Biofilm-i: A Platform for Predicting Biofilm Inhibitors Using Quantitative Structure—Relationship (QSAR) Based Regression Models to Curb Antibiotic Resistance

Antibiotic drug resistance has emerged as a major public health threat globally. One of the leading causes of drug resistance is the colonization of microorganisms in biofilm mode. Hence, there is an urgent need to design novel and highly effective biofilm inhibitors that can work either synergistically with antibiotics or individually. Therefore, we have developed a recursive regression-based platform “Biofilm-i” employing a quantitative structure–activity relationship approach for making generalized predictions, along with group and species-specific predictions of biofilm inhibition efficiency of chemical(s). The platform encompasses eight predictors, three analysis tools, and data visualization modules. The experimentally validated biofilm inhibitors for model development were retrieved from the “aBiofilm” resource and processed using a 10-fold cross-validation approach using the support vector machine and andom forest machine learning techniques. The data was further sub-divided into training/testing and independent validation sets. From training/testing data sets the Pearson’s correlation coefficient of overall chemicals, Gram-positive bacteria, Gram-negative bacteria, fungus, Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans, and Escherichia coli was 0.60, 0.77, 0.62, 0.77, 0.73, 0.83, 0.70, and 0.71 respectively via Support Vector Machine. Further, all the QSAR models performed equally well on independent validation data sets. Additionally, we also checked the performance of the random forest machine learning technique for the above datasets. The integrated analysis tools can convert the chemical structure into different formats, search for a similar chemical in the aBiofilm database and design the analogs. Moreover, the data visualization modules check the distribution of experimentally validated biofilm inhibitors according to their common scaffolds. The Biofilm-i platform would be of immense help to researchers engaged in designing highly efficacious biofilm inhibitors for tackling the menace of antibiotic drug resistance.     

Silica Nanospheres Coated Silver Islands as an Effective Opto-Plasmonic SERS Active Platform for Rapid and Sensitive Detection of Prostate Cancer Biomarkers

The in vitro diagnostics of cancer are not represented well yet, but the need for early-stage detection is undeniable. In recent decades, surface-enhanced Raman spectroscopy (SERS) has emerged as an efficient, adaptable, and unique technique for the detection of cancer molecules in their early stages. Herein, we demonstrate an opto-plasmonic hybrid structure for sensitive detection of the prostate cancer biomarker sarcosine using silica nanospheres coated silver nano-islands as a facile and efficient SERS active substrate. The SERS active platform has been developed via thin (5–15 nm) deposition of silver islands using a simple and cost-effective Radio Frequency (RF) sputtering technique followed by the synthesis and decoration of silica nanospheres (~500 nm) synthesized via Stober’s method. It is anticipated that the coupling of Whispering Gallery Modes and photonic nano-jets in SiO₂ nanospheres induce Localized Surface Plasmon Resonance (LSPR) in Ag nano-islands, which is responsible for the SERS enhancement. The as-fabricated SERS active platform shows a linear response in the physiological range (10 nM to 100 μM) and an extremely low limit of detection (LOD) of 1.76 nM with a correlation coefficient of 0.98 and enhancement factor ~2 × 10⁷. The findings suggest that our fabricated SERS platform could be potentially used for the rapid detection of bio-chemical traces with high sensitivity.     

Binegativity of two qubits under noise

Recently, it was argued that the binegativity might be a good quantifier of entanglement for two-qubit states. Like the concurrence and the negativity, the binegativity is also analytically computable quantifier for all two qubits. Based on numerical evidence, it was conjectured that it is a PPT (positive partial transposition) monotone and thus fulfills the criterion to be a good measure of entanglement. In this work, we investigate its behavior under noisy channels which indicate that the binegativity is decreasing monotonically with respect to increasing noise. We also find that the binegativity is closely connected to the negativity and has closed analytical form for arbitrary two qubits. Our study supports the conjecture that the binegativity is a monotone.     

A new and facile route for the synthesis of chiral 1,2-diamines and 2,3-diamino acids

The synthesis of chiral diamines and diamino acids has been achieved from the corresponding N-arylsulfonyl aziridines through reaction with a chiral isocyanate and subsequent hydrolysis of 2-imidazolidinones. The method appears to be general and of wide applicability.     

Conjugate polymer-based membranes for gas separation applications: current status and future prospects

Conjugate polymers provide the possibility of exploiting both the chemical and physical attributes of the polymers for membrane-based gas separation. The presence of delocalized π electrons provides high chain stiffness with low packing density, thus making the membrane a rigid structure that favors facilitated transport. Historically, the polymeric membranes were constrained by the tradeoff relationship between gas permeability and gas selectivity. So, different methods were investigated to prepare the membranes that can overcome the limitation. In recent years, electroconductive polymeric membranes have gained attention with their enhanced transportation properties combining the separation behavior depending on both molecular size discrimination as well as the facilitated transport. They offer better selectivity toward polar gases such as CO₂ because of the increased solubility. This review is aimed to provide a literature survey on gas separation using conjugate polymers such as polyaniline, polypyrrole, and some derivatives of polythiophenes. It contains various methods used by different researchers to enhance the gas separation properties of the membranes with improved mechanical and thermal stability such as changing the morphology and membrane preparation methods. In addition, it provides the pros and cons of various factors affecting the conjugate polymer membrane performance. The major challenges and future work that can be done in improving the transportation properties through the membrane to achieve viable membranes are also discussed so that they can be used for commercial and practical applications in the future.     

Palladium-catalyzed cross-coupling reactions between dihydropyranylindium reagents and aryl halides. synthesis of C-aryl glycals

[reaction: see text] Palladium(0)-catalyzed cross-coupling reactions between tris(dihydropyranyl)indium 1 and aryl halides 2 have been investigated. Aryl iodides and electron-deficient aryl bromides couple efficiently with the in situ-generated indium reagents in the presence of 1-5 mol % Cl(2)Pd(PPh(3))(2) to produce substituted dihydropyrans 3 with minimal (<10%) dimer (4) formation. Organoindium reagents derived from D-glucal also undergo cross couplings with aryl iodides to produce C-aryl glycals.     

Ionic liquid-promoted one-pot oxidative Michael addition of TMSCN to Baylis-Hillman adducts

The first example of ionic liquid-promoted one-pot oxidative conjugate hydrocyanation of Baylis-Hillman adducts with trimethylsilyl cyanide (TMSCN) is reported. The oxidation of Baylis-Hillman adducts with IBX/[bmim]Br or isomerization-oxidation with NaNO₃/[Hmim]HSO₄ systems affords β-ketomethylene compounds or [E]-cinnamaldehydes, respectively. These α,β-unsaturated carbonyl compounds undergo Michael addition with TMSCN in the same vessel to afford the corresponding thermodynamically more stable β-cyanated products. Thermodynamically less stable 1,2-addition products were not formed. The present regioselective reactions are promoted by ionic liquids, which can be recycled easily for further use without any loss of efficiency.     

Dirhenium carbonyl complexes bearing 2-vinylpyridine,morpholine and 1-methylimidazole ligands

Treatment of the labile compound [Re₂(CO)₈(MeCN)₂] with 2-vinylpyridine in refluxing benzene affords exclusively the new compound [Re₂(CO)₈(μ-η¹:η²-NC₅H₄CHCH₂)] (1) in 39% yield in which the μ-η¹:η²-vinylpyridine ligand is coordinated to one Re atom through the nitrogen and to the other Re atom via the olefinic double bond. Reaction of [Re₂(CO)₈(MeCN)₂] with morpholine in refluxing benzene furnishes two compounds, [Re₂(CO)₉(η¹-NC₄H₉O)] (2) and [Re₂(CO)₈(η¹-NC₄H₉O)₂] (3) in 5% and 29% yields, respectively. Reaction of [Re₂(CO)₈(MeCN)₂] with 1-methylimidazole gives [Re₂(CO)₈{η¹-NC₃H₃N(CH₃)}₂] (4) and the mononuclear compound fac-[ReCl(CO)₃{η¹-NC₃H₃N(CH₃)}₂] (5) in 18% and 26% yields, respectively. In the disubstituted compounds 2 and 4, the heterocyclic ligands occupy equatorial coordination sites. The mononuclear compound 5 consists of three CO groups, two N coordinated η¹-1-methylimidazole ligands and a terminal Cl ligand. The XRD structures of complexes 1, 3 and 5 are reported.     

Photophysical and theoretical investigations on fullerene/phthalocyanine supramolecular complexes

The present paper reports the photophysical aspects of a very interesting and unique host-guest interaction between fullerene and phthalocyanines, viz., free base phthalocyanine (H2-Pc) and zinc-phthalocyanine (Zn-Pc), in toluene medium. Ground state electronic interaction between these two supramolecules has been evidenced from the observation of well-defined charge transfer (CT) absorption bands in the visible region. Vertical ionization potentials of the phthalocyanines have been determined utilizing CT transition energy. Magnitude of degrees of CT reveals that, in the ground state, 2-4% CT takes place. Binding constants (K) for the fullerene/phthalocyanine complexes were determined from the fluorescence quenching experiment. Large K values in the ranges approximately 4.7 x 10(4) to 7.3 x 10(4) and 2.3 x 10(4) to 2.5 x 10(4) dm(3) x mol(-1) were obtained for the 1:1 fullerene complexes of Zn and H 2-Pc, respectively. Values of K suggest that both H 2- and Zn-Pc could not serve as an efficient discriminators between C60 and C70. Theoretical calculations as well as (13)C NMR studies establish that the orientation of C 70 toward phthalocyanine is favored in end-on orientation, which proves that interaction between fullerenes and phthalocyanines were governed by the electrostatic mechanism rather than dispersive forces associated with pi-pi interaction.