Impact of core polarity on smectic B-induced hydrogen bond liquid crystals

The novel series of hydrogen bond liquid crystals were synthesized from the 2-methylglutaric acid (MGA) and 4-alkyloxybenzoic acid (nOBA) compounds. The induced smectic B phase with different texture (spine texture, needle texture, mosaic texture, natural mosaic texture and marble texture) were identified by polarizing optical microscope. Due to breaking of in-plane rotational symmetry within molecular layers, smectic B phase is tempted by suppressing other usual mesophases. The mesomorphic transition temperature, enthalpy and entropy values were calculated by differential scanning calorimeter which strongly proves the existence of mesomorphism. H-bond interaction and functional groups were confirmed by the observed peak between 2910 and 2954 cm^-1 in the FTIR spectra. Thermal stability and extended mesophase width (for MGA + 12OBA = 31.1) of Sm B mesophase were reported and it clearly reveals the existence of mono-phase variance in the MGA + nOBA HBLC complex. Due to the steric effect, and the increased molecular core polarity, the highly stabilized Sm B phase with different textures were observed while varying alkyloxy carbon number n = 7 to 12. Further, the origination of Sm B phase and its detailed characteristics were reported.

Occurrence of Banana bract mosaic virus on Musa ornata Roxb based hybrids in India

Musa ornata, wild species of banana is being used as a cut flower, potted plants and for landscape gardening etc., They are also being utilized in banana hybridization programmes for introgressing pest and disease tolerant traits into banana cultivars in addition to the development of inter specific ornamental banana hybrids. Symptoms of banana bract mosaic virus (BBrMV) was observed in the bracts of interspecific M. ornata based hybrid developed using another wild species i.e., Musa rubra Kurz at ICAR-National Research Centre for Banana (NRCB), Tiruchirapalli. Presence of the virus in the bracts, leaves and roots of symptomatic plants was confirmed through triple antibody sandwich enzyme linked immunosorbent assay with BBrMV monoclonal and polyclonal antibodies. BBrMV HC-Pro (1370 bp), CP (900 bp) and VPg (570 bp) genes were amplified from the infected bracts using reverse transcriptase polymerase chain reaction with BBrMV respective gene primers. The amplicons of these three genes were cloned and sequenced. Blastn analysis revealed that HC-Pro, VPg and CP gene sequences has 97.67%, 97.72% and 99.67% similarity with the respective gene sequences of BBrMV infecting banana. Phylogenetic analysis clustered the test isolate with other BBrMV isolates of banana and other hosts based on CP and HC-Pro and VPg gene sequences. The virus is transmitted through Pentalonia nigronervosa and the transmitted plants expressed symptoms under glass house conditions. To the best of our knowledge, this is the first report of BBrMV on ornamental M. ornata hybrid in India and its transmission occurs through Pentalonia nigronervosa.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13337-022-00788-6.

Efficacy and dose-response relationship of oral treprostinil in PAH patients on monotherapy or dual background therapy

Background

FREEDOM-C and FREEDOM-C2 were randomized, placebo-controlled, double-blinded international, multicenter studies investigating the use of oral treprostinil (TRE) in subjects on mono or dual background pulmonary arterial hypertension (PAH) therapies. Both had a primary endpoint of change in 6-minute walk distance (6MWD) at Week 16 vs baseline. Previous post-hoc analyses combining mono and dual therapy subjects (PDE-5i and/or ERA) from these studies revealed a TRE dose-dependent increase in 6MWD. (1. White & Rao, 2016)

Purpose

This post-hoc analysis was performed to determine if subjects from FREEDOM-C and FREEDOM-C2 derive improvements in 6MWD with increasing doses of TRE when stratified by mono or dual background therapy and to determine if PAH background therapies (mono or dual) impacted 6MWD.

Methods

All active subjects (n=331) from FREEDOM-C and FREEDOM-C2 were grouped into TRE dose tertiles (low-dose: ≤2 mg BID, mid-dose: >2 mg to ≤3.5 mg BID, and high-dose: >3.5 mg BID). Placebo subjects (n=329) were in a separate 0 mg dose group. No data imputation was implemented.

Comparisons of 6MWD change at Weeks 4, 8, 12, and 16 between mono and dual therapy subgroups at any dose group were performed using a two-sample t-test or nonparametric Wilcoxon rank-sum test. The nonparametric Kruskal-Wallis test was conducted with subsequent pairwise comparisons of 6MWD change at Week 16 between the four dose groups through Dunn's approach. Additionally, the Jonckheere-Terpstra test was used to assess the linear trend for 6MWD improvement with higher doses of TRE.

Results

Baseline characteristics of the combined intention to treat (ITT) population and summary of 6MWD for subjects with both baseline and Week 16 data are in Table 1. 6MWD change improved steadily to Week 16 in subjects at higher TRE doses, regardless of the number of PAH background therapies (Figure 1). No statistical differences were found between mono and dual therapy at any time point or for any dose group. At Week 16, there was a significant difference in 6MWD change between the placebo group and high dose group within both mono and dual background therapy subjects. The difference between the low- and high-dose groups was significant for subjects on dual background therapy. There was a significant positive linear trend for TRE doses in 6MWD improvement at Week 16 for both monotherapy subjects (one-sided p-value = 0.0002) and dual therapy subjects (one-sided p-value = 0.0242).

Conclusions

6MWD improved in PAH patients regardless of their background therapy (monotherapy or dual background) and derive greater 6MWD improvements with higher doses of TRE. The observed dose-dependent 6MWD increase supports the use of TRE in sequential combination with background therapies (mono or dual).

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): United Therapeutics Corporation

New record of mungbean yellow mosaic India virus in Desmodium laxiflorum and association of bhendi yellow vein mosaic betasatellite in Abelmoschus moschatus in Andhra Pradesh, India

Mungbean yellow mosaic India virus (MYMIV) is one of the most serious commonly occurring yellow mosaic virus (YMV's) group in majority of the pulses especially black gram and green gram in southern India compared to previously reported mungbean yellow mosaic virus. In January 2020 Desmodium laxiflorum and Abelmoscus moschatus showing mosaic symptoms and vein yellowing were collected from Guntur and Prakasam districts respectively in Andhra Pradesh. PCR analysis using MYMIV and betasatellite specific primers gave desired expected amplification from the infected samples of A. moschatus (YMV-ABEL) whereas only MYMIV specific amplification was obtained in D. laxiflorum (YMV-DES). However, no PCR amplification was obtained in respective healthy leaf samples of both plants. Sequence analysis showed that the CP sequence of YMV-ABEL and YMV-DES showed a similarity of 99.19% with MYMIV (KP677496) and 99.75% with MYMIV (JN181003) respectively. The full-length betasatellite (1356 bp) showed highest identity of 90% with bhendi yellow vein mosaic betasatellite (BYVMB) (GU111977). Phylogenetic analysis clustered the test isolates with south Indian isolates of MYMIV whereas the betasatellite sequence clustered with various isolates of BYVMB, tomato leaf curl New Delhi virus betasatellite and okra leaf curl betasatellite reported from India and Pakistan. To the best of our knowledge, this is the first report of a MYMIV in D. laxiflorum and A. moschatus and MYMIV betasatellite complex in A. moschatus.

Azaindole Based Potentiator of Antibiotics against Gram-Negative Bacteria

We discovered azaindole-based compounds with weak innate activity that exhibit substantial potentiation of antibacterial activities of different antibiotics, viz., rifampicin, erythromycin, solithromycin, and novobiocin in Gram-negative bacteria. In the presence of the azaindole derivatives, these antibiotics exhibited submicromolar minimum inhibitory concentrations (MICs) against Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii. The fold improvements in MIC of these antibiotics that were otherwise weak or inactive on their own against these bacteria were also observed against drug-resistant clinical isolates. Our studies indicate that this selective potentiation is probably through destabilization of the outer membrane's integrity, known to be regulated by the lipopolysaccharides (LPS). Thus, the azaindole based compounds described here open opportunities for those antibiotics that are otherwise ineffective due to LPS mediated entry barriers in Gram-negative bacteria.

Investigation of FSSW parameters on shear fracture load of AA6061 and copper alloy joints

In this research, Friction stir spot welding (FSSW) is extensively employed to join dissimilar metals consisting of AA6061-T6 Aluminium Alloy and Commercial Copper Alloy. These alloys were friction stir spot welded using process parameters with the major impact, such as Dwell Time (DT), Rotational Speed (RS), Plunge Rate (PR) and Tool Diameter Ratio (D/d). Trail experiments have been carried out using Design of Experiments. Sound welded joints exhibiting a maximum shear fracture load of 4.79 kN were obtained at a RS of 2000 rpm, PR of 7 mm/min, DT of 25 s and D/d of 3.5, Balanced material flow around the pin was also observed at this condition, and it is evident that the superior metallurgical properties and geometric features at this condition results in the higher strength. Moreover, the joint also exhibited higher load-bearing capabilities due to an optimal hook height of 0.89 mm, hook width of 1.3 mm and hook initiation distance of 1.4 mm. The continuous formation of intermetallic compound such as ɤ₂-Cu₉Al₄ in the Cu zone and ɳ₂-CuAl in the Al zone may also enhance the shear fracture load.

Observation of Induced Luminescence and Thermochromism in Achiral Hydrogen Bonded Liquid Crystal Complexes

A novel hydrogen bonded liquid crystal (HBLC) complexes are obtained from the non-mesogenic (benzylmalonic acid) and mesogenic (p-n-alkyloxybenzoic acid, where n = 6, 7 and 8) compound via intermolecular hydrogen bonds (H-bond). H-bonds are experimentally confirmed by the Fourier transform infrared spectroscopic (FT-IR) studies and the same is validated using density functional theory (DFT). Induced thermochromism is observed by the polarizing optical microscope (POM) and its possible applications are reported. Phase transition temperature and their analogous enthalpy values, stability factor and span width are determined by the differential scanning calorimetry (DSC) studies. Band gap energy is calculated using UV-visible and photoluminescence spectrum. Hyper conjugative stabilization energy and atomic charge distribution is studied by the natural bond orbital (NBO) studies. Mulliken analysis clearly reveals the intermolecular interaction and steric effect of the HBLC complexes. An interesting phenomenon is that the observation of luminescence and thermochromism in the highly fluidity nematic phase. This peculiar behavior is attributed due to the intermolecular H-bonding interaction between the BMA and nOBA compounds and the effect of rotatory motion of the molecules in nematic phase. Luminescence increases when the spacer moiety decreases in the present complexes is also reported. In nematic phase, the molecules are in different degrees of the excited state which is correlated with the hyper conjugative energy through NBO studies.

Data set on prediction of friction stir welding parameters to achieve maximum strength of AA2014-T6 aluminium alloy joints

Statistical tools such as design of experiments (DoE), analysis of variance (ANOVA) were used to develop the empirical relationship, to predict the ultimate tensile strength of the joint at the 95% percent confidence level. Response surface graph and contour plots were constructed using response surface methodology (RSM) concept. From this investigation, it is found that the joint fabricated with a tool rotational speed of 1500 rpm, welding speed of 40 mm/min, tool tilt angle of 1.5° and tool shoulder diameter of 6 mm, exhibited maximum tensile strength of 380 MPa.

Hot tensile properties and constant load stress corrosion cracking test data of autogenous weld joints of super 304HCu stainless steel in boiling MgCl2 solution

Hot tensile test data of Gas Tungsten Arc Welded (GTAW) autogenous joints of Super 304HCu tubes tested at their operating temperature are presented along with the microstructure of the weld joint. The GTAW joints exhibited lower tensile strength than the parent metal and the failure occurred in the weld metal region for all test temperatures. Constant load Stress Corrosion Cracking (SCC) test data of the GTAW weld joints tested in boiling MgCl₂ environment at different applied stress level are presented. SCC curves obtained from the test were analyzed to derive SCC parameters such as rate of steady state elongation, the time required for set-in of tertiary region, and time to complete fracture. The fracture surfaces of SCC samples were examined using Scanning Electron Microscope to reveal the mode of fracture. Super 304HCu stainless steel being used as construction material for super heaters and reheaters of advanced ultra super critical boilers, this data will be an addition to the design data available for material selection in design of power plants.

Post-Transcriptional Regulation of Hepatic DDAH1 with TNF Blockade Leads to Improved eNOS Function and Reduced Portal Pressure In Cirrhotic Rats

Portal hypertension (PH) is a major cause of morbidity and mortality in chronic liver disease. Infection and inflammation play a role in potentiating PH and pro-inflammatory cytokines, including TNF, are associated with severity of PH. In this study, cirrhotic bile duct ligated (BDL) rats with PH were treated with Infliximab (IFX, a monoclonal antibody against TNF) and its impact on modulation of vascular tone was assessed. BDL rats had increased TNF and NFkB compared to sham operated rats, and their reduction by IFX was associated with a reduction in portal pressure. IFX treatment also reduced hepatic oxidative stress, and biochemical markers of hepatic inflammation and injury. IFX treatment was associated with an improvement in eNOS activity and increased l-arginine/ADMA ratio and DDAH1 expression. In vitro analysis of HepG2 hepatocytes showed that DDAH1 protein expression is reduced by oxidative stress, and this is in part mediated by post-transcriptional regulation by the 3′UTR. This study supports a role for the DDAH1/ADMA axis on the effect of inflammation and oxidative stress in PH and provides insight for new therapies.

Discovery of Imidazo[1,2-a]pyridine Ethers and Squaramides as Selective and Potent Inhibitors of Mycobacterial Adenosine Triphosphate (ATP) Synthesis

The approval of bedaquiline to treat tuberculosis has validated adenosine triphosphate (ATP) synthase as an attractive target to kill Mycobacterium tuberculosis (Mtb). Herein, we report the discovery of two diverse lead series imidazo[1,2-a]pyridine ethers (IPE) and squaramides (SQA) as inhibitors of mycobacterial ATP synthesis. Through medicinal chemistry exploration, we established a robust structure-activity relationship of these two scaffolds, resulting in nanomolar potencies in an ATP synthesis inhibition assay. A biochemical deconvolution cascade suggested cytochrome c oxidase as the potential target of IPE class of molecules, whereas characterization of spontaneous resistant mutants of SQAs unambiguously identified ATP synthase as its molecular target. Absence of cross resistance against bedaquiline resistant mutants suggested a different binding site for SQAs on ATP synthase. Furthermore, SQAs were found to be noncytotoxic and demonstrated efficacy in a mouse model of tuberculosis infection.

Complete coverage of space favors modularity of the grid system in the brain

Grid cells in the entorhinal cortex fire when animals that are exploring a certain region of space occupy the vertices of a triangular grid that spans the environment. Different neurons feature triangular grids that differ in their properties of periodicity, orientation, and ellipticity. Taken together, these grids allow the animal to maintain an internal, mental representation of physical space. Experiments show that grid cells are modular, i.e., there are groups of neurons which have grids with similar periodicity, orientation, and ellipticity. We use statistical physics methods to derive a relation between variability of the properties of the grids within a module and the range of space that can be covered completely (i.e., without gaps) by the grid system with high probability. Larger variability shrinks the range of representation, providing a functional rationale for the experimentally observed comodularity of grid cell periodicity, orientation, and ellipticity. We obtain a scaling relation between the number of neurons and the period of a module, given the variability and coverage range. Specifically, we predict how many more neurons are required at smaller grid scales than at larger ones.

Nitroarenes as Antitubercular Agents: Stereoelectronic Modulation to Mitigate Mutagenicity

Nitroarenes are less preferred in drug discovery due to their potential to be mutagenic. However, several nitroarenes were shown to be promising antitubercular agents with specific modes of action, namely, nitroimidazoles and benzothiazinones. The nitro group in these compounds is activated through different mechanisms, both enzymatic and non-enzymatic, in mycobacteria prior to binding to the target of interest. From a whole-cell screening program, we identified a novel lead nitrobenzothiazole (BT) series that acts by inhibition of decaprenylphosphoryl-β-d-ribose 2'-epimerase (DprE1) of Mycobacterium tuberculosis (Mtb). The lead was found to be mutagenic to start with. Our efforts to mitigate mutagenicity resulted in the identification of 6-methyl-7-nitro-5-(trifluoromethyl)-1,3-benzothiazoles (cBTs), a novel class of antitubercular agents that are non-mutagenic and exhibit an improved safety profile. The methyl group ortho to the nitro group decreases the electron affinity of the series, and is hence responsible for the non-mutagenic nature of these compounds. Additionally, the co-crystal structure of cBT in complex with Mtb DprE1 established the mode of binding. This investigation led to a new non-mutagenic antitubercular agent and demonstrates that the mutagenic nature of nitroarenes can be solved by modulation of stereoelectronic properties.

Scaffold morphing leading to evolution of 2,4-diaminoquinolines and aminopyrazolopyrimidines as inhibitors of the ATP synthesis pathway

2,4-Diaminoquinazolines, 2,4-diaminoquinolines and aminopyrazolopyrimidines, inhibitors of mycobacterial ATP synthesis, are novel lead molecules towards discovery and development of new anti-tubercular agents.

Discovery of benzothiazoles as antimycobacterial agents: Synthesis, structure-activity relationships and binding studies with Mycobacterium tuberculosis decaprenylphosphoryl-β-D-ribose 2'-oxidase

We report the discovery of benzothiazoles, a novel anti-mycobacterial series, identified from a whole cell based screening campaign. Benzothiazoles exert their bactericidal activity against Mycobacterium tuberculosis (Mtb) through potent inhibition of decaprenylphosphoryl-β-d-ribose 2'-oxidase (DprE1), the key enzyme involved in arabinogalactan synthesis. Specific target linkage and mode of binding were established using co-crystallization and protein mass spectrometry studies. Most importantly, the current study provides insights on the utilization of systematic medicinal chemistry approaches to mitigate safety liabilities while improving potency during progression from an initial genotoxic hit, the benzothiazole N-oxides (BTOs) to the lead-like AMES negative, crowded benzothiazoles (cBTs). These findings offer opportunities for development of safe clinical candidates against tuberculosis. The design strategy adopted could find potential application in discovery of safe drugs in other therapy areas too.

Population structure of Banana bract mosaic virus reveals recombination and negative selection in the helper component protease (HC-Pro) gene

Banana bract mosaic virus (BBrMV) is a serious constraint in the production of banana and plantain in India. In this study, we have cloned, sequenced and analyzed the helper component proteinase (HC-Pro) gene of 22 isolates from India and compared with previously reported BBrMV isolates. Sequence identity of BBrMV isolates encoding HC-Pro gene, were 92-100 % both at the nucleotide (nt) and amino acid level. Phylogenetic analysis based on nt sequences of non recombinant isolates showed that TN15, TN9 and TN24 formed one cluster and all the remaining isolates formed into another cluster. Different functional motifs in the central region of HC-Pro gene of BBrMV isolates were found conserved. Four potential recombinants with a total of 15 breakpoints were mostly observed at the N and a few from C terminal regions. The codon based selection analysis revealed that most of the codons were under purifying or negative selection except a codon at position 74 which was under positive selection. It is likely that recombination identified in Indian BBrMV isolates, along with strong purifying selection, enhances the speed of elimination of deleterious mutations in the HC-Pro gene. This study suggested that negative selection and recombination were important evolutionary factors driving the genetic diversification and population structure of Indian BBrMV isolates. To the best of our knowledge, this is the first report on the diversity analysis and occurrence of recombination in the HC-Pro gene of BBrMV.

Enhancement of in vitro high-density polyethylene (HDPE) degradation by physical, chemical, and biological treatments

Partially degraded high-density polyethylene (HDPE) was collected from plastic waste dump yard for biodegradation using fungi. Of various fungi screened, strain MF12 was found efficient in degrading HDPE by weight loss and Fourier transform infrared (FT-IR) spectrophotometric analysis. Strain MF12 was selected as efficient HDPE degraders for further studies, and their growth medium composition was optimized. Among those different media used, basal minimal medium (BMM) was suitable for the HDPE degradation by strain MF12. Strain MF12 was subjected to 28S rRNA sequence analysis and identified as Aspergillus terreus MF12. HDPE degradation was carried out using combinatorial physical and chemical treatments in conjunction to biological treatment. The high level of HDPE degradation was observed in ultraviolet (UV) and KMnO4/HCl with A. terreus MF12 treatment, i.e., FT10. The abiotic physical and chemical factors enhance the biodegradation of HDPE using A. terreus MF12.

Muscle fatigue based evaluation of bicycle design

Bicycling posture leads to considerable discomfort and a variety of chronic injuries. This necessitates a proper bicycle design to avoid injuries and thereby enhance rider comfort. The objective of this study was to investigate the muscle activity during cycling on three different bicycle designs, i.e., rigid frame (RF), suspension (SU) and sports (SP) using surface electromyography (sEMG). Twelve male volunteers participated in this study. sEMG signals were acquired bilaterally from extensor carpi radialis (ECR), trapezius medial (TM), latissimus dorsi medial (LDM) and erector spinae (ES), during 30 min of cycling on each bicycle and after cycling. Time domain (RMS) and frequency domain (MPF) parameters were extracted from acquired sEMG signals. From the sEMG study, it was found that the fatigue in right LDM and ES were significantly (p < 0.05) higher in SP bicycle. This was corroborated by a psychophysical assessment based on RBG pain scale. The study also showed that there was a significantly lesser fatigue with the SU bicycle than the RF and SP bicycles.

Inhomogeneous thermalization in strongly coupled field theories

To describe theoretically the creation and evolution of the quark-gluon plasma, one typically employs three ingredients: a model for the initial state, nonhydrodynamic early time evolution, and hydrodynamics. In this Letter we study the nonhydrodynamic early time evolution using the AdS/CFT correspondence in the presence of inhomogeneities. We find that the AdS description of the early time evolution is well matched by free streaming. Near the end of the early time interval where our analytic computations are reliable, the stress tensor agrees with the second order hydrodynamic stress tensor computed from the local energy density and fluid velocity. Our techniques may also be useful for the study of far-from-equilibrium strongly coupled systems in other areas of physics.