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Thalassemia is a genetic disease that significantly affects human health. The common treatment of thalassemia is the regular injection of red blood cell, which is associated with the accumulation of iron in different tissues of the body, and makes chelation therapy necessary. Deferiprone and deferoxamine are broadly used as iron chelating agents in the vast majority of thalassemia cases. In this study, an efficient method for the synthesis of deferiprone was used by reacting maltol with methylamine in a mixture of water and ethanol as solvent. The structure of deferiprone was assigned using different spectroscopic techniques such as IR, 1H-NMR, and 13C-NMR. The advantages of this pathway are simple, practical, one-pot cascade, mild condition and high yield. The statistics of the Ministry of Health of Iran show the growing trend of deferiprone drug consumption in the country. Therefore, the domestic preparation of this drug can help the pharmaceutical industry in order to reduce costs and make it available for target patients.Keywords: Synthesis, Deferiprone, Maltol, Methylamine, Iron chelating agent.

Nitric acid (NA) has recently been found to enhance sulfuric acid (SA)-driven new particle formation (NPF) at low temperatures (≤240 K). However, studies on the role of NA in atmospheric NPF remain limited. Herein, we explored the enhancement effect of NA on binary SA–methylamine (MA) nucleation by investigating the mechanism and kinetics of (NA)x(SA)y(MA)z (0 ≤ x, 0 ≤ y, x + y ≤ 3, 0 ≤ z ≤ 3) clusters using quantum chemical calculations and cluster dynamics simulations. We found that the mixed ternary NA-SA-MA clusters have lower evaporation rates compared to the corresponding NA-SA–dimethylamine (DMA) and NA-SA–ammonia (A) clusters, indicating the stronger binding ability of NA with respect to SA-MA clusters. At atmospheric conditions (T ≥ 278.15 K), NA can enhance the cluster formation rate of SA-MA by about six orders of magnitude, demonstrating a surprisingly high enhancing potential. Moreover, NA acts as an important participant in the cluster growth pathways of the NA-SA-MA system, as opposed to the "bridging" role of NA in the previously studied NA-SA-A system. This study proposes the first case of NA efficiently enhancing SA–amine nucleation at ambient temperature, suggesting a larger impact of NA in atmospheric NPF than previously expected. [ABSTRACT FROM AUTHOR]

In this study, well-defined tungsten oxide (WO3) nanowall (NW) thin films were synthesized via a controlled hot filament chemical vapor deposition (HFCVD) technique and applied for electrochemical detection of methylamine toxic substances. Herein, for the thin-film growth by HFCVD, the temperature of tungsten (W) wire was held constant at ~1450 °C and gasification was performed by heating of W wire using varied substrate temperatures ranging from 350 °C to 450 °C. At an optimized growth temperature of 400 °C, well-defined and extremely dense WO3 nanowall-like structures were developed on a Si substrate. Structural, crystallographic, and compositional characterizations confirmed that the deposited WO3 thin films possessed monoclinic crystal structures of high crystal quality. For electrochemical sensing applications, WO3 NW thin film was used as an electrode, and cyclic voltammetry (CV) and linear sweep voltammetry (LSV) were measured with a wide concentration range of 20 μM~1 mM of methylamine. The fabricated electrochemical sensor achieved a sensitivity of ~183.65 μA mM−1 cm−2, a limit of detection (LOD) of ~20 μM and a quick response time of 10 s. Thus, the fabricated electrochemical sensor exhibited promising detection of methylamine with considerable stability and reproducibility. [ABSTRACT FROM AUTHOR]

Thalassemia is a genetic disease that significantly affects human health. The common treatment of thalassemia is the regular injection of red blood cell, which is associated with the accumulation of iron in different tissues of the body, and makes chelation therapy necessary. Deferiprone and deferoxamine are broadly used as iron chelating agents in the vast majority of thalassemia cases. In this study, an efficient method for the synthesis of deferiprone was used by reacting maltol with methylamine in a mixture of water and ethanol as solvent. The structure of deferiprone was assigned using different spectroscopic techniques such as IR, 1H-NMR, and 13C-NMR. The advantages of this pathway are simple, practical, one-pot cascade, mild condition and high yield. The statistics of the Ministry of Health of Iran show the growing trend of deferiprone drug consumption in the country. Therefore, the domestic preparation of this drug can help the pharmaceutical industry in order to reduce costs and make it available for target patients. [ABSTRACT FROM AUTHOR]

A theoretical investigation of the microsolvation effect on proton exchange (PE) between carbonic acid and methylamine (CA-MTA) has been explored by quantum dynamics simulations. The structural, energy, and dynamic properties of the CA-MTA complex with and without an explicit water molecule are elucidated at the molecular level. The reactions from this study have been clarified into different types: single-step PE (SSPE) and stepwise PE (SWPE). Without the water molecule, the SSPE mechanism is hardly found but observable with a low probability of 0.2. In particular, the water molecule interacting through intermolecular hydrogen-bonded network between CA and MTA in CA-MTA-Win could affect PE by showing both SSPE and SWPE mechanisms. In addition, the existing water molecule plays the significant role in shortening intermolecular hydrogen bonding interactions within the complex resulting in increasing the probability of PE up to 0.92 especially in CA-MTA-Wout. Hence, one water molecule could be used to provide reliable results to represent the significant activity that occurs for the proton exchangeability of the CA and MTA complex.

A number of compounds with various structures was obtained by the reaction of 2-propenylphenol, formaldehyde, and methylamine. The treatment of the condensation products with HBr resulted in their quaternary ammonium salts. The anticorrosion and biocidal properties and also antimicrobial activity of the obtained compounds and their ammonium salts in relation to S. aureus, E. coli, C. albicans, Sh. flexneri, S. enterica, and A. niger strains were studied. It was found that the ammonium salts have higher bactericidal properties than the standard (amoxicillin). The results obtained were also confirmed by electron microscopy studies. [ABSTRACT FROM AUTHOR]

Objectives: The present preliminary study aimed to investigate the salivary metabolic profile in patients with asymptomatic oral lichen planus (OLP) using nuclear magnetic resonance (NMR) spectroscopy. Material and methods: Stimulated whole mouth saliva (SWMS) samples were collected from 15 reticular OLP female patients and 15 from age- and sex-matched controls (HCs). A total of 23 metabolites were identified and quantified. Mann–Whitney’s U test was used to compare the determined concentration salivary metabolite concentrations between OLP patients and the healthy controls. Results: The concentration of acetate, methylamine, and pyruvate was elevated, whereas the concentration of tyrosine was decreased in the saliva of OLP patients compared with HCs. To identify a combination of metabolites, multivariate discrimination function analysis (DFA) was conducted. DFA analysis have shown that the most powerful discrimination between the groups was achieved when methylamine and tyrosine were considered as combined biomarkers. Conclusions: Salivary tyrosine was of particular interest and a promising finding for the screening of OLP and its progression. Further longitudinal studies are required to establish it as a reliable salivary biomarker in OLP. Clinical relevance: The salivary metabolic profiling can describe the pathologic characteristics of OLP on non-invasive saliva samples and NMR analysis. Salivary metabolites provide details to considered early detectors and to impact oral health of OLP patients. [ABSTRACT FROM AUTHOR]

Abstract Background Methanotrophy by the sponge-hosted microbiome has been mainly reported in the ecological context of deep-sea hydrocarbon seep niches where methane is either produced geothermically or via anaerobic methanogenic archaea inhabiting the sulfate-depleted sediments. However, methane-oxidizing bacteria from the candidate phylum Binatota have recently been described and shown to be present in oxic shallow-water marine sponges, where sources of methane remain undescribed. Results Here, using an integrative -omics approach, we provide evidence for sponge-hosted bacterial methane synthesis occurring in fully oxygenated shallow-water habitats. Specifically, we suggest methane generation occurs via at least two independent pathways involving methylamine and methylphosphonate transformations that, concomitantly to aerobic methane production, generate bioavailable nitrogen and phosphate, respectively. Methylphosphonate may be sourced from seawater continuously filtered by the sponge host. Methylamines may also be externally sourced or, alternatively, generated by a multi-step metabolic process where carnitine, derived from sponge cell debris, is transformed to methylamine by different sponge-hosted microbial lineages. Finally, methanotrophs specialized in pigment production, affiliated to the phylum Binatota, may provide a photoprotective function, closing a previously undescribed C1-metabolic loop that involves both the sponge host and specific members of the associated microbial community. Conclusion Given the global distribution of this ancient animal lineage and their remarkable water filtration activity, sponge-hosted methane cycling may affect methane supersaturation in oxic coastal environments. Depending on the net balance between methane production and consumption, sponges may serve as marine sources or sinks of this potent greenhouse gas. Video Abstract

Nitric acid (NA) has recently been found to enhance sulfuric acid (SA)-driven new particle formation (NPF) at low temperatures (≤240 K). However, studies on the role of NA in atmospheric NPF remain limited. Herein, we explored the enhancement effect of NA on binary SA–methylamine (MA) nucleation by investigating the mechanism and kinetics of (NA)x(SA)y(MA)z (0 ≤ x, 0 ≤ y, x + y ≤ 3, 0 ≤ z ≤ 3) clusters using quantum chemical calculations and cluster dynamics simulations. We found that the mixed ternary NA-SA-MA clusters have lower evaporation rates compared to the corresponding NA-SA–dimethylamine (DMA) and NA-SA–ammonia (A) clusters, indicating the stronger binding ability of NA with respect to SA-MA clusters. At atmospheric conditions (T ≥ 278.15 K), NA can enhance the cluster formation rate of SA-MA by about six orders of magnitude, demonstrating a surprisingly high enhancing potential. Moreover, NA acts as an important participant in the cluster growth pathways of the NA-SA-MA system, as opposed to the “bridging” role of NA in the previously studied NA-SA-A system. This study proposes the first case of NA efficiently enhancing SA–amine nucleation at ambient temperature, suggesting a larger impact of NA in atmospheric NPF than previously expected.

In this study, well-defined tungsten oxide (WO3) nanowall (NW) thin films were synthesized via a controlled hot filament chemical vapor deposition (HFCVD) technique and applied for electrochemical detection of methylamine toxic substances. Herein, for the thin-film growth by HFCVD, the temperature of tungsten (W) wire was held constant at ~1450 °C and gasification was performed by heating of W wire using varied substrate temperatures ranging from 350 °C to 450 °C. At an optimized growth temperature of 400 °C, well-defined and extremely dense WO3 nanowall-like structures were developed on a Si substrate. Structural, crystallographic, and compositional characterizations confirmed that the deposited WO3 thin films possessed monoclinic crystal structures of high crystal quality. For electrochemical sensing applications, WO3 NW thin film was used as an electrode, and cyclic voltammetry (CV) and linear sweep voltammetry (LSV) were measured with a wide concentration range of 20 μM~1 mM of methylamine. The fabricated electrochemical sensor achieved a sensitivity of ~183.65 μA mM−1 cm−2, a limit of detection (LOD) of ~20 μM and a quick response time of 10 s. Thus, the fabricated electrochemical sensor exhibited promising detection of methylamine with considerable stability and reproducibility.

For ureosmotic marine elasmobranchs, the acquisition and retention of nitrogen is critical for the synthesis of urea. To better understand whole-body nitrogen homeostasis, we investigated mechanisms of nitrogen trafficking in North Pacific spiny dogfish (Squalus acanthias suckleyi). We hypothesized that the presence of nitrogen within the spiral valve lumen would affect both the transport of nitrogen and the mRNA abundance of a urea transporter (UT) and two ammonia transport proteins (Rhp2, Rhbg) within the intestinal epithelium. The in vitro preincubation of intestinal tissues in NH4Cl, intended to simulate dietary nitrogen availability, showed that increased ammonia concentrations did not significantly stimulate the net uptake of total urea or total methylamine. We also examined the mRNA abundance of UT, Rhp2, and Rhbg in the gills, kidney, liver, and spiral valve of fasted, fed, excess urea fed, and antibiotic-treated dogfish. After fasting, hepatic UT mRNA abundance was significantly lower, and Rhp2 mRNA in the gills was significantly higher than the other treatments. Feeding significantly increased Rhp2 mRNA levels in the kidney and mid spiral valve region. Both excess urea and antibiotics significantly reduced Rhbg mRNA levels along all three spiral valve regions. The antibiotic treatment also significantly diminished UT mRNA abundance levels in the anterior and mid spiral valve, and Rhbg mRNA levels in the kidney. In our study, no single treatment had significantly greater influence on the overall transcript abundance of the three transport proteins compared to another treatment, demonstrating the dynamic nature of nitrogen balance in these ancient fish. [ABSTRACT FROM AUTHOR]

Particle formation in the atmosphere from gas-phase precursors has been observed around the world; however, our fundamental understanding of the key species responsible and mechanisms involved remains uncertain. Recent laboratory studies demonstrated that acid-base reactions involving methanesulfonic acid (CH3SO3H, MSA) and small alkylamines may contribute significantly to new particle formation. To date, most of the investigations have been focused on particle number concentration and size distribution measurements in combination with quantum chemistry predictions of the most stable clusters. Here, we present the first measurements of the size-resolved chemical composition of sub-20 nm particles generated in a custom flow reactor from the reaction of MSA with methylamine (MA) in the presence or absence of NH3 using thermal desorption chemical ionization mass spectrometry (TDCIMS). A novel design of the TDCIMS inlet was evaluated, and the measurement of the chemical composition of particles was extended down to 5 nm in diameter, the smallest size yet reported for this method. MSA-MA particles with diameters smaller than 9 nm were found to be more acidic, with an acid/base molar ratio of 1.8 ± 0.4 (1σ) for 5 nm particles compared to the larger particles which were neutral. A similar acid/base molar ratio trend was observed when NH3 was added to the MSA-MA combination. In the MSA-MA-NH3 system, the MA/NH3 molar ratio was higher than 1 (up to 2.6) for all particle sizes despite the much larger concentration of NH3 in the gas phase (the gas-phase MA/NH3 ratio was ∼0.23), indicating that MA is a key component in particle formation from this system. The potential reasons for this based on previous calculations of small clusters in this system are discussed.

Background: Methanotrophy by the sponge-hosted microbiome has been mainly reported in the ecological context of deep-sea hydrocarbon seep niches where methane is either produced geothermically or via anaerobic methanogenic archaea inhabiting the sulfate-depleted sediments. However, methane-oxidizing bacteria from the candidate phylum Binatota have recently been described and shown to be present in oxic shallow-water marine sponges, where sources of methane remain undescribed. Results: Here, using an integrative -omics approach, we provide evidence for sponge-hosted bacterial methane synthesis occurring in fully oxygenated shallow-water habitats. Specifically, we suggest methane generation occurs via at least two independent pathways involving methylamine and methylphosphonate transformations that, concomitantly to aerobic methane production, generate bioavailable nitrogen and phosphate, respectively. Methylphosphonate may be sourced from seawater continuously filtered by the sponge host. Methylamines may also be externally sourced or, alternatively, generated by a multi-step metabolic process where carnitine, derived from sponge cell debris, is transformed to methylamine by different sponge-hosted microbial lineages. Finally, methanotrophs specialized in pigment production, affiliated to the phylum Binatota, may provide a photoprotective function, closing a previously undescribed C1-metabolic loop that involves both the sponge host and specific members of the associated microbial community. Conclusion: Given the global distribution of this ancient animal lineage and their remarkable water filtration activity, sponge-hosted methane cycling may affect methane supersaturation in oxic coastal environments. Depending on the net balance between methane production and consumption, sponges may serve as marine sources or sinks of this potent greenhouse gas. 3rpQ8ar2d6vfELht75ymrg Video Abstract [ABSTRACT FROM AUTHOR]

Semicarbazide-sensitive amine oxidase (SSAO) is both a soluble- and membrane-bound transmembrane protein expressed in the vascular endothelial and in smooth muscle cells. In vascular endothelial cells, SSAO contributes to the development of atherosclerosis by mediating a leukocyte adhesion cascade; however, its contributory role in the development of atherosclerosis in VSMCs has not yet been fully explored. This study investigates SSAO enzymatic activity in VSMCs using methylamine and aminoacetone as model substrates. The study also addresses the mechanism by which SSAO catalytic activity causes vascular damage, and further evaluates the contribution of SSAO in oxidative stress formation in the vascular wall. SSAO demonstrated higher affinity for aminoacetone when compared to methylamine (Km = 12.08 µM vs. 65.35 µM). Aminoacetone- and methylamine-induced VSMCs death at concentrations of 50 & 1000 µM, and their cytotoxic effect, was reversed with 100 µM of the irreversible SSAO inhibitor MDL72527, which completely abolished cell death. Cytotoxic effects were also observed after 24 h of exposure to formaldehyde, methylglyoxal and H2O2. Enhanced cytotoxicity was detected after the simultaneous addition of formaldehyde and H2O2, as well as methylglyoxal and H2O2. The highest ROS production was observed in aminoacetone- and benzylamine-treated cells. MDL72527 abolished ROS in benzylamine-, methylamine- and aminoacetone-treated cells (**** p < 0.0001), while βAPN demonstrated inhibitory potential only in benzylamine-treated cells (* p < 0.05). Treatment with benzylamine, methylamine and aminoacetone reduced the total GSH levels (**** p < 0.0001); the addition of MDL72527 and βAPN failed to reverse this effect. Overall, a cytotoxic consequence of SSAO catalytic activity was observed in cultured VSMCs where SSAO was identified as a key mediator in ROS formation. These findings could potentially associate SSAO activity with the early developing stages of atherosclerosis through oxidative stress formation and vascular damage. [ABSTRACT FROM AUTHOR]

The performance of a film‐based fluorescent sensor is highly dependent on the innovative design of the sensing films aiming to elevate usability of sensing units, and enhance mass transfer of analytes within the fluorescent adlayer. Herein, a highly porous and uniform fluorescent nanofilm which is fabricated through an interfacially confined dynamic‐covalent reaction between benzene‐1,3,5‐tricarbo‐hydrazide and a mono‐boron complex of 8‐hydroxy‐quinoline is reported. Remarkably, the thicknesses of the nanofilms prepared in this way can be modulated from tens to hundreds of nanometers. In addition, the nanofilms demonstrate much improved photochemical stability. Sensing performance studies reveal that the nanofilm is super‐sensitive and selective to the presence of amines, especially methylamine (MA) in vapor phase. Specifically, the detection limit to MA is lower than 2.82 mg m−3, and the presence of the vapors of water, aromatic hydrocarbons, aliphatic hydrocarbons, alcohols, ketones, and other common organic compounds showed little effect upon the sensing. Moreover, the sensing is highly reversible. With the innovation in adlayer structure, substrate effect as commonly found in routine film‐based sensing is avoided, which must bring convenience for device making. In this work, different film‐based sensors are fabricated, suggesting their potential applications in various scenarios. [ABSTRACT FROM AUTHOR]

• HNMs formation increased and then decreased with increasing Br‒ concentration. • BIF value increased while BUF value decreased with increasing Br− concentration. • pH value and Cl 2 :Br− ratio seriously affected the formation and species of HNMs. • The possible mechanisms of HNMs formation from methylamine were proposed. • The formation rule of HNMs was verified in two real waters containing methylamine. The UV/Cl 2 process is commonly used to achieve a multiple-barrier disinfection and maintain residuals. The study chose methylamine as a precursor to study the formation of high-toxic halonitromethanes (HNMs) in the presence of bromide ions (Br−) during UV/Cl 2 disinfection. The maximum yield of HNMs increased first and then decreased with increasing concentration of Br−. An excessively high concentration of Br− induced the maximum yield of HNMs in advance. The maximum bromine incorporation factor (BIF) increased, while the maximum bromine utilization factor (BUF) decreased with the increase of Br− concentration. The maximum yield of HNMs decreased as pH value increased from 6.0 to 8.0 due to the deprotonation process. The BUF value remained relatively higher under an acidic condition, while pH value had no evident influence on the BIF value. The maximum yield of HNMs and value of BUF maximized at a Cl 2 :Br− ratio of 12.5, whereas the BIF value remained relatively higher at low Cl 2 :Br− ratios (2.5 and 5). The amino group in methylamine was first halogenated, and then released into solution as inorganic nitrogen by the rupture of C-N bond or transformed to nitro group by oxidation and elimination pathways. The maximum yield of HNMs in real waters was higher than that in pure water due to the high content of dissolved organic carbon. Two real waters were sampled to verify the law of HNMs formation. This study helps to understand the HNMs formation (especially brominated species) when the UV/Cl 2 process is adopted as a disinfection technique. [Display omitted] [ABSTRACT FROM AUTHOR]

Methylamine exists as an endogenous amine in the brains of birds and mammals, and on the other hand, it acts as a neuromodulator in the release of some neurotransmitters such as serotonin. The effects of methylamine have been well established in mice, but there is no evidence about the effect of methylamine on feeding behavior in poultry. So, the present study was designed to evaluate the effect of intracerebroventricular (ICV) injection of methylamine and involvement of central methylamine/serotonergic systems on feeding behavior in FD3 neonatal meat type chicks. In experiment 1, chicks were ICV injected with different doses of methylamine (15, 30, 45, 60 and 75 μg). In experiment 2, chicks received a dose of either the control solution, 75 μg methylamine, 1/5 μg PCPA (serotonin synthesis inhibitor) or a combination of methylamine plus PCPA. Experiments 3 was similar to experiment 2 except that 1/5 μg SB242084 (antagonist of HT2C receptor) was used instead of 1/5 μg PCPA, respectively. Cumulative food intake was determined until 30, 60, 120 minutes post-injection. The volume of injections in each group was 10 μl. According to the results, methylamine significantly decreased food intake in a dose dependent manner. Therefore, the effective dose of methylamine was considered to be a continuation of the 75 μg test. It was also found that the hypophagic effect of methylamine by PCPA (inhibitor of serotonin synthesis, 1.5 μg) and SB242084 (antagonist of 5-HT2C receptor, 1.5 μg) was significantly attenuated. These results suggest that methylamine has a hypophagic effect on food intake in broiler chickens, and that this reduction in methylamine-induced food intake is mediated by serotonin (a 5-HT2C receptor). [ABSTRACT FROM AUTHOR]

[Display omitted] • ZrO 2 thin films were obtained by spray pyrolysis technique. • A ZrO 2 film showed a linear sensing response towards MMA vapour at 30 °C. • The lowest detection limit of MMA was determined to be 250 ppb. • The response and recovery times for 250 ppb of MMA were 90 s and 10 s, respectively. • Machine learning approaches for predicting low concentrations of MMA vapours. Methylamines are considered to be potential biomarker for disease diagnosis through exhaled breath analysis. Hence, the demand for probing methylamines has been increasing rapidly. Towards this, we report the room temperature selective Chemiresistive probing of methylamine using nanostructured-ZrO 2 thin film-based sensing elements deposited using spray pyrolysis method. The structural and morphological studies confirmed the formation of a monoclinic crystal phase and closely packed nanograins of ZrO 2 , respectively. The sensor showed a sensing response of 68 % with good sensitivity and fast switching transients towards 0.25 ppm of methylamines. The sensor showed selective sensing characteristics towards methylamine vapour among the different test volatiles with a minimum detection limit of 250 ppb. Also, the sensor showed a detection range of 250 ppb to 50 ppm concentration of methylamines. These significant figures of merit of the sensor operating at ambient temperature (30 °C) widely open up a new window for probing methylamine vapour effectively. [ABSTRACT FROM AUTHOR]

Metal–semiconductor–metal (MSM) configuration of perovskite photodetectors (PPDs) suggests easy and low-cost manufacturing. However, the basic structures of MSM PPDs include vertical and lateral configurations, which require the use of expensive materials such as transparent conductive oxides or/and sophisticated fabrication techniques such as lithography. Integrating metallic nanowire-based electrodes into the perovskite photo-absorber layer to form one-half of the MSM PPD structure could potentially resolve the key issues of both configurations. Here, a manufacturing of solution-processed and self-powered MSM PPDs with embedded silver nanowire electrodes is demonstrated. The embedding of silver nanowire electrode into the perovskite layer is achieved by treating the silver nanowire/perovskite double layer with a methylamine gas vapor. The evaporated gold layer is used as the second electrode to form MSM PPDs. The prepared MSM PPDs show a photoresponsivity of 4 × 10−5 AW−1 in the UV region and 2 × 10−5 AW−1 in the visible region. On average, the devices exhibit a photocurrent of 1.1 × 10−6 A under white light (75 mW cm−2) illumination with an ON/OFF ratio of 83.4. The results presented in this work open up a new method for development and fabrication of simple, solution-processable MSM self-powered PPDs. [ABSTRACT FROM AUTHOR]

In order to improve our understanding of the origin and production processes of methylamine in the atmosphere and its contribution to the particulate WSON, simultaneous measurements of methylamine in size-segregated aerosols and the gas phase were conducted at a forested site in Yamanashi Prefecture, Japan, over one year. The concentration of the atmospheric methylamine that is the sum of methylamine in the gas phase, coarse-mode, and fine-mode particles was 0.962 ng-N m−3 on average. About 77% of the atmospheric methylamine was detected in the fine-mode particles and about 17% was in the gas phase. Similar seasonal variations were found in the fine-mode and gaseous methylamine including higher concentrations recorded in summer. The relationship between the concentrations of the gaseous methylamine and ammonia showed a significant positive correlation, suggesting that methylamine in the gas phase has similar sources with ammonia; for instance, the volatilization from soil and/or emission from forest biological activities. The concentration of the fine-mode methylamine showed a significant positive correlation with that of the gaseous methylamine, and the concentration ratio of the fine-mode methylamine to the sum of the fine-mode and gaseous methylamine that can be an indicator of the conversion of methylamine from the gas phase to the particulate phase showed a significant positive correlation with the fine-mode non-sea salt SO42- (nss-SO42-) concentration, suggesting that the gaseous methylamine is converted into the particulate methylamine through the acid-base reaction with sulfuric acid and/or nss-SO42-. Significant positive correlation was not obtained in the comparison of the concentration ratio of the fine-mode methylamine to the sum of the fine-mode and gaseous methylamine with the excessive amount of sulfuric acid for complete neutralization of ammonia, which implies the possibility that the sulfuric acid more preferentially reacts with the gaseous methylamine than ammonia.

The new copper(II) complex, namely, di-μ-chlorido-bis{chlorido[methyl(pyridin-2-ylmethylidene)amine-κ2N,N′]copper(II)}, [Cu2Cl4(C7H8N2)2], (I), with the ligand 2-pyridylmethyl-N-methylimine (L, a product of Schiff base condensation between methylamine and 2-pyridinecarbaldehyde) is built of discrete centrosymmetric dimers. The coordination about the CuII ion can be described as distorted square pyramidal. The base of the pyramid consists of two nitrogen atoms from the bidentate chelate L [Cu—N = 2.0241 (9), 2.0374 (8) Å] and two chlorine atoms [Cu—Cl = 2.2500 (3), 2.2835 (3) Å]. The apical position is occupied by another Cl atom with the apical bond being significantly elongated at 2.6112 (3) Å. The trans angles of the base are 155.16 (3) and 173.79 (2)°. The Cu...Cu separation in the dimer is 3.4346 (3) Å. In the crystal structure, the loosely packed dimers are arranged in stacks propagating along the a axis. The X-band polycrystalline 77 K EPR spectrum of (I) demonstrates a typical axial pattern characteristic of mononuclear CuII complexes. Compound (I) is redox active and shows a cyclic voltammetric response with E1/2 = −0.037 V versus silver–silver chloride electrode (SSCE) assignable to the reduction peak of CuII/CuI in methanol as solvent.

The voltammetric behaviour of the macrolide based antibiotic: Erythromycin (ERT), Clarithromycin (CLA) and Azithromycin (AZT) was presented in this work. Carbon electrodes and platinum (Pt) electrode were applied as working electrodes. Cyclic voltamograms of each molecule in each electrode were recorded and similar electrochemical behaviour of macrolides was observed for all carbon based electrodes, which gave more defined current intensity peaks than platinum. Other organic compounds were tested trying to clarify electro‐active groups of macrolides. Experiments on mechanism of electrochemical reaction were performed, and studies on the influence of pH on peak current and peak potential were also carried out. [ABSTRACT FROM AUTHOR]

CCSD(T)-F12 theory is applied to determine electronic ground state spectroscopic parameters of various isotopologues of methylamine (CH3-NH2) containing cosmological abundant elements, such as D, 13C and 15N. Special attention is given to the far infrared region. The studied isotopologues can be classified in the G12, G6 and G4 molecular symmetry groups. The rotational and centrifugal distortion constants and the anharmonic fundamentals are determined using second order perturbation theory. Fermi displacements of the vibrational bands are predicted. The low vibrational energy levels corresponding to the large amplitude motions are determine variationally using a flexible three-dimensional model depending on the NH2 bending and wagging and the CH3 torsional coordinates. The model has been defined assuming that, in the amine group, the bending and the wagging modes interact strongly. The vibrational levels split into six components corresponding to the six minima of the potential energy surface. The accuracy of the kinetic energy parameters has an important effect on the energies. Strong interactions among the large amplitude motions are observed. Isotopic effects are relevant for the deuterated species.

New methylamine derivatives with 1,2-azole fragments (phenylisoxazole, p-tolylisoxazole, 2,5-dimethylphenylisoxazole and 4,5-dichloroisothiazole) and their palladium complexes were synthesized. It was shown that palladium complexes with the obtained N-methyl-1-(1,2-azol-3-yl)methylamine exhibit high catalytic activity in the Suzuki reaction in aqueous medium. [ABSTRACT FROM AUTHOR]

Reports of biogenic methane (CH4) synthesis associated with a range of organisms have steadily accumulated in the literature. This has not happened without controversy and in most cases the process is poorly understood at the gene and enzyme levels. In marine and freshwater environments, CH4 supersaturation of oxic surface waters has been termed the "methane paradox" because biological CH4 synthesis is viewed to be a strictly anaerobic process carried out by O2-sensitive methanogens. Interest in this phenomenon has surged within the past decade because of the importance of understanding sources and sinks of this potent greenhouse gas. In our work on Yellowstone Lake in Yellowstone National Park, we demonstrate microbiological conversion of methylamine to CH4 and isolate and characterize an Acidovorax sp. capable of this activity. Furthermore, we identify and clone a gene critical to this process (encodes pyridoxylamine phosphate-dependent aspartate aminotransferase) and demonstrate that this property can be transferred to Escherichia coli with this gene and will occur as a purified enzyme. This previously unrecognized process sheds light on environmental cycling of CH4, suggesting that O2-insensitive, ecologically relevant aerobic CH4 synthesis is likely of widespread distribution in the environment and should be considered in CH4 modeling efforts. [ABSTRACT FROM AUTHOR]

• The sensitivity and adsorption mechanism of MA and TMA on MnN 4 -C surface were studied. • MnN 4 -C exhibits good structural stability, and displays high sensitivity towards MA and TMA gases. • The gas sensing performance can be controlled by applying electric field. • MnN 4 -C can be regarded as the excellent reusability sensor for monitoring fish spoilage. From the perspective of raw material losses and human health, monitoring fish-based food quality has become more prominent. As a nondestructive technology, gas sensors have received extensive attention for evaluating the freshness of fish. In this study, the sensing and electronic properties of methylamine (MA) and trimethylamine (TMA) molecule adsorption on MnN 4 embedded zeolite templated carbon (MnN 4 -C) were studied by density functional theory (DFT) method. The results show that the MnN 4 -C exhibits good structural stability, and displays high sensitivity toward MA and TMA gases by analysis of the interaction distance, adsorption energy, charge transfer and sensing response. It is worth noting that the ambient humidity has demonstrated no effect on the gas-sensing properties of MnN 4 -C for the studied gases. Meanwhile, applying a positive electric field can increase the adsorption energy and charge transfer, which enhances the MA and TMA gas sensitivity of MnN 4 -C. The recovery time reveals that MnN 4 -C can be an excellent reusability sensor for MA and TMA gases. This study provides theoretical direction for exploring the sensing application of MnN 4 -C in evaluating freshness of fish. [ABSTRACT FROM AUTHOR]

N-methylcantharidimide (NMC), a derivative of cantharidin (C), shows antitumor properties. In this study, NMC was synthesized from C and methylamine with a yield of over 90%. We investigated the influences of different amounts of methylamine used in this reaction, and found that the optimal methylamine dosage was twice the theoretical amount. Furthermore, in the purification of NMC, distilled water was the most suitable solvent. This improved method is both simple and economical, and this process could be further developed at an industrial scale for the synthesis of NMC. [ABSTRACT FROM AUTHOR]

The structure of the title compound, [Ni2(C9H10NO2)4], is built up by discrete centrosymmetric dimers. Two nitrogen and three oxygen atoms of two Schiff base ligands singly deprotonated at the phenolate site form a square-pyramidal environment for each metal atom. The ligands are bonded differently to the metal centre: one of the phenolic O atoms is bound to one nickel atom, whereas another bridges the two metal atoms to form the dimer. The Ni—N/O distances fall in the range 1.8965 (13)–1.9926 (15) Å, with the Ni—N bonds being slightly longer; the fifth contact of the metal to the bridging phenolate oxygen atom is substantially elongated [2.533 (1) Å]. A similar coordination geometry was observed in the isomorphous Cu analogue previously reported by us [Sydoruk et al. (2013). Acta Cryst. E69, m551–m552]. In the crystal, the [Ni2L4] molecules form sheets parallel to the ab plane with the polar methoxy groups protruding into the intersheet space and keeping the sheets apart. Within a sheet, the molecules are stacked relative to each other in such a way that the Ni2O2 planes of neighbouring molecules are orthogonal.

In recent years, several deuterated drugs have entered clinical trials and have been approved for use. Deuterated methylamine and dimethylamine as important intermediates play significant roles in the preparation of deuterated drugs. In this study, we have developed a new method to prepare deuterated methylamine and dimethylamine. This method employs Boc-benzylamine as the starting material and TsOCD3 as the deuterated methylation reagent. Our method gives relatively high yields and involves simple purifications, which provide a favourable supplement for the development and synthesis of deuterated drugs in the future. [ABSTRACT FROM AUTHOR]

Metal–semiconductor–metal (MSM) configuration of perovskite photodetectors (PPDs) suggests easy and low-cost manufacturing. However, the basic structures of MSM PPDs include vertical and lateral configurations, which require the use of expensive materials such as transparent conductive oxides or/and sophisticated fabrication techniques such as lithography. Integrating metallic nanowire-based electrodes into the perovskite photo-absorber layer to form one-half of the MSM PPD structure could potentially resolve the key issues of both configurations. Here, a manufacturing of solution-processed and self-powered MSM PPDs with embedded silver nanowire electrodes is demonstrated. The embedding of silver nanowire electrode into the perovskite layer is achieved by treating the silver nanowire/perovskite double layer with a methylamine gas vapor. The evaporated gold layer is used as the second electrode to form MSM PPDs. The prepared MSM PPDs show a photoresponsivity of 4 × 10−5 AW−1 in the UV region and 2 × 10−5 AW−1 in the visible region. On average, the devices exhibit a photocurrent of 1.1 × 10−6 A under white light (75 mW cm−2) illumination with an ON/OFF ratio of 83.4. The results presented in this work open up a new method for development and fabrication of simple, solution-processable MSM self-powered PPDs.

A detailed chemical kinetic model for oxidation of methylamine has been developed, based on theoretical work and a critical evaluation of data from the literature. The rate coefficients for the reactions of CH3NH2 + O2→ CH2NH2 / CH3NH + HO2, CH3NH2 + H → CH3 + NH3, CH3NH → CH2NH2, and CH3NH + O2→ CH2NH + HO2 were calculated from ab initio theory. The mechanism was validated against experimental results from batch reactors, flow reactors, shock tubes, and premixed flames. The model predicts satisfactorily explosion limits for CH3NH2 and its oxidation in a flow reactor. However, oxidation in the presence of nitric oxide, which strongly promotes reaction at lower temperatures, is only described qualitatively. Furthermore, calculated flame speeds are higher than reported experimental values; the model does not capture the inhibiting effect of the NH2 group in CH3NH2 compared to CH4. More work is desirable to confirm the products of the CH3NH + NO reaction and to look into possible pathways to NH3 in methylamine oxidation. [ABSTRACT FROM AUTHOR]

The title compound, [CoCd(C9H10NO2)3Cl2]·H2O, is a solvatomorph of the corresponding hemihydrate recently published by us [Nesterova et al. (2018). Appl. Cat. A, 560, 171–184]. The current structure reveals different cell parameters and space group compared with the published one while both are monoclinic with almost the same cell volume. The title compound is formed of discrete neutral dinuclear molecules with no crystallographically imposed symmetry and water molecules of crystallization. The overall geometry about the cobalt(III) ion is octahedral with an N3O3 environment; each ligand acts as a meridional ONO donor. The CdII coordination sphere approximates an irregular square pyramid with a chlorine atom at the apex. There is significant shortening of a Cd—O bond length to the oxygen atom of the methoxo group on one of the ligands [2.459 (3) Å] compared to the corresponding distance in the published structure [2.724 (7) Å], while other Cd—Cl/N/O bonds remain roughly the same. In the crystal lattice, the heterometallic molecules, which are related by the crystallographic n-glide plane and interlinked by weak hydrogen bonds to solvent water molecules, form columns along [101]. Adjacent columns lie antiparallel to each other.

The reaction of 4-X-substituted 1-[(difluoromethyl)sulfinyl]-2,3,5,6-tetrafluorobenzenes (X = CF3, H, OMe) with methylamine and ammonia in MeCN, Et2O, and hydrocarbons occurs involves nucleophilic substitution in position 2 of the substrate. The reaction time increases with increasing donor ability of substituent X in the series X = CF3 < H < OMe, as well as with decreasing solvent polarity. Further substitution of fluorine in position 6 of the substrate by methylamine is also possible, but requires a higher reaction temperature. The reaction of ammonia with 1-[(difluoromethyl)sulfinyl]-4-methoxy-2,3,5,6-tetrafluorobenzene is accompanied by partial demethylation to form 2-[(difluoromethyl)sulfinyl]-3,4,6-trifluoro-5-methoxy-N-methylaniline and 4-[(difluoromethyl)sulfinyl]-2,3,5,6-tetrafluorophenol. [ABSTRACT FROM AUTHOR]

A detailed chemical kinetic model has been developed for supercritical water oxidation (SCWO) of methylamine, CH3NH2, providing insight into the intermediates and final products formed in this process as well as the dominant reaction pathways. The model was adapted from previous mechanisms, with a revision of the peroxyl radical chemistry to include imine formation, which has recently been identified as the dominant gas‐phase pathway in amine oxidation. The developed model can reproduce previous experimental data on methylamine consumption and major product formation to reasonable accuracy, although with deficiencies in describing the induction time. Our simulations indicate that oxidation of the •CH2NH2 radical to methanimine, CH2NH, is the major channel in methylamine SCWO, with subsequent hydrolysis of CH2NH providing the experimentally observed reaction products ammonia and formaldehyde. Integral‐averaged reaction rates were used to identify major reaction pathways, and a first‐order sensitivity analysis indicated that the concentration of CH3NH2 is most sensitive to OH radical kinetics. Overall, this work clarifies the importance of imine chemistry in the oxidation of nitrogen‐containing compounds and indicates that they are necessary to model these compounds in SCWO processes. [ABSTRACT FROM AUTHOR]

A highly efficient protocol for the amination of 4-fluoronitrobenzene by using methylamine aqueous solution as the amination reagent was developed. The reaction proceeds smoothly to provide the desired product in high yield and excellent purity within 15 min at 70 °C. The particle size of the product obtained in this approach was less than 100 μm. And the reaction media exhibited excellent reusability after recovering four times. [ABSTRACT FROM AUTHOR]

The new copper(II) complex, namely, di-μ-chlorido-bis­{chlorido­[meth­yl(pyri­din-2-yl­methyl­idene)amine-κ²N,N′]copper(II)}, [Cu2Cl4(C7H8N2)2], (I), with the ligand 2-pyridyl­methyl-N-methyl­imine (L, a product of Schiff base condensation between methyl­amine and 2-pyridine­carbaldehyde) is built of discrete centrosymmetric dimers. The coordination about the CuII ion can be described as distorted square pyramidal. The base of the pyramid consists of two nitro­gen atoms from the bidentate chelate L [Cu—N = 2.0241 (9), 2.0374 (8) Å] and two chlorine atoms [Cu—Cl = 2.2500 (3), 2.2835 (3) Å]. The apical position is occupied by another Cl atom with the apical bond being significantly elongated at 2.6112 (3) Å. The trans angles of the base are 155.16 (3) and 173.79 (2)°. The Cu...Cu separation in the dimer is 3.4346 (3) Å. In the crystal structure, the loosely packed dimers are arranged in stacks propagating along the a axis. The X-band polycrystalline 77 K EPR spectrum of (I) demonstrates a typical axial pattern characteristic of mononuclear CuII complexes. Compound (I) is redox active and shows a cyclic voltammetric response with E1/2 = −0.037 V versus silver–silver chloride electrode (SSCE) assignable to the reduction peak of CuII/CuI in methanol as solvent. [ABSTRACT FROM AUTHOR]

The adsorption of a methoxy radical ( OCH 3 ) on the low-energy flat gold surfaces Au(111), Au(100) and Au(110) and on surface defects (adatoms) was compared with those of methanethiol ( SCH 3 ) and methylamine ( NHCH 3 ) radicals. Using dispersion-corrected DFT, we showed that the adsorption energy of OCH 3 on gold is significantly lower than that of SCH 3 but not very far from that of NHCH 3 . Whatever the molecule, we found that the adsorption energy is of the same order on Au(110) and Au(100), and smaller on Au(111) and that the charge transfer goes from the surface to the molecule. The charge transferred to SCH 3 is very small, while that transferred to NHCH 3 is slightly larger, but still three times smaller than in the case of OCH 3 . Concerning the competition between adsorption sites, we observed that undercoordinated atoms are not systematically more favoured than flat surfaces. [ABSTRACT FROM AUTHOR]

The scientific interest in catalytic hydroaminoalkylation reactions of alkenes has vastly increased over the past decade, but these reactions have struggled to become a viable option for general laboratory or industrial use because of reaction times of several days. The titanium‐based catalytic system introduced in this work not only reduces the reaction time by several orders of magnitude, into the range of minutes, but the catalyst is also demonstrated to be easily available from common starting materials, at a cost of approximately 1 € per millimole of catalyst. We were also able to formally perform C−H activation of methylamine and achieve coupling to a broad variety of alkenes, through silyl protection of the amine and simple deprotection by water. [ABSTRACT FROM AUTHOR]

Luminescent chemosensor properties of Eu(III) carboxylate dibenzoylmethanates are observed. It is shown that the interaction of Eu(III) complexes with ammonia or methylamine vapors leads to an increase in the Eu(III) luminescence intensity. An optical response mechanism related to the interaction between the analyte and Eu(III) complex molecules and to suppression of luminescence quenching is proposed. [ABSTRACT FROM AUTHOR]

The conversion of methylamine (CH 3 NH 2 , 1000 ppm) has been studied in an atmospheric-pressure flow reactor from both experimental and modeling points of view. Several values of the oxygen excess ratio (λ), from pyrolysis to fuel-lean conditions, have been tested, and a large number of different species have been quantified experimentally by three different diagnostic techniques: gas chromatography, Fourier Transform Infra-red spectroscopy (FTIR) and an infra-red NO analyzer. For the first time, the influence of NO addition (500 and 1000 ppm) on the stoichiometric oxidation of methylamine has also been experimentally evaluated, and the main products of such interaction have been identified. Results indicate that, unlike the little influence of oxygen availability on methylamine conversion, the presence of different concentrations of NO promotes methylamine oxidation at lower temperatures. A literature mechanism has been validated against the present experimental data since previous experimental works under these conditions are scarce. The largest discrepancies have been found for the formation of NH 3 and NO as oxidation products, which are under and overestimated by the model, respectively, and under pyrolysis conditions, where modification of the kinetic parameters for the reaction CH 2 NH 2 ⇌ CH 2 NH + H from the original mechanism notably improves the agreement between experimental and simulated results. [ABSTRACT FROM AUTHOR]

[Display omitted] We undertook density functional theory (DFT) computations for inspecting the decomposition and adsorption of methylamine (MLA) onto the surface of a pure boron nitride nano-tube (BNNT). We also obtained the activation energies of viable elementary reactions and the adsorption energies of stable complexes. The most suitable reaction pathway which generated one hydrogen cyanide molecule as well as 4 hydrogen atoms was relatively endothermal. For MLA decomposition, the energy barrier was around 44.6 kcal/mol. Due to the fact that the activation energy for the side reaction which generated NH 2 as well as CH 3 was somewhat high, reducing the temperature could depress the generation of side products. [ABSTRACT FROM AUTHOR]

Relevance of the work is caused by the lack of mathematical description of ammonia and methylamines absorption from multicomponent gas mixtures in a regular packing. The main aim in the study is to develop a mathematical model and the method of calculating ammonia and methylamines absorption from a gas mixture in a new regular tape packing. The nozzle can increase the degree of purification of process gases and intensify the absorption. The methods used in the study. Differential equations of mathematical model, incorporating material balance equation and mass transfer equations, are solved numerically. The results. The authors have calculated the volumetric mass transfer coefficient in a regular belt layer and the nozzle layer of Raschig rings at ammonia absorption from a gas mixture. The distribution of concentrations of the components over the packed bed height was determined and the comparative analysis of the mass transfer efficiency of a mixture of ammonia and amines absorption on regular and circular nozzles was carried out. It is shown that the volumetric coefficient of ammonia mass transfer on Raschig rings is in 1,2 times lower than that in a regular nozzle tape with an equal equivalent diameter and the mass transfer coefficient for a nozzle of the chord is in 1,72 times lower than that on a regular nozzle tape. When replacing the Raschig rings by a regular nozzle tape with the same mode of operation of the column and equal packed bed height the methylamines and ammonia concentration in gas phase at the outlet of the absorber is reduced by 10 %. At reducing fluid flow rate excess from 3 to 2 in the curve of change in trimethylamine concentration in gas by the packed bed height the layer extremum occurs. This can be explained by the relative decrease in trimethylamine absorption rate due to reduction of water consumption and increase in its temperature.

The effects of methylamine on human health have been debated for several years, but the exact adverse outcomes and definite signaling cascades have not been elucidated yet. Herein, a NF-κB signal pathway, a positive regulator of inflammation was identified as the main pathway of methylamine exposure induced adverse effects in bronchial airway cells (16HBE) for the first time. The results indicated that methylamine could stimulate the overproduction of reactive oxygen species (ROS) in cytoplasm and mitochondria of 16HBE cells. Moreover, ROS accelerate the translocation and phosphorylation of NF-κB in nucleic and promote the expression of inflammatory, such as IL-8 and IL-6. As a result, methylamine was found to be increased ROS-mediated NF-κB activation in cells, leading to the production of inflammatory cytokine. Furthermore, the results also showed that methylamine could affect the expression of cytokines related genes, p53, STAT3, Bcl2, c-myc, Cyclin D, Hes1, Mcl-1, TGF-β2. The breakdown of those cell proliferation and apoptosis related genes were leading to a common toxic mechanism of cell death. In summary, our work uncovers a mechanism by which methylamine can induce the formation of inflammation response and demonstrates potential inflammation and carcinogenesis in human airway cell upon the methylamine inhaled. Image 1 • Cell death and proliferation in epithelial cells concurred under methylamine exposure. • Apoptosis and proliferation related genes were high expressed with time and dose dependent. • Methylamine lead to inflammation via IL6 and IL8 overexpression in epithelial cells. • Elevated ROS and activated NF-κB signaling pathway induced by methylamine exposure. Methylamine disrupts proliferation and death homeostasis via ROS activated NF-κB pathway with inflammation and abnormal transcriptions in bronchial epithelial cell. [ABSTRACT FROM AUTHOR]

The atmospheric oxidation of amines proceeds via initial radical attack at C–H or N–H bonds to form carbon‐ and nitrogen‐centered radicals, respectively. It is conventionally assumed that nitrogen‐centered aminyl radicals react slowly with oxygen in the troposphere and associate predominantly with the radicals •NO and NO2• to form toxic nitrosamines and nitramines. We have used theoretical kinetic modeling techniques to study the prototypical CH3N•H + O2 reaction and have shown that it proceeds to CH2NH + HO2• under tropospheric conditions with a rate coefficient of 3.6 × 10−17 cm3 molecule−1 s−1. Although this value is low compared to the competing NOx reactions (∼10−11 cm3 molecule−1 s−1), the much higher concentration of O2 versus NOx in air makes it the dominant process in the atmospheric oxidation of methylamine for NOx concentrations below 100 ppb. The mechanism identified here is available to amines with primary, secondary, and tertiary α carbons and suggests that they may be less likely to form nitramines and nitrosamines than is currently thought. [ABSTRACT FROM AUTHOR]

In many tissues and organisms, large amount of urea gets accumulated to maintain osmotic balance. To evade the threatening impact of urea, living organisms accumulate methylamines, a class of osmolytes, in proportion of 2:1 (urea:methylamine). To understand underlying cause(s) for protein-specific counteraction behavior, thermodynamic stability (Δ G D o) of three disulfide free proteins (myoglobin, bovine cytochrome c and barstar) in the mixture of urea and methylamine has been estimated from guanidinium chloride-(GdmCl) driven denaturation curves. Using the experimentally measured values of Δ G D o obtained in the presence of individual methylamines and urea, we predicted the molar ratio of urea and a methylamine required for perfect compensation for each of the proteins. Interestingly, for all proteins studied, a similar ratio has been observed for perfect compensation. The predicted ratio for perfect compensation in terms of thermodynamic parameters was about 2:1 M ratio of urea to methylamine. Furthermore, a partial counteraction was observed in the myoglobin and barstar. However, for bovine cytochrome c , perfect compensation was observed in both GdmCl- and heat-driven denaturations. Our observations clearly suggest that the counteraction phenomenon depends on the extent of the unfolding of the denatured states of proteins. [ABSTRACT FROM AUTHOR]