The Atoh7 remote enhancer provides transcriptional robustness during retinal ganglion cell development.

The retinal ganglion cell (RGC) competence factor ATOH7 is dynamically expressed during retinal histogenesis. ATOH7 transcription is controlled by a promoter-adjacent primary enhancer and a remote shadow enhancer (SE). Deletion of the ATOH7 human SE causes nonsyndromic congenital retinal nonattachment (NCRNA) disease, characterized by optic nerve aplasia and total blindness. We used genome editing to model NCRNA in mice. Deletion of the murine SE reduces Atoh7 messenger RNA (mRNA) fivefold but does not recapitulate optic nerve loss; however, SEdel/knockout (KO) trans heterozygotes have thin optic nerves. By analyzing Atoh7 mRNA and protein levels, RGC development and survival, and chromatin landscape effects, we show that the SE ensures robust Atoh7 transcriptional output. Combining SE deletion and KO and wild-type alleles in a genotypic series, we determined the amount of Atoh7 needed to produce a normal complement of adult RGCs, and the secondary consequences of graded reductions in Atoh7 dosage. Together, these data reveal the workings of an evolutionary fail-safe, a duplicate enhancer mechanism that is hard-wired in the machinery of vertebrate retinal ganglion cell genesis.

Effect of a contact lens on mouse retinal in vivo imaging: Effective focal length changes and monochromatic aberrations.

For in vivo mouse retinal imaging, especially with Adaptive Optics instruments, application of a contact lens is desirable, as it allows maintenance of cornea hydration and helps to prevent cataract formation during lengthy imaging sessions. However, since the refractive elements of the eye (cornea and lens) serve as the objective for most in vivo retinal imaging systems, the use of a contact lens, even with 0 Dpt. refractive power, can alter the system's optical properties. In this investigation we examined the effective focal length change and the aberrations that arise from use of a contact lens. First, focal length changes were simulated with a Zemax mouse eye model. Then ocular aberrations with and without a 0 Dpt. contact lens were measured with a Shack-Hartmann wavefront sensor (SHWS) in a customized AO-SLO system. Total RMS wavefront errors were measured for two groups of mice (14-month, and 2.5-month-old), decomposed into 66 Zernike aberration terms, and compared. These data revealed that vertical coma and spherical aberrations were increased with use of a contact lens in our system. Based on the ocular wavefront data we evaluated the effect of the contact lens on the imaging system performance as a function of the pupil size. Both RMS error and Strehl ratios were quantified for the two groups of mice, with and without contact lenses, and for different input beam sizes. These results provide information for determining optimum pupil size for retinal imaging without adaptive optics, and raise critical issues for design of mouse optical imaging systems that incorporate contact lenses.

Colloidal Synthesis and Photophysics of M3 Sb2 I9 (M=Cs and Rb) Nanocrystals: Lead-Free Perovskites.

Herein we report the colloidal synthesis of Cs3 Sb2 I9 and Rb3 Sb2 I9 perovskite nanocrystals, and explore their potential for optoelectronic applications. Different morphologies, such as nanoplatelets and nanorods of Cs3 Sb2 I9 , and spherical Rb3 Sb2 I9 nanocrystals were prepared. All these samples show band-edge emissions in the yellow-red region. Exciton many-body interactions studied by femtosecond transient absorption spectroscopy of Cs3 Sb2 I9 nanorods reveals characteristic second-derivative-type spectral features, suggesting red-shifted excitons by as much as 79 meV. A high absorption cross-section of ca. 10-15  cm2 was estimated. The results suggest that colloidal Cs3 Sb2 I9 and Rb3 Sb2 I9 nanocrystals are potential candidates for optical and optoelectronic applications in the visible region, though a better control of defect chemistry is required for efficient applications.

OCT imaging with temporal dispersion induced intense and short coherence laser source.

Lower coherence length and higher intensity are two indispensable requirements on the light source for high resolution and large penetration depth OCT imaging. While tremendous interest is being paid on engineering various laser sources to enlarge their bandwidth and hence lowering the coherence length, here we demonstrate another approach by employing strong temporal dispersion onto the existing laser source. Cholesteric liquid crystal (CLC) cells with suitable dispersive slope at the edge of 1-D organic photonic band gap have been designed to provide maximum reduction in coherence volume while maintaining the intensity higher than 50%. As an example, the coherence length of a multimode He-Ne laser is reduced by more than 730 times.

Exploiting soft organic optical resonant structure towards large range electro-optic tunable devices.

Very fine molecular arrangement of cholesteric liquid crystal (CLC), can be compressed by applying an external electric field in the liquid crystal cell geometry. This enables very fine tuning of the wavelength of the reflected light. The compression of the periodic dielectric molecular arrangement continues till the chiral energy density meets its repulsive-type excluded volume interaction and hence the corresponding resonant wavelength jumps back to the original spectral position. Experimentally, the tuning range is observed to be highly affected by the concentration of the chiral dopant in the mixture. Analytically, it is shown that, use of chiral molecules with higher helical twisting power (HTP) can reduce the concentration of the chiral dopant for a desired pitch length in visible range and hence, the spectral tuning can be exploited over the entire visible range.

Effect of wheat and rice straw biochars on pyrazosulfuron-ethyl sorption and persistence in a sandy loam soil.

The objective of this research was to investigate the effect of wheat and rice biochars on pyrazosulfuron-ethyl sorption in a sandy loam soil. Pyrazosulfuron-ethyl was poorly sorbed in the soil (3.5-8.6%) but biochar amendment increased the herbicide adsorption, and the effect varied with the nature of the feedstock and pyrolysis temperature. Biochars prepared at 600°C were more effective in adsorbing pyrazosulfuron-ethyl than biochars prepared at 400°C. Rice biochars were better than wheat biochars, and higher herbicide adsorption was attributed to the biochar surface area/porosity. The Freundlich constant 1/n suggested nonlinear isotherms, and nonlinearlity increased with increase in the level of biochar amendment. Desorption results suggested sorption of pyrazosulfuron-ethyl was partially irreversible, and the irreversibility increased with increase in the level of biochar. Both sorption and desorption of pyrazosulfuron-ethyl correlated well with the content of biochars. The free energy change (ΔG) indicated that the pyrazosulfuron-ethyl sorption process was exothermic, spontaneous and physical in nature. Persistence studies indicated that biochar (0.5%) amendment did not have significant effect on herbicide degradation, and its half-life values in the control, 0.5% WBC600- and RBC600-amended rice planted soils were 7, 8.6, and 10.4 days, respectively.

Effect of organic carbon chemistry on sorption of atrazine and metsulfuron-methyl as determined by (13)C-NMR and IR spectroscopy.

Soil organic matter (SOM) content is the major soil component affecting pesticide sorption. However, recent studies have highlighted the fact that it is not the total carbon content of the organic matter, but its chemical structure which have a profound effect on the pesticide's sorption. In the present study, sorption of atrazine and metsulfuron-methyl herbicides was studied in four SOM fractions viz. commercial humic acid, commercial lignin, as well as humic acid and humin extracted from a compost. Sorption data was fitted to the Freundlich adsorption equation. In general, the Freundlich slope (1/n) values for both the herbicides were <1. Except for atrazine sorption on commercial humic acid, metsulfuron-methyl was more sorbed. Desorption results suggested that atrazine was more desorbed than metsulfuron-methyl. Lignin, which showed least sorption of both the herbicides, showed minimum desorption. Sorption of atrazine was best positively correlated with the alkyl carbon (adjusted R (2) = 0.748) and carbonyl carbon (adjusted R (2) = 0.498) but, their effect was statistically nonsignificant (P = 0.05). Metsulfuron-methyl sorption showed best positive correlation with carbonyl carbon (adjusted R (2) = 0.960; P = 0.05) content. Sorption of both the herbicides showed negative correlation with O/N-alkyl carbon. Correlation of herbicide's sorption with alkyl and carbonyl carbon content of SOM fractions suggested their contribution towards herbicide sorption. But, sorption of metsulfuron-methyl, relatively more polar than atrazine, was mainly governed by the polar groups in SOM. IR spectra showed that H-bonds and charge-transfer bonds between SOM fraction and herbicides probably operated as mechanisms of adsorption.

Development and validation of LC-MS/MS method for trace analysis of acrylamide, acrylic acid and N, N-methylene bis acrylamide in sandy loam soil.

Acrylamide and N, N-methylene bis acrylamide are most commonly used monomer and crosslinker compounds employed in synthesis of super absorbent hydrogels. When applied as soil conditioners, there are apprehensions that these hydrogels degrade over time and thus may release the toxic monomers in the soil. A method was thus developed using Liquid Chromatography tandem mass spectrometry (LC-MS/MS) for the trace level quantification of acrylamide (AD), acrylic acid (AA) and N,N-methylene-bis-acrylamide (MBA) in sandy loam soil amended by two test hydrogels the Pusa Hydrogel and SPG 1118 hydrogel prepared using AD and MBA. The MRM (multiple reaction monitoring) transitions were optimized for both the compounds. Soil samples were extracted using dispersive solid-phase extraction (dSPE) with a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) technique, employing acetonitrile. All analytes were quantified at trace levels within a five-minute run using UHPLC equipped with a C-18 column. Single laboratory validation of the developed method in soil matrix was conducted based on specificity, linearity, sensitivity, accuracy, precision, matrix effect and measurement of uncertainty. LC-MS/MS exhibited a linear response in the concentration range of 0.001 to 1 µg mL-1, with correlation coefficient >+0.99. Acceptable recovery (within 70-120 %) with repeatability (%RSD ≤20 %) was obtained at 0.01 to 1 µg g-1 fortification levels. LOQ (Limit of quantification) of the method for AD, AA and MBA in soil matrix were 0.05, 1 and 0.01 µg g-1, respectively. Both intra-laboratory repeatability and intermediate precision at LOQ suggested well acceptable precise (HorRat≈ 0.3) method for quantification. Matrix enhancement effect was observed in the order: AA>AD>MBA. The Expanded Uncertainty (EU) in soil matrix at LOQ was 21.64 %, 28 % and 19 % for AD, AA and MBA respectively. Groundnut and wheat grown with application of the hydrogels showed no detectable residues of monomers in soil samples (total n = 60) near the root zone at the time of crop harvesting.

Effect of elevated CO2 on degradation of azoxystrobin and soil microbial activity in rice soil.

An experiment was conducted in open-top chambers (OTC) to study the effect of elevated CO2 (580 ± 20 µmol mol(-1)) on azoxystrobin degradation and soil microbial activities. Results indicated that elevated CO2 did not have any significant effect on the persistence of azoxystrobin in rice-planted soil. The half-life values for the azoxystrobin in rice soils were 20.3 days in control (rice grown at ambient CO2 outdoors), 19.3 days in rice grown under ambient CO2 atmosphere in OTC, and 17.5 days in rice grown under elevated CO2 atmosphere in OTC. Azoxystrobin acid was recovered as the only metabolite of azoxystrobin, but it did not accumulate in the soil/water and was further metabolized. Elevated CO2 enhanced soil microbial biomass (MBC) and alkaline phosphatase activity of soil. Compared with rice grown at ambient CO2 (both outdoors and in OTC), the soil MBC at elevated CO2 increased by twofold. Elevated CO2 did not affect dehydrogenase, fluorescein diacetate, and acid phosphatase activity. Azoxystrobin application to soils, both ambient and elevated CO2, inhibited alkaline phosphates activity, while no effect was observed on other enzymes. Slight increase (1.8-2 °C) in temperature inside OTC did not affect microbial parameters, as similar activities were recorded in rice grown outdoors and in OTC at ambient CO2. Higher MBC in soil at elevated CO2 could be attributed to increased carbon availability in the rhizosphere via plant metabolism and root secretion; however, it did not significantly increase azoxystrobin degradation, suggesting that pesticide degradation was not the result of soil MBC alone. Study suggested that increased CO2 levels following global warming might not adversely affect azoxystrobin degradation. However, global warming is a continuous and cumulative process, therefore, long-term studies are necessary to get more realistic assessment of global warming on fate of pesticide.

A modular scaffold for triggerable and tunable nitroxyl (HNO) generation with a fluorescence reporter.

Nitroxyl (HNO) is a short-lived mediator of cell signalling and can enhance the sulfane sulfur pool, a cellular antioxidant reservoir, by reacting with hydrogen sulfide (H2S). Here, we report esterase-activated HNO-generators that are suitable for tunable HNO release and the design of these donors allows for real-time monitoring of HNO release. These tools will help gain a better understanding of the cross-talk among short-lived gaseous signalling molecules that have emerged as major players in health and disease.

Biopolymeric superabsorbent hydrogels enhance crop and water productivity of soybean-wheat system in Indo-Gangetic plains of India.

Environmental crises, declining factor productivity, and shrinking natural resource is a threat to global agricultural sustainability. The task is much more daunting in the Indo-Gangetic northern plains of India, where depletion of the underground water table and erratic rains due to the changing climate pose a major challenge to agriculture. To address these challenges a field investigation was carried out during 2016-2018 to test the efficacy of biopolymeric superabsorbent hydrogels namely Pusa Hydrogel (P-hydrogel: a semi-synthetic cellulose derivative-based product) and kaolin derivative of Pusa Hydrogel (K-hydrogel: semi-synthetic cellulose derivative) to assess their effect on crop and water productivity, soil moisture, root dynamics, and economics of soybean (Glycine max L.)-wheat (Triticum aestivum L.) system under three irrigation regimes namely full irrigation, limited irrigation and rainfed. The results revealed that the full irrigation along with P-hydrogel led to enhanced grain yield, biomass yield, and water productivity (WP) of soybean (1.61-10.5%, 2.2-9.5%, and 2.15-21.8%, respectively) and wheat (11.1-18.3%, 12-54% and 11.1-13.1%, respectively) over control plots. Likewise, under water stressed plots of rainfed conditions with P-hydrogel exhibited 52.7 and 20.6% higher system yields (in terms of wheat equivalent yield) over control and other combinations during the respective study years. Whereas the magnitude of increase in system yield under limited irrigation with P-hydrogel was ~ 15.1% and under full irrigation with P-hydrogel was 8.0-19.4%. Plots treated with P-hydrogel retained 3.0-5.0% higher soil moisture compared to no-hydrogel plots, while K-hydrogel treated plots held the lower moisture (4.0-6.0%) than the control. In terms of profitability, full irrigation along with P-hydrogel plots registered 12.97% higher economic returns over control. The results suggested that P-hydrogel (2.5 kg ha-1) reduces runoff water loss in full irrigation applied plots and retained more water, where loss of water is more thus reduces number of irrigations. Hence P-hydrogel with irrigation water is a viable option for sustainable production of soybean-wheat systems in the Indo-Gangetic plains of India and other similar eco-regions of the world.

Leveraging an enzyme/artificial substrate system to enhance cellular persulfides and mitigate neuroinflammation.

Persulfides and polysulfides, collectively known as the sulfane sulfur pool along with hydrogen sulfide (H2S), play a central role in cellular physiology and disease. Exogenously enhancing these species in cells is an emerging therapeutic paradigm for mitigating oxidative stress and inflammation that are associated with several diseases. In this study, we present a unique approach of using the cell's own enzyme machinery coupled with an array of artificial substrates to enhance the cellular sulfane sulfur pool. We report the synthesis and validation of artificial/unnatural substrates specific for 3-mercaptopyruvate sulfurtransferase (3-MST), an important enzyme that contributes to sulfur trafficking in cells. We demonstrate that these artificial substrates generate persulfides in vitro as well as mediate sulfur transfer to low molecular weight thiols and to cysteine-containing proteins. A nearly 100-fold difference in the rates of H2S production for the various substrates is observed supporting the tunability of persulfide generation by the 3-MST enzyme/artificial substrate system. Next, we show that the substrate 1a permeates cells and is selectively turned over by 3-MST to generate 3-MST-persulfide, which protects against reactive oxygen species-induced lethality. Lastly, in a mouse model, 1a is found to significantly mitigate neuroinflammation in the brain tissue. Together, the approach that we have developed allows for the on-demand generation of persulfides in vitro and in vivo using a range of shelf-stable, artificial substrates of 3-MST, while opening up possibilities of harnessing these molecules for therapeutic applications.

A Comprehensive in vitro and in silico Analysis of Nematicidal Action of Essential Oils.

Nematicidal potential of essential oils (EOs) has been widely reported. Terpenoids present in most of the essential oils have been reported responsible for their bioactivity though very less is known about their modes of action. In the present study, an in vitro screening of nine Eos, namely, Citrus sinensis (OEO), Myrtus communis (MTEO), Eucalyptus citriodora (CEO), Melaleuca alternifolia (TEO), Acorus calamus (AEO), Commiphora myrrha (MREO), Cymbopogon nardus (CNEO), Artemisia absinthium (WEO), and Pogostemon cablin (PEO) against Meloidogyne incognita revealed OEO, CNEO, and TEO as most effective with LC50 39.37, 43.22, and 76.28 µg ml-1 respectively. EOs had varying compositions of mono- and sesquiterpenes determined by gas chromatography-mass spectrometry (GC-MS) analysis. The in silico molecular interactions screening of major EO constituents and the seven selected target proteins of the nematode indicated highest binding affinity of geraniol-ODR1 (odorant response gene 1) complex (ΔG = -36.9 kcal mol-1), due to extensive H-bonding, hydrophobic and π-alkyl interactions. The relative binding affinity followed the order: geraniol-ODR1 > ß-terpineol-ODR1 > citronellal-ODR1 > l-limonene-ODR1 > γ-terpinene-ODR1. Taken together, the cumulative in vitro and computational bioefficacy analysis related to the chemoprofiles of EOs provides useful leads on harnessing the potential of EOs as bionematicides. The insight on biochemical ligand-target protein interactions described in the present work will be helpful in logical selection of biomolecules and essential oils for development of practically viable bionematicidal products.

Factors Impacting Efficacy of AAV-Mediated CRISPR-Based Genome Editing for Treatment of Choroidal Neovascularization.

Frequent injections of anti-vascular endothelial growth factor (anti-VEGF) agents are a clinical burden for patients with neovascular age-related macular degeneration (AMD). Genomic disruption of VEGF-A using adeno-associated viral (AAV) delivery of clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 has the potential to permanently suppress aberrant angiogenesis, but the factors that determine the optimal efficacy are unknown. Here, we investigate two widely used Cas9 endonucleases, SpCas9 and SaCas9, and evaluate the relative contribution of AAV-delivery efficiency and genome-editing rates in vivo to determine the mechanisms that drive successful CRISPR-based suppression of VEGF-A, using a mouse model of laser-induced choroidal neovascularization (CNV). We found that SpCas9 demonstrated higher genome-editing rates, greater VEGF reduction, and more effective CNV suppression than SaCas9, despite similar AAV transduction efficiency between a dual-vector approach for SpCas9 and single-vector system for SaCas9 to deliver the Cas9 orthologs and single guide RNAs (gRNAs). Our results suggest that successful VEGF knockdown using AAV-mediated CRISPR systems may be determined more by the efficiency of genome editing rather than viral transduction and that SpCas9 may be more effective than SaCas9 as a potential therapeutic strategy for CRISPR-based treatment of CNV in neovascular AMD.

Sequential Targeting in Crosslinking Nanotheranostics for Tackling the Multibarriers of Brain Tumors.

The efficacy of therapeutics for brain tumors is seriously hampered by multiple barriers to drug delivery, including severe destabilizing effects in the blood circulation, the blood-brain barrier/blood-brain tumor barrier (BBB/BBTB), and limited tumor uptake. Here, a sequential targeting in crosslinking (STICK) nanodelivery strategy is presented to circumvent these important physiological barriers to improve drug delivery to brain tumors. STICK nanoparticles (STICK-NPs) can sequentially target BBB/BBTB and brain tumor cells with surface maltobionic acid (MA) and 4-carboxyphenylboronic acid (CBA), respectively, and simultaneously enhance nanoparticle stability with pH-responsive crosslinkages formed by MA and CBA in situ. STICK-NPs exhibit prolonged circulation time (17-fold higher area under curve) than the free agent, allowing increased opportunities to transpass the BBB/BBTB via glucose-transporter-mediated transcytosis by MA. The tumor acidic environment then triggers the transformation of the STICK-NPs into smaller nanoparticles and reveals a secondary CBA targeting moiety for deep tumor penetration and enhanced uptake in tumor cells. STICK-NPs significantly inhibit tumor growth and prolong the survival time with limited toxicity in mice with aggressive and chemoresistant diffuse intrinsic pontine glioma. This formulation tackles multiple physiological barriers on-demand with a simple and smart STICK design. Therefore, these features allow STICK-NPs to unleash the potential of brain tumor therapeutics to improve their treatment efficacy.

Temporal speckle-averaging of optical coherence tomography volumes for in-vivo cellular resolution neuronal and vascular retinal imaging.

It has been recently demonstrated that structures corresponding to the cell bodies of highly transparent cells in the retinal ganglion cell layer could be visualized noninvasively in the living human eye by optical coherence tomography (OCT) via temporal averaging. Inspired by this development, we explored the application of volumetric temporal averaging in mice, which are important models for studying human retinal diseases and therapeutic interventions. A general framework of temporal speckle-averaging (TSA) of OCT and optical coherence tomography angiography (OCTA) is presented and applied to mouse retinal volumetric data. Based on the image analysis, the eyes of mice under anesthesia exhibit only minor motions, corresponding to lateral displacements of a few micrometers and rotations of a fraction of 1 deg. Moreover, due to reduced eye movements under anesthesia, there is a negligible amount of motion artifacts within the volumes that need to be corrected to achieve volume coregistration. In addition, the relatively good optical quality of the mouse ocular media allows for cellular-resolution imaging without adaptive optics (AO), greatly simplifying the experimental system, making the proposed framework feasible for large studies. The TSA OCT and TSA OCTA results provide rich information about new structures previously not visualized in living mice with non-AO-OCT. The mechanism of TSA relies on improving signal-to-noise ratio as well as efficient suppression of speckle contrast due to temporal decorrelation of the speckle patterns, enabling full utilization of the high volumetric resolution offered by OCT and OCTA.

Directional optical coherence tomography reveals melanin concentration-dependent scattering properties of retinal pigment epithelium.

Optical coherence tomography (OCT) is a powerful tool in ophthalmology that provides in vivo morphology of the retinal layers and their light scattering properties. The directional (angular) reflectivity of the retinal layers was investigated with focus on the scattering from retinal pigment epithelium (RPE). The directional scattering of the RPE was studied in three mice strains with three distinct melanin concentrations: albino (BALB/c), agouti (129S1/SvlmJ), and strongly pigmented (C57BL/6J). The backscattering signal strength was measured with a directional OCT system in which the pupil entry position of the narrow OCT beam can be varied across the dilated pupil of the eyes of the mice. The directional reflectivity of other retinal melanin-free layers, including the internal and external limiting membranes, and Bruch's membrane (albinos) were also measured and compared between the strains. The intensity of light backscattered from these layers was found highly sensitive to the angle of illumination, whereas the inner/outer segment (IS/OS) junctions showed a reduced sensitivity. The reflections from the RPE are largely insensitive in highly pigmented mice. The differences in directional scattering between strains shows that directionality decreases with an increase in melanin concentrations in RPE, suggesting increasing contribution of Mie scattering by melanosomes.

Aperture phase modulation with adaptive optics: a novel approach for speckle reduction and structure extraction in optical coherence tomography.

Speckle is an inevitable consequence of the use of coherent light in imaging and acts as noise that corrupts image formation in most applications. Optical coherence tomographic imaging, as a technique employing coherence time gating, suffers from speckle. We present here a novel method of suppressing speckle noise intrinsically compatible with adaptive optics (AO) for confocal coherent imaging: modulation of the phase in the system pupil aperture with a segmented deformable mirror (DM) to introduce minor perturbations in the point spread function. This approach creates uncorrelated speckle patterns in a series of images, enabling averaging to suppress speckle noise while maintaining structural detail. A method is presented that efficiently determines the optimal range of modulation of DM segments relative to their AO-optimized position so that speckle noise is reduced while image resolution and signal strength are preserved. The method is active and independent of sample properties. Its effectiveness and efficiency are quantified and demonstrated by both ex vivo non-biological and in vivo biological applications.

A Vinyl-Boronate Ester-Based Persulfide Donor Controllable by Hydrogen Peroxide, a Reactive Oxygen Species (ROS).

A vinyl boronate ester-based persulfidating agent that is selectively activated by hydrogen peroxide, which is a reactive oxygen species (ROS), and efficiently generated a persulfide by a hitherto unexplored 1,4-O,S-relay mechanism is reported. This donor was found to protect cells from cytotoxicity induced by oxidants, and the major byproduct is cinnamaldehyde, which is widely used in the food industry as an additive.

Isotropic Elastic Stress Induced Large Temperature Range Liquid Crystal Blue Phase at Room Temperature.

A thermodynamically stable blue phase (BP) based on the conventional rod like nematogen is demonstrated for the first time at room temperature by only diluting a chiral-nematic mixture with the help of some nonmesogenic isotropic liquid. It is observed that addition of this isotropic liquid does not only stabilize the BPs at room temperature, but also significantly improves the temperature range (reversible during heating and cooling) of the BPs to the level of more than 28 °C. Apart from that, we have observed its microsecond electro-optic response time and, external electric field induced wavelength tuning, which are the two indispensable requirements for next generation optical devices, photonic displays, lasers, and many more. Here we propose that the isotropic liquid plays two crucial roles simultaneously. On one hand, it reduces the effective elastic moduli (EEM) of the BP mixtures and stabilizes the BPs at room temperature, and on the other hand, it increases the symmetry of the mutual orientation ordering among the neighboring unit cells of the BP. Hence, the resultant mixture becomes better resistive to some microscopic change due to the change in temperature, even over a large range.