Self-assembling properties of mono and di-rhamnolipids characterized using small-angle X-ray scattering.

Rhamnolipids are glycolipid surfactants composed by a hydrophilic head of either one (mono-RL) or two (di-RL) rhamnose moieties coupled to hydroxyaliphatic chains that can be of different lengths. In spite of their importance in different fields of applications, as bioremediation processes for instance, self-aggregation physico-chemical properties of RLs are not unique. This because a variety of aggregates morphologies (shape and size) can either exist or coexist in aqueous dispersion due to mono-RL:di-RL molar ratio, hydrophobic tails length, pH and the presence of co-surfactants and additives. Recently, a theorethical approach reported the self-assembling morphologies of either pure mono or di-RL in aqueous environment, predicting the formation of spherical to ellipsoidal micelles to worm-like and disk-like aggregates depending on RL concentration and fatty acid chain length. In order to add new information to those previously available, the present work investigated the self-assembling properties of mono-RL-C10-C10 and di-RL-C10-C10 separately in aqueous dispersion by small angle X-Ray scattering (SAXS). A novel approach was applied to the data analysis coupling the scattering length density profiles of the RLs chemical groups and Monte Carlo simulations. Such an approach allowed us to infer about the preferred mono-RL and di-RL conformations that fit better in the self-assembling morphologies. In this way, we show that mono-RL-C10-C10 self-assembles into lamella-like aggregates coexisting with 30 % of multi-lamella aggregates (circa of 5 closed stacked lamella) from a concentration ranging from 10 to 50 mM, with hydrophobic thickness of about 12 Å, a hydrated polar head thickness of 10 Å, and an area per glycolipid of 76 Å2. On the other hand, di-RL prefers to self-associate into flexible cylinder-like aggregates, from 70 mM to 110 mM concentration, with hydrophobic radius on the order of 7.5 Å, a hydrated polar shell of 21.5 Å, with hydropobic/polar interface of 110 Å2 per glycolipid. Interestingly, the parameters obtained from the best fitting to the experimental data associated to the volume fraction distribution of the chemical groups within the aggregates revealed that the hydrophobic chains are more disordered in mono-RL planar aggregates than in di-RL worm-like aggregates, as well as the hydration properties. Further, the addition of 100 mM NaCl in di-RL aqueous dispersion leads to the formation of longer worm-like aggregates. Taking together, this work opens a new avenue regarding characterization of biosurfactants self-assembling properties by using SAXS, also contributing to prepare more efficient biosurfactant dispersions depending on the desired applications in industrial sectors and bioremediation.

Analysis of Bioactive Compounds Produced by Bacillus mojavensis ZA1 and Their Antagonistic Effect on Colletotrichum coccodes by GC-MS.

The plant disease Colletotrichum coccodes, which lowers potato yields, poses a severe danger to the booming potato industry. Isolated plant endophytic bacteria from highland pasture can produce a variety of metabolites that lessen the risk that the pathogen C. coccodes poses to plant growth and development. Therefore, the objective of our work was to assess substances with antipathogenic properties made by the endophytic bacteria Bacillus mojavensis ZA1. Gas chromatography-mass spectrometry (GC-MS) was used in our investigation to accomplish a thorough structural elucidation of the antipathogenic compounds produced by the endophytic bacterial strain B. mojavensis ZA1. The results showed that the metabolites extracted from ethyl acetate as an extractant were the most effective in inhibiting the pathogen C. coccodes, with 60.95% inhibition. Thirty-five distinct chemicals, including acids, esters, ketones, alcohols, amino acid ammonium salts, cyclic ethers, aromatic hydrocarbons, and heterocyclic compounds, were among the metabolites that may inhibit C. coccodes. Further analysis of the chemical groups in the compound structures revealed the potential of driving groups, such as hydroxyl, carbonyl, ester, benzene, carbon-carbon double bonds, and carbon rings, that prevent C. coccodes from performing its function. This study opens up new opportunities for plant protection programs by demonstrating that natural chemicals produced by B. mojavensis ZA1 can be used as candidates for cutting-edge plant disease management treatments.

Effect of Polybutylene Succinate Additive in Polylactic Acid Blend Fibers via a Melt-Blown Process.

This work aimed to study the influence of the polybutylene succinate (PBS) content on the physical, thermal, mechanical, and chemical properties of the obtained polylactic acid (PLA)/PBS composite fibers. PLA/PBS blend fibers were prepared by a simple melt-blown process capable of yielding nanofibers. Morphological analysis revealed that the fiber size was irregular and discontinuous in length. Including PBS affected the fiber size distribution, and the fibers had a smoother surface with increased amounts of added PBS. Differential scanning calorimetry analysis (DSC) revealed that the crystallization temperature of the PLA sheet (105.8 °C) was decreased with increasing PBS addition levels down to 91.7 °C at 10 wt.% PBS. This suggests that the addition of PBS may affect PLA crystallization, which is consistent with the X-ray diffraction analysis that revealed that the crystallinity of PLA (19.2%) was increased with increasing PBS addition up to 28.1% at 10 wt% PBS. Moreover, adding PBS increased the tensile properties while the % elongation at break was significantly decreased.

Effects of the surface chemical groups of cellulose nanocrystals on the vulcanization and mechanical properties of natural rubber/cellulose nanocrystals nanocomposites.

Cellulose nanocrystals (CNCs), as the promising reinforcing fillers in the rubber industry, their surface chemical groups have vital effects on the vulcanization kinetics, cross-linking densities, and mechanical properties of rubber composites. Herein, CNCs with acidic carboxyl (CCA) and alkaline amino groups (CCP) were produced by modifying the sulfonic CNCs (CCS) in environment-friendly ways. Studies found the CCS and CCA with acid groups have obvious inhibiting effects on the vulcanization of natural rubber (NR), while CCP with alkaline amino groups accelerates the vulcanization of NR. Differential scanning calorimeter, Fourier transform infrared spectroscopy, and Electron paramagnetic resonance, etc. were performed to clarify the effecting mechanisms of CNCs surface groups on NR vulcanization. It was found that NR/CCS and NR/CCA nanocomposites vulcanize through radical reactions, and the surface acidic groups of CCS and CCA, i.e., hydroxyl, sulfonate, and carboxyl groups inactivate the sulfur radicals generated during vulcanization and depress the vulcanization activity. The amino groups of the polyethyleneimine of CCP promote the ring opening of sulfur (S8) or the breaking of polysulfide bonds connected to NR molecular chains to form sulfur anion with a strong nucleophilic ability, which leads to the cross-linking of NR/CCP reacts via ionic reaction mainly. The vulcanization rate and cross-linking density of NR/CCP are improved by the ionic reaction. And benefiting from the higher cross-linking density and the reinforcement of CCP, NR/CCP had the best physical and mechanical properties. Our work elucidates the mechanism of the surface chemical groups of CNCs affecting NR vulcanization and may provide ideas for the preparation of high-performance rubber composites reinforced by CNCs.

Safety of 37 feed additives consisting of flavouring compounds belonging to different chemical groups for use in all animal species (FEFANA asbl).

Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the supplementary information submitted on the safety of 37 compounds belonging to different chemical groups, when used as sensory additives (flavourings) in feed for all animal species formerly assessed by the Panel in the context of the re-evaluation of these feed additives. The FEEDAP Panel concludes that ethyl oleate [09.192] and benzyl cinnamate [09.738] are safe at the proposed use level of 5 mg/kg complete feed for all animal species, the consumer and the environment; ethyl salicylate [09.748] is safe up to the maximum proposed use level of 5 mg/kg complete feed for all animal species and the consumer. No new data were submitted on the safety for the user that would allow the FEEDAP Panel to change its previous conclusion for 26 out of the 37 compounds under assessment. The use of 4-terpinenol [02.072], linalyl butyrate [09.050], linalyl formate [09.080], linalyl propionate [09.130], linalyl isobutyrate [09.423], isopulegol [02.167] and 1,2-dimethoxy-4-(prop-1-enyl)-benzene [04.013] as flavouring additives at the proposed use level of 5 mg/kg in feed for all animal species is considered safe for the environment. The use of 3-methyl-2-cyclopenten-1-one [07.112] at 0.5 mg/kg and methyl dihydrojasmonate [09.520] at 5 mg/kg in feed for all animal species except marine animals is considered safe for the environment.

New approaches with ATR-FTIR, SEM, and contact angle measurements in the adaptation to extreme conditions of some endemic Gypsophila L. taxa growing in gypsum habitats.

Gypsophila L. taxa growing on gypsum soils have to withstand limiting and restrictive conditions for plant life. This study aims to identify functional mechanisms determine the main functional groups in the vegetative and reproductive organs of some endemic Gypsophila taxa growing in gypsum soils, as well as to understand the relationship between the hidrophobicities and their micromorphological structures of the leaves of these plants grown in arid conditions. In this context, a series of Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR), water contact angle (CA) measurements, and scanning electron microscopy (SEM) analyses were performed that may help to understand the survival mechanisms of Gypsophila eriocalyx Boiss., Gypsophila germanicopolitana Hub.-Mor. and Gypsophila simonii Hub.-Mor. growing in gypsum habitats. Our results showed the presence of O-H and C-O stretching bands belong to gypsum and calcium oxalate in the roots, stems, leaves and flowers of Gypsophila taxa is thought to be a way of tolerating the excess Ca and sulphate in the extreme habitat where these species grow. Leaves of Gypsophila taxa showed CAs above 90°, which indicates that G. eriocalyx, G. germanicopolitana, and G. simonii were hydrophobic. This study offers new approaches to understanding the adaptation of Gypsophila taxa to the extreme conditions typical of gypsum soils. The characterization of gypsum plants such as Gypsophila taxa, whose mechanisms for competition and survival on gypsum are still not fully understood, is very important in terms of shedding light on the adaptation of endemic plants to gypsum habitats.

Evaluating the structural properties of bioactive-loaded nanocarriers with modern analytical tools.

With the emergence of nanocarriers for offering smart transformers improving the bioavailability and functionality of food bioactive compounds, a critical issue is experimental and analytical evaluation of the bioactive-loaded nanocarriers; so, further technical advancements are necessary for the precise structural characterization of these nanodelivery systems and application of sophisticated analytical techniques. Here, we have portrayed the current progress in the structural characterization approaches including X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, fluorescence spectroscopy, circular dichroism, Fourier-transform infrared spectroscopy, nuclear magnetic resonance, X-ray photoelectron spectroscopy, and small-angle X-ray scattering/small-angle neutron scattering as powerful and informative tools to have a better control on the design, development, and appraisal of nanoengineered bioactive delivery systems. Different examples and case studies have been tabulated along with illustrative and schematic representation of relevant results. An emerging view concerning the challenges for future structural characterization of these systems is also discussed in detail.

Effects of different chemical groups on behaviors of bladder cancer cells.

Chemical groups of microenvironment play an important role in the adhesion, proliferation, and apoptosis of tumor cells. The different chemical groups (CH3 , OH, COOH) were grafted on the surfaces with the same density by self-assembly monolayer (SAM) technique to introduce the influence of different microenvironments of the human bladder cancer (5637) cells. The results indicated that the 5637 cells on COOH surface exhibited the lowest proliferation rate and the highest apoptosis rate on the first and fifth day because of negative charge and polarity of the COOH group, which might help optimize biomedicine materials and find new methods to treat bladder cancer.

Risk of Nephrotic Syndrome for Non-Steroidal Anti-Inflammatory Drug Users.

BACKGROUND AND OBJECTIVES: Nonsteroidal anti-inflammatory drugs (NSAIDs) have been associated with AKI. Their association with nephrotic syndrome has not been systematically studied. This study aimed to assess the risk of nephrotic syndrome associated with NSAID use. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: A matched case-control study was performed in the UK primary care database. Cases were patients with a first diagnosis of nephrotic syndrome and controls were those without nephrotic syndrome. NSAID exposure (grouped either based on cyclooxygenase enzyme selectivity and chemical groups) was classified as either current (use at the nephrotic syndrome diagnosis date and corresponding date in the control group), recent, or past use. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated using unconditional logistic regression analysis. RESULTS: We included 2620 cases and 10,454 controls. Compared with non-use, current use of 15-28 days and >28 days of conventional NSAIDs was associated with a higher relative risk of nephrotic syndrome: adjusted OR, 1.34; 95% CI, 1.06 to 1.70, and OR, 1.42; 95% CI, 0.79 to 2.55, respectively. Also, recent use (discontinuation 1-2 months before nephrotic syndrome diagnosis date; OR, 1.55; 95% CI, 1.11 to 2.15) and past use (discontinuation 2 months-2 years; OR, 1.24; 95% CI, 1.07 to 1.43), but not current use of <15 days (OR, 0.78; 95% CI, 0.46 to 1.31) nor past use (discontinuation >2 years; OR, 0.96; 95% CI, 0.85 to 1.09) were associated with a higher relative risk of nephrotic syndrome as well as past use of selective COX-2 inhibitors (discontinuation 2-24 months; OR, 1.24; 95% CI, 0.98 to 1.58). Categorization based on chemical groups showed that acetic acid and propionic acid derivatives were associated with a higher risk of nephrotic syndrome. CONCLUSIONS: The use of conventional NSAIDs was associated with a higher risk of nephrotic syndrome starting from at least 2 weeks of exposure, as well as for recent and past exposure up to 2 years before the diagnosis of nephrotic syndrome. This higher risk appeared mainly attributable to acetic acid and propionic acid derivatives.

DFT study of electronic and optical properties of silicene functionalized with chemical groups.

In the last years, a band-gap tunability is particularly interesting for the fabrication of flexible and ultrathin optical devices since it is known from earlier studies that two-dimensional materials can display a much larger sunlight absorption than commonly employed semiconductors. Using density functional theory, we study the structural, electronic and optical properties such as dielectric function, absorption coefficient, conductivity, and a refractive index of silicene monolayer functionalized with chemical groups or atoms (i.e, X-Si-Y, Cl-Si-Br, and X'-Si-X' with X = Cl, F, or OH; Y = CN; X'  = CN, CH, or NH). In this framework, by means of AIMD calculations, we show that they are dynamically stable, while their electronic band-gap, as obtained with the GGA approximation, ranges between 1.25 and 2.13 eV, except for CH-Si-CH and NH-Si-NH, which are found to be metallic. Additionally, we show that an external electric field can modify significantly the electronic structure of some of these systems.

Cyclo-oxygenase selectivity and chemical groups of nonsteroidal anti-inflammatory drugs and the frequency of reporting hypersensitivity reactions: a case/noncase study in VigiBase.

To date, no reports of hypersensitivity reactions (HSRs) among nonsteroidal anti-inflammatory drugs (NSAIDs) according to cyclo-oxygenase (COX) selectivity and chemical groups have been published in a single study. The present study assessed the reporting frequency of HSRs for NSAIDs based on their relative inhibitory potency toward COX enzymes and chemical groups, including the presence/absence of a functional sulfonamide group, in strata observed 5 years after market authorization. A case/noncase study was performed among individual case safety reports (ICSRs) with NSAIDs as suspected drugs in VigiBase, the WHO spontaneous reporting database. Cases were ICSRs mentioning angioedema and anaphylactic/anaphylactoid shock conditions, while noncases were ICSRs without HSRs. NSAIDs were categorized into (i) NSAIDs with high COX-2 selectivity (coxibs), (ii) noncoxib NSAIDs with COX-2 preference, (iii) NSAIDs with poor selectivity, or (iv) NSAIDs with unknown selectivity. Chemical groups were defined based on the Anatomical Therapeutic Chemical classification system and the presence/absence of a functional sulfonamide group. Reporting odds ratios (RORs) and 95% confidence intervals (95% CIs) were calculated using logistic regression analysis. We identified 13 229 cases and 106 444 noncases. In the first 5 years after marketing, poor-selectivity NSAIDs and acetic acid derivatives were associated with the highest ROR of HSRs (age- and sex-adjusted ROR 2.12, 95% CI 1.98-2.28; and ROR 2.21, 95% CI 1.83-2.66, respectively) compared with coxibs, and sulfonamide NSAIDs were associated with the highest ROR of HSRs compared with nonsulfonamide NSAIDs (age- and sex-adjusted ROR 1.38, 95% CI 1.29-1.47). After the first 5 years of marketing, most of the RORs returned to approximately 1.

Electrospun Flexible Cellulose Acetate-Based Separators for Sodium-Ion Batteries with Ultralong Cycle Stability and Excellent Wettability: The Role of Interface Chemical Groups.

Na-ion batteries are one of the best technologies for large-scale applications depending on almost infinite and widespread sodium resources. However, the state-of-the-art separators cannot meet the engineering needs of large-scale sodium-ion batteries to match the intensively investigated electrode materials. Here, a kind of flexible modified cellulose acetate separator (MCA) for sodium-ion batteries was synthesized via the electrospinning process and subsequently optimizing the interface chemical groups by changing acetyl to hydroxyl partly. Upon the rational design, the flexible MCA separator exhibits high chemical stability and excellent wettability (contact angles nearly 0°) in electrolytes (EC/PC, EC/DMC, diglyme, and triglyme). Moreover, the flexible MCA separator shows high onset temperature of degradation (over 250 °C) and excellent thermal stability (no shrinkage at 220 °C). Electrochemical measurements, importantly, show that the Na-ion batteries with flexible MCA separator exhibit ultralong cycle life (93.78%, 10 000 cycles) and high rate capacity (100.1 mAh g-1 at 10 C) in the Na/Na3V2(PO4)3 (NVP) half cell (2.5-4.0 V) and good cycle performance (98.59%, 100 cycles) in the Na/SnS2 half cell (0.01-3 V), respectively. Moreover, the full cell (SnS2/NVP) with flexible MCA separator displays the capacity of 98 mAh g-1 and almost no reduction after 40 cycles at 0.118 A g-1. Thus, this work provides a kind of flexible modified cellulose acetate separator for Na-ion batteries with great potential for practical large-scale applications.

Surface chemistry induces mitochondria-mediated apoptosis of breast cancer cells via PTEN/PI3K/AKT signaling pathway.

Tumor cell can be significantly influenced by various chemical groups of the extracellular matrix proteins. However, the underlying molecular mechanisms involved in the interaction between cancer cells and functional groups in the extracellular matrix remain unknown. Using chemically modified surfaces with biological functional groups (CH3, NH2, OH), it was found that hydrophobic surfaces modified with CH3 and NH2 suppressed cell proliferation and induced the number of apoptotic cells. Mitochondrial dysfunction, cytochrome c release, Bax upregulation, cleaved caspase-3 and PARP, and Bcl-2 downregulation indicated that hydrophobic surfaces with CH3 and NH2 triggered the activation of intrinsic apoptotic signaling pathway. Cells on the CH3- and NH2-modified hydrophobic surfaces showed downregulated expression and activation of integrin ß1, with a subsequent decrease of focal adhesion kinase (FAK) activity. The RhoA/ROCK/PTEN signaling was then activated to inhibit the phosphorylation of PI3K and AKT, which are essential for cell proliferation. However, pretreatment of MDA-MB-231 cells with SF1670, a PTEN inhibitor, abolished the hydrophobic surface-induced activation of the intrinsic pathway. Taken together, the present results indicate that CH3- and NH2-modified hydrophobic surfaces induce mitochondria-mediated apoptosis by suppressing the PTEN/PI3K/AKT pathway, but not OH surfaces. These findings are helpful to understand the interaction between extracellular matrix and cancer cells, which might provide new insights into the mechanism potential intervention strategies for tumor prognosis.