuvant (O-2ʹ-HACC/pFDNA microparticles). Results The O-2ʹ-HACC/pFDNA exhibited a regular spherical morphology with a particle size of 202.3 ± 0.52 nm, a zeta potential of 50.8 ± 8.21 mV, encapsulation efficiency of 90.74 ± 1.10%, and a loading capacity of 49.84 ± 1.20%. The plasmid DNA could be sustainably released from the O-2ʹ-HACC/pFDNA after an initial burst release. Intranasal vaccination of chickens immunized with O-2ʹ-HACC/pFDNA not only induced higher anti-NDV IgG and sIgA antibody titers but also significantly promoted lymphocyte proliferation and produced higher levels of IL-2, IL-4, IFN-γ, CD4+, and CD8 + T lymphocytes compared with the NDV commercial live attenuated vaccine. Intranasal delivery of the O-2ʹ-HACC/pFDNA enhanced humoral, cellular, and mucosal immune responses and protected chickens from the infection of highly virulent NDV compared with the intramuscular delivery. Conclusions Collectively, our findings indicated that the O-2ʹ-HACC could be used as a vaccine adjuvant and delivery system for mucosal immunity and have an immense application promise. Graphic Abstract

A novel method utilizing non-aqueous capillary electrophoresis (NACE) with indirect ultraviolet detection (IUD) has been developed for the analysis of five quaternary ammonium compounds (QACs). The QACs analyzed in this study include dodecyl trimethyl ammonium bromide, tetradecyl trimethyl ammonium bromide, dioctyl dimethyl ammonium chloride, octyldecyl dimethyl ammonium chloride and didecyl dimethy ammonium bromide. The separation process was carried out on an uncoated fused quartz capillary with a total length of 50.2 cm (effective length 40.0 cm) and a diameter of 50 μm. The separation buffer consisted of a mixture of MeOH/ACN (90:10, v/v) containing 2 mmol/L sodium acetate, 2 mmol/L trifluoroacetic acid (TFA) and 16 mmol/L dodecyl dimethyl benzyl ammonium chloride. The sample buffer utilized a mixture of MeOH/ACN (20:80, v/v) containing 2 mmol/L TFA. During analysis, a separation voltage of 7 kV was applied, resulting in a current of approximately 2.3 μA. The detection wavelength was set at 214 nm to ensure optimal sensitivity. Under optimal conditions, the method exhibited excellent performance characteristics, with a limit of detection of 0.5 mg/L and a limit of quantitation of 5.0 mg/L for the five QACs. Linear calibration curves were obtained in a concentration range of 5.0 to 100.0 mg/L, with correlation coefficients exceeding 0.999 for all compounds. The recoveries of the five QACs ranged from 92.3% to 114.7%, with relative standard deviations below 7.4%. To assess the applicability of the NACE-IUD method, 17 commercially available samples were successfully analyzed. The results confirmed the suitability of the method for accurate determination of the five QACs in disinfectant products. Notably, this method offers an environmentally friendly approach for the analysis of these QACs.

Chitosan has potential applications in many fields, due to its biocompatibility, biodegradability and reproducibility. However, the insolubility in water restricts its wide application. In order to expand the application of chitosan in the delivery of oil-soluble drugs and improve the efficacy of oil-soluble drugs, N-Glycidyltrimethyl ammonium chloride-modified chitosan (GTA-m-CS) and N,N-Dimethyl-N-dodecyl-N-(1,2-epoxy propyl) ammonium chloride (DDEAC), a kind of reactive surfactant, were synthesized and characterized by FTIR, NMR and XRD methods. The interactions between GTA-m-CS and DDEAC was studied by surface tension, viscosity, conductivity and fluorescence methods. The parameters, including equilibrium surface tension, critical micelle concentrations of DDEAC with different GTA-m-CS concentration, critical aggregation concentration of DDEAC, the amount of DDEAC adsorbed on GTA-m-CS, pc20 and πcmc were obtained from the surface tension curves. The influence of temperature on the above parameters were evaluated. The degree of counterion binding to micelle and the thermodynamic parameters of the system were calculated from the conductivity curves. According to the change of conductivity with temperature, the thermodynamic parameters of micellar formation were calculated. The aggregation number of DDEAC molecules in GTA-m-CS/DDEAC aggregates were calculated from steady-state fluorescence data. Based on the experimental results, the interaction models between GTA-m-CS and DDEAC were proposed. The GTA-m-CS/DDEAC aggregates could be used as curcumin carries, and achieved sustained release.

Ammonium (NH 4 + ), a breakdown product of amino acids that can be toxic at high levels, is detected by taste systems of organisms ranging from C. elegans to humans and has been used for decades in vertebrate taste research. Here we report that OTOP1, a proton-selective ion channel expressed in sour (Type III) taste receptor cells (TRCs), functions as sensor for ammonium chloride (NH 4 Cl). Extracellular NH 4 Cl evoked large dose-dependent inward currents in HEK-293 cells expressing murine OTOP1 (mOTOP1), human OTOP1 and other species variants of OTOP1, that correlated with its ability to alkalinize the cell cytosol. Mutation of a conserved intracellular arginine residue (R292) in the mOTOP1 tm 6-tm 7 linker specifically decreased responses to NH 4 Cl relative to acid stimuli. Taste responses to NH 4 Cl measured from isolated Type III TRCs, or gustatory nerves were strongly attenuated or eliminated in an Otop1 −/− mouse strain. Behavioral aversion of mice to NH 4 Cl, reduced in Skn-1a −/− mice lacking Type II TRCs, was entirely abolished in a double knockout with Otop1 . These data together reveal an unexpected role for the proton channel OTOP1 in mediating a major component of the taste of NH 4 Cl and a previously undescribed channel activation mechanism. Ammonium is detected by chemosensory systems of humans and other animals to guide avoidance or attractive behavior. Here, the authors show that the proton channel OTOP1 is activated by ammonium, is required for ammonium taste responses in mice, and identify a conserved residue involved in ammonium sensitivity.

Minimizing the decrease in intracellular pH during high-intensity exercise training promotes greater improvements in mitochondrial respiration. This raises the intriguing hypothesis that pH may affect the exercise-induced transcription of genes that regulate mitochondrial biogenesis. Eight males performed 10x2-min cycle intervals at 80% VO2speak intensity on two occasions separated by ~2 weeks. Participants ingested either ammonium chloride (ACID) or calcium carbonate (PLA) the day before and on the day of the exercise trial in a randomized, counterbalanced order, using a crossover design. Biopsies were taken from the vastus lateralis muscle before and after exercise. The mRNA level of peroxisome proliferator-activated receptor co-activator 1α (PGC-1α), citrate synthase, cytochome c and FOXO1 was elevated at rest following ACID (P<0.05). During the PLA condition, the mRNA content of mitochondrial- and glucose-regulating proteins was elevated immediately following exercise (P<0.05). In the early phase (0-2 h) of post-exercise recovery during ACID, PGC-1α, citrate synthase, cytochome C, FOXO1, GLUT4, and HKII mRNA levels were not different from resting levels (P>0.05); the difference in PGC-1α mRNA content 2 h post-exercise between ACID and PLA was not significant (P = 0.08). Thus, metabolic acidosis abolished the early post-exercise increase of PGC-1α mRNA and the mRNA of downstream mitochondrial and glucose-regulating proteins. These findings indicate that metabolic acidosis may affect mitochondrial biogenesis, with divergent responses in resting and post-exercise skeletal muscle.

Distal renal tubular acidosis (RTA) can lead to rickets in children or osteomalacia in adults if undetected. This disorder is normally diagnosed by means of an oral ammonium chloride-loading test; however, the procedure often leads to vomiting and abandonment of the test. In this study, we assess an alternative, more palatable approach to test urinary acidification. This was achieved by the simultaneous oral administration of the diuretic furosemide and the mineralocorticoid fludrocortisone to increase distal tubular sodium delivery, principal cell sodium reabsorption, and α-intercalated cell proton secretion. We evaluated 11 control subjects and 10 patients with known distal RTA by giving oral ammonium chloride or furosemide/fludrocortisone in random order on separate days. One control and two patients were unable to complete the study owing to vomiting after NH4Cl; however, there were no adverse effects with the furosemide/fludrocortisone treatment. The urine pH decreased to less than 5.3 in the controls with both tests, whereas none of the patients was able to lower the urine pH below 5.3 with either test. We conclude that the simultaneous administration of furosemide and fludrocortisone provides an easy, effective, and well-tolerated alternative to the standard ammonium chloride urinary acidification test for the diagnosis of distal RTA.

ObjectivesTo investigate the efficacy and safety of CS1002, an over-the-counter cough treatment containing diphenhydramine, ammonium chloride and levomenthol in a cocoa-based demulcent.DesignA multicentre, randomised, parallel group, controlled, single-blinded study in participants with acute upper respiratory tract infection-associated cough.Setting4 general practitioner (GP) surgeries and 14 pharmacies in the UK.ParticipantsParticipants aged ≥18 years who self-referred to a GP or pharmacist with acute cough of <7 days' duration. Participant inclusion criterion was cough severity ≥60 mm on a 0–100 mm visual analogue scale (VAS). Exclusion criteria included current smokers or history of smoking within the past 12 months (including e-cigarettes). 163 participants were randomised to the study (mean participant age 38 years, 57% females).InterventionsParticipants were randomised to CS1002 (Unicough) or simple linctus (SL), a widely used cough treatment, and treatment duration was 7 days or until resolution of cough.Main outcome measuresThe primary analysis was intention-to-treat (157 participants) and comprised cough severity assessed using a VAS after 3 days' treatment (prespecified primary end point at day 4). Cough frequency, sleep disruption, health status (Leicester Cough Questionnaire (LCQ-acute)) and cough resolution were also assessed.ResultsAt day 4 (primary end point), the adjusted mean difference (95% CI) in cough severity VAS between CS1002 and SL was −5.9 mm (−14.4 to 2.7), p=0.18. At the end of the study (day 7) the mean difference in cough severity VAS was −4.2 mm (−12.2 to 3.9), p=0.31. CS1002 was associated with a greater reduction in cough sleep disruption (mean difference −11.6 mm (−20.6 to 2.7), p=0.01) and cough frequency (mean difference −8.1 mm (−16.2 to 0.1), p=0.05) compared with SL. There was greater improvement in LCQ-acute quality of life scores with CS1002 compared with SL: mean difference (95% CI) 1.2 (0.05 to 2.36), p=0.04 after 5 days' treatment. More participants prematurely stopped treatment due to cough improvement in the CS1002 group (24.4%) compared with SL (10.7%; p=0.02). Adverse events (AEs) were comparable between CS1002 (20.5%) and SL (27.6%) and largely related to the study indication. 6 participants (7%) in the CS1002 group reduced the dose of medication due to drowsiness/tiredness, which subsequently resolved. These events were not reported by participants as AEs.ConclusionsAlthough the primary end point was not achieved, CS1002 was associated with greater reductions in cough frequency, sleep disruption and improved health status compared with SL.Trial registration numberEudraCT number 2014-004255-31.

Cationization of cotton fabrics was performed by exhaustion procedure utilizing four different reagents provided with quaternary ammonium groups: poly diallyldimethylammonium chloride (PDDACl), poly acrylamide-co-diallyldimethylammonium chloride (PAcD), poly[bis(2-chloroethyl) ether-alt-1,3-bis[3-(dimethylamino)propyl]urea] quaternized (P42) and 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTAC). Pretreated samples were dyed using Reactive Red 195 dye. The cationic fabrics were analyzed by colorimetric and fastness properties, zeta potential, SEM, FTIR and an estimate of the bactericidal effect. Cationic cotton treated with PDDACl and CHPTAC showed a higher affinity for the reactive dye, with color strength (K/S) values varying from 41 to 48, against 32 for conventional dyeing. P42 presented competitive results with K/S of 27–28. The cationic dyeing considerably reduced the amount of effluent, especially for the CHPTAC samples, which requires a single washing bath for complete removal of unfixed dye. The PDDACl and P42 samples presented bactericidal activity.Graphic abstract

Purpose This study examined whether changes in pH throughout the physiologic range would have a differential effect on central and peripheral factors associated with fatigue and force production during submaximal lower limb isometric exercise to task failure. Methods Eight males completed three experimental trials [0.2 g kg −1 ammonia chloride (ACD); 0.3 g kg −1 calcium carbonate (PLA); or 0.3 g kg −1 sodium bicarbonate (ALK)], each consisting of submaximal calf contractions at 55 % of maximal voluntary contraction (MVC) to task failure. Every minute of the task subjects performed an MVC, coupled with stimulation of the tibial nerve during and immediately post MVC. Results Time to task failure was not different between trials (ACD 531 ± 166 s, PLA 592 ± 163 s, ALK 596 ± 150 s; p  = 0.31). MVC force in all trials declined 29 % from the start of exercise to the fifth minute (mean decline of 371 ± 26 N; p  < 0.001), however was not different between trials ( p  = 0.21). Fatigue was mediated in all trials by central and peripheral factors, as declines in voluntary activation, V/M-wave in the soleus and the potentiated resting twitch amplitudes were evident throughout the task ( p  < 0.05). Central fatigue appeared to be muscle specific, as reductions in central drive (V/M-wave and rate of sEMG rise) persisted in the soleus but not the medial gastrocnemius. Conclusions These data suggest that calf fatigue associated with intermittent, isometric contractions to task failure is unaffected by alterations in pH; however, central drive reductions may be muscle specific.