Size-Dependent Fullerenes for Enhanced Interaction of l-Leucine: A Combined DFT and MD Simulations Approach.

Fullerene-based biosensors have received great attention due to their unique electronic properties that allow them to transduce electrical signals by accepting electrons from amino acids. Babies with MSUD (maple syrup urine disease) are unable to break down amino acids such as l-leucine, and excess levels of the l-leucine are harmful. Therefore, sensing of l-leucine is foremost required. We aim to investigate the interaction tendencies of size-variable fullerenes (CX; X = 24, 36, 50, and 70) toward l-leucine (LEU) using density functional theory (DFT-D3) and classical molecular dynamics (MD) simulation. The C24 fullerene shows the highest affinity of the LEU biomolecule in the gas phase. Smaller fullerenes (C24 and C36) show stronger interactions with leucine due to their higher curvature in water environments. Moreover, recovery times in the ranges of 1010 and 104 s make it a viable candidate for the isolation application of LEU from the biological system. Further, the interaction between LEU and fullerenes is in line with the natural bond order (NBO) analysis, Mulliken charge analysis, quantum theory atom in molecule (QTAIM) analysis, and reduced density gradient (RDG) analysis. At 310 K, employing the explicit water model in classical MD simulations, fullerenes C24 and C36 demonstrate notably elevated binding free energies (-24.946 kJ/mol) in relation to LEU, showcasing their potential as sensors for l-leucine. Here, we demonstrate that the smaller fullerene exhibits a higher potential for l-leucine sensors than the larger fullerene.

Advocating for Routine Post-natal Surveillance and Urgent Neonatal Inguinal Hernia Repair.

ABSTRACT: Inguinal hernias are more common in preterm and neonates and incidence of incarceration are reported to be more in the first 6 months of life. Strangulation follows incarceration and various incarcerated and strangulated contents having been reported in the sac. The fistulation of the herniated content through the scrotal skin is quite rare with only a few reported cases. We present the case of entero-scrotal fistula in a neonate managed with staged repair along with a brief review of the literature. A 27-days-old, full-term male presented with faecal discharge from the right scrotum. He had no tell-tale signs of obstructed hernia. A faecal fistulous opening was located in the right hemi-scrotum. The terminal ileum was seen as the content with an antimesenteric perforation, divided ileostomy and scrotal debridement was done and later ileo-ascending anastomosis was performed electively. Neonatal hernias should be considered an urgency and we advocate early surgery. The resource-limited setting and poor post-natal surveillance may have added to the worries. In our case, swelling and fistulation occurred in a very brief period of 36 h. We managed the child with a diversion stoma followed by ileo-ascending anastomosis later.

Toward Continuous Breath Monitoring on a Mobile Phone Using a Frugal Conducting Cloth-Based Smart Mask.

A frugal humidity sensor that can detect changes in the humidity of exhaled breath of individuals has been fabricated. The sensor comprises a humidity-sensitive conducting polymer that is in situ formed on a cloth that acts as a substrate. Interdigitated silver electrodes were screen-printed on the modified cloth, and conducting threads connected the electrodes to the measurement circuit. The sensor's response to changing humidity was measured as a voltage drop across the sensor using a microcontroller. The sensor was capable of discerning between fast, normal, and slow breathing based on the response time. A response time of ∼1.3 s was observed for fast breathing. An Android-based mobile application was designed to collect sensor data via Bluetooth for analysis. A time series classification algorithm was implemented to analyze patterns in breathing. The sensor was later stitched onto a face mask, transforming it into a smart mask that can monitor changes in the breathing pattern at work, play, and sleep.

Industrial Utilization of Capacitive Deionization Technology for the Removal of Fluoride and Toxic Metal Ions (As3+/5+ and Pb2+).

Capacitive deionization (CDI) is an emerging desalination technology, particularly useful for removing ionic and polarizable species from water. In this context, the desalination performance of fluoride and other toxic species (lead and arsenic) present in brackish water at an industrial scale of a few kilo liters using a CDI prototype built by InnoDI Private Limited is demonstrated. The prototype is highly efficient in removing ionic contaminants from water, including toxic and heavy metal ions. It can remove fluoride ions below the World Health Organization (WHO) limit (1.5 ppm) at an initial concentration of 7 ppm in the input feed water. The fluoride removal efficiency of the electrodes (at a feed concentration of 6 ppm) deteriorates by ≈4-6% in the presence of bicarbonate and phosphate ions at concentrations of 100 ppm each. The removal efficiency depends on flow rate, initial total dissolved solids, and other co-ions present in the feed water. Interestingly, toxic species (As3+/5+ and Pb2+) are also removed efficiently (removal efficiency > 90%) by this technology. The electrodes are characterized extensively before and after adsorption to understand the mechanism of adsorption at the electrode.

2D-Molybdenum Disulfide-Derived Ion Source for Mass Spectrometry.

Generation of current or potential at nanostructures using appropriate stimuli is one of the futuristic methods of energy generation. We developed an ambient soft ionization method for mass spectrometry using 2D-MoS2, termed streaming ionization, which eliminates the use of traditional energy sources needed for ion formation. The ionic dissociation-induced electrokinetic effect at the liquid-solid interface is the reason for energy generation. We report the highest figure of merit of current generation of 1.3 A/m2 by flowing protic solvents at 22 µL/min over a 1 × 1 mm2 surface coated with 2D-MoS2, which is adequate to produce continuous ionization of an array of analytes, making mass spectrometry possible. Weakly bound ion clusters and uric acid in urine have been detected. Further, the methodology was used as a self-energized breath alcohol sensor capable of detecting 3% alcohol in the breath.

Microdroplet Impact-Induced Spray Ionization Mass Spectrometry (MISI MS) for Online Reaction Monitoring and Bacteria Discrimination.

Microdroplet impact-induced spray ionization (MISI) is demonstrated involving the impact of microdroplets produced from a paper and their impact on another, leading to the ionization of analytes deposited on the latter. This cascaded process is more advantageous in comparison to standard spray ionization as it performs reactions and ionization simultaneously in the absence of high voltage directly applied on the sample. In MISI, we apply direct current (DC) potential only to the terminal paper, used as the primary ion source. Charge transfer due to microdroplet/ion deposition on the flowing analyte solution on the second surface generates secondary charged microdroplets from it carrying the analytes, which ionize and get detected by a mass spectrometer. In this way, up to three cascaded spray sources could be assembled in series. We show the detection of small molecules and proteins in such ionization events. MISI provides a method to understand chemical reactions by droplet impact. The C-C bond formation reactions catalyzed by palladium and alkali metal ion encapsulation using crown ether were studied as our model reactions. To demonstrate the application of our ion source in a bioanalytical context, we studied the noninvasive in situ discrimination of bacteria samples under ambient conditions.

In situ monitoring of electrochemical reactions through CNT-assisted paper cell mass spectrometry.

A novel method of coupling electrochemistry (EC) with mass spectrometry (MS) is illustrated with a paper-based electrochemical cell supported by carbon nanotubes (CNTs). The electrochemically formed ions, created at appropriate electrochemical potentials, are ejected into the gas phase from the modified paper, without the application of additional potential. The electrochemical cell was fabricated by using a rectangular CNT-coated Whatman 42 filter paper with printed electrodes, using silver paste. This was used for studying the electrochemical conversion of thiols to disulfides, and the functionalization of polycyclic aromatic hydrocarbons (PAHs), which involve S-S and C-C bond formations, respectively. We also demonstrate the versatility of the set-up by utilizing it for the detection of radical cations of metallocenes, monitoring the oxidation of sulfides through the detection of reactive intermediates, and the detection of radical cations of PAHs, all of which occur at specific applied potentials. Finally, the applicability of this technique for qualitative and quantitative analyses of environmentally relevant molecules has been demonstrated by studying the electrochemical oxidation of glucose (Glu) to gluconic acid (GlcA) and saccharic acid (SacA).

Highly Sensitive As3+ Detection Using Electrodeposited Nanostructured MnOx and Phase Evolution of the Active Material during Sensing.

A simple, one-step electrodeposition approach has been used to fabricate MnOx on an indium-doped tin oxide substrate for highly sensitive As3+ detection. We report an experimental limit of detection of 1 ppb through anodic stripping voltammetry with selectivity to As3+ in the presence of 10 times higher concentrations of several metal ions. Additionally, we report the simultaneous phase evolution of active material occurring through multiple stripping cycles, wherein MnO/Mn2O3 eventually converts to Mn3O4 as a result of change in the oxidation states of manganese. This occurs with concomitant changes in morphology. Change in the electronic property (increased charge transfer resistance) of the material due to sensing results in an eventual decrease in sensitivity after multiple stripping cycles. In a nutshell, this paper reports stripping-voltammetry-induced change in morphology and phase of as-prepared Mn-based electrodes during As sensing.

Determination of vertical ionization potential of nitroso-benzoimidazothiazole using charge transfer interaction with a series of acceptors.

This is the first report of UV-Vis spectral investigations of electron donor-acceptor complexes of bio active 3-Nitroso-2-phenylbenzo[d]imidazo[2,1-b]thiazole (BIT1) with chloranils, nitrobenzenes and fullerenes in DMSO medium. Well defined charge transfer (CT) absorption bands in the visible region have been sited. Oscillator strengths, transition dipole and resonance energies of the CT complexes have been estimated. Utilizing Mulliken's equation vertical ionization potential of BIT1 has been determined. A possible mechanism for the interaction between electronic subsystems of chloranils, nitrobenzenes, [60]- and [70] fullerenes with this benzoimidazothiazole compound (BIT1) have been discussed in comparing the parameters like degree of charge transfer and binding constant in polar DMSO. 1H NMR study helps to explain the mechanism well. Comparison of complexes is done with DFT/PW1PW91/6-31G* optimized gas phase geometries and FMO features of adducts.

Holey MoS2 Nanosheets with Photocatalytic Metal Rich Edges by Ambient Electrospray Deposition for Solar Water Disinfection.

A new method for creating nanopores in single-layer molybdenum disulfide (MoS2) nanosheets (NSs) by the electrospray deposition of silver ions on a water suspension of the former is introduced. Electrospray-deposited silver ions react with the MoS2 NSs at the liquid-air interface, resulting in Ag2S nanoparticles which enter the solution, leaving the NSs with holes of 3-5 nm diameter. Specific reaction with the S of MoS2 NSs leads to Mo-rich edges. Such Mo-rich defects are highly efficient for the generation of active oxygen species such as H2O2 under visible light which causes efficient disinfection of water. 105 times higher efficiency in disinfection for the holey MoS2 NSs in comparison to normal MoS2 NSs is shown. Experiments are performed with multiple bacterial strains and a virus strain, demonstrating the utility of the method for practical applications. A conceptual prototype is also presented.

Metal-free C-H arylation of imidazoheterocycles with aryl hydrazines.

A simple and efficient metal-free arylation of imidazo[1,2-a]pyridines at the C-3 position with arylhydrazine has been achieved at room temperature under ambient air conditions. Various 2,3-disubstituted imidazopyridines and imidazothiazoles were synthesized with high yields. The present methodology demonstrates the usefulness of commercially available aryl hydrazine as an arylating agent.

Visible Light Organic Photoredox-Catalyzed C-H Alkoxylation of Imidazopyridine with Alcohol.

The visible light-mediated C-3 alkoxylation of imidazopyridines with alcohols has been achieved using rose bengal as an organic photoredox catalyst at room temperature. Widely abundant air acts as the terminal oxidant that avoids the use of a stoichiometric amount of peroxo compounds. A wide range of functional groups could be tolerated under the reaction conditions to produce C(sp2)-H alkoxylated products in high yields.

Ligand sensitized strong luminescence from Eu3+-doped LiYF4 nanocrystals: a photon down-shifting strategy to increase solar-to-current conversion efficiency.

Lanthanide (Ln)-doped nanocrystals generally display low luminescence quantum efficiency due to forbidden nature of the 4f-4f transition besides possessing low absorption cross sections (∼10 M-1 cm-1). Considering the demand for these materials, particularly for light emission and bioimaging applications, it is very important to improve their quantum efficiency. This work demonstrates a strategy to enhance Si solar cell efficiency via sensitization of Eu3+ ions luminescence from colloidal nanocrystals. We have for the first time developed a simple ligand exchange approach to attach 4,4,4-trifluoro-1-phenyl-1,3 butanedione (TPB) to the surface of Eu3+-doped LiYF4 nanocrystals (NCs). Owing to the good overlap between the emission of the TPB ligands and the energy levels of Eu3+ ions, an efficient energy transfer takes place from the ligand to Eu3+ ions upon ultraviolet (UV) excitation of the ligand, leading to intense red emission. The sensitization of Eu3+ ions greatly enhanced the quantum yield of Eu3+ ions (∼31%) compared to the ∼5% obtained via direct excitation of Eu3+ ions (λexi = 394 nm) in Eu3+-doped LiYF4 NCs. A device was fabricated by embedding the nanocrystals on a Si solar cell to capture the UV photons and convert them into visible ones, which subsequently creates charge carriers inside the cell. Upon exposure to UV light, the nanocrystal embedded Si solar cell shows overall enhancement in the photocurrent upon excitation under UV radiation.

Copper-Catalyzed Regioselective Synthesis of Multisubstituted Furans by Coupling between Ketones and Aromatic Olefins.

A regioselective synthesis of multisubstituted furan derivatives has been developed via Cu(II)-catalyzed intermolecular annulation of aryl ketones with a wide range of aromatic olefins under ambient air in good yields. This protocol is applicable to both cyclic and acyclic aryl ketones.

(Diacetoxy)iodobenzene-Mediated Oxidative C-H Amination of Imidazopyridines at Ambient Temperature.

(Diacetoxy)iodobenzene (PIDA)-mediated direct oxidative C-H amination for the synthesis of 3-amino substituted imidazopyridines has been achieved under metal-free conditions at room temperature in short reaction times. This methodology is also applicable for the regioselective amination of indolizines. Experimental results suggest that the reaction likely proceeds through a radical pathway.

Zn(OTf)2-Catalyzed Synthesis of Imidazole-Substituted Allenes.

A Zn(OTf)2-catalyzed simple and efficient method has been developed for the synthesis of imidazole-substituted allenes by the reaction of 1,1,3-triphenylprop-2-yn-1-ol and imidazoheterocycles. A library of tetrasubstituted allenes with broad functionalities have been prepared with excellent yields. The present methodology is also applicable to imidazo[1,2-a]pyrimidine, imidazo[2,1-b]thiazole and benzo[d]imidazo[2,1-b]thiazole.

Switching the regioselectivity in the copper-catalyzed synthesis of iodoimidazo[1,2-a]pyridines.

A unique copper-catalyzed binucleophilic switching of 2-aminopyridine has been developed for the regioselective synthesis of 2- and 3-iodoimidazo[1,2-a]pyridines using alkenes/alkynes as coupling partners in the presence of molecular iodine under aerobic reaction conditions. This method was also applied to the synthesis of 2-iodo-3-phenylbenzo[d]imidazo[2,1-b]thiazoles. This protocol offers an easy route towards the synthesis of 2,3-diarylimidazo[1,2-a]pyridines.

Regioselective synthesis of nitrosoimidazoheterocycles using tert-butyl nitrite.

A simple and practical method has been developed for the regioselective nitrosylation of imidazopyridines via C(sp(2))-H bond functionalization using tert-butyl nitrite under mild reaction conditions in a short time. A library of 3-nitrosoimidazopyridines with broad functionalities was synthesized in near quantitative yields. The present protocol is also applicable to imidazo[2,1-b]thiazole and benzo[d]imidazo[2,1-b]thiazole.

Start codon targeted (SCoT) polymorphism reveals genetic diversity in wild and domesticated populations of ramie (Boehmeria nivea L. Gaudich.), a premium textile fiber producing species.

Twenty-four start codon targeted (SCoT) markers were used to assess genetic diversity and population structure of indigenous, introduced and domesticated ramie (Boehmeria nivea L. Gaudich.). A total of 155 genotypes from five populations were investigated for SCoT polymorphism, which produced 136 amplicons with 87.5% polymorphism. Polymorphism information content and resolving power of the SCoT markers were 0.69 and 3.22, respectively. The Indian ramie populations exhibited high SCoT polymorphism (> 50%), high genetic differentiation (GST = 0.27) and moderate gene flow (Nm = 1.34). Analysis of molecular variance identified significant differences for genetic polymorphism among the populations explaining 13.1% of the total variation. The domesticated population exhibited higher genetic polymorphism and heterozygosity compared to natural populations. Cluster analysis supported population genetic analysis and suggested close association between introduced and domesticated genotypes. The present study shows effectiveness of employing SCoT markers in a cross pollinated heterozygous species like Boehmeria, and would be useful for further studies in population genetics, conservation genetics and cultivar improvement.

Computational analysis and predictive modeling of polymorph descriptors.

BACKGROUND: A computation approach based on integrating high throughput binding affinity comparison and binding descriptor classifications was utilized to establish the correlation among substrate properties and their affinity to Breast Cancer Resistant Protein (BCRP). The uptake rates of Mitoxantrone in the presence of various substrates were evaluated as an in vitro screening index for comparison of their binding affinity to BCRP.The effects of chemical properties of various chemotherapeutics, such as antiviral, antibiotic, calcium channel blockers, anticancer and antifungal agents, on their affinity to BCRP, were evaluated using HEK (human embryonic kidney) cells in which 3 polymorphs, namely 482R (wild type) and two mutants (482G and 482T) of BCRP, have been identified. The quantitative structure activity relationship (QSAR) model was developed using the sequential approaches of Austin Model 1 (AM1), CODESSA program, heuristic method (HM) and multiple linear regression (MLR) to establish the relationship between structural specificity of BCRP substrates and their uptake rates by BCRP polymorphs. RESULTS: The BCRP mutations may induce conformational changes as manifested by the altered uptake rates of Mitoxantrone by BCRP in the presence of other competitive binding substrates that have a varying degree of affinities toward BCRP efflux. This study also revealed that the binding affinity of test substrates to each polymorph was affected by varying descriptors, such as constitutional, topological, geometrical, electrostatic, thermodynamic, and quantum chemical descriptors. CONCLUSION: Descriptors involved with the net surface charge and energy level of substrates seem to be the common integral factors for defining binding specificity of selected substrates to BCRP polymorph. The reproducible outcomes and validation process further supported the accuracy of the computational model in assessing the correlation among descriptors involved with substrate affinity to BCRP polymorph. A quantitative computation approach will provide important structural insight into optimal designing of new chemotherapeutic agents with improved pharmacological efficacies.