Changes in high-order interaction measures of synergy and redundancy during non-ordinary states of consciousness induced by meditation, hypnosis, and auto-induced cognitive trance.

High-order interactions are required across brain regions to accomplish specific cognitive functions. These functional interdependencies are reflected by synergistic information that can be obtained by combining the information from all the sources considered and redundant information (i.e., common information provided by all the sources). However, electroencephalogram (EEG) functional connectivity is limited to pairwise interactions thereby precluding the estimation of high-order interactions. In this multicentric study, we used measures of synergistic and redundant information to study in parallel the high-order interactions between five EEG electrodes during three non-ordinary states of consciousness (NSCs): Rajyoga meditation (RM), hypnosis, and auto-induced cognitive trance (AICT). We analyzed EEG data from 22 long-term Rajyoga meditators, nine volunteers undergoing hypnosis, and 21 practitioners of AICT. We here report the within-group changes in synergy and redundancy for each NSC in comparison with their respective baseline. During RM, synergy increased at the whole brain level in the delta and theta bands. Redundancy decreased in frontal, right central, and posterior electrodes in delta, and frontal, central, and posterior electrodes in beta1 and beta2 bands. During hypnosis, synergy decreased in mid-frontal, temporal, and mid-centro-parietal electrodes in the delta band. The decrease was also observed in the beta2 band in the left frontal and right parietal electrodes. During AICT, synergy decreased in delta and theta bands in left-frontal, right-frontocentral, and posterior electrodes. The decrease was also observed at the whole brain level in the alpha band. However, redundancy changes during hypnosis and AICT were not significant. The subjective reports of absorption and dissociation during hypnosis and AICT, as well as the mystical experience questionnaires during AICT, showed no correlation with the high-order measures. The proposed study is the first exploratory attempt to utilize the concepts of synergy and redundancy in NSCs. The differences in synergy and redundancy during different NSCs warrant further studies to relate the extracted measures with the phenomenology of the NSCs.

Polymerizable sol-gel synthesis of dark-visible light antibacterial magnetically-recoverable AgBr-loaded iron oxide/alumina nanocomposite.

The demand for a facile approach for synthesizing multifunctional nanocomposites is increasingly vital across diverse applications. In this study, a polymerizable sol-gel synthesis has been reported to obtain nanocomposites of magnetic iron oxide deposited over alumina nanopowder. The synthesis is mediated by the deposition of a calculated amount of iron(III) methacrylate, along with ethylene glycol dimethacrylate crosslinker, over alumina nanopowder, followed by thermally-inducing free radical polymerization at 125 °C for 30 min. The powder thus obtained has been subjected to calcination at 400 °C for 150 min and the resultant nanocomposites were characterized using wide-angle x-ray scattering, attenuated total reflectance-Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy, field-emission scanning electron microscopy, ultraviolet-diffuse reflectance spectroscopy, vibrating sample magnetometer and Brunauer-Emmett-Teller surface area measurements. The nanocomposites containing 15 and 20 wt% of iron oxide have been found to exhibit a saturation magnetization (Ms) value ranging from 12 to 14 emu g-1. To the nanocomposite containing 20 wt% of iron oxide, 5 wt% of AgBr was loaded through thoroughly mixing a surfactant-based precursor, silver-tetraoctyl ammonium bromide (Ag-TOAB), followed by thermolysis. All the nanocomposites have been studied for their antibacterial activity against a representative gram-negative bacterium,Escherichia coli, under dark and visible light conditions. While a 3 mg ml-1loading of the AgBr-loaded nanocomposite has exhibited complete clearance of the bacterial growth by 90 min in the dark, a similar activity has been observed in 60 min under light. The study has revealed the multifunctionality and high potential of the AgBr-loaded iron oxide/alumina nanocomposite as a promising dual-mode antibacterial and magnetically recoverable photocatalyst material.

Patterning at the Resolution Limit of Commercial Electron Beam Lithography.

It has been long known that low molecular weight resists can achieve a very high resolution, theoretically close to the probe diameter of the electron beam lithography (EBL) system. Despite technological improvements in EBL systems, the advances in resists have lagged behind. Here we demonstrate that a low-molecular-mass single-source precursor resist (based on cadmium(II) ethylxanthate complexed with pyridine) is capable of a achieving resolution (4 nm) that closely matches the measured probe diameter (∼3.8 nm). Energetic electrons enable the top-down radiolysis of the resist, while they provide the energy to construct the functional material from the bottom-up─unit cell by unit cell. Since this occurs only within the volume of resist exposed to primary electrons, the minimum size of the patterned features is close to the beam diameter. We speculate that angstrom-scale patterning of functional materials is possible with single-source precursor resists using an aberration-corrected electron beam writer with a spot size of ∼1 Å.

Naked-eye colorimetric detection of HCV RNA mediated by a 5' UTR-targeted antisense oligonucleotide and plasmonic gold nanoparticles.

The increasing incidence of hepatitis C viral (HCV) infection worldwide is a major concern for causing liver cirrhosis and hepatocellular carcinoma, leading to increased morbidity and mortality. Currently, the prevalence of HCV infection is estimated to be in the range of ∼3%. According to the World Health Organization, antiviral drugs can cure more than 95% of the HCV infected cases, if timely diagnosis and treatment are provided. The gold standard RT-qPCR assay is expensive and requires a minimum turnaround time of 4 h. Hence, a rapid and cost-effective detection assay that can be used even in resource-limited settings would be highly beneficial for mass level screening. Herein, we present an Au NP based facile strategy for rapid, early-stage, and sensitive detection of HCV RNA in clinical samples which avoids thiol tagging to the antisense oligonucleotide and expensive infrastructure. This technique utilizes the hybridization of a short-chain antisense oligonucleotide from the 5' untranslated region (UTR) of the viral genome with the isolated HCV RNA samples. Using a specific sequence universal to all HCV genotypes-obtained through the NCBI BLASTn tool-the HCV positive samples have stabilized the citrate capped Au NPs against salt-induced aggregation, retaining their red color. On the other hand, negative controls, including HBV and HIV positive samples, do not stabilize the Au NPs, which results in purple coloration. Besides, the assay is successfully tested with a RNase A enzyme-treated HCV positive sample, which does not stabilize the Au NPs, thus confirming the role of the viral HCV RNA in this strategy. This Au NP based assay takes about 30 min using the viral RNA isolate and has high specificity with a detection limit of 100 IU mL-1, which is ∼10 fold lower than the state-of-the-art Au NP based strategy.

Genotyping simplified: rationally designed antisense oligonucleotide-mediated PCR amplification-free colorimetric sensing of viral RNA in HCV genotypes 1 and 3.

Molecular diagnosis of viral genotyping devoid of polymerase chain reaction (PCR) amplification in clinical cohorts has hitherto been challenging. Here we present a simplified molecular diagnostic strategy for direct genotyping of hepatitis C virus (HCV) 1 and 3 (prevalent worldwide) using a combination of rationally designed genotype-specific antisense oligonucleotides (ASOs) and plasmonic gold nanoparticles. The ASOs specific to genotypes 1 and 3 have been designed from the nonstructural region 5A (NS5A) of the viral genome using the ClustalW multiple sequence alignment tool. A total of 79 clinical samples including 18 HCV genotype 1, 18 HCV genotype 3, one HIV positive, one HBV positive, and 41 healthy controls have been tested against both the designed ASOs. The study reveals 100% specificity and sensitivity with the employed samples and thereby opens up new avenues for PCR-free direct genotyping of other viruses as well, through the rational design of ASOs.

Effects of free patchy ends in ssDNA and dsDNA on gold nanoparticles in a colorimetric gene sensor for Hepatitis C virus RNA.

The presence or absence and nature of the free patchy ends in DNA sequences has a decisive effect on the performance of colorimetric sensors based on the use of gold nanoparticles (Au NPs). The authors have designed two unmodified gene probes (probe 1: a 19-mer; probe 2: an 18-mer). They are complementary to either half of a 37-mer target derived from the conserved region of Hepatitis C Virus (HCV) RNA. Each probe has further been modified with 10-mer poly(A) and thiol-functionalized 10-mer poly(A) at the 5' positions. Nine combinations of probe and HCV RNA were then designed to investigate the effect of free patchy ends on the stability of citrate-modified Au NPs against salt-induced aggregation which lead to color change from red to blue. The aggregation of Au NPs can be monitored by ratiometric spectroscopy at wavelengths of 520 and 700 nm. The differentiation between HCV RNA and control has also been studied by varying the concentration of probe and analyte. The particle size and zeta potentials were determined before and after aggregation. It is demonstrated that the change in surface charge density of the Au NPs governs the critical coagulation concentration of NaCl. The method presented here can be used to quantify HCV RNA in the 370 nM to 3 µM concentration range, and the detection limit is 500 nM. The results obtained with Au NPs that are chemically non-conjugated with the oligonucleotides have been found to be valuable in rationally devising the design rules for rapid and efficient colorimetric sensing of oligonucleotides. Graphical abstract Schematic representation of the nine combinatorial pairs of oligonucleotides that vary in the length of patchy ends and their position to unearth their effect in rapid gold nanoparticle-based colorimetric gene sensing without time-consuming and expensive thiol-conjugation step.

Amplifying bactericidal activity: Surfactant-mediated AgBr thin film coating over two-dimensional vertically aligned ZnO nanorods for dark-light dual mode disinfection.

Thin film coatings with potent antibacterial properties find critical applications in diverse domains such as medical devices, frequently touched surfaces, and food packaging for combating microbial proliferation across diverse scenarios. Two-dimensional photocatalytic antimicrobial coatings, offering a substantial actual-to-apparent surface ratio, hold immense potential for achieving this objective. However, realizing antibacterial performance not just under light but also in dark conditions remains a challenge. To address this, we present AgBr-coated vertically aligned ZnO nanorods (NRs) thin film architecture, employing a unique surfactant-mediated solution-phase spin-coating approach for achieving uniform deposition of AgBr onto ZnO NRs. The resulting ZnO NRs/AgBr heterojunction architectures have been characterized for their microstructural, morphological, elemental, optical, and wettability attributes. The studies have ascertained the tunability of AgBr content by modulating the concentration of its surfactant-based precursor solution. Further, valence band (VB) analyses revealed an increase in the electron density near to the VB edge. The dual role of AgBr as an antimicrobial agent and a photosensitizer, effectively enhancing the visible-light photodisinfection efficacy of ZnO NRs, has been evident through the dark-light dual mode antibacterial studies. Electron paramagnetic resonance measurements have shown hydroxyl radicals being majorly responsible for the visible-light photodisinfection performance. Encouragingly, reusability assessments showcase significant promise, while artificial sweat-wiping studies on the structures unveil heightened photodisinfection efficacy. This enhancement could be attributed to components like urea and lactic acid, speculated to augment the photocatalytic efficiency by minimizing charge recombination.

Overcoming microbial resuscitation using stable ultrafine gold nanosystems.

While ultrafine gold nanosystems (UGNs) are being extensively studied for their antimicrobial activities, hitherto, no report is available on their propensity towards mitigating bacterial resuscitation-a potential factor contributing to the antimicrobial resistance. The investigations herein with two categories of gold nanosystems-modulated for their stability and surface accessibility through glutathione capping-have provided insights into overcoming resuscitation. Additionally, the study cautions that even moderate resistance development in bacteria exposed to nanosystems can result in significant cross-resistance against conventional antibiotics.

Probing the Effects of Antimicrobial-Lysozyme Derivatization on Enzymatic Degradation of Poly(ε-caprolactone) Film and Fiber.

Surface derivatization is essential for incorporating unique functionalities into biodegradable polymers. Nonetheless, its precise effects on enzymatic biodegradation still lack comprehensive understanding. In this study, a facile solution-based method is employed to surface derivatize poly(ε-caprolactone) films and electrospun fibers with lysozyme, aiming to impart antimicrobial properties and examine the impact on enzymatic degradation. The derivatized films and fibers have shown high antibacterial efficacy against Escherichia coli and Staphylococcus aureus. Through gravimetric analysis, it is observed that the degradation rate experiences a slight decrease upon lysozyme derivatization. However, this reduction is effectively countered by the inclusion of Tween-20, as affirmed by isothermal titration calorimetry. Comparing films and fibers, the latter undergoes degradation at a more accelerated pace, coupled with a rapid decline in molecular weight. This study provides valuable insights into the factors influencing the degradation of surface-derivatized biopolymers through electrospinning, offering a simple strategy to mitigate biomaterial-associated infections.

Bio-inspired artificial synapse for neuromorphic computing based on NiO nanoparticle thin film.

The unprecedented need for data processing in the modern technological era has created opportunities in neuromorphic devices and computation. This is primarily due to the extensive parallel processing done in our human brain. Data processing and logical decision-making at the same physical location are an exciting aspect of neuromorphic computation. For this, establishing reliable resistive switching devices working at room temperature with ease of fabrication is important. Here, a reliable analog resistive switching device based on Au/NiO nanoparticles/Au is discussed. The application of positive and negative voltage pulses of constant amplitude results in enhancement and reduction of synaptic current, which is consistent with potentiation and depression, respectively. The change in the conductance resulting in such a process can be fitted well with double exponential growth and decay, respectively. Consistent potentiation and depression characteristics reveal that non-ideal voltage pulses can result in a linear dependence of potentiation and depression. Long-term potentiation (LTP) and Long-term depression (LTD) characteristics have been established, which are essential for mimicking the biological synaptic applications. The NiO nanoparticle-based devices can also be used for controlled synaptic enhancement by optimizing the electric pulses, displaying typical learning-forgetting-relearning characteristics.

Direct experimental evidence for the boronic acid-mediated bridging of DNA hybrids.

The use of terminal deoxynucleotidyl transferase for the first time in a mechanistic exploration-through colorimetric sensing and isothermal titration calorimetric studies-has provided direct experimental evidence of a boronic acid moiety bridging two DNA duplexes via the 3' hydroxyl groups, offering new opportunities and insights into the domain of DNA (nano)biotechnology.

Direct nanoimprint lithography of Al2O3 using a chelated monomer-based precursor.

Nanostructuring of Al2O3 is predominantly achieved by the anodization of aluminum film and is limited to obtaining porous anodized aluminum oxide (AAO). One of the main restrictions in developing approaches for direct fabrication of various types of Al2O3 patterns, such as lines, pillars, holes, etc, is the lack of a processable aluminum-containing resist. In this paper, we demonstrate a stable precursor prepared by reacting aluminum tri-sec-butoxide with 2-(methacryloyloxy)ethyl acetoacetate, a chelating monomer, which can be used for large area direct nanoimprint lithography of Al2O3. Chelation in the precursor makes it stable against hydrolysis whilst the presence of a reactive methacrylate group renders it polymerizable. The precursor was mixed with a cross-linker and their in situ thermal free-radical co-polymerization during nanoimprinting rigidly shaped the patterns, trapped the metal atoms, reduced the surface energy and strengthened the structures, thereby giving a ~100% yield after demolding. The imprinted structures were heat-treated, leading to the loss of organics and their subsequent shrinkage. Amorphous Al2O3 patterns with line-widths as small as 17 nm were obtained. Our process utilizes the advantages of sol-gel and methacrylate routes for imprinting and at the same time alleviates the disadvantages associated with both these methods. With these benefits, the chelating monomer route may be the harbinger of the universal scheme for direct nanoimprinting of metal oxides.

Single EOG channel performs well in distinguishing sleep from wake state for both healthy individuals and patients.

Using a single EOG channel, sleep-wake states of patients with different sleep disorders are accurately classified. We used polysomnography data of 27 patients (mixed apnea, periodic limb movement syndrome, sleep apnea-hypopnea syndrome, and dyssomnia) from DRMS-PAT and 20 healthy subjects from DRMS-SUB databases. We extracted a 67-dimensional feature vector, involving statistical features derived from ensemble empirical mode decomposition, approximate entropy, and relative powers in different frequency bands. Of these, the most relevant features are selected by exploiting mutual information between the features and corresponding labels. RUSBoost classifier is deployed to take care of the unbalanced data distribution. We achieved a high sensitivity of 97.5% and 95.3% as well as high specificity of 96.4% and 93.3% for sleep state in healthy and patients' groups, respectively. Ten-fold crossvalidation accuracies of 91.6% and 95% are achieved for patients and healthy individuals, respectively, using a single EOG channel. Clinical relevance-Accurate detection of sleep-wake states is crucial for the diagnosis of various sleep disorders including apnea-hypopnea syndrome and insomnia. Automated sleep-wake classification using EOG facilitates easy and convenient long-term sleep monitoring of patients without disturbing their sleep, thereby assisting the clinicians to analyze their sleeping patterns.

Assessment of submentalis muscle activity for sleep-wake classification of healthy individuals and patients with sleep disorders.

This work proposes a method utilizing only the submentalis EMG channel for the classification of sleep and wake states among the healthy individuals and patients with various sleep disorders such as sleep apnea hypopnea syndrome, dyssomnia, etc. We extracted autoregressive model parameters, discrete wavelet transform coefficients, Hjorth's complexity and mobility, relative bandpowers, Poincaré plot descriptors and statistical features from the EMG signal. We also used the energy of each epoch as a feature to distinguish between the sleep and wake states. Mutual information based feature selection approach was considered to obtain the top 25 features which provided maximum accuracy. For classification, we employed an ensemble of decision trees with random undersampling and boosting technique to deal with the class-imbalance problem in the sleep data. We achieved an overall accuracy of about 85% for the healthy population and about 70% on an average across different pathological groups. This work shows the potential of EMG chin activity for sleep analysis. Clinical Relevance- Automatic and reliable sleep-wake classification can reduce the burden of sleep experts in analyzing overnight sleep data (~ 8 hours) and also assist them to diagnose various neurological disorders at an early stage. Utilizing EMG channel provides an easier and convenient long-term recording of data without causing much disturbance in sleepunlike EEG which is inconvenient and hampers the natural sleep.

Fluorescence-based simultaneous dual oligo sensing of HCV genotypes 1 and 3 using magnetite nanoparticles.

Nucleic acid tests (NATs) have gained an important position in biosensing in the context of the increasing need to meet the stringent requirements for accurate diagnosis of infectious diseases with high sensitivity and selectivity. Recently, the development of new strategies towards multiplex detection of analytes in a single assay is gaining impetus since such an approach would lead to high throughput analysis, leading to substantial benefits in terms of time, infrastructure, labor, and cost. In this work, we demonstrate a facile fluorescence-based simultaneous dual oligo sensing of genotypes 1 and 3 by employing two target sequences (36-mers each) derived from the NS4B and NS5A regions of HCV genome, respectively. A set of 18-mer amine-tagged probes and another set of 18-mer fluorescently-labeled probes that were complementary to each half of the 36-mer target sequences were designed. The amine-tagged probes were immobilized over aldehyde-derivatized magnetite nanoparticles (NPs) via imine bond formation, which was characterized using X-ray photoelectron spectroscopy (XPS) and energy dispersive spectroscopy (EDS) mapping techniques. The successful hybridization between the two probes with their target followed by magnetic removal of the NPs from the solution enabled quantitative analysis of the target by measuring the fluorescence intensity of the residual concentration of the fluorescently-tagged probe. In this manner, the targets corresponding to genotypes 1 and 3 were simultaneously detected with the detection limit in the range of 10-15 nM. The current strategy can potentially be amalgamated with existing nanotechnology-based techniques towards multiplex oligo sensing of several pathogens.

Boronic acid chemistry for fluorescence-based quantitative DNA sensing.

Contrary to the long-standing opinion of boronic acids being typically reactive with 1,2- and 1,3-diols and hence not suitable for quantitative sensing of DNA containing only a mono-ol unit, this proof-of-concept study has successfully shown the feasibility to quantitatively detect DNA in the concentration range of 5 to 50 nM plausibly through boronic acid-mediated bridging of two DNA double helices via the 3' hydroxy groups, which opens up new avenues in the realm of oligonucleotide biochemistry.

Room-Temperature Deep-UV Photoluminescence from Low-Dimensional Hexagonal Boron Nitride Prepared Using a Facile Synthesis.

Identification and evaluation of defect levels in low-dimensional materials is an important aspect in quantum science. In this article, we report a facile synthesis method of low-dimensional hexagonal boron nitride (h-BN) and study light emission characteristics due to the defects. The thermal annealing procedure is optimized to obtain clean multilayered h-BN as revealed by transmission electron microscopy. UV-vis spectroscopy shows the optical energy gap of 5.28 eV, which is comparable to the reported energy gap for exfoliated, clean h-BN samples. X-ray photoelectron spectroscopy reveals the location of the valence band edge at 2 eV. The optimized synthesis route of h-BN generates two kinds of defects, which are characterized using room-temperature photoluminescence (PL) measurements. The defects emit light at 4.18 eV [deep-UV (DUV)] and 3.44 eV (UV) photons. The intensity of PL has an oscillatory dependence on the excitation energy for the defect emitting DUV light. A series of spectral lines are observed with the energy ranging between 2.56 and 3.44 eV. The average peak-to-peak energy separation is about 125 meV. The locations of the spectral lines can be modeled using Franck-Condon-type transition and associated with displaced harmonic oscillator approximation. Our facile route gives an easier approach to prepare clean h-BN, which is essential for classical two-dimensional material-based electronics and single-photon-based quantum devices.

Enhanced antibacterial, antioxidant and anticancer activity of caffeic acid by simple acid-base complexation with spermine/spermidine.

Caffeic acid (CA) is a naturally occurring plant-derived polyphenol possessing diverse biological properties. However, the poor water-solubility of CA restricts its widespread applications. On the other hand, biogenic amines such as spermine and spermidine are natural constituents in eukaryotes. In this work, we present water-soluble complexes of CA with spermine and spermidine by exploiting the acid-base interaction. Four different compositions have been prepared by varying the CA to amine ratios, whose chemical structures have been probed in detail using Fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) studies that have revealed the acid-base interaction between the constituent precursors. The obtained acid-base complexes at their native pH values have shown enhanced antibacterial and antioxidant activities than pristine CA. Further, the CA-polyamine complexes have shown high anticancer performances in the concentration range that is compatible with the normal cell lines.

Signature of weak-antilocalization in sputtered topological insulator Bi2Se3 thin films with varying thickness.

We report a low-temperature magneto transport study of Bi2Se3 thin films of different thicknesses (40, 80 and 160 nm), deposited on sapphire (0001) substrates, using radio frequency magnetron sputtering technique. The high-resolution x-ray diffraction measurements revealed the growth of rhombohedral c-axis {0003n} oriented Bi2Se3 films on sapphire (0001). Vibrational modes of Bi2Se3 thin films were obtained in the low wavenumber region using Raman spectroscopy. The surface roughness of sputtered Bi2Se3 thin films on sapphire (0001) substrates were obtained to be ~ 2.26-6.45 nm. The chemical and electronic state of the deposited Bi2Se3 was confirmed by X-ray photoelectron spectroscopy and it showed the formation of Bi2Se3 compound. Resistivity versus temperature measurements show the metallic nature of Bi2Se3 films and a slight up-turn transition in resistivity at lower temperatures < 25 K. The positive magneto-resistance value of Bi2Se3 films measured at low temperatures (2-100 K) confirmed the gapless topological surface states in Bi2Se3 thin films. The quantum correction to the magnetoconductivity of thin films in low magnetic field is done by employing Hikami-Larkin-Nagaoka theory and the calculated value of coefficient 'α' (defining number of conduction channels) was found to be 0.65, 0.83 and 1.56 for film thickness of 40, 80 and 160 nm, respectively. These observations indicate that the top and bottom surface states are coupled with the bulk states and the conduction mechanism in Bi2Se3 thin films varied with the film thicknesses.

Water-soluble caffeic acid-dopamine acid-base complex exhibits enhanced bactericidal, antioxidant, and anticancer properties.

Despite the highly potent biological characteristics, the poor water-solubility of caffeic acid (CA) limits its applications in various domains. Here, we present a facile approach, wherein CA has been treated with dopamine hydrochloride (Dopa.HCl) to obtain a water-soluble acid-base complex, which does not possess any covalent bond between the individual components and thus retains their nativity. Simple mixing of CA and Dopa.HCl did not provide water solubility to CA, but the complex became readily soluble in water when the mineral acid was scavenged using sodium bicarbonate. The obtained CA-Dopa complex had been characterized using FT-IR, 1H NMR, 13C NMR, 2D 1H-1H NOESY NMR, XPS, and DSC techniques. The complex was found to exhibit excellent bactericidal, antibiofilm, antioxidant, and anticancer properties in the physiologically relevant pH range of 5.5 to 7.5. The results have revealed the high potential of the simple acid-base complex of CA in diverse domains.