Novel supramolecular luminescent metallogels containing Tb(iii) and Eu(iii) ions with benzene-1,3,5-tricarboxylic acid gelator: advancing semiconductor applications in microelectronic devices

A novel strategy was employed to create supramolecular metallogels incorporating Tb(iii) and Eu(iii) ions using benzene-1,3,5-tricarboxylic acid (TA) as a gelator in N,N-dimethylformamide (DMF). Rheological analysis demonstrated their mechanical robustness under varying stress levels and angular frequencies. FESEM imaging revealed a flake-like hierarchical network for Tb-TA and a rod-shaped architecture for Eu-TA. EDX analysis confirmed essential chemical constituents within the metallogels. FT-IR, PXRD, Raman spectroscopy, and thermogravimetric analysis assessed their gelation process and material properties, showing semiconducting characteristics, validated by optical band-gap measurements. Metal-semiconductor junction-based devices integrating Al metal with Tb(iii)- and Eu(iii)-metallogels exhibited non-linear charge transport akin to a Schottky diode, indicating potential for advanced electronic device development. Direct utilization of benzene-1,3,5-tricarboxylic acid and Tb(iii)/Eu(iii) sources underscores their suitability as semiconducting materials for device fabrication. This study explores the versatile applications of Tb-TA and Eu-TA metallogels, offering insights for material science researchers.

Rapid Semiconducting Supramolecular Mg(II)-Metallohydrogel: Exploring Its Potential in Nonvolatile Resistive Switching Applications and Antiseptic Wound Healing Properties

An effective strategy was employed for the rapid development of a supramolecular metallohydrogel of Mg(II) ion (i.e., Mg@PEHA) using pentaethylenehexamine (PEHA) as a low-molecular-weight gelator in aqueous medium under ambient conditions. The mechanical stability of the synthesized Mg@PEHA metallohydrogel was characterized by using rheological analysis, which showed its robustness across different angular frequencies and oscillator stress levels. The metallohydrogel exhibited excellent thixotropic behavior, which signifies that Mg@PEHA has a self-healing nature. Field emission scanning electron microscopy and transmission electron microscopy images were utilized to explore the rectangular pebble-like hierarchical network of the Mg@PEHA metallohydrogel. Elemental mapping through energy-dispersive X-ray spectroscopy analysis confirmed the presence of primary chemical constituents in the metallohydrogel. Fourier transform infrared spectroscopy spectroscopy provided insights into the possible formation strategy of the metallohydrogel. In this work, Schottky diode structures in a metal-semiconductor-metal geometry based on a magnesium(II) metallohydrogel (Mg@PEHA) were constructed, and the charge transport behavior was observed. Additionally, a resistive random access memory (RRAM) device was developed using Mg@PEHA, which displayed bipolar resistive switching behavior at room temperature. The researchers investigated the switching mechanism, which involved the formation or rupture of conduction filaments, to gain insights into the resistive switching process. The RRAM device demonstrated excellent performance with a high ON/OFF ratio of approximately 100 and remarkable endurance of over 5000 switching cycles. RRAM devices exhibit good endurance, meaning they can endure a large number of read and write cycles without significant degradation in performance. RRAM devices have shown promising reliability in terms of long-term performance and stability, making them suitable for critical applications that require reliable memory solutions. Significant inhibitory activity against the drug-resistant Klebsiella pneumonia strain and its biofilm formation ability was demonstrated by Mg@PEHA. The minimum inhibitory concentration value of the metallohydrogel was determined to be 3 mg/mL when it was dissolved in 1% DMSO. To study the antibiofilm activity, an MTT assay was performed, revealing that biofilm inhibition (60%) commenced at 1 mg/mL of Mg@PEHA when dissolved in 1% DMSO. Moreover, in the mouse excisional wound model, Mg@PEHA played a crucial role in preventing postoperative wound infections and promoting wound healing.

Exploration of a wide bandgap semiconducting supramolecular Mg(II)-metallohydrogel derived from an aliphatic amine: a robust resistive switching framework for brain-inspired computing

A rapid metallohydrogelation strategy has been developed of magnesium(II)-ion using trimethylamine as a low molecular weight gelator in water medium at room temperature. The mechanical property of the synthesized metallohydrogel material is established through the rheological analysis. The nano-rose like morphological patterns of Mg(II)-metallohydrogel are characterized through field emission scanning electron microscopic study. The energy dispersive X-ray elemental mapping analysis confirms the primary gel forming elements of Mg(II)-metallohydrogel. The possible metallohydrogel formation strategy has been analyzed through FT-IR spectroscopic study. In this work, magnesium(II) metallohydrogel (Mg@TMA) based metal-semiconductor-metal structures have been developed and charge transport behaviour is studied. Here, it is confirmed that the magnesium(II) metallohydrogel (Mg@TMA) based resistive random access memory (RRAM) device is showing bipolar resistive switching behaviour at room temperature. We have also explored the mechanism of resistive switching behaviour using the formation (rupture) of conductive filaments between the metal electrodes. This RRAM devices exhibit excellent switching endurance over 10,000 switching cycles with a large ON/OFF ratio (~ 100). The easy fabrication techniques, robust resistive switching behaviour and stability of the present system makes these structures preferred candidate for applications in non-volatile memory design, neuromorphic computing, flexible electronics and optoelectronics etc.

Concentration- and Solvent-Induced Chiral Tuning by Manipulating Non-Proteinogenic Amino Acids in Glycoconjugate Supra-Scaffolds: Interaction with Protein, and Streptomycin Delivery

We showed solvent- and concentration-triggered chiral tuning of the fibrous assemblies of two novel glycoconjugates Z-P(Gly)-Glu and Z-F(4-N)-Glu made by chemical attachment of Cbz-protected [short as Z)] non-proteinogenic amino acids L-phenylglycine [short as P(Gly)] and 4-Nitro-L-phenylalanine [short as F(4-N)] with D-glucosamine [short as Glu]. Both biomimetic gelators can form self-healing and shape-persistent gels with a very low critical gelator concentration in water as well as in various organic solvents, indicating they are ambidextrous supergelators. Detailed spectroscopic studies suggested β-sheet secondary structure formation during anisotropic self-aggregation of the gelators which resulted in the formation of hierarchical left-handed helical fibers in acetone with an interlayer spacing of 2.4 nm. After the physical characterization of the gels, serum protein interaction with the gelators was assessed, indicating they may be ideal for biomedical applications. Further, both gelators are benign, non-immunogenic, non-allergenic, and non-toxic in nature, which was confirmed by performing the blood parameters and liver function tests on Wister rats. Streptomycin-loaded hydrogels showed efficacious antibacterial activity in vitro and in vivo as well. Finally, cell attachment and biocompatibility of the hydrogels were demonstrated which opens a newer avenue for promising biomedical and therapeutic applications.

A 5-aminoisophthalic acid low molecular weight gelator based novel semiconducting supramolecular Zn(ii)-metallogel: unlocking an efficient Schottky barrier diode for microelectronics

A novel method has been successfully developed for creating supramolecular metallogels using zinc(ii) ions and 5-aminoisophthalic acid as the gelator (low molecular weight gelator) in a dimethylformamide (DMF) solvent at room temperature. Comprehensive rheological investigations confirm the robust mechanical strength of the resulting zinc(ii)-metallogel. Microstructural analysis conducted through field-emission scanning electron microscopy (FESEM) unveils a unique flake-like morphology, with energy-dispersive X-ray (EDX) elemental mapping confirming the prevalence of zinc as the primary constituent of the metallogel. To understand the formation mechanism of this metallogel, Fourier-transform infrared (FT-IR) spectroscopy was employed. Notably, these supramolecular zinc(ii)-metallogel assemblies exhibit electrical conductivity reminiscent of metal-semiconductor (MS) junction electronic components. Surprisingly, the metallogel-based thin film device showcases an impressive electrical conductivity of 1.34 × 10-5 S m-1. The semiconductor characteristics of the synthesized zinc(ii)-metallogel devices, including their Schottky barrier diode properties, have been extensively investigated. This multifaceted study opens up a promising avenue for designing functional materials tailored for electronic applications. It harnesses the synergistic properties of supramolecular metallogels and highlights their significant potential in the development of semiconductor devices. This work represents a novel approach to the creation of advanced materials with unique electronic properties, offering exciting prospects for future innovations in electronic and semiconductor technologies.

Two novel low molecular weight gelator-driven supramolecular metallogels efficient in antimicrobial activity applications

A remarkable ultrasonication technique was successfully employed to create two novel metallogels using citric acid as a low molecular weight gelator, in combination with cadmium(ii)-acetate and mercury(ii)-acetate dissolved in N,N-dimethyl formamide at room temperature and under ambient conditions. The mechanical properties of the resulting Cd(ii)- and Hg(ii)-metallogels were rigorously examined through rheological analyses, which revealed their robust mechanical stability under varying angular frequencies and shear strains. Detailed characterization of the chemical constituents within these metallogels was accomplished through EDX mapping experiments, while microstructural features were visualized using field emission scanning electron microscope (FESEM) images. Additionally, FT-IR spectroscopic analysis was employed to elucidate the metallogel formation mechanism. Significantly, the antimicrobial efficacy of these novel metallogels was assessed against a panel of bacteria, including Gram-positive strains such as Bacillus subtilis and Staphylococcus epidermidis, as well as Gram-negative species like Escherichia coli and Pseudomonas aeruginosa. The results demonstrated substantial antibacterial activity, highlighting the potential of Cd(ii) and Hg(ii)-based citric acid-mediated metallogels as effective agents against a broad spectrum of bacteria. In conclusion, this study provides a comprehensive exploration of the synthesis, characterization, and antimicrobial properties of Cd(ii) and Hg(ii)-based citric acid-mediated metallogels, shedding light on their promising applications in combating both Gram-positive and Gram-negative bacterial infections. These findings open up exciting prospects for the development of advanced materials with multifaceted industrial and biomedical uses.

A novel supramolecular Zn(ii)-metallogel: an efficient microelectronic semiconducting device application

A unique strategy for the synthesis of a supramolecular metallogel employing zinc ions and adipic acid in DMF medium has been established at room temperature. Rheological analysis was used to investigate the mechanical characteristics of the supramolecular Zn(ii)-metallogel. Field emission scanning electron microscopy and transmission electron microscopy were used to analyse the hexagonal shape morphological features of the Zn(ii)-metallogel. Interestingly, the electrical conductivity is observed in the electronic device with Zn(ii)-metallogel based metal-semiconductor (MS) junctions. All aspects of the metallogel's electrical properties were investigated. The electrical conductivity of the metallogel-based thin film device was 7.38 × 10^-5 S m^-1. The synthesised Zn(ii)-metallogel based device was investigated for its semi-conductive properties, such as its Schottky barrier diode nature.

A multistimulus-responsive self-healable supramolecular copper(ii)-metallogel derived from l-(+) tartaric acid: an efficient Schottky barrier diode

A low molecular weight gelator l-(+) tartaric acid- based self-healing supramolecular Cu(ii)-metallogel offers an electronic device of Schottky barrier diode at room temperature.

Chronic diarrhea - The poetic masquerade

Chronic diarrhea, by definition, is the passage of loose/liquid stools, with increased frequency (more than three times/day), or an output of over 200 g/day, lasting for a duration of four or more weeks. The clinical approach to identify the cause of chronic diarrhea generally depends on the local socioeconomic status. In high-income countries, systemic causes such as irritable bowel syndrome (IBS), inflammatory bowel disease, malabsorption syndromes (lactose intolerance/coeliac disease) are primarily considered. In mid- to low-income countries, infective causes like chronic bacterial, mycobacterial, fungal infections, HIV, bowel cancer are considered before systemic causes/malabsorption syndromes. Amyloidosis, more accurately, reactive amyloidosis is one of the rarer causes of chronic/persistent diarrhea. Inflammatory colitis secondary to POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes) as a cause for chronic diarrhea has been reported only in a handful of cases and is often missed. We present such a case of chronic diarrhea in a middle-aged man, who was eventually diagnosed to have POEMS syndrome.

Pattern of Glomerular Disease in a Tertiary Care Hospital of Bangladesh

Glomerular disease is one of the most important causes of chronic kidney disease in developing countries like Bangladesh as well as the whole world. The pattern of glomerular disease varies in different countries and can have different clinical presentations. The aim of the study was to analyze the clinical profile and to determine the histological pattern of glomerular diseases in a large tertiary care hospital in Bangladesh. All kidney biopsies performed in Mymensingh Medical College Hospital, Bangladesh from October 2018 to March 2020 were prospectively analyzed in the study. A total of 101 patients with kidney biopsy were examined by clinical and laboratory findings and by light and immuno-fluorescence microscopy. The mean age was 30.0±14.6 years and 50(49.5%) were male and 51(50.5%) were female with a male to female ratio of 1:1. The clinical syndromes namely nephrotic syndrome, nephritic syndrome, nephrito-nephrotic presentation, RPGN like presentation, macroscopic haematuria and asymptomatic urine abnormality were present in 31.7%, 34.5%, 22.8%, 11.9%, 19.8% and 10.9% patients respectively. The most common histological varieties found in the study were mesangial proliferative glomerulonephritis (MesPGN) (18.8%) and focal segmental glomerulosclerosis (FSGS) (18.8%). Other histopathological pattern among the studied subjects revealed minimal change disease (MCD) in 5.9%, membranous nephropathy (MN) in 7.9%, membranoproliferative glomerulonephritis (MPGN) in 16.8%, IgA nephropathy in 5%, IgM nephropathy in 2%, IgG nephropathy in 2%, diffuse proliferative glomerulonephritis (DPGN) in 1%, focal proliferative glomerulo-nephritis (FPGN) in 3%, crescentic GN in 3%, lupus nephritis (LN) in 13.9%, amyloidosis in 1% and fibrillary glomerulopathy in 1% patient. The pattern of glomerular disease found in this study was similar to other studies performed in Bangladesh with a little variation. It may guide the future researchers to establish a national kidney biopsy registry in Bangladesh.

0717 Peer-intervention Can Reduce Health Disparities In Patients With Obstructive Sleep Apnea

Introduction

In patients with obstructive sleep apnea (OSA), adherence to continuous positive airway pressure (CPAP) therapy is a major problem. Moreover, up to 20% of patients with suspected OSA who are referred to sleep study testing do not adhere to such diagnostic work-up. Although, peer-driven intervention with an interactive voice response system (PDI-IVR) can improve CPAP adherence, whether such an intervention can improve adherence to sleep study testing is unknown. Also, there remain health disparities with greater levels of CPAP nonadherence disproportionately affecting individuals of lower socioeconomic status. We aimed to determine whether PDI-IVR can improve adherence to sleep study testing and CPAP adherence in a lower income population.

Methods

We performed a prospective, randomized, parallel group, controlled trial wherein patients with suspected OSA were randomly assigned to receive PDI-IVR or provided with educational information regarding OSA and CPAP therapy (attention-control group) while both groups received usual care. The PDI-IVR interactions aimed at promoting adherence to sleep study testing and in patients diagnosed with OSA the peer-intervention was focused on improving CPAP adherence. In the PDI-IVR group, trained peers (peer-buddies) with OSA were paired with randomized patients over a 6-month period combined with an ability to meet in-person, email, text message, or phone an inter-disciplinary team of providers.

Results

In this pilot study, there were 63 patients (48.4 ± 12.5 years; 30 men) who were randomized to intervention (n=31) and attention-control (n=32) arms. There were 36 peer-buddies who mentored the patients in the intervention group. Intention to treat analysis revealed that failure to undergo sleep study testing was 15.6% of patients in the attention-control arm and 9.7% in the PDI-IVR arm (P=0.7). Per protocol analysis revealed that failure to undergo sleep study testing was 18.4% of patients in the attention-control arm and 4% in the PDI-IVR arm (P=0.13). At 6 months, CPAP adherence was greater in PDI-IVR arm (290 ± 45 min [SE]) than attention-control arm (181 ± 43 min; P=0.01).

Conclusion

In a lower income population, PDI-IVR improved CPAP adherence with a tendency for better adherence to sleep-study testing. Peer-intervention can reduce sleep health disparities.

Support

HL138377

Perfluoroarene induces a pentapeptidic hydrotrope into a pH-tolerant hydrogel allowing naked eye sensing of Ca2+ ions

Self-assembly of a novel thermoresponsive, pyrene-appended oligopeptide sequence VPGKP (PyP) leads to the formation of spherical aggregates in water. The sizes of the globular aggregates of the peptide, PyP, strongly depend on the temperature of its suspension in water and decrease with the decrease in temperature showing a lower critical solution temperature (LCST) phenomenon. Furthermore, a pyrene-octafluoronaphthalene (OFN) 'pair' has been used as a supramolecular synthon to induce hydrogelation of PyP in the presence of an equimolar amount of OFN via complementary quadrupole-quadrupole interactions. The gel shows excellent pH tolerance and thixotropic behavior. Detailed studies suggest the existence of lamellar packing of the gelators in a right-handed helical fashion which yields globular aggregates. The globular aggregates are sticky in nature and form a gel via inter-globular interactions. Addition of Ca2+ ions reinforces the mechanical strength and also reduces the critical gelator concentration of the native gel through coordination with the free -COO- group of the gelator. Therefore, the present hydrogel system could further be used as a naked eye sensor of Ca2+ ions.

Suppressing depolarization by tail substitution in an organic supramolecular ferroelectric

Despite being very well established in the field of electro-optics, ferroelectric liquid crystals so far lacked interest from a ferroelectric device perspective due to a typically high operating temperature, a modest remnant polarization and/or poor polarization retention. Here, we experimentally demonstrate how simple structural modification of a prototypical ferroelectric liquid-crystal benzene-1,3,5-trisamide (BTA) - introduction of branched-tail substituents - results in materials with a wide operating temperature range and a data retention time of more than 10 years in thin-film solution-processed capacitor devices at room temperature. The observed differences between linear- and branched-tail compounds are analyzed using density functional theory (DFT) and molecular dynamics (MD) simulations. We conclude that morphological factors like improved packing quality and reduced disorder, rather than electrostatic interactions or intra/inter-columnar steric hindrance, underlay the superior properties of the branched-tailed BTAs. Synergistic effects upon blending of compounds with branched and linear side-chains can be used to further improve the materials' characteristics.

Palladium-induced transformation of nematic liquid crystals to robust metallogel comprising self-assembled nanowires

Transformation of nematic liquid crystals to metallogels.

Homeotropic Self-Alignment of Discotic Liquid Crystals for Nanoporous Polymer Films

Nanostructured polymer films with continuous, membrane-spanning pores from polymerizable hexagonal columnar discotic liquid crystals (LCs) were fabricated. A robust alignment method was developed to obtain homeotropic alignment of columns between glass surfaces by adding a small amount of a tri(ethylene glycol) modified analogue of the mesogen as a dopant that preferentially wets glass. The homeotropic LC alignment was fixated via a photoinitiated free radical copolymerization of a high-temperature tolerant trisallyl mesogen with a divinyl ester. Removal of the hydrogen-bonded template from the aligned columns afforded a nanoporous network with pores of nearly 1 nm in diameter perpendicular to the surface, and without noticeable collapse of the nanopores. The effect of pore orientation was demonstrated by an adsorption experiment in which homeotropic film showed a threefold increase in the initial uptake rate of methylene blue compared to planarly aligned films.

Accuracy of quick Sequential Organ Failure Assessment (qSOFA) score and systemic inflammatory response syndrome (SIRS) criteria for predicting mortality in hospitalized patients with suspected infection: a meta-analysis of observational studies

OBJECTIVE

To identify sensitivity, specificity and predictive accuracy of quick sequential organ failure assessment (qSOFA) score and systemic inflammatory response syndrome (SIRS) criteria to predict in-hospital mortality in hospitalized patients with suspected infection.

METHODS

This meta-analysis followed the Meta-analysis of Observational Studies in Epidemiology (MOOSE) group consensus statement for conducting and reporting the results of systematic review. PubMed and EMBASE were searched for the observational studies which reported predictive utility of qSOFA score for predicting mortality in patients with suspected or proven infection with the following search words: 'qSOFA', 'q-SOFA', 'quick-SOFA', 'Quick Sequential Organ Failure Assessment', 'quick SOFA'. Sensitivity, specificity, area under receiver operating characteristic (ROC) curves with 95% confidence interval (CI) of qSOFA and SIRS criteria for predicting in-hospital mortality was collected for each study and a 2 × 2 table was created for each study.

RESULTS

Data of 406 802 patients from 45 observational studies were included in this meta-analysis. Pooled sensitivity (95% CI) and specificity (95% CI) of qSOFA ≥2 for predicting mortality in patients who were not in an intensive care unit (ICU) was 0.48 (0.41-0.55) and 0.83 (0.78-0.87), respectively. Pooled sensitivity (95% CI) of qSOFA ≥2 for predicting mortality in patients (both ICU and non-ICU settings) with suspected infection was 0.56 (0.47-0.65) and pooled specificity (95% CI) was 0.78 (0.71-0.83).

CONCLUSION

qSOFA has been found to be a poorly sensitive predictive marker for in-hospital mortality in hospitalized patients with suspected infection. It is reasonable to recommend developing another scoring system with higher sensitivity to identify high-risk patients with infection.

Pore size dependent cation adsorption in a nanoporous polymer film derived from a plastic columnar phase

Nanoporous polymer films were fabricated from a plastic columnar phase that showed pore size and shape (whether open or collapsed) dependent cation adsorption properties.

Bioconversion of fish solid waste into PHB using Bacillus subtilis based submerged fermentation process

Currently, one of the major problem affecting the world is solid waste management, predominantly petroleum-based plastic and fish solid waste (FSW). However, it is very difficult to reduce the consumption of plastic as well as fish products, but it is promising to convert FSW to biopolymer to reduce eco-pollution. On account of that, the bioconversion of FSW extract to polyhydroxybutyrate (PHB) was undertaken by using Bacillus subtilis (KP172548). Under optimized conditions, 1.62 g/L of PHB has been produced by the bacterium. The purified compound was further characterized by advanced analytical technologies to elucidate its chemical structure. Results indicated that the biopolymer was found to be PHB, the most common homopolymer of polyhydroxyalkanoates (PHAs). This is the first report demonstrating the efficacy of B. subtilis to utilize FSW extract to produce biopolymer. The biocompatibility of the PHB against murine macrophage cell line RAW264.7 demonstrated that, it was comparatively less toxic, favourable for surface attachment and proliferation in comparison with poly-lactic acid (PLA) and commercially available PHB. Thus, further exploration is highly indispensable to use FSW extract as a substrate for production of PHB at pilot scale.

Tailoring Pore Size and Chemical Interior of near 1 nm Sized Pores in a Nanoporous Polymer Based on a Discotic Liquid Crystal

A triazine based disc shaped molecule with two hydrolyzable units, imine and ester groups, was polymerized via acyclic diene metathesis in the columnar hexagonal (Colhex) LC phase. Fabrication of a cationic nanoporous polymer (pore diameter ∼1.3 nm) lined with ammonium groups at the pore surface was achieved by hydrolysis of the imine linkage. Size selective aldehyde uptake by the cationic porous polymer was demonstrated. The anilinium groups in the pores were converted to azide as well as phenyl groups by further chemical treatment, leading to porous polymers with neutral functional groups in the pores. The pores were enlarged by further hydrolysis of the ester groups to create ∼2.6 nm pores lined with -COONa surface groups. The same pores could be obtained in a single step without first hydrolyzing the imine linkage. XRD studies demonstrated that the Colhex order of the monomer was preserved after polymerization as well as in both the nanoporous polymers. The porous anionic polymer lined with -COOH groups was further converted to the -COOLi, -COONa, -COOK, -COOCs, and -COONH4 salts. The porous polymer lined with -COONa groups selectively adsorbs a cationic dye, methylene blue, over an anionic dye.

3-Amino-4-aminoximidofurazan derivatives: small molecules possessing antimicrobial and antibiofilm activity against Staphylococcus aureus and Pseudomonas aeruginosa

AIM

The therapeutic treatment of microbial infections involving biofilm becomes quite challenging because of its increasing antibiotic resistance capacities. Towards this direction, in the present study we have evaluated the antibiofilm property of synthesized 3-amino-4-aminoximidofurazan compounds having polyamine skeleton. These derivatives were synthesized by incorporating furazan and biguanide moieties.

METHODS AND RESULTS

Different 3-amino-4-aminoximidofurazan derivatives (PI1-4) were synthesized via protic acid catalysis and subsequently characterized by (1) H NMR and (13) C NMR spectra, recorded at 400 and 100 MHz respectively. We have tested the antimicrobial and antibiofilm activities of these synthetic derivatives (PI1-4) against both Staphylococcus aureus and Pseudomonas aeruginosa. The compounds so tested were also compared with standard antibiotics namely Tobramycin (Ps. aeruginosa) and Azithromycin (Staph. aureus) which were used as a positive control in all experimental sets. All these compounds (PI1-4) exhibited moderate to significant antimicrobial activities against both micro-organisms wherein compound PI3 showed maximum activity. Biofilm inhibition of both micro-organisms was then evaluated by crystal violet and safranin staining, estimation of biofilm total protein and microscopy methods using sub-MIC dose of these compounds. Results showed that all compounds executed anti biofilm activity against both Staph. aureus and Ps. aeruginosa wherein compound PI3 exhibited maximum activity. In relation with microbial biofilm inhibition, we have observed reduction in bacterial motility, proteolytic activity and secreted exo-polysaccharide (EPS) from both Staph. aureus and Ps. aeruginosa when they were grown in presence of these compounds. While addressing the issue of toxicity on host, we have observed that these molecules exhibited minimum level of R.B.C degradation.

CONCLUSION

These findings establish the antibacterial and anti biofilm properties of 3-amino-4-aminoximidofurazan derivatives (PI1-4).

SIGNIFICANCE AND IMPACT OF THE STUDY

Therefore, our current findings demonstrate that 3-amino-4-aminoximidofurazan derivatives (PI1-4) may hold promise to be effective biofilm and microbial inhibitors that may be clinically significant.

Multilevel programming in Cu/NiO y /NiO x /Pt unipolar resistive switching devices

The application of a NiO y /NiO x bilayer in resistive switching (RS) devices with x > y was studied for its ability to achieve reliable multilevel cell (MLC) characteristics. A sharp change in resistance brought about by sweeping the voltage, along with an improved on/off ratio (>10(3)) and endurance (10(4)) were achieved in the bilayer structure as compared to the single NiO x layer devices. Moreover, it was found that nonvolatile and stable resistance levels, especially the multiple low-resistance states of Cu/NiO y /NiO x /Pt memory devices, could be controlled by varying the compliance current. All the multilevel resistance states of the Cu/NiO y /NiO x /Pt bilayer devices were stable for up to 500 consecutive dc switching cycles, as compared to the Cu/NiO x /Pt single layer devices. The temperature-dependent variation of the high and low resistance states of both the bilayer and single layer devices was further investigated to elucidate the charge conduction mechanism. Finally, based on a detailed analysis of the experimental results, comparisons of the possible models for RS in bilayer and single layer memory devices have also been discussed.

Proximate Kitaev quantum spin liquid behaviour in a honeycomb magnet

Quantum spin liquids (QSLs) are topological states of matter exhibiting remarkable properties such as the capacity to protect quantum information from decoherence. Whereas their featureless ground states have precluded their straightforward experimental identification, excited states are more revealing and particularly interesting owing to the emergence of fundamentally new excitations such as Majorana fermions. Ideal probes of these excitations are inelastic neutron scattering experiments. These we report here for a ruthenium-based material, α-RuCl3, continuing a major search (so far concentrated on iridium materials) for realizations of the celebrated Kitaev honeycomb topological QSL. Our measurements confirm the requisite strong spin-orbit coupling and low-temperature magnetic order matching predictions proximate to the QSL. We find stacking faults, inherent to the highly two-dimensional nature of the material, resolve an outstanding puzzle. Crucially, dynamical response measurements above interlayer energy scales are naturally accounted for in terms of deconfinement physics expected for QSLs. Comparing these with recent dynamical calculations involving gauge flux excitations and Majorana fermions of the pure Kitaev model, we propose the excitation spectrum of α-RuCl3 as a prime candidate for fractionalized Kitaev physics.

First report of charge-transfer induced heat-set hydrogel. Structural insights and remarkable properties

The remarkable ability of a charge-transfer (CT) complex prepared from a pyrene-based donor (Py-D) and a naphthalenediimide-based acceptor (NDI-A) led to the formation of a deep-violet in color, transparent hydrogel at room temperature (RT-gel). Simultaneously, the RT-gel was diluted beyond its critical gelator concentration (CGC) to obtain a transparent sol. Very interestingly, the resultant sol, on heating above 70 °C, transformed into a heat-set gel instantaneously with a hitherto unknown CGC value. Detailed studies revealed the smaller globular aggregates of the RT-gels fuse to form giant globules upon heating, which, in turn, resulted in heat-set gelation through further aggregation. The thermoresponsive property of Py-D alone and 1 : 1 Py-D : NDI-A CT complex was investigated in detail which revealed the hydrophobic collapse of the oxyethylene chains of the CT complex upon heating was mainly responsible for heat-set gelation. Thixotropy, injectability, as well as stimuli responsiveness of the RT-gels were also addressed. In contrast, heat-set gel did not show thixotropic behavior. The X-ray diffraction (XRD) patterns of the xerogel depicted lamellar packing of the CT stacks in the gel phase. Single crystal XRD studies further evidenced the 1 : 1 mixed CT stack formation in the lamellae and also ruled out orthogonal hydrogen bonding possibilities among the hydrazide unit in the CT gel although such interaction was observed in a single crystal of NDI-A alone. In addition, a Ag(+)-ion triggered metallogelation of NDI-A and nematic liquid-crystalline property of Py-D were also observed.

Remarkable Role of C-I···N Halogen Bonding in Thixotropic 'Halo'gel Formation

Halogen-bonding-induced self-assembly in the solution of equimolar mixtures of certain pyridyl-ended oligo p-phenylenevinylene (OPV)-derivatives with 1,4-diiodotetrafluorobenzene is reported. The mode of self-assembly, that is, cocrystallization, thixotropic gelation, or precipitation, depends strongly on the nature of chains (n-alkyl chains as a function of length or short oxyethylene chain) appended to the OPV-backbone as well as on the cooling rate of the corresponding hot solution. Single-crystal X-ray diffraction studies of the cocrystals reveal the "infinite" chain formation via C-I···N halogen-bonding interactions between the two components. In addition, multiple noncovalent interactions induce cross-links among these halogen-bonded "infinite" chains. Interestingly, the molecular packing in the "Cogel" bearing OPV-derivative with oxyethylene chains is found to be very similar to that of the cocrystal of the same.