Automated Synthesis of [11C]PiB via [11CH3OTf]-as Methylating Agent for PET Imaging of ß-Amyloid.

AIM: Efficient synthesis of precursor from commercially available starting materials and automated radiosynthesis of [11C]PiB using commercially available dedicated [11C]- Chemistry module from the synthesized precursor. BACKGROUND: [11C]PiB is a promising radiotracer for PET imaging of ß-Amyloid, advancing Alzheimer's disease research. The availability of precursors and protocols for efficient radiolabelling foster the applications of any radiotracer. Efficient synthesis of PiB precursor was performed using anisidine and 4-nitrobenzoyl chloride as starting materials in 5 steps, having addition, substitutions, and cyclization chemical methodologies. This precursor was used for fully automated radiosynthesis of [11C]PiB in a commercially available synthesizer, MPS-100 (SHI, Japan). The synthesized [11C]PiB was purified via solid-phase methodology, and its quality control was by the quality and safety criteria required for clinical use. METHODS: The synthesis of desired precursors and standard authentic compounds started with commercially available materials with 70-80% yields. The standard analytical methods characterized all synthesized compounds. The fully automated [11C]-chemistry synthesizer (MPS-100) used for radiosynthesis of [11C]PiB with [11C]CH3OTf acts as a methylating agent. For radiolabelling, varied amounts of precursor and time of reaction were explored. The resulting crude product underwent purification through solid-phase cartridges. The synthesized radiotracer was analyzed using analytical tools such as radio TLC, HPLC, pH endo-toxicity, and half-life. RESULTS: The precursor for radiosynthesis of [11C]PiB was achieved in excellent yield using simple and feasible chemistry. A protocol for radiolabelling of precursor to synthesized [11C]PiB was developed using an automated synthesizer. The crude radiotracer was purified by solid-phase cartridge, with a decay-corrected radiochemical yield of 40±5% and radiochemical purity of more than 97% in approx 20 minutes (EOB). The specific activity was calculated and found in a 110-121 mCi/µmol range. CONCLUSION: A reliable methodology was developed for preparing precursor followed by fully automated radiolabeling using [11C]MeOTf as a methylating agent to synthesize [11C]PiB. The final HPLC-free purification yielded more than 97% radiochemical purity tracer within one radionuclide half-life. The method was reproducible and efficient for any clinical center.

CRISPR-Cas9: A Potent Gene-editing Tool for the Treatment of Cancer.

The prokaryotic adaptive immune system has clustered regularly interspaced short palindromic repeat. CRISPR-associated protein (CRISPR-Cas) genome editing systems have been harnessed. A robust programmed technique for efficient and accurate genome editing and gene targeting has been developed. Engineered cell therapy, in vivo gene therapy, animal modeling, and cancer diagnosis and treatment are all possible applications of this ground-breaking approach. Multiple genetic and epigenetic changes in cancer cells induce malignant cell growth and provide chemoresistance. The capacity to repair or ablate such mutations has enormous potential in the fight against cancer. The CRISPR-Cas9 genome editing method has recently become popular in cancer treatment research due to its excellent efficiency and accuracy. The preceding study has shown therapeutic potential in expanding our anticancer treatments by using CRISPR-Cas9 to directly target cancer cell genomic DNA in cellular and animal cancer models. In addition, CRISPR-Cas9 can combat oncogenic infections and test anticancer medicines. It may design immune cells and oncolytic viruses for cancer immunotherapeutic applications. In this review, these preclinical CRISPRCas9- based cancer therapeutic techniques are summarised, along with the hurdles and advancements in converting therapeutic CRISPR-Cas9 into clinical use. It will increase their applicability in cancer research.

Fibroblast Activation Protein Inhibitor-Based Radionuclide Therapies: Current Status and Future Directions.

Metastatic malignancies have limited management strategies and variable treatment responses. Cancer cells develop beside and depend on the complex tumor microenvironment. Cancer-associated fibroblasts, with their complex interaction with tumor and immune cells, are involved in various steps of tumorigenesis, such as growth, invasion, metastasis, and treatment resistance. Prooncogenic cancer-associated fibroblasts emerged as attractive therapeutic targets. However, clinical trials have achieved suboptimal success. Fibroblast activation protein (FAP) inhibitor-based molecular imaging has shown encouraging results in cancer diagnosis, making them innovative targets for FAP inhibitor-based radionuclide therapies. This review summarizes the results of preclinical and clinical FAP-based radionuclide therapies. We will describe advances and FAP molecule modification in this novel therapy, as well as its dosimetry, safety profile, and efficacy. This summary may guide future research directions and optimize clinical decision-making in this emerging field.

Insight into Tumor Hypoxia: Radionuclide-based Biomarker as Diagnostic Tools.

The radiolabeled tracers have been extensively utilized to access various physiological and pathological conditions non-invasively, such as cancers, inflammation, and organ-specific imaging. These tracers demonstrate and study tumor hypoxia in several malignancies. Hypoxia is commonly seen in solid tumors. Tumor Hypoxia is a non-physiological condition of reduced oxygen concentration in the tumor. Hypoxia is associated with adverse outcomes such as treatment resistance and metastases in solid tumors. Tumor hypoxia may result in resistance to radiation therapy and chemotherapy, leading to a poor prognosis. It is one of the clinically paramount factors in treatment planning. Various chemical scaffolds are labeled with compatible radioisotopes for imaging hypoxia by Single-photon emission computed tomography (SPECT) and Positron emission tomography (PET). Radionuclides, such as [18F]Flourine, [99mTc]Technetium, [131I]Iodine, [124I] Iodine, and [64Cu]Copper are used for incorporation into different chemical scaffolds.Among them, [18F]Flourine and [64Cu]Copper tagged radiopharmaceuticals are most explored, such as [18F]FMISO, [18F]FAZA, [18F]FETNIM, and N4-methyl thiosemicarbazone [64Cu][Cu (ATSM)]. Some of the promising scaffolds for imaging hypoxia are [18F]EF1, [18F]EF5, [18F]EF3, and [18F]HX4. This review is focused on developing radiochemistry routes to synthesize different radiopharmaceuticals for imaging hypoxia in clinical and preclinical studies, as described in the literature. The chemist and radiochemist exerted enormous efforts to overcome these obstacles. They have successfully formulated multiple radiopharmaceuticals for hypoxia imaging. Radionuclide incorporation in high selectivity and efficiency (radiochemical yield, specific activity, purity, and radio-scalability) is a need for application perspective. Versatile chemistry, including nucleophilic and electrophilic substitutions, allows the direct or indirect introduction of radioisotopes into molecules of interest. This review will discuss the chemical routes for synthesizing and utilizing different precursors for radiolabeling with radionuclides.We will briefly summaries these radio-labeled tracers' application and biological significance.

AI-based face mask detection system: a straightforward proposition to fight with Covid-19 situation.

The whole world is suffering from a novel coronavirus, which has become an epidemic. According to a World Health Organization report, this is a communicable disease, i.e., it transfers from an infected person to a healthy person. Therefore, wearing a mask is the most important precaution to protect from COVID-19. This paper presented a deep learning-based approach to design a Face Mask Detection framework to predict whether a person is wearing a mask or not. The proposed method uses a Single Shot Multibox detector as a face detector model and a deep Inception V3 architecture (SSDIV3) to extract the pertinent features of images and discriminate them in mask and without masks labels. Optimizing the SSDIV3 approach using different modeling parameters is a genuine contribution of this work. In addition to this, the system is tested and analyzed on VGG16, VGG19, Xception, Mobilenet V2 models at different modeling parameters. Furthermore, two synthesized novel Face Mask Datasets are introduced containing diversified masks (2d_printed, 3d_printed, handkerchief, transparent, natural-looking mask appearance masks) and unmask images of humans collected in outdoor and indoor environments such as parks, homes, laboratories. The experiment outcomes demonstrate that the proposed system has achieved an accuracy of 98% on the synthesized benchmark datasets, which comparatively outperforms other state-of-art methods and datasets in a real-time environment.

Recent developments on computer aided systems for diagnosis of diabetic retinopathy: a review.

Diabetes is a long-term condition in which the pancreas quits producing insulin or the body's insulin isn't utilised properly. One of the signs of diabetes is Diabetic Retinopathy. Diabetic retinopathy is the most prevalent type of diabetes, if remains unaddressed, diabetic retinopathy can affect all diabetics and become very serious, raising the chances of blindness. It is a chronic systemic condition that affects up to 80% of patients for more than ten years. Many researchers believe that if diabetes individuals are diagnosed early enough, they can be rescued from the condition in 90% of cases. Diabetes damages the capillaries, which are microscopic blood vessels in the retina. On images, blood vessel damage is usually noticeable. Therefore, in this study, several traditional, as well as deep learning-based approaches, are reviewed for the classification and detection of this particular diabetic-based eye disease known as diabetic retinopathy, and also the advantage of one approach over the other is also described. Along with the approaches, the dataset and the evaluation metrics useful for DR detection and classification are also discussed. The main finding of this study is to aware researchers about the different challenges occurs while detecting diabetic retinopathy using computer vision, deep learning techniques. Therefore, a purpose of this review paper is to sum up all the major aspects while detecting DR like lesion identification, classification and segmentation, security attacks on the deep learning models, proper categorization of datasets and evaluation metrics. As deep learning models are quite expensive and more prone to security attacks thus, in future it is advisable to develop a refined, reliable and robust model which overcomes all these aspects which are commonly found while designing deep learning models.

Mycosynthesis of highly fluorescent selenium nanoparticles from Fusarium oxysporum, their antifungal activity against black fungus Aspergillus niger, and in-vivo biodistribution studies.

In the past few years, photo-luminescent inorganic materials have been studied extensively as fluorescent sensors, and diagnostic and bioimaging tools. The assessment of photoluminescence (PL) properties of selenium nanoparticles (Se NPs), especially mycosynthesized Se NPs, is still in its infancy. Herein, we have biosynthesized highly dispersed fluorescent Se NPs (42 nm) using endophytic fungus Fusarium oxysporum, and fully characterized them using sophisticated instruments like TEM, XRD, UV-Vis spectrophotometer, FTIR, and PL spectrometer. To determine the therapeutic efficacy and side effect profiles, these crystalline Se NPs were radiolabeled with technetium-99m (99mTc) and their biodistribution and renal clearance times were investigated in the normal Wister rat. The results showed that these Se NPs may be useful for targeting the lungs and liver dysfunction as significant accumulation of these NPs was observed in the liver (approx. 19.47 ± 4%) and lungs (at 6 ± 1%) after 10 min of post-injection. Quick circulation and the presence of Se NPs in kidney (3.8 ± 2%) also suggested the easy excretion of these NPs from the body through urinary tract. Furthermore, the antioxidant activity of Se NPs (IC50, 159.5 µg/mL) has been investigated using DPPH free radical scavenging assay with scavenging efficacy of 80.4% where ascorbic acid (IC50, 5.6 µg/mL) was used as a positive control. Additionally, the microscopic study of the inhibition zone encircled around Se NPs confirmed their strong antifungal and antisporulant activity against the black fungus Aspergillus niger.

Fully Automated Synthesis of Nitrogen-13-NH3 by SHIs HM-18 Cyclotron and Dedicated Module for Routine Clinical Studies: Our Institutional Experiences.

Aims: The production of nitrogen-13 (13N)-NH3 by ethanol method using automated synthesizer and accessing the production yield, quality control for clinical application. Context: 13N, together with 18F, 15O, and 11C, is one of the positron emitters that can be produced on the multi-gigabecquerel scale in biomedical cyclotrons. (13N)-ammonia is frequently used for cardiac PET studies. It is widely applied for the evaluation of myocardial perfusion in the clinical assessment of cardiac disorders. Simple, fast, and reliable preparation methods have contributed to the routine application of this tracer. Although only two methods are available, a challenge remains to adopt a more efficient and consistent approach to its production. For clinical application, routine production of this tracer is mandatory in compliance with regulatory guidelines. Being at hospital radiopharmacy it is our responsibility to support the clinical service with uninterrupted production and supply of (13N)-NH3. Materials and Methods: The chemicals were used commercially available from Sigma Aldrich, India, Ltd., and Fisher Scientific, India, Ltd. (Mumbai, India), Sep-Pak CM cartridges (Waters India, Pvt., Ltd.,). Radio-thin layer chromatography was carried out using aluminum sheets precoated with silica gel 60 F254 (E. Merck, India). Results: The protocol developed with MPS-100 synthesizer yield (13N)-NH395-97% (EOB) with a synthesis time of around 7 min. Conclusions: With the installation of HM-18 cyclotron at our hospital, center is capable to produce (13N)-NH3 of good yield and purity through the ethanol method, for mycocardial perfusion studies. Our protocol is simple, reproducible, and robust.

Cd2+ -induced Fluorescent Metallogel: A Case of CHEF and ACQ Phenomena.

A fluorescent metallogel (1 %w/v) has been synthesized from deprotonation of a non-fluorescent adipic acid-derived ligand H2 AL with LiOH followed by coordination with Cd2+ in DMF. Cd2+ not only induces the coordination complex formation but also leads to aggregation, formation of nanofibers of about ≈12 nm average diameter and gelation. The metallogel was also found to be reversibly stimuli-responsive towards heating and mechanical shaking whereas it was resistant to ultrasound. The involvement of chelation-enhanced fluorescence (CHEF), aggregation-induced emission (AIE) and aggregation-caused quenching (ACQ) during the course of gelation has been well established by fluorescence experiments. Further, the coordination complex involved in metallogel formation has been well characterized by ESI-MS and Job's plot. The synthesized metallogel has a true gel phase as shown by detailed rheological studies. The mechanism of gelation is well established by using FTIR, UV-vis, fluorescence, lifetime measurement, Job's plot, ESI-MS, PXRD and TEM techniques.

A face mask detection system: An approach to fight with COVID-19 scenario.

A new coronavirus has caused a pandemic crisis around the globe. According to the WHO, this is an infectious illness that spreads from person to person. Therefore, the only way to avoid this infection is to take precautions. Wearing a mask is the most critical COVID-19 protection method because it prevents the virus from spreading from an infected person to a healthy one. This study reflects a deep learning method to create a system for detecting Face Masks. The paper proposes a unique FMDRT (Face Mask Dataset in Real-Time) dataset to determine whether a person is wearing a mask or not. The RFMD and Face Mask datasets are also taken from the internet to evaluate the performance of the proposed method. The CLAHE preprocessing method is employed to enhance the image quality, then resizing and Image augmentation techniques are used to convert it into a standard format and increase the size of the dataset, respectively. The pretrained Caffe face detector model is used to detect the faces, and then the lightweight transfer learning-based Xception model is applied for the feature extraction process. This paper recommended a novel model that is, CL-SSDXcept to distinguish the Face Mask or no mask images. However, accession with the MobileNetV2, VGG16, VGG19, and InceptionV3 models with different hyperparameter settings has been tested on the FMDRT dataset. We have also compared the results of the synthesized dataset FMDRT to the existing Face Mask datasets. The experimental results attained 98% test accuracy on the suggested dataset 'FMDRT' using the CL-SSDXcept method. The empirical findings have been reported at 50 iterations with tuned hyperparameter values with an average accuracy 98% and a loss of 0.05.

Assessing the role of vanadium technologies in decarbonizing hard-to-abate sectors and enabling the energy transition.

The decarbonization of heavy industry and the emergence of renewable energy technologies are inextricably linked to access to mineral resources. As such, there is an urgent need to develop benchmarked assessments of the role of critical elements in reducing greenhouse gas emissions. Here, we explore the role of vanadium in decarbonizing construction by serving as a microalloying element and enabling the energy transition as the primary component of flow batteries used for grid-level storage. We estimate that vanadium has enabled an avoided environmental burden totaling 185 million metric tons of CO2 on an annual basis. A granular analysis estimates savings for China and the European Union at 1.15% and 0.18% of their respective emissions, respectively. Our results highlight the role of critical metals in developing low-carbon infrastructure while underscoring the need for holistic assessments to inform policy interventions that mitigate supply chain risks.

Establishing the [18F]-FDG Production via Two Different Automated Synthesizers for Routine Clinical Studies: Our Institutional Experiences of 4 years.

INTRODUCTION: [18F]-Fluorodeoxyglucose ([18F]-FDG) is the most widely used positron-emission tomography tracer used for imaging in clinical studies such as early detection of cancer or its malignancies, quantifications, staging, and restaging of several malignancies. For clinical application, routine production of this tracer is mandatory in compliance to regulatory guidelines. Several dedicated commercial synthesizers are currently used for producing[18F]-FDG for clinical usage. Being at hospital radiopharmacy, it is our responsibility and duty to support the clinical service with uninterrupted production and supply of [18F]-FDG. This document describes the production of [18F]-FDG using two different automated synthesizers in terms of its production yield, time of synthesis, and analyze the quality control (QC) of the produced [18F]-FDG. MATERIALS AND METHODS: The precursor, mannose triflate ultra-pure, authentic nonradioactive standard FDG and [18O]-water were obtained from ABX, Germany. Solvents and reagents were purchased from Sigma Aldrich India Ltd. and Fisher Scientific India Ltd., (Mumbai, Maharashtra, India). RESULTS: The protocol developed for the synthesis with MPS-100 synthesizer yield of [18F]-FDG is approximate about 45% End of Bombardment (EOB) with synthesis time of around 35 min, whereas with F300E synthesizer it is around 60% with synthesis time of 25 min. The quality of the tracer produced by both synthesizers is at par with the QC parameter for clinical applications. CONCLUSIONS: Finally, we have developed the production using two automated synthesis modules which have the capability to produce [18F]-FDG, to do the patient studies in good yield and purity. Our protocol is simple, reproducible, and robust.

Punching above its weight: life cycle energy accounting and environmental assessment of vanadium microalloying in reinforcement bar steel.

Steel-reinforced concrete is ubiquitously used in construction across the world. The United Nations estimates that the worldwide energy consumption of buildings accounts for 30-40% of global energy production, underlining the importance of the judicious selection of construction materials. Much effort has focused on the use of high-strength low-alloy steels in reinforcement bars whose economy of materials use is predicated upon improved yield strengths in comparison to low-carbon steels. While microalloying is known to allow for reduced steel consumption, a sustainability analysis in terms of embodied energy and CO2 has not thus far been performed. Here we calculate the impact of supplanting lower grade reinforcement bars with higher strength vanadium microalloyed steels on embodied energy and carbon footprint. We find that the increased strength of vanadium microalloyed steel translates into substantial material savings over mild steel, thereby reducing the total global fossil carbon footprint by as much as 0.385%. A more granular analysis pegs savings for China and the European Union at 1.01 and 0.19%, respectively, of their respective emissions. Our cradle-to-gate analysis provides an accounting of the role of microalloying in reducing the carbon footprint of the steel and construction industries and highlights the underappreciated role of alloying elements.

An Exposition of 11C and 18F Radiotracers Synthesis for PET Imaging.

The development of new radiolabeled Positron emission tomography tracers has been extensively utilized to access the increasing diversity in the research process and to facilitate the development in research methodology, clinical usage of drug discovery and patient care. Recent advances in radiochemistry, as well as the latest techniques in automated radio-synthesizer, have encouraged and challenged the radiochemists to produce the routinely developed radiotracers. Various radionuclides like 18F, 11C, 15O, 13N 99mTc, 131I, 124I and 64Cu are used for incorporating into different chemical scaffolds; among them, 18F and 11C tagged radiotracers are mostly explored such as 11C-Methionine, 11C-Choline, 18F-FDG, 18F-FLT, and 18F-FES. This review is focused on the development of radiochemistry routes to synthesize different radiotracers of 11C and 18F for clinical studies.

The Utility of 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Differentiated Thyroid Cancer Patients with Biochemical Recurrence and Negative Whole-Body Radioiodine Scintigraphy and Evaluation of the Possible Role of a Limited Regional Scan.

PURPOSE OF THE STUDY: 18F-Fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) is used in the management of recurrent differentiated thyroid cancer (DTC) patients presented with rising thyroglobulin (Tg) or anti-Tg antibody (Atg) levels and negative whole-body I-131 scan (WBS). We aimed to evaluate the utility of regional or limited PET/CT in a large population preset with variable Tg/(ATg) levels. MATERIALS AND METHODS: In a retrospective study, we analyzed 137 PET/CT done on DTC patients presented with raised Tg/Atg and negative WBS. Retrospective evaluation of other available clinical information was done. RESULTS: One hundred and thirty-seven patients aged 8-72 years (41 ± 17.7 years) were included in the study. Eighty-nine (64.9%) patients had positive findings on 18F-FDG PET-CT. It included thyroid bed recurrence, cervical, mediastinal lymphadenopathy, lung, and bone lesions. In addition, 36 patients had metabolically inactive lung nodules detected on CT. Serum Tg and female sex were the only predictors for a positive PET scan. In most (97.1%) of the patients, the disease was limited to the neck and thoracic region. CONCLUSIONS: PET/CT is an excellent imaging modality for evaluating DTC patients presented with biochemical recurrence. It not only finds the disease in more than 80% of the patients but also detects distant metastatic disease, which precludes regional therapies. Lesions were noted mostly in the neck and thoracic region with very few distant skeletal metastases (4/137 patients). In most of the patients, routine vertex to mid-thigh imaging could be avoided.

An innovative technique for electronic transport model of group-III nitrides.

An optimized empirical pseudopotential method (EPM) in conjunction with virtual crystal approximation (VCA) and the compositional disorder effect is used for simulation to extract the electronic material parameters of wurtzite nitride alloys to ensure excellent agreement with the experiments. The proposed direct bandgap results of group-III nitride alloys are also compared with the different density functional theories (DFT) based theoretical results. The model developed in current work, significantly improves the accuracy of calculated band gaps as compared to the ab-initio method based results. The physics of carrier transport in binary and ternary nitride materials is investigated with the help of in-house developed Monte Carlo algorithms for solution of Boltzmann transport equation (BTE) including nonlinear scattering mechanisms. Carrier-carrier scattering mechanisms defined through Coulomb-, piezoelectric-, ionized impurity-, surface roughness-scattering with acoustic and intervalley scatterings, all have been given due consideration in present model. The direct and indirect energy bandgap results have been calibrated with the experimental data and use of symmetric and asymmetric form factors associated with respective materials. The electron mobility results of each binary nitride material have been compared and contrasted with experimental results under appropriate conditions and good agreement has been found between simulated and experimental results.

Investigation of the Mechanism Behind Conductive Fluorescent and Multistimuli-responsive Li+ -enriched Metallogel Formation.

A fluorescent metallogel (2.6 % w/v) has been obtained from two non-fluorescent components viz. phenyl-succinic acid derived pro-ligand H2 PSL and LiOH (2 equiv.) in DMF. Li+ ion not only plays a crucial role in gelation through aggregation, but also contributed towards enhancement of fluorescence by imposing restriction over excited state intramolecular proton transfer (ESIPT) followed by origin of chelation enhanced fluorescence (CHEF) phenomenon. Further, the participation of CHEF followed by aggregation-caused quenching (ACQ) and aggregation-induced emission (AIE) in the gelation process have been well established by fluorescence experiments. Transmission electron microscopy (TEM) analysis disclosed the sequential creation of nanonuclei followed by nanoballs and their alignment towards the generation of fibers of about 3, 31 and 40 nm diameter, respectively. The presence of a long-range fibrous morphology inside the metallogel was further attested by scanning electron microscopy (SEM). Rheological studies on the metallogel showed its true gel-phase material nature. Nyquist impedance study shows a resistance value of 7.4 kΩ for the metallogel which upon applying ultrasound increased to 8.5 kΩ, while an elevated temperature of 70 °C caused reduction in the resistance value to 4.8 kΩ. The mechanism behind metallogel formation has been well established by using FTIR, UV-vis, SEM, TEM, PXRD, 1 H NMR, fluorescence and ESI-MS.

An Li+-enriched Co2+-induced metallogel: a study on thixotropic rheological behaviour and conductance.

An alkali base and counterion-selective red metallogel (1% w/v) has been synthesized by mixing the adipic acid-derived ligand H2AL with LiOH, followed by the addition of 1 equivalent of Co(OAc)2 in DMF. The addition of Co(OAc)2 not only resulted in the formation of a 2 : 2 (M : L) complex, but also led to the consecutive steps of aggregation, fiber creation, entrapment of the solvent and eventually gelation. The metallogel formation and the mechanism behind gelation have been well characterized and established using various instrumental techniques such as FTIR spectroscopy, UV-vis spectroscopy, FE-SEM, TEM, PXRD, ESI-mass spectrometry, Job's plot and rheology analysis. Nyquist plots suggested a large decrease in the resistance value from 11.3 kΩ to 4.2 kΩ for the solution obtained from the ligand deprotonated by LiOH (AL2-) and Co(OAc)2 containing the metallogel. The Nyquist plot and resistance of the metallogel have also been studied under the influence of temperature and ultrasound stimuli. The extensive rheological measurements provide information about the strength of the gel network and the highly reversible nature and thixotropic behaviour of the metallogel.

Design and development of novel p-aminobenzoic acid derivatives as potential cholinesterase inhibitors for the treatment of Alzheimer's disease.

Based on the quantitative structure-activity relationship (QSAR), some novel p-aminobenzoic acid derivatives as promising cholinesterase enzyme inhibitors were designed, synthesized, characterized and evaluated to enhance learning and memory. The in vitro enzyme kinetic study of the synthesized compounds revealed the type of inhibition on the respective acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. The in vivo studies of the synthesized compounds exhibited significant reversal of cognitive deficits in the animal models of amnesia as compared to standard drug donepezil. Further, the ex vivo studies in the specific brain regions like the hippocampus, hypothalamus, and prefrontal cortex regions also exhibited AChE inhibition comparable to standard donepezil. The in silico molecular docking and dynamics simulations studies of the most potent compound 22 revealed the consensual interactions at the active site pocket of the AChE.

Li+-Induced fluorescent metallogel: a case of ESIPT-CHEF and ICT phenomenon.

A fluorescent metallogel (1% w/v) has been synthesized from non-fluorescent ingredients viz. the smallest possible low molecular weight aromatic symmetrical ligand H2SA (1) and LiOH in a chloroform and methanol mixture. The chelation of Li+ is not only responsible for the inhibition of excited state intramolecular proton transfer (ESIPT) or the origin of fluorescence through chelation enhanced fluorescence (CHEF) in 1, but also for aggregation leading to gelation. The metallogel obtained from 1/Li+ reveals a fibrous morphology while 1 with other, bigger size, alkali metal ions like Na+/K+/Cs+ demonstrates the growth of crystals with different shapes. The effect of the size of the alkali metal ion over gel formation is well explored by FTIR, UV-vis, fluorescence, average lifetime measurements, SEM and PXRD. The metallogel shows multi-stimuli responsive behaviour towards thermal and mechanical stress as well as reswelling properties. The regioisomer H2PBA (2) also shows emission upon treatment with LiOH due to the presence of intramolecular charge transfer (ICT), this is well established by various experiments. The mechanism of gel formation is well established by FTIR, 1H NMR, UV-vis, fluorescence, lifetime measurements, SEM and single crystal and powder XRD instrumental techniques. The involvement of various phenomena in gel formation has been further supported by other synthesized model compounds viz. H2MBA (3), PMO (4), H2SEA (5) and H2SPA (6). True gel phase material is proved by detailed rheological experiments.