Empirical relation to evaluate blast induced crack development zone while using explosives of different detonation pressure in opencast bench blasting.

The optimum utilisation of explosive energy in the rock blasting operation is a prime challenge for the blast designers. The explosive energy in this operation is used for movement of burden. The optimum fracturing of the rock mass to meet the production demand takes place along tension. In the process of blasting, the detonation pressure of the explosives in the blasthole induces shock wave to the rock mass. The propagating shock wave is initially compressive in nature and becomes tensile after being reflected from the free face. The extent of tensile damage zone would give the optimum burden for blasting. The explosive properties along with the rock mass properties and charge configuration influences the extent of tensile damage zone. In this study, an empirical relation has been developed for estimation of blast induced tensile damage zone. The experimental trials were conducted at a coal mine using two different types of explosives for the validation of the developed empirical relation. The ground vibration predictors were developed using the data of experimental trials. The induced damage zone was computed using empirical relation proposed by Forsyth (1993) and developed ground vibration predictors. The estimated damage zone using developed empirical predictor and Forsyth relation were compared. The difference in the induced damage zone using two approaches is within 10%. The predicted values using developed empirical relation are accurate with RMSE value of 0.227 m. Hence, the developed empirical relation would be beneficial for estimation of blast induced crack zone.

G9a Inhibition Promotes Neuroprotection through GMFB Regulation in Alzheimer's Disease.

Epigenetic alterations are a fundamental pathological hallmark of Alzheimer's disease (AD). Herein, we show the upregulation of G9a and H3K9me2 in the brains of AD patients. Interestingly, treatment with a G9a inhibitor (G9ai) in SAMP8 mice reversed the high levels of H3K9me2 and rescued cognitive decline. A transcriptional profile analysis after G9ai treatment revealed increased gene expression of glia maturation factor ß (GMFB) in SAMP8 mice. Besides, a H3K9me2 ChIP-seq analysis after G9a inhibition treatment showed the enrichment of gene promoters associated with neural functions. We observed the induction of neuronal plasticity and a reduction of neuroinflammation after G9ai treatment, and more strikingly, these neuroprotective effects were reverted by the pharmacological inhibition of GMFB in mice and cell cultures; this was also validated by the RNAi approach generating the knockdown of GMFB/Y507A.10 in Caenorhabditis elegans. Importantly, we present evidence that GMFB activity is controlled by G9a-mediated lysine methylation as well as we identified that G9a directly bound GMFB and catalyzed the methylation at lysine (K) 20 and K25 in vitro. Furthermore, we found that the neurodegenerative role of G9a as a GMFB suppressor would mainly rely on methylation of the K25 position of GMFB, and thus G9a pharmacological inhibition removes this methylation promoting neuroprotective effects. Then, our findings confirm an undescribed mechanism by which G9a inhibition acts at two levels, increasing GMFB and regulating its function to promote neuroprotective effects in age-related cognitive decline.

Discovery of thiazolidin-4-one analogue as selective GSK-3ß inhibitor through structure based virtual screening.

GSK-3ß directly phosphorylate tubulin binding site of tau protein, indicating its importance in tau aggregation and, therefore, in Alzheimer's disease pathology. New GSK-3ß inhibitors were identified using a structure-based screening, ADMET analysis. These studies revealed that ZINC09036109, ZINC72371723, ZINC72371725, and ZINC01373165 approached optimal ADMET properties along with good MM-GBSA dG binding. Protein kinase assays of these compounds against eight disease-relevant kinases were performed. During disease-relevant kinase profiling, ZINC09036109 ((E)-2-((3,4-dimethylphenyl)imino)-5-(3-methoxy-4-(naphthalen-2-ylmethoxy)benzyl)thiazolidin-4-one) emerged as a selective GSK-3ß inhibitor with more than 10-fold selectivity over other disease-relevant kinases. Molecular dynamics study of ZINC09036109 molecule revealed interactions with Ile62, Phe67, Val135, Leu188, Asp200 amino acid residues of the binding site of GSK-3ß, which were highly comparable to the co-crystallized molecule and hence validating comparative better activity of this compound compared to overall screened molecules.

Probing voltage sensing domain of KCNQ2 channel as a potential target to combat epilepsy: a comparative study.

Multidrug resistance along with side-effects of available anti-epileptic drugs and unavailability of potent and effective agents in submicromolar quantities presents the biggest therapeutic challenges in anti-epileptic drug discovery. The molecular modeling techniques allow us to identify agents with novel structures to match the continuous urge for its discovery. KCNQ2 channel represents one of the validated targets for its therapy. The present study involves identification of newer anti-epileptic agents by means of a computer-aided drug design adaptive protocol involving both structure-based virtual screening of Asinex library using homology model of KCNQ2 and 3D-QSAR based virtual screening with docking analysis, followed by dG bind and ligand efficiency calculations with ADMET studies, of which 20 hits qualified all the criterions. The best ligands of both screenings with least potential for toxicity predicted computationally were then taken for molecular dynamic simulations. All the crucial amino acid interactions were observed in hits of both screenings such as Glu130, Arg207, Arg210 and Phe137. Robustness of docking protocol was analyzed through Receiver operating characteristic (ROC) curve values 0.88 (Area under curve AUC = 0.87) in Standard Precision and 0.84 (AUC = 0.82) in Extra Precision modes. Novelty analysis indicates that these compounds have not been reported previously as anti-epileptic agents.

Molecular Docking and Molecular Dynamics Simulation Based Approach to Explore the Dual Inhibitor Against HIV-1 Reverse Transcriptase and Integrase.

BACKGROUND: HIV integrase (IN) and reverse transcriptase (RT) are key enzymes for the replication of HIV-1. DNA polymerase and ribonuclease H (RNase H) are the two catalytic domains of HIV-1 RT which are validated as drug targets because of their essence for replication. IN and RNase H domain of RT shares striking structural similarity; it contains conserved DDE triad (two aspartates and one glutamate) and a pair of divalent Mg2+/Mn2+ ions at their catalytic core domain. OBJECTIVE: To search for novel compounds with dual inhibition of IN and RNase H for the drug development against both wild and drug-resistant strains of HIV. METHODS: In the present work, attempts have been made to search compounds against both IN and the RNase H domain of RT. Using structure-based virtual screening approach; Asinex database of small molecules was screened against the viral IN. Top thirty ranked hits obtained, were further evaluated against RNase H domain of RT using Extra Precision (XP) mode of Glide docking. Furthermore, eleven common potential hits were observed which were subjected to the in-silico prediction of drug-likeness properties. Later on, molecular dynamics simulation was performed for the best common active hit (AS6), in the complex with selected enzymes. RESULT: In silico screening of Asinex database compounds against IN and RNase H resulted in total seven compounds namely AS3, AS5, AS6, AS15, AS17, AS18, and AS20 having dual inhibition activity. CONCLUSION: This study warrants the dual inhibition activity of AS6 against IN and RNase H confirms its anti-HIV activity.

Identification of novel acetylcholinesterase inhibitors through e-pharmacophore-based virtual screening and molecular dynamics simulations.

Alzheimer's disease (AD), a progressive neurodegenerative disorder is the most common cause of dementia among elderly people. To date, the successful therapeutic strategy to treat AD is maintaining the levels of acetylcholine via inhibiting acetylcholinesterase (AChE). The present study involves identification of newer AChE inhibitors by dual approach of e-pharmacophore and structure-based virtual screening of Asinex library. Robustness of docking protocol was validated by enrichment calculation with ROC value .71 and BEDROC value .028. Among 11 selected hits, ZINC72338524 with best MM-GBSA dG binding shows optimal range of CNS properties and ligand-AChE complex stability. Further, molecular dynamics study revealed its molecular interactions with Trp86, Phe338, and Tyr341 amino acid residues of catalytic anionic site and Tyr124, Ser125, and Trp286 amino acid residues of peripheral anionic site. Physicochemical properties and ADMET risk prediction indicates their potential in druggability and safety.

Pharmacophore modeling, 3D-QSAR, and in silico ADME prediction of N-pyridyl and pyrimidine benzamides as potent antiepileptic agents.

Biological mechanism attributing mutations in KCNQ2/Q3 results in benign familial neonatal epilepsy (BFNE), a rare form of epilepsy and thus neglected. It offers a potential target for antiepileptic drug discovery. In the present work, a pharmacophore-based 3D-QSAR model was generated for a series of N-pyridyl and pyrimidine benzamides possessing KCNQ2/Q3 opening activity. The pharmacophore model generated contains one hydrogen bond donor (D), one hydrophobic (H), and two aromatic rings (R). They are the crucial molecular write-up detailing predicted binding efficacy of high affinity and low affinity ligands for KCNQ2/Q3 opening activity. Furthermore, it has been validated by using a biological correlation between pharmacophore hypothesis-based 3D-QSAR variables and functional fingerprints of openers responsible for the receptor binding and also by docking of these benzamides into the validated homology model. Excellent statistical computational tools of QSAR model such as good correlation coefficient (R2 > 0.80), higher F value (F > 39), and excellent predictive power (Q2 > 0.7) with low standard deviation (SD <0.3) strongly suggest that the developed model could be used for prediction of antiepileptic activity of newer analogs. A preliminary pharmacokinetic profile of these derivatives was also performed on the basis of QikProp predictions.

Design, synthesis and biological evaluation of selected 3-[3-(amino) propoxy] benzenamines as acetylcholinesterase inhibitors.

The present paper describes design, synthesis, and biological evaluation of a series of some 3-[3-(amino)propoxy]benzenamines as acetylcholinesterase inhibitors using mice as a model and piracetam as a reference drug. The structures of these compounds were confirmed by spectral analysis and compounds were tested for memory enhancing activity using elevated plus maze test and acetylcholinesterase inhibitory assay. The inhibitory range of synthesized compounds was from 8.99 to 28.31 µM. The synthesized compounds possessed higher or equivalent percent retention as compared to piracetam at 1 mg/kg with no other CNS-related activities (locomotor and muscle relaxant, analgesic and anticonvulsant activities). Compound 3-[3-(imidazolo)propoxy]benzenamine has shown significant dose-dependent (1 and 3 mg/kg) memory enhancing activity, while 3-[3-(pyrrolidino)propoxy]benzenamine also showed activity equivalent to reference drug piracetam at 1 mg/kg. Both compounds 3-[3-(pyrrolidino)propoxy]benzenamine and 3-[3-(imidazolo)propoxy]benzenamine were also found to show AChE inhibition with IC50 value of 8.99 and 17.87 µM. The molecular docking, MM-GBSA and molecular dynamics simulation studies were performed in order to establish a relationship between the biological results. RMSD, root-mean-square fluctuations, and interaction patterns of 10a-AChE and Sck-AChE complexes proved that the binding affinity of 10a toward AChE was highly stable with the proposed binding orientations.

Structure-based screening, ADMET profiling, and molecular dynamic studies on mGlu2 receptor for identification of newer antiepileptic agents.

Structure-based screening approach targeting mGlu2 receptor was carried out to identify good chemical starting points for anti-epileptic therapy. Interactive modes of final 12 compounds identified on the basis of screening of Asinex library, binding energy analysis, ADME profiling with special emphasis for CNS ranges, and toxicity analysis were studied and showed good binding modes in the mGluR2-active site. Enrichment studies for validating screening protocol were carried out which gave ROC values 0.98 (AUC = 0.96) for SP, 0.97 (AUC = 0.95) for XP with BEDROC analysis. Our results indicate that all the 12 hits showed good CNS drug-like properties, have better binding free energy and ADME profile as compared to co-crystallized ligand with the best ligand hit retaining conserved hydrogen bond interactions with Ala-166, Thr-168, Ser-145, and Arg-61 residues in bilobatevenus fly-trap domain of mGluR2 receptor. Molecular dynamics simulations proved that the two potential hits, qualifying all screening parameters, are stable in the receptor active site pocket, confirming the potential of the identified hits as a specific target for mGluR2. Because the newly discovered mGluR2 agonists are structurally different with Tc values ranging from 0.57 to 0.92, all of them can be considered for further de novo design methods.