Molecular Weight Compounds Research Articles

Periodic membrane fractionation of freshwater organic matter reveals various reactivity patterns during chlorine/chloramine disinfection

Although drinking water disinfection has significantly reduced mortality from waterborne diseases, the formation of potentially harmful disinfection by-products (DBPs) remains a concern today. These DBPs emerge from the reaction of dissolved organic matter (DOM) with chlor(am)ine during disinfection. Identifying these DBP precursors from heterogeneous and complex DOM mixtures is challenging and to address this, a novel membrane fractionation protocol was developed to isolate and identify the organic DBP precursors from fresh water sources. A tight ultrafiltration and nanofiltration membrane were carefully selected to partition DOM into three molecular weight (MW) fractions: high (>20 kDa), medium (0.3–20 kDa) and low (<0.3 kDa) as defined by high performance-size exclusion chromatography- total organic carbon analysis. A mathematical tool was developed to optimize the fractionation protocol. Therefore, ultrafiltration was executed before nanofiltration and the concentration factor was maximized without inducing fouling to obtain the purest fractions. The mathematical tool was also set in place to predict the necessary diafiltration factor for each individual fractionation experiment based on the initial organic matter composition of the surface water allowing the fractionation protocol to be effective at all times. The protocol was applied to surface water samples collected six times across three seasons yielding a fraction enriched in high MW compounds (up to 50 %), a fraction having more than 80 % of medium MW compounds and a fraction only containing low MW compounds. Although the medium MW fraction showed the highest reactivity for the majority of the investigated DBPs, the low MW fraction showed high reactivity for iodinated trihalomethanes during chlorination and for haloacetonitriles during chloramination. The high MW fraction had the lowest reactivity towards DBPs, which can have important implications for a drinking water treatment since this fraction is generally the most effectively removed by e.g. coagulation, while the more important fractions for DBP formation such as the medium and low MW compounds remain in the water until the disinfection step.

What Is the Molecular Weight of "High" Molecular Weight Dissolved Organic Matter?

The use of ultrafiltration to isolate high molecular weight dissolved organic matter (HMWDOM) from seawater is a fundamental tool in the environmental organic chemist's toolbox. Yet, important characteristics of HMWDOM relevant to its origin and cycling, such as its molecular weight distribution, remain poorly defined. We used diffusion-ordered NMR spectroscopy coupled with mixed-mode chromatography to separate and characterize two major components of marine HMWDOM: acylpolysaccharides (APS) and high molecular weight humic substances (HS). The molecular weights (MWs) of APS and HS both fell within distinct, narrow envelopes; 2.0-16 kDa for APS and 0.9-6.5 kDa for HS. In water samples from the North Pacific Ocean the average MW of both components decreased with depth through the mesopelagic. However, the minimum MW of APS was >2 kDa, well above the molecular weight cutoff of the ultrafilter, suggesting APS removal processes below 2 kDa are highly efficient. The MW distribution of APS shows only small variations with depth, while the MW distribution of HS narrowed due to removal of HMW components. Despite the narrowing of the MW distribution, the concentration of HS did not decrease with depth between 15 and 915 m. This suggests that HMW HS produced in surface waters was either degraded into lower MW compounds without significant remineralization, or that HMW HS was remineralized but replaced by an additional source of HS in the mesopelagic ocean. Based on these results, we propose potential pathways for the production and removal of these major components of HMWDOM.

Astrochemistry and Astrobiology over the last 20 years

A review of the achievements of astrochemistry and astrobiology over the past 20 years is given. Advances in astrochemistry in understanding the processes of emergence and survival high molecular weight chemical compounds are directly related to the conditions of prebiomolecules origin, like -amino acids and complex hydrocarbons. And if on the case of amino acids and hydrocarbons synthesis , the astrophysical picture seems quite clear, then on the case of the emergence of chiral amino acids, of which the proteins of living organisms are composed, there is no generally accepted point of view. Probably they occurred in certain photochemical transformations under the influence of circularly polarized radiation in the conditions of star formation regions of molecular clouds.

Sesquiterpene lactones enriched-fractions obtained from Cynara cardunculus extract diaultrafiltration

Sesquiterpene lactones (SL) are allelopathic compounds that demonstrate great potential of use in sustainable weed management. In this study, membrane processing technology was used for ethanolic Cynara cardunculus leaves extract (CcLE) ultra- and nanofiltration to produce SL-enriched fractions with increased phytotoxic activity. Experiments were conducted to select an ultrafiltration membrane (DuraMem500, DuraMem900 and SuezGH2000) for SL recovery and high molecular weight compounds (MWC) removal. SuezGH2000, which had rejection percentage of 50 % and 88 % for cynaropicrin (Cyn) and chlorophyll, respectively, was used for a sequential purification along with DuraMem200 for lower MWC removal. Since Cyn content on initial feed (11.9 %) and permeate (11.2 %) were similar, as well as phytotoxic activity, the results suggested that DuraMem200 was unsuitable for CcLE fractionation. SuezGH2000 revealed a slight increase on SL content, so, the permeation profile and enhancement of SL content were evaluated. An increase on SL content (36.0–71.0 %) was obtained after 2.3 diavolumes, followed by a decrease between 2.6 and 4.7 diavolumes. Phytotoxic activity evaluations revealed a direct association with SL content with enhancement of activity, particularly at inhibiting shoot growth of Portulaca oleracea. This study revealed SuezGH2000 effectiveness on SL purity improvement on CcLE fractions after 2.3 diavolumes and its potential to be used as a bioherbicide active component.

GCMS-based phytochemical profiling and in vitro pharmacological activities of plant Alangium salviifolium (L.f) Wang

BackgroundThere is an urge for traditional herbal remedies as an alternative to modern medicine in treating several diseases. A significant number of modern pharmaceutical drugs are based on or derived from medicinal plants or their extracts. These drugs derived from the plant origin have various antimicrobial, antioxidant, anticancer, anti-inflammatory activities. Alangium salviifolium belongs to Cornaceae family and is well known for its medicinal properties. The present study was carried out to evaluate the antibacterial, antioxidant effect and possible bioactive components present in the chloroform, acetone, ethanol, methanol and aqueous extract of Alangium salviifolium leaves.MethodologyDried leaves of Alangium salviifolium were subjected to serial solvent extraction using increasing polarity of solvents, i.e., chloroform, acetone, methanol, ethanol, and distilled water. Crude extracts were further tested for qualitative analysis of phytochemicals using standard procedure, while GCMS analysis was performed to identify the probable phytocompounds. Antibacterial activity was performed against bacterial pathogens using agar well method, whereas antioxidant activity was performed using in vitro PM, DPPH and FRAP assays.ResultsPhytochemical analysis of the extracts revealed the presence of key phytochemical classes. Using gas chromatography-mass spectrometry, several high and low molecular weight chemical compound kinds were discovered. These chemical substances are regarded as having significant biological and pharmacological effects. All crude extracts had considerable and comparable in vitro antioxidant and antibacterial properties.ConclusionsAccording to the findings of this study, Alangium salviifolium leaves are a rich source of phytoconstituents that are crucial in stopping the advancement of numerous disorders.

Traveling wave solution and the stability of critical points of an enzyme-inhibitor system under diffusion effects: with special reference to dimer molecule

Enzymes are absolutely essential biological catalysts in human body that catalyze all cellular processes in physiological network. However, there are certain low molecular weight chemical compounds known as inhibitors, that reduce or completely inhibit the enzyme catalytic activity. Mathematical modeling plays a key role in the control and stability of metabolic enzyme inhibition. Enzyme stability is an important issue for protein engineers, because of its great importance and impact on optimal utility of material in biological tissues. In this outlook, we have first determined the existence of traveling wave solution for the enzyme-inhibitor system and then emphasized the stability of critical points that arise in the reactions. The study of traveling wave solution of an enzyme-inhibitor system with reaction diffusion equations involve quite complex mathematical analysis. The results obtained in this model indicate that the traveling wave solution may give a well explained method for improving enzyme kinetic stability. The present study will be helpful in understanding the stability of critical points of an enzyme-inhibitor system to give an idea about the inhibition of less stable enzymes. Moreover, the role of diffusion on the enzyme activity has been exhaustively discussed using mathematical tools related to eigen values and eigen function analysis.

Evaluation of Phyto components in the Ethanolic Extract from Launaea Nudicaulis

Launaea nudicaulis is a significant medicinal plant with anti-inflammatory, anti-cancer, antidiabetic and antibacterial properties. In the present study, we have studied the phytochemical analysis of Launaea nudicaulis leaf extract by using NMR and GC-MS technique. According to the preliminary phytochemical analysis, identify the various active ingredients. For the purposes GC-MS study was suggested to look into the organic compounds of the unique drug Launaea nudicaulis. From the results, Launaea nudicaulis' ethanolic whole plant extract was found 11 different phytochemical compounds. The GC-MS analysis confirmed their presence various Phenyl methyl esters of 6, 9, and 12-octadecatrienoic acid (368) and Phytol (296) Molecular weight compounds. Squalene, an important chemical, was identified in the fraction using a GC-MS analysis, with an 80% match rate. By analyzing the extract using spectroscopy, 1HNMR 13C NMR and GC-MS techniques, the compound squalene could be identified.

Correlation between Molecular Docking Score and Ligand Molar Mass: Statistical Approach

In recent days, pharmacology researchers have studied secondary metabolic compounds because they are naturally produced by plants, bacteria, fungi, and marine sponges, leading to increased worldwide use of the computational technique of molecular modelling approaches to drug discovery. Flavonoids, which belong to secondary metabolic compounds, play a role in biological activity. In the present study, the flavonoids subclass of secondary metabolic compounds molecular docking binding energy was dependent on the compound's molecular weight on binding interaction with antioxidant proteins using the statistical approaches of correlation coefficient and cluster statistical analysis. To evaluate a strong negative relationship, higher molecular mass flavonoids compounds had high active properties and lower molecular mass flavonoids compounds had low active properties, as reported on antioxidant proteins in correlation (r = -0.76 to -0.91 for a strong relationship) and cluster analysis. Flavonoids subclass compounds molecular docking binding scores were based on ligand molecular mass and depended on a similarly strong negative relationship in molecular mass vs 1HD2, 1MFM, 2F8A, and 2HCK antioxidant proteins. In this study, statistical analysis concluded that molecular docking binding energy depends on ligand molecular mass. Overall, the higher molecular mass compounds have higher active properties may be used in biological activity.

Mitigation of ultrafiltration membrane fouling by a simulated sunlight-peroxymonosulfate system with the assistance of irradiated NOM

Oxidation pretreatments prior to ultrafiltration are hindered by the need for energy input and sludge disposal. Herein, a simulated sunlight-induced natural organic matter (NOM) for peroxymonosulfate (PMS) activation was used as pretreatment to alleviate ultrafiltration membrane fouling caused by NOM itself in the Songhua River water. When light intensity was over 100 mW/cm2, the pretreatment removed NOM effectively, characterized with UV254, dissolved organic carbon (DOC) and maximum fluorescent intensity (Fmax), and improved filtration flux. At 200 mW/cm2 light intensity and 0.5 mM PMS, 57.5% of UV254 and 18.5% of DOC were removed, and humic-like fluorescent component was degraded by 84%-94% while ∼60% for protein-like substance. Membrane flux was increased by 94%, and reversible and irreversible fouling resistances were reduced by 62.4% and 51.9%, respectively. Both total fouling index (TFI) and hydraulic irreversible fouling index (HIFI) were moderately correlated with the DOC, whereas they prominently correlated with the UV254 and the Fmaxs of all fluorescence components, which could be served as key indicators to predict and control membrane fouling. Mathematical modeling showed that the pretreatment alleviated the fouling in the membrane pores and cake layer. The simulated sunlight-induced NOM (3NOM* and eaq¯) could activate PMS to form active species, which enabled to oxidize high molecular weight (MW) substances and mineralize low MW compounds in NOM as well as hinder their linking with inorganic cations, thereby reducing organic and inorganic membrane fouling simultaneously. This study may provide a new strategy for decentralized potable water treatment, especially in a single household or community.

Mn(II) Complexes of Enlarged Scorpiand-Type Azamacrocycles as Mimetics of MnSOD Enzyme

Living organisms depend on superoxide dismutase (SOD) enzymes to shield themselves from the deleterious effects of superoxide radical. In humans, alterations of these protective mechanisms have been linked to the pathogenesis of many diseases. However, the therapeutic use of the native enzyme is hindered by, among other things, its high molecular size, low stability, and immunogenicity. For this reason, synthetic SOD mimetic compounds of low molecular weight may have therapeutic potential. We present here three low-molecular-weight compounds, whose Mn2+ complexes can mimic, at least partially, the protective activity of SOD-enzymes. These compounds were characterized by NMR, potentiometry, and, to test whether they have protective activity in vitro, by their capacity to restore the growth of SOD-deficient strains of E. coli. In this report, we provide evidence that these compounds form stable complexes with Mn2+ and have an in vitro protective effect, restoring up to 75% the growth of the SOD-deficient E. coli.

Optimization of Extraction Conditions and Characterization of Volatile Organic Compounds of Eugenia klotzschiana O. Berg Fruit Pulp.

Eugenia klotzschiana O. Berg is a native species to the Cerrado biome with significant nutritional value. However, its volatile organic compounds (VOCs) chemical profile is not reported in the scientific literature. VOCs are low molecular weight chemical compounds capable of conferring aroma to fruit, constituting quality markers, and participating in the maintenance and preservation of fruit species. This work studied and determined the best conditions for extraction and analysis of VOCs from the pulp of Eugenia klotzschiana O. Berg fruit and identified and characterized its aroma. Headspace solid-phase microextraction (HS-SPME) was employed using different fiber sorbents: DVB/CAR/PDMS, PDMS/DVB, and PA. Gas chromatography and mass spectrometry (GC-MS) were employed to separate, detect, and identify VOCs. Variables of time and temperature of extraction and sample weight distinctly influenced the extraction of volatiles for each fiber. PDMS/DVB was the most efficient, followed by PA and CAR/PDMS/DVB. Thirty-eight compounds that comprise the aroma were identified among sesquiterpenes (56.4%) and monoterpenes (30.8%), such as α-fenchene, guaiol, globulol, α-muurolene, γ-himachalene, α-pinene, γ-elemene, and patchoulene.

Improvement in the Measurement Method for the Relative Molecular Weight of Compounds Based on Boiling Point Elevation

Improvement in the Measurement Method for the Relative Molecular Weight of Compounds Based on Boiling Point Elevation

Isolation and Identification of New Pigment From Monascus purpureus

This research was aimed to isolate and identify the new pigment from the main pigments of Monascus purpureus, which derive from five different isolates and through with solid fermentation used IR-64 rice as substrate. The measurement of pigment was done by extracting t samples using methanol in the 14th day of fermentation process. The absorbance of main pigment was measured by a UV-Visible spectrophotometer at the wavelengths of 364, 365, 375, 400, 480 and 500 nm. The results showed that the absorbance of each pigments isolate varied within ranges from 0.219 to 0.559. Result followed of Thin Layer Chromatography (TLC) method with chloroform: acetone (9: 1). TLC results were followed by isolating IPB-B samples using Thin Layer Chromatography- Preparative (TLC-P), whereas the band obtained was identified by using Liquid Chromatography-Mass Spectrum (LC-MS) instrument. The isolated and identified IPB-B samples showed that there was found a new compound of Molecular Weight (MW), which was Monaphilol A with Molecular Weight (MW) of 384.47.

Molecular dynamics between amorphous and crystalline phases of e-beam irradiated piezoelectric PVDF thin films employing solid-state NMR spectroscopy

Piezoelectric bi-axially and uni-axially stretched PVDF films subjected to e-beam irradiation doses of 5 kGy, 500 kGy and 1 MGy and films not irradiated have been studied. It was found that the piezoelectric responses of both untreated and e-beam irradiated PVDF films under strain strongly depends on their initial manufacturing processing. The initial structural differences were mainly based on crystalline phase composition, notably the α to β polymorph ratio. 19F MAS Solid State NMR measurements performed with fast sample spinning (31.25 kHz) allow us to accurately determine the proportion of crystal and amorphous phases. Considering only the crystalline phases, it was concluded that the uni-axial ((β)-PVDF) film was almost composed of 100% of β-phase while the biaxially-oriented ((α-β)-PVDF) was composed of 81% β-phase and 19% of α-phase. It was also shown that the changes of local dynamic processes of PVDF chains in kHz timescale enable to reflect the degradation of both the crystalline and amorphous phases. Presence of small molecular-weight chemical compounds was evidenced by Carr–Purcell–Meiboom–Gill (CPMG) 1H MAS NMR experiment. The degradation process was in agreement with melting peak decrease registered by DSC. 19F/1H T1ρ relaxation times and analysis of cross-polarization (CP) buildup curves are discussed. Significant scatter of relaxation parameters (19F T1ρ and 1H T1ρ) suggested an important degradation of polymer structure. The 1H T1ρ values for PVDF samples irradiated at 1 MGy mainly imply chain scission mechanisms of degradation rather than cross-linking processes. SS NMR spectroscopy data supported assumption that e-beam irradiation brings flexibility to piezoelectric PVDF films which improved their piezoelectric voltage output generated by deformation up to doses of 500kGy. Above this dose range, degradations were very important and affected severely PVDF films mechanical properties.

English

Rheum emodi Wall. ex Meissn is a popular medicinal herb having wide application in traditional medicine for treating of several diseases. The present study was aimed to identify and isolate phytochemicals present in ethyl acetate extract fraction of R. emodi and to evaluate the anticancer and anti-inflammatory activities of water/organic solvent fractions and isolated compounds of R. emodi rhizome extracts. Based on the structure, flavonoid compound i.e., Myricitrin (sym. Myricetin 3- rhamnoside), myricetin 3-galloylrhamnoside and myricetin were identified to be present in ethyl acetate extract. The molecular weight of compound 1 cannot be identified; while compound 5 remained unknown as there was not enough evidence to propose its structure. The isolated compounds and different solvent fractions were tested for their anticancer and antiinflammatory activities. Among Myricetins derivatives, particularly unknown compounds significantly induced the apoptosis and restrained the proliferation of cancer cell lines (A549 and MCF-7) and inhibited the LPS induced NO production (proinflammatory mediator), IL-6 activity, IL-1β and TNF-α (cytokines) activity in RAW 264.7 macrophages in a dose dependent manner and was effective even at lower concentration (50 µg/mL). Similarly, the higher concentration of aqueous and solvent fractions exhibited strong cytotoxic and anti-inflammatory activities. However, water and dichloromethane fractions were most effective in inhibiting the anticancer activities in A549 and MCF-7 cancer cell lines, respectively. At lower concentration (50 and 100 µg/mL), highest inhibition activity for NO, IL-6 and IL-1β was noted with ethyl acetate fractions and n-Hexane fractions; while water and n-Butanol (fractions) strongly inhibited the TNF-α activity at lower (100 µg/mL) and high (200 µg/mL) concentration, respectively. In conclusion, the isolated compounds from R. emodi rhizome extracts and its rhizome solvent fractions exhibit strong anti-cancer and anti-inflammatory activities and can be used to develop chemotherapeutics and anti-inflammation drugs. © 2021 Friends Science Publishers

Accuracy and uniformity of the nomenclature of biogenic amines and polyamines in metabolomics studies: A preliminary study.

Metabolomics is one of the newest areas in biochemistry dedicated to investigating small biomolecules in biofluids, tissues, and cells. Cutting edge instruments used in metabolomics studies make it possible to identify thousands of biomolecules and determine their interactions with biological networks. This tremendous area has increased the significance of accurate chemical nomenclature of compounds. Therefore, the classification of the organic molecules has become one of the most important issues in the field. Biogenic amines are nitrogenous compounds of low molecular weight formed by the decarboxylation of amino acids or by the amination and the transamination of aldehydes and ketones during normal metabolic processes. This letter covers the topic of nomenclature with respect to the current usage of biogenic amines in scientific literature. We use metabolomics as an example of field reporting data on trace levels of molecules that may be miscategorized in primary literature. We suggest that the incorrect classification of molecules will influence science education adversely because resources used for teaching are drawn from primary literature references that may contain errors.

Analysis of the Structure of Viscous Oil Flow for the Development of a System to Prevent the Formation of Paraffin Deposits in Pipelines

The detection of paraffin deposits in the systems of main oil pipelines today is a very important problem, since they lead to emergency oil spills, environmental disasters and economic losses both for the enterprise and for the country as a whole. This work is aimed at studying the physicochemical properties of asphaltic resin paraffins, as well as the mechanism of phase transition from liquid to crystalline. Such studies make it possible to estimate the absorption coefficient of the paraffin phase, which was previously not possible due to the complex nature of oil, consisting of hydrocarbons and many organic compounds of various molecular weights, and to provide high-precision non-contact measurements of the concentration of suspended asphalt-resin-paraffins in the oil flow in the pipeline. The analysis of the morphology and chemical composition of paraffins of various deposits is carried out, the dependence of the phase transition depending on the temperature gradient is determined.

Porous Structure Influence of Coconut Carbon Sorbents and Acidity on the Sorption of Some Biologically Active Organic Compounds

The paper investigates the regulation of the hydrophobicity of KARBON™ carbon adsorbents by restoring its surface during heat treatment in argon and hydrogen, as well as oxidizing it with nitric acid. The sorption capacity of KARBON™ with respect to the tryptophan, arginine, indole, creatinine and vitamin B12 as biologically active organic compounds of different molecular weight was studied. It was determined that the adsorption capacity of KARBON™ samples with respect to all the studied substances changes as follows: Ind&gt;Cr&gt;Trp&gt;Arg&gt;B12. It has been shown that the sorption capacity of argon-treated KARBON™ adsorbent at pH=7.5 is 2.6; 2.7 and 0.09 mmol/g in relation to tryptophan, creatinine and vitamin B12, respectively. The adsorption capacity of these compounds is almost unchanged when the acidity changes from 7.5 to 2.0. The results obtained allows the use of KARBON™ adsorbent as a therapeutic and/or prophylactic agent for oral administration in chronic kidney and liver diseases, as well as a hemosorbent for the purification of blood outside the human body.&#x0D;

Identification of Unique Aldehyde Dimers in Sorghum Wax Recovered after Fermentation in a Commercial Fuel Ethanol Plant

AbstractSorghum wax can be extracted from the surface of sorghum (Sorghum bicolor) kernels. It is composed mostly of a mixture of unsaturated C28 and C30 alkanes, fatty acids, fatty alcohols, and fatty aldehydes. Like carnauba wax, sorghum wax is a hard wax with a high melting point and it has potential edible and industrial applications. The yield of sorghum wax from the surface of sorghum kernels is 0.2–0.5 g of wax per 100 g of kernels. Sorghum wax can also be recovered from the “distillers oil” which is obtained after fermentation of sorghum (milo) or sorghum/corn blends in dry grind fuel ethanol plants. This distillers sorghum wax can potentially be obtained in yields of up to 10% by chilling the distillers oil to precipitate the wax and then recovering it via centrifugation or filtration. Like sorghum kernel wax, distillers sorghum wax is mainly composed of C28 and C30 alkanes, alcohols, and aldehydes in the molecular weight (MW) range of 350–450. However, we found that 7–49% w/w of distillers sorghum wax is composed of larger wax components with MW of 799–912. Analysis via high‐resolution atmospheric pressure chemical ionization mass spectrometry (APCI) and gas chromatography with electron ionization mass spectrometry (GC/MS‐EI) resulted in exact mass data and fragmentation patterns that suggested that these high MW compounds are monounsaturated fatty aldehyde dimers, likely formed by aldol condensation. Further confirmation supporting the GC/MS data for the aldol reaction was obtained by comparison with similar aldol products.

Polycyclic aromatic hydrocarbons in Mullus surmuletus from the Catania Gulf (Sicily, Italy): distribution and potential health risks

Different specimens of Mullus surmuletus from the Catania Gulf (Sicily) were sampled and analysed for the quantification of 16 priority polycyclic aromatic hydrocarbons (PAHs) in order to evaluate the distribution of these pollutants and the potential human health risks associated to the consumption of fish. The determined PAHs concentration values ranged from 0.25 to 6.10 ng/g wet weight and the most abundant PAHs detected were lower molecular weight (LMW) compounds with 2 to 3 rings. Relying on the PAHs concentration values, on the consumption data and on the total toxic equivalent (TEQ), the incremental lifetime cancer risk (ILCR) was assessed and its calculated value (2.97 × 10−7) is far below the “maximum acceptable risk level” (ARL), suggesting a low potential carcinogenic risk on consuming M. surmuletus for local population. Even though the study shows a quite low contamination level in M. surmuletus, intensive monitoring programmes are still highly needed in order to provide a better picture of the PAHs distribution in Catania Gulf and of the human health risk linked to fish consumption.