Different Strategies of Asymmetric Synthesis

Asymmetric synthesis is one of the significant subjects of research in recent times. It incorporates regulating stereochemistry of compounds to produce enantiomerically pure chemical substances. Chiral auxiliaries/substrates and enantioselective reagents and organocatalysis are used for the synthesis of enantiomerically pure molecules in organic synthesis. Significance of chiral compounds results in the generation of new bonds in a stereo and enantio-controlled method. Separation of enantiomers from enantiomerically impure sources is a difficult process. Asymmetric synthesis finds its challenging applications in medicinal chemistry, pharmacology, life sciences, chromatography, and extraterrestrial chemistry. This article features the eco- friendly approach and cost-effectiveness of different strategies of asymmetric synthesi

Influence of surface gravity waves on sediment transport and deposition of hummocky cross-stratified sands on marine shelves

Hummocky cross-stratification (HCS) is widely interpreted in wave-influenced ancient shallow-marine deposits. Currently, debate is abundant surrounding HCS with differences in opinions driven partly by poor understanding of the nature and magnitude of processes that lead to HCS formation; lack of enough data to characterize HCS three-dimensional architecture, lateral variability and facies; and inadequate knowledge of how the presence of waves influences sediment movement on marine shelves. This dissertation focusses on filling these knowledge gaps by conducting a tripartite study involving numerical analysis of outcrop exposures of HCS-bearing shelf sands, geostatistical analysis of post-storm-generated bedforms on a modern shelf, and physical modeling of wave interaction with turbid hyperpycnal flows. Numerical analysis and estimated wave time periods from HCS measurements in Late Cretaceous marine transgressive strata in southeastern San Juan Basin, New Mexico, and in deposits of the Cape Sebastian Sandstone (CSS) in southwestern Oregon suggest that HCS in these deposits was more likely formed by decayed swell waves that had travelled long distances away from powerful storms, rather than by active storm waves. These studies suggest that the maximum sustainable wind speeds during greenhouse periods such as those that characterize the late Cretaceous could have been higher than those of modern storms. Study of modern storm deposits shows that sand ridge hydrodynamics affects grain-size variation across the large-scale bedforms (sand ridges and sorted bedforms), which in turn governs the variation in surficial bedforms (megadunes, hummocky bedforms, and 2.5 dimensional dunes). Results indicate that while large-scale bedforms are more current-driven, the small-scale bedforms are more likely to have formed under wave-dominated conditions. These results underscore the role of seafloor morphology on distribution of hummocky bedforms and associated structures on the marine shelf. Lastly, study of wave interaction with turbid hyperpycnal shelf flows shows that wave-generated turbulence helps maintain elevated density in the flows and hence maintains the driving forces of current movement. These elements enable the flow to sustain its energy despite low shelf gradients. These results highlight the contribution of waves in sediment transport across the shelf. Overall, this doctoral dissertation enhances our ability to predict paleo-conditions responsible for deposition of HCS in the geological record, improves our understanding of the role of waves in sand movement on and across shelves, and is the first research to document the relationship between hummocky bedforms and storm processes in the modern shelf.Geological Science

Laser assisted modified lip repositioning surgery for the treatment of excessive gingival display using Y V plasty: A case report

Excessive gingival display is matter of concern for a lot of patients and affects their psychological well-being. Various methods have been employed to reduce excessive gingival display but with variable results. Modified Lip repositioning is a surgical way to correct gummy smile by limiting the retraction of the elevator smile muscles and yet preserve the labial frenum using Y-V plasty using a method that gives long term results along with being non-invasive and has high patient compliance. After thorough disinfection and achieving adequate anaesthesia, the strip of mucosa which had to ablated was marked with a laser, which was twice the amount of gingival display seen in the patient. After carrying out laser ablation of the marked tissue, and performing Y-V plasty, the surgical area was evaluated and the wound margins were approximated with multiple interrupted sutures. The patient was put on a regular follow-up. The results revealed a marked reduction in gingival display at the 3-month follow-up. Overall gingival display reduced from 6 mm to 2 mm

Delineating the molecular responses of a halotolerant microalga using integrated omics approach to identify genetic engineering targets for enhanced TAG production

Abstract Background Harnessing the halotolerant characteristics of microalgae provides a viable alternative for sustainable biomass and triacylglyceride (TAG) production. Scenedesmus sp. IITRIND2 is a fast growing fresh water microalga that has the capability to thrive in high saline environments. To understand the microalga’s adaptability, we studied its physiological and metabolic flexibility by studying differential protein, metabolite and lipid expression profiles using metabolomics, proteomics, real-time polymerase chain reaction, and lipidomics under high salinity conditions. Results On exposure to salinity, the microalga rewired its cellular reserves and ultrastructure, restricted the ions channels, and modulated its surface potential along with secretion of extrapolysaccharide to maintain homeostasis and resolve the cellular damage. The algal-omics studies suggested a well-organized salinity-driven metabolic adjustment by the microalga starting from increasing the negatively charged lipids, up regulation of proline and sugars accumulation, followed by direction of carbon and energy flux towards TAG synthesis. Furthermore, the omics studies indicated both de-novo and lipid cycling pathways at work for increasing the overall TAG accumulation inside the microalgal cells. Conclusion The salt response observed here is unique and is different from the well-known halotolerant microalga; Dunaliella salina, implying diversity in algal response with species. Based on the integrated algal-omics studies, four potential genetic targets belonging to two different metabolic pathways (salt tolerance and lipid production) were identified, which can be further tested in non-halotolerant algal strains

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Not AvailableCucumber is a model plant for studying parthenocarpy with abundant slicing- and pickling-type germplasm. This study was undertaken to understand the role of the important cytokines (CKs), auxin (AUX) and gibberellin (GA) biosynthesis and degradation genes for the induction of parthenocarpy in slicing and pickling germplasm. Two genotypes of gynoecious parthenocarpic cucumber, PPC-6 and DG-8, along with an MABC-derived gynoecious non-parthenocarpic line, IMPU-1, were evaluated in this study. The slicing and pickling cucumber genotypes PPC-6 and DG-8 were strongly parthenocarpic in nature and set fruit normally without pollination. Endogenous auxin and gibberellin were significantly higher in parthenocarpic than non-parthenocarpic genotypes, whereas the concentration of cytokinins varied among the genotypes at different developmental stages. However, the exogenous application of Zeatin and IAA + Zeatin was effective in inducing parthenocarpic fruit in IMPU-1. Expression analysis with important CK, AUX, and GA biosynthesis-related genes was conducted in IMPU-1, PPC-6, and DG-8. The expression of the CK synthase, IPT, IPT3, PaO, LOG1, LOG2, CYP735A1, and CYP735A2 was up-regulated in the parthenocarpic genotypes. Among the transcription factor response regulators (RRs), positive regulation of CSRR8/9b, CSRR8/9d, CSRR8/9e, and CSRR16/17 and negative feedback of the CK signalling genes, such as CsRR3/4a, CsRR3/4b, CsRR8/9a, and CsRR8/9c, were recorded in the parthenocarpic lines. Homeostasis between cytokinin biosynthesis and degradation genes such as CK oxidases (CKXs) and CK dehydrogenase resulted in a non-significant difference in the endogenous CK concentration in the parthenocarpic and non-parthenocarpic genotypes. In addition, up-regulation of the key auxin-inducing proteins and GA biosynthesis genes indicated their crucial role in the parthenocarpic fruit set of cucumber. This study establishes the critical role of the CKs, AUX, and GA regulatory networks and their cross-talk in determining parthenocarpy in slicing and pickling cucumber genotypes.Not Availabl

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Not AvailableCucumber fruits are perishable in nature and become unfit for market within 2–3 days of harvesting. A natural variant, DC-48 with exceptionally high shelf life was developed and used to dissect the genetic architecture and molecular mechanism for extended shelf life through RNA-seq for first time. A total of 1364 DEGs were identified and cell wall degradation, chlorophyll and ethylene metabolism related genes played key role. Polygalacturunase (PG), Expansin (EXP) and xyloglucan were down regulated determining fruit firmness and retention of fresh green colour was mainly attributed to the low expression level of the chlorophyll catalytic enzymes (CCEs). Gene regulatory networks revealed the hub genes and cross-talk associated with wide variety of the biological processes. Large number of SSRs (21524), SNPs (545173) and InDels (126252) identified will be instrumental in cucumber improvement. A web genomic resource, CsExSLDb developed will provide a platform for future investigation on cucumber post-harvest biology.Not Availabl