Presence Of KI Research Articles

Complete photodynamic inactivation of Pseudomonas aeruginosa biofilm with use of potassium iodide and its comparison with enzymatic pretreatment

Pseudomonas aeruginosa, a gram-negative bacterium, accounts for 7% of all hospital-acquired infections. Despite advances in medicine and antibiotic therapy, P. aeruginosa infection still results in high mortality rates of up to 62% in certain patient groups. This bacteria is also known to form biofilms, that are 10 to 1000 times more resistant to antibiotics compared to their free-floating counterparts. Photodynamic Inactivation (PDI) has been proved to be an effective antimicrobial technique for microbial control. This method involves the incubation of the pathogen with a photosensitizer (PS), then, a light at appropriated wavelength is applied, leading to the production of reactive oxygen species that are toxic to the microbial cells. Studies have focused on strategies to enhance the PDI efficacy, such as a pre-treatment with enzymes to degrade the biofilm matrix and/or an addition of inorganic salts to the PS. The aim of the present study is to evaluate the effectiveness of PDI against P. aeruginosa biofilm in association with the application of the enzymes prior to PDI (enzymatic pre-treatment) or the addition of potassium iodide (KI) to the photosensitizer solution, to increase the inactivation effectiveness of the treatment. First, a range of enzymes and PSs were tested, and the best protocols for combined treatments were selected. The results showed that the use of enzymes as a pre-treatment was effective to reduce the total biomass, however, when associated with PDI, mild bacterial reductions were obtained. Then, the use of KI in association with the PS was evaluated and the results showed that, PDI mediated by methylene blue (MB) in the presence of KI was able to completely eradicate the biofilm. However, when the PDI was performed with curcumin and KI, no additive reduction was observed. In conclusion, out of all strategies evaluated in the present study, the most promising strategy to improve PDI against P. aeruginosa biofilm was the use of KI in association with MB, resulting in eradication with 108 log bacterial inactivation.

Inside Back Cover

The cover displays a selective oxidative sulfonylation of alkenes with selenium sulfonate depended on the reaction conditions. The electrochemical C—H sulfonylation proceeded smoothly to afford (E)‐vinyl sulfones with good selectivity in an undivided cell without external oxidant. While aerobic trifunctionalization of alkenes occurred in the presence of KI in the air, which provides β‐keto selenosulfones via the formation of C—O, C—S, and C—Se bonds in one‐pot. This selective synthesis is like interstellar racing, reaching distant planets from the same starting point through different paths. Following control experiments, a plausible mechanism is proposed to rationalize the experimental results. More details are discussed in the article by Cao et al. on page 1367—1372.image

Oxidative rearrangement of enaminones to α-keto amides in the presence of KI, TBHP and octanoic acid

A novel method for the direct conversion of enaminones to α-keto amides has been developed. This transformation involves an oxidative rearrangement of enaminones under free radical conditions. In the presence of KI, TBHP and octanoic acid, a series of α-keto amides were obtained in moderate to excellent yields. This reaction demonstrates excellent functional group compatibility, utilizes readily available materials, and is easy to perform. Additionally, when o-hydroxyphenyl enaminone was utilized as the substrate, the reaction yielded 3-iodochromone in a high yield.

Electrochemical Oxidative Cross-Coupling Reactions of Ketene Dithioacetals and Dichalcogenides to Construct C−Se/C−S Bonds

A green protocol for construction of C−Se bonds from ketene dithioacetals and diselenides through direct electrochemical oxidative cross-coupling has been developed. This reaction was carried out in an undivided cell system with NaBF4 as the electrolyte and CH3CN as the solvent through galvanostatic electrolysis. A series of substituted ketene dithioacetals and diselenides were tolerant and the desired tetrasubstituted alkenyl selenides were obtained in moderate to excellent yields. In addition, construction of C−S bond from ketene dithioacetals and disulfides through electrochemical method in the presence of KI was also successfully realized. It exhibited high efficiency and broad functional group tolerance.

Synergistic effect of KI on corrosion inhibition of carbon steel by Styphnolobium japonicum (L.) Schott in H2SO4 solution

This work explored the synergistic effect of Styphnolobium japonicum (L.) Schott extract (SE) and potassium iodide (KI) on the corrosion inhibition of carbon steel (CS) in 0.5 mol/L H2SO4 solution. Firstly, the functional groups in the SE were identified using FTIR. The results of UPLC–Q–TOF–MS analysis confirmed the major phytoconstituents presence in SE were Glutaric acid, 2,3-Dihydroxybenzoic acid, Oxoadipic acid, Isoleucine, 2-Oxovaleric acid, l-phenylalanine, Indoline, and Trigonelline. Further a comprehensive investigation of anticorrosive properties of SE in the absence and presence of KI was conducted employing various techniques, including electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), ultraviolet visible spectroscopy (UV‒vis), and X-ray photoelectron spectroscopy (XPS) and theoretical studies like quantum chemical calculations (QC) and molecular dynamics simulations (MS). The results demonstrated that the SE+KI blend outperforms SE or KI individually, achieving an appreciable corrosion inhibition of 94.6 % for CS in H2SO4 solution. SEM analysis confirmed that the CS surface was smoother when SE+KI was added in the aggressive solution. Theoretical calculations were carried out to determine the dipole moments, Mulliken charges, and Fukui parameters of the eight major molecules found in SE. The results showed that SE can inhibit corrosion.

Controllable Construction of Vinyl Sulfones and β‐Keto Selenosulfones via Selective Oxidative Sulfonylation of Alkenes

Comprehensive SummaryThe selective oxidative sulfonylation of alkenes with selenium sulfonate depended on the reaction conditions. The electrochemical C—H sulfonylation proceeded smoothly to afford (E)‐vinyl sulfones with good selectivity in an undivided cell without external oxidant. While aerobic trifunctionalization of alkenes occurred in the presence of KI in the air, which provides β‐keto selenosulfones via the formation of C—O, C—S, and C—Se bonds in one‐pot. Following control experiments, a plausible mechanism is proposed to rationalize the experimental results.

Ortho-iodination of aromatic carboxylic acids in aqueous media

A straightforward method has been developed for Pd(II) catalyzed ortho-iodination of benzoic acids in aqueous media. In this paper, mono-iodination of benzoic acids is reported in the presence of KI as the iodine source.

Selective detection of Cysteine via plasmonic silver nanotriangles in the presence of KI with an emphasis on mechanism

Silver nanotriangles (Ag NTs), as the plasmonic sensor, were synthesized for the selective and sensitive detection of Cysteine in the aqueous media in the presence of KI. The identification of Cysteine, among other biogenic amino acids, was achieved within the range of 5–80 μM using UV–Vis spectroscopy; i.e., a red-shift was observed in the wavelength of the dipole plasmon resonance (λDPR) in the presence of Cysteine. The detection limit of the sensor was estimated 120 nM. The mechanism behind this selective detection was attributed to the inhibition effect of the Cysteine in the oxidation of the sharp corners of Ag NTs that would happen in the presence of KI. The concentration of Cysteine was correlated with the λDPR red-shift that stems from the Cysteine stabilization of Ag NTs against KI.

Improvement of Photocatalytic Degradation and Adsorption of Ciprofloxacin by Bismuth Oxyiodide

AbstractBismuth oxyiodide (BiOI) hierarchical structures were fabricated by the solution route at room temperature (BiOI‐R) and solvothermal synthesis (BiOI‐S) in the presence of KI and ethylene glycol to improve the photocatalytic and adsorption ability for the removal of ciprofloxacin from the aqueous environment. BiOI was characterized by X‐ray diffraction, scanning electron microscopy, N2 adsorption‐desorption isotherm, UV‐Vis absorption spectroscopy, and pH of the point of zero charge. It was observed that BiOI‐S has better adsorption and photocatalysis capacity as a result of having higher surface area, higher light absorption ability, and lower band‐gap energy than BiOI‐R. BiOI‐S exhibited good ciprofloxacin adsorption and photocatalytic degradation under visible‐light irradiation. Adsorption isotherm and kinetic studies fitted the Langmuir and Freundlich isotherm and pseudo‐second‐order models respectively. The photocatalytic degradation of ciprofloxacin by BiOI‐S followed a pseudo‐first‐order reaction based on Langmuir‐Hinshelwood kinetics.

Comparative Effect of Physiological Salts upon Micellization of T1304 and T1307.

We present a comprehensive investigation on the interaction of tetronics (T1304 and T1307) with some important physiological salts (NaH2PO4, KH2PO4, Na2CO3, NaCl, and KI). Thermodynamic and microstructural aspects of these interactions were studied as a function of the solution temperature, pH and salt concentration. Characterizations were performed using turbidimetric, calorimetric, and scattering techniques. We show that, at ambient temperature, T1304 molecules aggregated to form spherical core-shell aggregates displaying a unimodal distribution pattern. On the other hand, unimers and large clusters dominated in the case of highly hydrophilic T1307. Its micellization was promoted in the presence of salts as per the following trend: NaCl < KH2PO4 < NaH2PO4 ≪ Na2CO3. Aggregation was found to be endothermic, and hydrophobic interactions (TΔSmic > ΔHmic) prevailed. The enthalpy-entropy compensation plot was found to be linear for both copolymers. Demicellization occurred in the presence of KI as it facilitated the buildup of water structures around the copolymer chains. This could be verified from the increase in the cloud point, critical micelle concentration, and free energy. Overall, the temperature and salts inflicted a stronger hydrophobic effect upon T1304 in comparison to T1307.

Reaction-induced iodine adsorption on Cu surfaces facilitates electrocatalytic CO2 reduction.

The electrolyte effect has been key to the electrochemical CO2 reduction reaction (CO2RR) and has received extensive attention in recent years. Here we combined atomic force microscopy, quasi-in situ X-ray photoelectron spectroscopy, and in situ attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) to study the effect of iodine anions on Cu-catalyzed CO2RR in the absence or presence of KI in the KHCO3 solution. Our results suggested that iodine adsorption caused coarsening of the Cu surface and altered its intrinsic activity for CO2RR. As the potential of the Cu catalyst became more negative, there was an increase in surface iodine anion concentration ([I-]), which could be connected to the reaction-enhanced adsorption of I- ions accompanying the increase in CO2RR activity. A linear relationship was observed between [I-] and current density. SEIRAS results further suggested that the presence of KI in the electrolyte strengthened the Cu-CO bond and facilitated the hydrogenation process, enhancing the production of CH4. Our results have thus provided insight into the role of halogen anions and aided in the design of an efficient CO2RR process.

Exploring the untapped catalytic application of a ZnO/CuI/PPy nanocomposite for the green synthesis of biologically active 2,4,5-trisubstituted imidazole scaffolds.

This work is focused on designing an innovative, efficient, and reusable heterogeneous ZnO/CuI/PPy nanocomposite via the self-assembly approach where pyrrole is oxidized into polypyrrole (PPy) and pyrrole also behaves as a reductant in the presence of KI. This so-obtained material was characterized by XRD, FTIR, FESEM, EDX, TEM, XPS, and ICP. TEM clearly shows a spherical morphology with the particle size ranging between 18 and 42 nm. The fabricated nanomaterial was tested for one-pot catalytic synthesis of biologically active 2,4,5-trisubstituted imidazoles under solvent-free conditions. The present work includes the benefits of an easy work-up procedure, higher product yield, shorter reaction duration, and no additional additive requirement under green and sustainable conditions. Moreover, the catalyst exhibited reusability for six runs with no considerable reduction in the respective yields and reactivity (confirmed by XRD, SEM, and TEM of the recycled catalyst). The ICP study shows very low leaching of copper (2.08 ppm) and zinc (0.12 ppm) metals. The approach also presented better values of green metrics like the E-factor, process mass intensity, carbon efficiency and reaction mass efficiency.

Complexation mechanism of crown ether with indium in the presence of KI: Toward efficient recovery of indium from secondary resources

The strong hydration of In3+ in the aqueous solution is a main factor which hinders the recovery of indium through a solvent extraction process. In the present study, KI was added to the indium-containing solution to form the complex ion of InI4− on the purpose of weakening the hydration of indium. The crown ethers (CEs) of benzo-12-crown-4 (B12C4), benzo-15-crown-5 (B15C5), and benzo-18-crown-6 (B18C6) were successfully synthesized, and the effects of KI concentration, CE cavity size, and CE/In mole ratio on the indium solvent extraction process were systematically investigated. The interactions of indium with water molecules and CEs during the solvent extraction process were theoretically analyzed through density functional theory (DFT) calculations from the aspects of geometric structure optimization, thermodynamics, as well as electrostatic potential. The complexation mechanism between CE and indium in the presence of KI was further clarified with Mass spectrum, 1H NMR spectrum, and SEM-EDS. Moreover, B18C6 showed excellent extraction kinetic and selectivity to indium that nearly 100% indium could be extracted in 0.5 min and the separation coefficients over the competing ions of Sn2+, Cu2+, Fe3+, and Al3+ were 67.03, 79.06, 73.41, and 70.60, respectively, showing the excellent application prospect of B18C6 for efficient indium recovery in the complex system.

Synthesis of Fused pyrazolo[4,3‐c]quinolines through KI‐Promoted Cyclization of Pyrazole‐arylamines and Benzyl Bromide

AbstractA simple and highly efficient protocol was developed for the formation of pyrazolo[4,3‐c]quinolines starting from 2‐(1H‐pyrazol‐5‐yl)anilines and benzyl bromide in the presence of KI, affording desired products in moderate to good yields. The reaction showed good tolerance for a range of substrates with variable substituents. In this methodolgy, benzyl bromide proved to be an available C1 synthon in organic synthesis. Moreover, benzyl bromide can be replaced with benzyl iodide to synthesize pyrazolo[4,3‐c]quinoline derivatives, and benzyl chloride could not apply in this reaction system.

Boosting the H2 Production Efficiency via Photocatalytic Organic Reforming: The Role of Additional Hole Scavenging System

The simultaneous photocatalytic H2 evolution with environmental remediation over semiconducting metal oxides is a fascinating process for sustainable fuel production. However, most of the previously reported photocatalytic reforming showed nonstoichiometric amounts of the evolved H2 when organic substrates were used. To explain the reasons for this phenomenon, a careful analysis of the products and intermediates in gas and aqueous phases upon the photocatalytic hydrogen evolution from oxalic acid using Pt/TiO2 was performed. A quadrupole mass spectrometer (QMS) was used for the continuous flow monitoring of the evolved gases, while high performance ion chromatography (HPIC), isotopic labeling, and electron paramagnetic resonance (EPR) were employed to understand the reactions in the solution. The entire consumption of oxalic acid led to a ~30% lower H2 amount than theoretically expected. Due to the contribution of the photo-Kolbe reaction mechanism, a tiny amount of formic acid was produced then disappeared shortly after the complete consumption of oxalic acid. Nevertheless, a much lower concentration of formic acid was generated compared to the nonstoichiometric difference between the formed H2 and the consumed oxalic acid. Isotopic labeling measurements showed that the evolved H2, HD, and/or D2 matched those of the solvent; however, using D2O decreased the reaction rate. Interestingly, the presence of KI as an additional hole scavenger with oxalic acid had a considerable impact on the reaction mechanism, and thus the hydrogen yield, as indicated by the QMS and the EPR measurements. The added KI promoted H2 evolution to reach the theoretically predictable amount and inhibited the formation of intermediates without affecting the oxalic acid degradation rate. The proposed mechanism, by which KI boosts the photocatalytic performance, is of great importance in enhancing the overall energy efficiency for hydrogen production via photocatalytic organic reforming.

P–365 Altered endometrial oestrogen-responsiveness and aberrant expression of cell-fate markers may contribute to the aetiology of recurrent pregnancy loss

Abstract Study question Do women with recurrent pregnancy loss (RPL) have an aberrant expression of oestrogen receptor-β(ERβ) and cell-fate markers during the window of implantation (WOI) endometrium? Summary answer Women with RPL are found to have significantly altered levels of ER βand Ki–67 in the WOI endometrium, possibly resulting in anti-proliferative and anti-angiogenic effects. What is known already RPL affects 1% of all women and has been associated with altered endometrial angiogenesis and proliferation when compared with the endometrium of healthy fertile women. RPL can be subcategorised into recurrent loss of anembryonic pregnancy, fetal loss (following evidence of a fetal heartbeat) and recurrent implantation failure (RIF). ERβis the only oestrogen-receptor (ER) known to be expressed in the vascular endothelium of the endometrium and is the dominant ER during the WOI. It has an important role in endometrial regeneration and is proposed to regulate the angiogenic and vascular changes that occur in embryo implantation. Study design, size, duration: This pilot case-control study took place at the Liverpool Women’s Hospital and included 38 women; 29 who suffered RPL and 9 controls with proven fertility (≥2 healthy pregnancies). Of the RPL group, 9 had recurrent loss of anembryonic pregnancy, 10 had recurrent fetal loss and 10 had RIF. Endometrial samples were collected during the WOI (cycle day 22+/–2). Participants/materials, setting, methods To determine whether markers of endometrial cell proliferation and oestrogen-responsiveness are associated with RPL, we assessed the immuno-staining for ER β, progesterone receptor (PR) and cell-fate marker Ki–67 in endometrial biopsies during the WOI using immunohistochemistry. A semi-quantitative immuno-staining score was used to assess the endometrial glands, stroma, luminal epithelium, perivascular and vascular endothelium compartments separately. Statistical differences between groups were calculated by non-parametric tests and significance level set at p &amp;lt; 0.05. Main results and the role of chance During the WOI, the endometrial epithelium of women with RIF and recurrent anembryonic pregnancy loss showed significantly higher levels of ER βwhen compared with fertile controls (p = 0.01 and p = 0.01, respectively). This may indicate an anti-proliferative process occurring at the site of implantation with very early pregnancy losses. In contrast, with women with recurrent fetal loss, a significantly lower level of ERβwas found within the vascular endothelium when compared with the fertile controls (p &amp;lt; 0.01). This supports the theory that increased oxygen levels may compromise trophoblastic invasion, thereby leading to fetal loss. The presence of Ki–67 (a marker of proliferation) was significantly lower within the vascular endothelium of all types of RPL: recurrent anembryonic loss (p = 0.02), RIF (p = 0.02) and recurrent fetal loss (p &amp;lt; 0.01). These findings suggest ineffective endometrial angiogenesis in RPL, resulting in a suboptimal endometrial microenvironment. PR was found to be significantly reduced (p &amp;lt; 0.01) in the perivascular area of women with RIF versus fertile controls. Since decidualisation and preparation of the endometrium for a successful implantation is controlled by critical target genes downstream of PR, this alteration in PR may be an important feature of their defective endometrial phenotype. Limitations, reasons for caution Samples analysed were taken from the functional endometrium and therefore the results do not reflect the basalis. The WOI was identified using history and histological appearance, rather than timing with ovulation. Although we detected statistical significance, generalisation of the results requires further studies with larger sample size. Wider implications of the findings: This data provides novel insight into the biological correlates of clinical types of RPL and suggests that specific alterations in the regulation of endometrial cell fate and oestrogen- responsiveness are associated with different types of RPL. This highlights possible new therapies for RPL, such as selective oestrogen receptor modulators (SERMs). Trial registration number Not applicable

Corrosion Inhibiting Effect of Cetyl Pyridinium Chloride on Aluminium in Acid Media in Presence of KI

Corrosion Inhibiting Effect of Cetyl Pyridinium Chloride on Aluminium in Acid Media in Presence of KI

Evaluating the corrosion inhibition properties of novel 1,2,3-triazolyl nucleosides and their synergistic effect with iodide ions against mild steel corrosion in HCl: A combined experimental and computational exploration

The search for new effective and eco-friendly corrosion inhibitors seems to be a never-ending task for practical applications. Herein, the principal objective of this work is to investigate the corrosion inhibition effect of novel 1,2,3-triazolyl nucleosides namely, 2-(acetoxymethyl)-5-(3-((1-benzyl-1H-1,2,3-triazol-4-yl)methyl)-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)tetrahydrofuran-3,4-diyl diacetate (TBAc) and 2-(acetoxymethyl)-5-(3-((1-(naphthalen-2-ylmethyl)-1H-1,2,3-triazol-4-yl)methyl)-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)tetrahydrofuran-3,4-diyl diacetate (TNAc) for mild steel (MS) in HCl solution. Different amounts of TBAc and TNAc inhibitors were prepared in 1.0 mol/L HCl medium, and their inhibition effect was investigated via electrochemical measurements, X-ray photoelectron spectroscopy (XPS), quantum chemical calculations (DFT), and molecular dynamics (MD) modeling. Further, we have examined the effect of iodide ions on inhibition efficiency, and the obtained data were compared and discussed. Results showed that these green compounds exhibited high inhibition performances thanks to their excellent molecular and electronic properties. They indicated that TNAc and TBAc showed high corrosion inhibition efficiencies at 5x10-3 mol/L with 0.1 mmol/L of KI. The inhibition efficiency of TNAc and TBAc reached 85% and 79% at 5x10-3 mol/L, while it improved to 94% and 91% in the presence of KI, respectively. Electrochemical tests revealed that the studied molecules acted as mixed-type inhibitors and they had a significant effect on the polarization resistance of mild steel.Moreover, the surface morphology analysis was performed using a scanning electron microscope (SEM) and XPS. Besides, a systematic understanding of how these molecules are adsorbed on steel surface was theoretically investigated. Taken together, experimental and theoretical results suggested a significant role of molecular properties of studied derivatives along with intermediate species in promoting their adsorption behavior. A consistent association was found between electrochemical measurements and theoretical calculations.

Cationic Pyrrolidine/Pyrroline-Substituted Porphyrins as Efficient Photosensitizers against E. coli.

New porphyrin–pyrrolidine/pyrroline conjugates were prepared by revisiting 1,3-dipolar cycloaddition reactions between a porphyrinic azomethine ylide and a series of dipolarophiles. Cationic conjugates obtained by alkylation of the pyrrolidine/pyrroline cycloadducts showed ability to generate singlet oxygen and to produce iodine in presence of KI when irradiated with visible light. Some of the cationic derivatives showed photobactericidal properties towards a Gram-negative bioluminescent E. coli. In all cases, these features were significantly improved using KI as coadjutant, allowing, under the tested conditions, the photoinactivation of the bacterium until the detection limit of the method with a drastic reduction of the required photosensitizer concentration and irradiation time. The obtained results showed a high correlation between the ability of the cationic porphyrin derivative to produce singlet oxygen and iodine and its E. coli photoinactivation profile.

Al2O3/CuI/PANI nanocomposite catalyzed green synthesis of biologically active 2-substituted benzimidazole derivatives.

This work is generally focused on the synthesis of an efficient, reusable and novel heterogeneous Al2O3/CuI/PANI nanocatalyst, which has been well synthesized by a simple self-assembly approach where aniline is oxidized into PANI and aniline in the presence of KI also acts as a reductant. The nanocatalyst was well characterized by XRD, FTIR, SEM, EDX, TEM, BET and XPS techniques. In this study, the fabricated material was employed for the catalytic one-pot synthesis of 2-substituted benzimidazoles via condensation between o-phenylenediamine and aldehydes in ethanol as a green solvent. The present method is facile and offers several advantages such as high % yield, less reaction time, and no use of additive/bases. Also, the catalyst showed better values of green metrics including low E-factor: 0.17, high reaction mass efficiency: 85.34%, high carbon efficiency: 94%, and high process mass intensity: 1.17.