Monte Carlo-based dosimetry of proposed bi-radionuclide (125I and 106Ru/106Rh) eye plaque: A feasibility study.

BACKGROUND: Combining the sharp dose fall off feature of beta-emitting 106Ru/106Rh radionuclide with larger penetration depth feature of photon-emitting125I radionuclide in a bi-radionuclide plaque, prescribed dose to the tumor apex can be delivered while maintaining the tumor dose uniformity and sparing the organs at risk. The potential advantages of bi-radionuclide plaque could be of interest in context of ocular brachytherapy. PURPOSE: The aim of the study is to evaluate the dosimetric advantages of a proposed bi-radionuclide plaque for two different designs, consisting of indigenous 125I seeds and 106Ru/106Rh plaque, using Monte Carlo technique. The study also explores the influence of other commercial 125I seed models and presence or absence of silastic/acrylic seed carrier on the calculated dose distributions. The study further included the calculation of depth dose distributions for the bi-radionuclide eye plaque for which experimental data are available. METHODS: The proposed bi-radionuclide plaque consists of a 1.2-mm-thick silver (Ag) spherical shell with radius of curvature of 12.5 mm, 20 µm-thick-106Ru/106Rh encapsulated between 0.2 mm Ag disk, and a 0.1-mm-thick Ag window, and water-equivalent gel containing 12 symmetrically arranged 125I seeds. Two bi-radionuclide plaque models investigated in the present study are designated as Design I and Design II. In Design I, 125I seeds are placed on the top of the plaque, while in Design II 106Ru/106Rh source is positioned on the top of the plaque. In Monte Carlo calculations, the plaque is positioned in a spherical water phantom of 30 cm diameter. RESULTS: The proposed bi-radionuclide eye plaque demonstrated superior dose distributions as compared to 125I or 106Ru plaque for tumor thicknesses ranges from 5 to 10 mm. Amongst the designs, dose at a given voxel for Design I is higher as compared to the corresponding voxel dose for Design II. This difference is attributed to the higher degree of attenuation of 125I photons in Ag as compared to beta particles. Influence of different 125I seed models on the normalized lateral dose profiles of Design I (in the absence of carrier) is negligible and within 5% on the central axis depth dose distribution as compared to the corresponding values of the plaque that has indigenous 125I seeds. In the presence of a silastic/acrylic seed carrier, the normalized central axis dose distributions of Design I are smaller by 3%-12% as compared to the corresponding values in the absence of a seed carrier. For the published bi-radionuclide plaque model, good agreement is observed between the Monte Carlo-calculated and published measured depth dose distributions for clinically relevant depths. CONCLUSION: Regardless of the type of 125I seed model utilized and whether silastic/acrylic seed carrier is present or not, Design I bi-radionuclide plaque offers superior dose distributions in terms of tumor dose uniformity, rapid dose fall off and lesser dose to nearby critical organs at risk over the Design II plaque. This shows that Design I bi-radionuclide plaque could be a promising alternative to 125I plaque for treatment of tumor sizes in the range 5 to 10 mm.

Endoscopic Ultrasound Guided Radiofrequency Ablation for Caudate Lobe Hepatocellular Carcinoma: A New Paradigm in Endohepatology.

Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) is a promising technique for treating small left hepatic lesions, particularly where ablation via percutaneous route is deemed to be technically difficult. Herein, we report a case of a 64-year-old cirrhotic patient with caudate lobe hepatocellular carcinoma (HCC) who underwent EUS-RFA, resulting in complete ablation of the tumor and also review the related literature.

Regioselective synthesis of 4-arylamino-1,2-naphthoquinones in eutectogel as a confined reaction medium using LED light.

Predicting selectivity and conversion in a confined reaction medium under photochemical conditions is highly challenging as compared to the corresponding conventional synthesis. Herein, we report the use of a simple carbohydrate-derived eutectogel to facilitate LED-light-induced regioselective synthesis of 4-arylamino-1,2-naphthoquinones in good yield. This methodology, by including a reusable reaction medium, proved to have the potential of affording the regioselective formation of various desired products in good yields.

Ethnoveterinary practises of medicinal plants used for the treatment of different cattle diseases: A case study in East Khasi Hill district of Meghalaya, North East India.

Introduction: For generations, the inhabitants of Meghalaya have relied on medicinal plants to maintain the health of their livestock and treat various illnesses that may afflict their animals. Due to the lack of survey for use and documentation, these plants have never been undertaken. Therefore, it is imperative to explore the diversity, utilization, and phytochemical profile of these plants and quantitatively analyse the data to identify important medicinal plants. By doing so, we can better understand the potential of these plants for developing novel drugs. Methods: Frequent field trips were made for the collection of ethnoveterinary data of medicinal plants from local animal-keepers, traditional healers (THs) and inhabitants of different age groups. This information was gathered through semi-structured interviews, individual discussions, direct field-use observation, and questionnaires. A total of 52 informants (35 females and 17 males) were interviewed from seven rural villages and the information obtained from them were quantitatively analysed using the informant consensus factor (ICF), and fidelity level (FL). Additionally, for each documented plant, available published literature was extensively surveyed to identify the presence of bioactive chemical compounds responsible for their therapeutic effects. Results: During the present study, a total 96 plants, distributed into 87 genera and 43 families were identified and recorded for their use in ethnoveterinary practices against more than 25 diseases. Out of the recorded plant species, the Fabaceae family was found to be the most dominant with seven species, followed by Poaceae and Lamiaceae with six species each, and Moraceae with five species. The leaves (50.00%) and seeds (12.50%) were the most frequently used plant parts, while the paste (30 species) was the common mode of application. Aegle marmelos Correa exhibited a fidelity level (FL) of 100% for indigestion, while Tagetes erecta L. had a fidelity level of 94.11% for wound treatment, making them the most promising candidates for further study. The highest FIC value of 1.00 was recorded for the treatment of neurological disorder (1.00), followed by foot and mouth disease (FIC 0.91), which depicted that some species were frequently utilized to treat multiple livestock ailments. Conclusion: The study presents trustworthy information about medicinal plants and their associated indigenous ethnoveterinary knowledge. It has been scientifically proven that these plants contain bioactive compounds responsible for their therapeutic properties. However, this knowledge is in danger of being lost due to factors like socioeconomic changes, environmental and technological alterations, and lack of interest from younger generations. Therefore, it is essential to document this empirical folklore knowledge systematically and take measures to protect and conserve it.

Self-Assembling Nanoarchitectonics of Twisted Nanofibers of Fluorescent Amphiphiles as Chemo-Resistive Sensor for Methanol Detection.

The inhalation, ingestion, and body absorption of noxious gases lead to severe tissue damage, ophthalmological issues, and neurodegenerative disorders; death may even occur when recognized too late. In particular, methanol gas present in traces can cause blindness, non-reversible organ failure, and even death. Even though ample materials are available for the detection of methanol in other alcoholic analogs at ppm level, their scope is very limited because of the use of either toxic or expensive raw materials or tedious fabrication procedures. In this paper, we report on a simple synthesis of fluorescent amphiphiles achieved using a starting material derived from renewable resources, this material being methyl ricinoleate in good yields. The newly synthesized bio-based amphiphiles were prone to form a gel in a broad range of solvents. The morphology of the gel and the molecular-level interaction involved in the self-assembly process were thoroughly investigated. Rheological studies were carried out to probe the stability, thermal processability, and thixotropic behavior. In order to evaluate the potential application of the self-assembled gel in the field of sensors, we performed sensor measurements. Interestingly, the twisted fibers derived from the molecular assembly could be able to display a stable and selective response towards methanol. We believe that the bottom-up assembled system holds great promise in the environmental, healthcare, medicine, and biological fields.

Electronically Robust Self-Assembled Supramolecular Gel as a Potential Material in Triboelectric Nanogenerators.

A series of self-assembling gluconamide conjugated naphthalimide amphiphiles (GCNA) was synthesized and the self-assembly of GCNA into gel rendered an increased electron density in naphthalimide moiety with an overall change in energy of 15.33×10-32  J via J-type aggregation. SEM analysis and X-ray diffraction underpinning the nanofibrillar formation, and rheological measurements confirmed the processablity and material fabrication. The enriched electron density in the aggregated GCNA4 via cooperative intermolecular non-covalent interactions makes it as effective electron donor in the fabrication of triboelectric nanogenerators (TENG). The TENG based on GCNA4-polydimethylsiloxane (PDMS) triboelectric pair generated an output voltage, current and power density of ∼250 V, 40 µA and ∼622 mW/m2 respectively, which is almost 2.4 times better in performance than the amorphous GCNA4 based TENG. The fabricated TENG can power-up 240 LEDs, wrist watch, thermometer, calculator and hygrometer.

Functionalized nanoparticles: Tailoring properties through surface energetics and coordination chemistry for advanced biomedical applications.

Significant advances in nanoparticle-related research have been made in the past decade, and amelioration of properties is considered of utmost importance for improving nanoparticle bioavailability, specificity, and catalytic performance. Nanoparticle properties can be tuned through in-synthesis and post-synthesis functionalization operations, with thermodynamic and kinetic parameters playing a crucial role. In spite of robust functionalization techniques based on surface chemistry, scalable technologies have not been explored well. The coordination enhancement via surface functionalization through organic/inorganic/biomolecules material has attracted much attention with morphology modification and shape tuning, which are indispensable aspects in the colloidal phase during biomedical applications. It is envisioned that surface amelioration influences the anchoring properties of nano interfaces for the immobilization of functional groups and biomolecules. In this work, various nanostructure and anchoring methodologies have been discussed, aiming to exploit their full potential in precision engineering applications. Simultaneous discussions on emerging characterization strategies for functionalized assemblies have been made to gain insights into functionalization chemistry. An overview of current advances and prospects of functionalized nanoparticles has been presented, with an emphasis on controllable attributes such as size, shape, morphology, functionality, surface features, Debye and Casimir interactions.

Domino Synthesis of Thiazolo-Fused Six- and Seven-Membered Nitrogen Heterocycles via Intramolecular Heteroannulation of In-Situ-Generated 2-(Het)aryl-4-amino-5-functionalized Thiazoles.

Synthesis of novel 2-(het)aryl-substituted thiazolo-fused six- and seven-membered heterocycles, such as thiazolo[4,5-b]pyridin-5(4H)-ones, thiazolo[4,5-c]isoquinolin-5(4H)-ones, thiazolo[4,5-b]quinolin-9(4H)-ones, 4H-benzo[e]thiazolo[4,5-b]azepine-5,10-diones, have been developed in a single-pot operation via intramolecular heteroannulation of in-situ-generated 2-(het)aryl-4-amino-5-functionalized thiazoles. These 4-amino-5-functionalized thiazoles were readily obtained in a one-pot process by treatment of a range of (het)aryldithioesters with cyanamide in the presence of NaH, followed by in situ S-alkylation-intramolecular condensations of the resulting thioimidate salts with appropriate activated methylene halides. On the other hand, the corresponding 4H-benzo[b]thiazolo[4,5-e][1,4]diazepin-10(9H)-ones were synthesized in a two-step process, requiring prior isolation of 5-carboethoxy-4-(2-nitrophenyl)aminothiazoles and their subsequent reductive cyclization. The activated methylene halides employed in these reactions for the synthesis of various thiazolo-fused heterocycles were methyl bromocrotonate, ethyl 2-(bromomethyl)benzoate, 2-fluorophenacyl bromides, ethyl 2-(2-bromoacetyl)benzoate, and ethyl bromoacetate. Several of these thiazolo-fused heterocycles display yellow green to green fluorescence, and their absorption and emission spectra have also been examined.

Effect of nitrogen and zinc nanofertilizer with the organic farming practices on cereal and oil seed crops.

Sustainable and precision agriculture practices are essential to meet the global food demand with minimal impact on soil, air and water. In the present study, nanofertilizers of nitrogen and zinc was used with the organic farming practice under field condition for the cereal i.e. wheat, pearl millet, and oil seed crops i.e. mustard, sesame. The field trial was compared with chemical fertilizer based agricultural settings. A total of 160 field demonstrations were conducted at two locations: Khaliyawas (28.19° N, 76.76° E) and Khatawali (28.22° N, 76.76° E) of Haryana, India with a total area of 1225 acre and randomized block design. It was found that an average yield was recorded 5.35% higher in wheat, 24.24% higher yield in sesame, 4.2% higher in pearl millet and 8.4% higher yield in mustard by applying nanofertilizers of nitrogen and zinc along with the organic farming practice. The increased yield corroborated with the development parameters of plants such as wheat tillers, ear head length of pearl millet, capsule number per plant in sesame and siliquae number per plant in mustard. The trial observation suggests that the fields with applied organic manure, bio-fertilizer and nanofertilizers in combination resulted in higher yield and better plant growth performances when compared to the fields under conventional chemical fertilizer practice. The results suggest that the intervention of nanotechnology along with organic farming practice can help in minimizing the mass volume requirement of conventional chemical fertilizer while improving crop production.

Single-Pot Preparation of 4-Amino-2-(het)aryl-5-Substituted Thiazoles Employing Functionalized Dithioesters as Thiocarbonyl Precursors.

An effective, diversity oriented, one-pot reaction of 4-amino-2-(het)aryl/alkyl-5-functionalized thiazoles has been disclosed, utilizing aryl/heteroaryl/alkyl dithioesters as thiocarbonyl coupling partners in a modified Thorpe-Ziegler type cyclization. The reaction proceeds at room temperature, under mild conditions, in excellent yields, displaying broad functional group compatibility at 2 and 5 positions of thiazoles. This synthetic strategy has been further expanded for the one-pot construction of two highly potent tubulin polymerization inhibitors, i.e., 2-(het)aryl-4-amino-5-(3,4,5-trimethoxyaroyl) thiazoles, in high yields.

Monte Carlo-based dosimetric studies of a locally developed170Tm LDR brachytherapy seed source.

170Tm is being explored as a source for applications in brachytherapy. Although it has adequate physical properties, such as a short half-life (128.6 d), high specific activity and a mean photon energy of about 66 keV, it has a drawback of low photon yield (only about six photon emissions/100 beta emissions). The objective of this work is to study the dosimetric characteristics of a locally developed170Tm brachytherapy seed source using the Monte Carlo-based EGSnrc code system. In this study, we calculate the dose rate constant, air-kerma strength, radial dose function, anisotropic function and 2D dose-rate distributions in water. Separate simulations are carried out by considering the photon (gamma and characteristic x-ray) and beta spectra of the source. For regions close to the source (surface of the source

Naphthalenediimides with High Fluorescence Quantum Yield: Bright-Red, Stable, and Responsive Fluorescent Dyes.

The naphthalenediimide (NDI) scaffold in contrast to its higher congeners possess low-fluorescence. In spite of elegant synthetic developments, a highly emissive NDI is quite rare to find, as well as, a green-light-emitting NDI is yet to be explored. Herein, we report a novel class of symmetric and asymmetric NH2 -substituted core-NDIs (1-5) with tunable fluorescence in the visible region and extending to the NIR frontier. Importantly, the bis-NH2 -substituted NDI 2 revealed quantum yield, Φ f of ≈81 and ≈68 % in toluene and DMSO, respectively, suggesting versatility of the fluorophore in a wide range of solvent polarity. The dye 1 is shown to be the first NDI-based green-light emitter. The donor piperidine group in 5 diminish the Φ f by 40-fold providing a lever to modulate the excited-state intramolecular proton transfer (ESIPT) process. Our synthetic protocol applies a Pd catalyst and a benign hydride source simplifying the non-trivial -NH2 group integration at the NDI-core. TD-DFT calculations predicted strong intramolecular hydrogen bonds in the excited state in the bulk nonpolar medium and responsiveness to solvent polarity. The maximization of the NDI emission outlined here would further boost the burgeoning repertoire of applications of the NDI scaffold.

Synthesis of Substituted Benzo[b]thiophenes via Base-Promoted Domino Condensation-Intramolecular C-S Bond Formation.

A novel synthesis of 2,3-substituted benzothiophenes is reported, involving a tandem base-mediated condensation of o-iodoarylacetonitriles/acetates/ketones with (hetero)aryldithioesters and an intramolecular C-S bond formation. The reaction affords diversely substituted benzothiophenes and heterofused thiophenes in excellent yields.

Halogen-Bonded Assemblies of Arylene Imides and Diimides: Insight from Electronic, Structural, and Computational Studies.

Halogen-bonding interactions in electron-deficient π scaffolds have largely been underexplored. Herein, the halogen-bonding properties of arylene imide/diimide-based electron-deficient scaffolds were studied. The influence of scaffold size, from small (phthalimide) to moderately sized (pyromellitic diimide or naphthalenediimides) to large (perylenediimide), axial-group modification, and number of halo substituents on the halogen bonding and its self-assembly was probed in a set of nine compounds. The structural modification leads to tunable optical and redox properties. The first reduction potential E 1 / 2 1 ranges between -1.09 and -0.17 V (vs. SCE). Two of the compounds, that is, 6 and 9, have deep-lying LUMOs with values reaching -4.2 eV. Single crystals of all nine systems were obtained, which showed Br⋅⋅⋅O, Br⋅⋅⋅Br, or Br⋅⋅⋅π halogen-bonding interactions, and a few systems are capable of forming all three types. These interactions lead to halogen-bonded rings (up to 12-membered), which propagate to form stacked 1D, 2D, or corrugated sheets. A few outliers were also identified, for example, molecules that prefer C-H⋅⋅⋅O hydrogen bonding over halogen bonding, or noncentrosymmetric rather than centrosymmetric organization. Computational studies based on Atoms in Molecules and Natural Bond Orbital analysis provided further insight into the halogen-bonding interactions. This study can lead to a predictive design tool-box to further explore related systems on surfaces reinforced by these weak directional forces.

Domino Synthesis of 2-Substituted Benzothiazoles by Base-Promoted Intramolecular C-S Bond Formation.

A new, transition-metal-free, domino synthesis of 2-substituted benzothiazoles has been developed, involving base-promoted one-pot addition of active methylene compounds to o-iodoarylisothioacyanates and subsequent intramolecular C-S bond formation of the resulting thioamidate anion. The reaction proceeds at room temperature within 1-3 h, affording diversely substituted benzothiazoles in high yields. A possible radical intermediate pathway, via an SRN1 mechanism, has been proposed for intramolecular C-S bond formation.

Fabrication of miniature 141Ce sources by chemical deposition towards possible use in the performance evaluation of gamma cameras - A feasibility study.

141Ce sources were fabricated for quality assurance of gamma cameras. The fabrication process consisted of electro-deposition of Ni on a Cu sphere in 0.01 N H2SO4 containing 30 mg/mL H3BO3 and 50 µg of NiSO4·7H2O at pH 2-3 followed by deposition of 141Ce on it. > 95% deposition of 141Ce on substrate could be achieved at pH 5. Source core was loaded in custom-made Al holder. Autoradiography confirmed uniform activity distribution. SEM and EDS analyses confirmed deposition of Cerium on substrate.

Electrochemical detection of paracetamol and dopamine molecules using nano-particles of cobalt ferrite and manganese ferrite modified with graphite.

Some electrodes for efficient detection of paracetamol and dopamine were developed from nano sized material of cobalt ferrite (np-CoFe2O4) and manganese ferrite (np-MnFe2O4). These oxides were synthesized by combustion method using cobalt nitrate, manganese acetate and ferric nitrate as precursors in the presence of sugar and ethanolamine. The crystallite size, shape and morphology of nano material were characterized by X-ray diffraction pattern (XRD), field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDS) techniques. The crystallite sizes of synthesized nano-particles (nps) were in the range from 10 to 12 nm (calculated using Debye-Scherrer equation) with cubic crystal system. These particles were utilized as electrode modified with graphite for simultaneous detection of paracetamol and dopamine through cyclic voltammetry and Differential pulse voltammetry techniques and was found to be superior to reported literatures. The minimum detection limit of paracetamol and dopamine at CoFe2O4/GP electrode were 250 nM and 350 nM while at MnFe2O4/GP electrode it was 300 nM and 400 nM, respectively. Both the electrodes exhibited the linearity range from3 µM to 200 µM & 3 µM-160 µM for paracetamol and 3 µM-180 µM & 5 µM to 200 for dopamine, respectively. Two oxidation peaks of paracetamol and dopamine were well separated in phosphate buffer (pH = 6) in mixture with 100 mVs-1 and 50 mVs-1 scan rate for cyclic voltammetry and Differential pulse voltammetry, respectively. Both the electrodes demonstrated satisfactory results in real samples of paracetamol and dopamine.

Doubly zwitterionic, di-reduced, highly electron-rich, air-stable naphthalenediimides: redox-switchable islands of aromatic-antiaromatic states.

The di-reduced state of the naphthalene moiety and its congeners have long captivated chemists as it is elusive to stabilize these intrinsically reactive electron-rich π-systems and for their emergent multifaceted properties. Herein we report the synthesis and isolation of two-electron (2e-) reduced, highly electron-rich naphthalenediimides (NDIs). A doubly zwitterionic structure is observed for the first time in a naphthalene moiety and validated by single crystal X-ray crystallography and spectroscopic methods. The synthesis avoids hazardous reducing agents and offers an easy, high-yielding route to bench-stable di-reduced NDIs. Notably, we realized high negative first oxidation potentials of up to -0.730 V vs. Fc/Fc+ in these systems, which establish these systems to be one of the strongest ambient stable electron donors. The study also provides the first insights into the NMR spectra of the di-reduced systems revealing a large decrease in diatropicity of the naphthalene ring compared to its 2e- oxidized form. The NICS, NICS-XY global ring current, gauge-including magnetically induced current (GIMIC) and AICD ring current density calculations revealed switching of the antiaromatic and aromatic states at the naphthalene and the imide rings, respectively, in the di-reduced system compared to the 2e- oxidized form. Notably, the substituents at the phosphonium groups significantly tune the antiaromatic-aromatic states and donor ability, and bestow an array of colors to the di-reduced systems by virtue of intramolecular through-space communication with the NDI scaffold. Computational studies showed intramolecular noncovalent interactions to provide additional stability to these unprecedented doubly zwitterionic systems.

Synthesis and Isolation of a Stable Perylenediimide Radical Anion and Its Exceptionally Electron-Deficient Precursor.

The synthesis and isolation of an ambient stable perylenediimide radical anion is reported, and its precursor is established as one of the strongest electron acceptors. The radical anion shows absorption up to 1400 nm and is stable in mixed aqueous solution. Interestingly, the radical anion can organize two electron-deficient molecules over its surface to form a π-stacked array. Calculations revealed weak spin polarization via noncovalent interactions. Such interactions are of significance for magnetic exchange and catalysis.