Spin-orbit exciton-induced phonon chirality in a quantum magnet.

The interplay of charge, spin, lattice, and orbital degrees of freedom in correlated materials often leads to rich and exotic properties. Recent studies have brought new perspectives to bosonic collective excitations in correlated materials. For example, inelastic neutron scattering experiments revealed non-trivial band topology for magnons and spin-orbit excitons (SOEs) in a quantum magnet CoTiO3 (CTO). Here, we report phonon properties resulting from a combination of strong spin-orbit coupling, large crystal field splitting, and trigonal distortion in CTO. Specifically, the interaction between SOEs and phonons endows chirality to two [Formula: see text] phonon modes and leads to large phonon magnetic moments observed in magneto-Raman spectra. The remarkably strong magneto-phononic effect originates from the hybridization of SOEs and phonons due to their close energy proximity. While chiral phonons have been associated with electronic topology in some materials, our work suggests opportunities may arise by exploring chiral phonons coupled to topological bosons.

Observation of interplay between phonon chirality and electronic band topology.

The recently demonstrated chiral modes of lattice motion carry angular momentum and therefore directly couple to magnetic fields. Notably, their magnetic moments are predicted to be strongly influenced by electronic contributions. Here, we have studied the magnetic response of transverse optical phonons in a set of Pb1-xSnxTe films, which is a topological crystalline insulator for x > 0.32 and has a ferroelectric transition at an x-dependent critical temperature. Polarization-dependent terahertz magnetospectroscopy measurements revealed Zeeman splittings and diamagnetic shifts, demonstrating a large phonon magnetic moment. Films in the topological phase exhibited phonon magnetic moment values that were larger than those in the topologically trivial samples by two orders of magnitude. Furthermore, the sign of the effective phonon g-factor was opposite in the two phases, a signature of the topological transition according to our model. These results strongly indicate the existence of interplay between the magnetic properties of chiral phonons and the topology of the electronic band structure.

Recent Advances in Additive Manufacturing, Applications and Challenges for Dentistry: A Review.

Technological advancement in the field of dentistry has to be proven in new avenues for professionals as well as laboratory programmers. An advanced type of technology is emerging based on digitalization, as a computerized three-dimensional (3-D) model, additive manufacturing also called 3-D printing, allows formation of block pieces by adding material layer-by-layer. The additive manufacturing (AM) approach has offered extreme progress in the broad choice of distinct zones, permitting the production of fragments of all possible varieties of substances such as metal, polymer, ceramic, and composites. The significant goal of current the article is to recapitulate the recent scenarios including the imminent perspective of AM techniques and challenges in dentistry. Moreover, this article reviews the recent developments of 3-D printing advancements along with the advantages and disadvantages. Herein, various AM technologies comprising vat photopolymerization (VPP), material jetting, material extrusion, selective laser sintering (SLS), selective laser melting (SLM), and direct metal laser sintering (DMLS) technologies based powder bed fusion technologies/direct energy deposition/sheet lamination centered on binder jetting technologies were discussed in detail. This paper attempts to provide a balanced view by emphasizing the economic, scientific, and technical challenges and presenting an overview of methods to discuss the similarities based on the authors' continuing research and development.

Light driven magnetic transitions in transition metal dichalcogenide heterobilayers.

Motivated by the recent excitement around the physics of twisted transition metal dichalcogenide (TMD) multilayer systems, we study strongly correlated phases of TMD heterobilayers under the influence of light. We consider both waveguide light and circularly polarized light. The former allows for longitudinally polarized light, which in the high frequency limit can be used to selectively modify interlayer hoppings in a tight-binding model. We argue based on quasi-degenerate perturbation theory that changes to the interlayer hoppings can be captured as a modulation to the strength of the moiré potential in a continuum model. As a consequence, waveguide light can be used to drive transitions between a myriad of different magnetic phases, including a transition from a 120∘Neel phase to a stripe ordered magnetic phase, or from a spin density wave phase to a paramagnetic phase, among others. When the system is subjected to circularly polarized light we find that the effective mass of the active TMD layer is modified by an applied electromagnetic field. By simultaneously applying waveguide light and circularly polarized light to a system, one has a high level of control in moving through the phase diagram in-situ. Lastly, we comment on the experimental feasibility of Floquet state preparation and argue that it is within reach of available techniques when the system is coupled to a judiciously chosen bath.

Interface of G-quadruplex with both stabilizing and destabilizing ligands for targeting various diseases.

Guanine-rich DNA sequences may fold back into non-canonical four-stranded secondary structures termed as G-quadruplexes. The role of G-quadruplexes has already been well established in different diseases like cancer, neurological and viral disorders etc. Also, several small molecules have been reported, which can influence the involvement of G-quadruplexes either through stabilization or destabilization in the cellular environment. Growing statistics have associated G-quadruplex assemblies to a discrete biological process in vivo, including DNA replication, transcription, genomic stability, and epigenetic regulation. DNA G-quadruplex existence in human telomere is well recognized attractive target for anticancer drugs. G-quadruplex-interactive ligands have been known to prevent telomerase access as well as telomere capping. To the best of our understanding, the role of G-quadruplexes in virology, neuropharmacology, cancer progression and its treatment has not been discussed on a single platform till date. This review aims to enhance our knowledge regarding these magical sticky quadruplex structures, which have been quite significantly proved to be the part of many cellular processes along with their established in vivo existence. Understanding regarding stabilizing or destabilizing ligands of these multistranded guanine quadruplex structures might be proved as the facilitator of drug discovery process for many incurable diseases in future.

Exploring the interaction of guanidine ligands Amiloride, Rimeporide and Cariporide with DNA for understanding their role as inhibitors of Na+/H+ exchangers (NHEs): A spectroscopic and molecular docking investigation.

The inhibition of Na+/H+ Exchangers (NHEs) has shown efficacy in the pathology of several diseases like tumors, cardiovascular, and neurological disorders. The role of guanidine ligands such as amiloride, cariporide, and rimeporide as NHE inhibitors is very well documented but their interaction studies with genomic DNA are still unexplored. In this study, a combination of various biophysical and molecular docking studies was employed to investigate their binding aspects.UV-Visible, fluorescence, and circular dichroism (CD) studies indicated that guanidine ligands bind to the grooves of Calf Thymus DNA (ctDNA). Fluorescence titration studies depict that amiloride binds to ctDNA with a binding constant in the order of 102 M-1 and free energy change (ΔG0) of -14.05 KJ mol-1. Competitive fluorescence studies indicated the minor groove binding property of amiloride, whereas major groove binding mode was deduced for rimeporide and cariporide. Molecular docking studies were also found to be in accordance with the experimental results, revealing the information about the binding energy of the guanidine ligand-ctDNA complex. The docked structures depicted binding energy of -6.4 kcal mol-1 for amiloride and - 6.6 kcal mol-1 for rimeporide and cariporide. Such physicochemical studies of DNA-ligand interactions may facilitate the understanding of the mechanisms of NHE inhibition.

Strategic targeting of non-small-cell lung cancer utilizing genetic material-based delivery platforms of nanotechnology.

Several limitations of conventional cancer treatment such as non-specific targeting, solubility problems, and ineffective entry of chemotherapeutics into cancer cells can be overcome by using nanotechnology targeted drug delivery systems. Some combinations of biomolecules and nanoparticles have proven to be excellent therapeutics for Non-small cell lung cancer (NSCLC) in the last decades. Targeted gene delivery has shown in vivo as well as in vitro promising results with therapeutic efficacy. Gene therapy has shown enhanced transfection efficiency and better targeting potential on several NSCLC cell lines. Still, there are several challenges in nanoparticle-mediated gene therapy, which include stability of biomolecules and nanoparticles during delivery, managing their biodistribution, and reducing the possible cytotoxic effects of the nanoparticles, which need to be solved before clinical trials. Evaluation of therapeutic efficacy of biomolecules and nanoparticle combination in gene therapy must be established to expand the application of nano-gene therapy in cancer treatment.

Gender differences, family size and fertility rate among patients with bipolar disorder: A study from India.

This study aimed to estimate the gender differences, family size and fertility rate among patients with Bipolar disorder (BD). 219 patients diagnosed with BD, who were married for at least 3 years and aged more than 25 years were assessed clinically for the course of illness as per the NIMH-life chart. Fertility and infertility were assessed based on the information on number of living children, abortions and medical termination of pregnancies. Significantly higher proportion of male patients had comorbid substance dependence while females had significantly higher prevalence of physical comorbidity. Additionally, female participants reported significantly higher mean number of depressive episodes per year of illness and suicidal attempts. When marriage was considered as a life event and its association with onset or relapse of illness was evaluated, about one-fourth (23.3%) of the study sample reported relapse of illness at the time of marriage or immediately following the marriage. About one-fourth (24.7%) of the couple with one of the partner having bipolar disorder had no living children even after four years of their marriage. To conclude, this study suggests that there are certain gender differences with regard to the clinical profile and longitudinal course of illness of BD.

Structural Switch from Hairpin to Duplex/Antiparallel G-Quadruplex at Single-Nucleotide Polymorphism (SNP) Site of Human Apolipoprotein E (APOE) Gene Coding Region.

A gradual dementia, which leads to the loss of memory and intellectual abilities, is the main characteristics of Alzheimer's disease. Amyloid-ß (Aß) plaques are the main components that accumulate and form clumps in the brains of people suffering from Alzheimer's disease. Apolipoprotein E (APOE), an amyloid-binding protein is considered as one of the main genetic risk factor of the late-onset Alzheimer's disease. Different isoforms of APOE gene named APOE2, APOE3, and APOE4 are known to exist, which differ from each other at certain positions involving single-nucleotide polymorphisms (SNPs). Out of these isoforms, APOE4 increases the risk of developing late-onset Alzheimer's disease, whereas APOE3 is the most common among the general population. APOE4 differs from the common APOE3 by only one nucleotide at position +2985 (T to C), which results in immense alteration in the structure and function of the APOE gene. A combination of gel electrophoresis (polyacrylamide gel electrophoresis, PAGE), circular dichroism (CD), CD melting, thermal difference spectra and UV-thermal denaturation (TM) techniques was used to investigate the structural polymorphism associated with T → C single-nucleotide polymorphism (SNP) at the GC-rich sequence (d-TGGAGGACGTGTGCGGCCGCCT; APOE22T). Herein, we report that APOE22T DNA sequence switches between hairpin to antiparallel quadruplex from low to high oligomer concentration. On the contrary, its C-counterpart (APOE22C) forms hairpin as well as intermolecular antiparallel duplex structure. This structural change may possibly contribute to the protein recognition pattern, which, in turn, might control the APOE gene expression.

Angular lens.

We propose a single phase-only optical element that transforms different orbital angular momentum (OAM) modes into localized spots at separated angular positions on a transverse plane. We refer to this element as an angular lens since it separates out OAM modes in a manner analogous to how a converging lens separates out transverse wave-vector modes at the focal plane. We also simulate the proposed angular lens using a spatial light modulator and experimentally demonstrate its working. Our work can have important implications for OAM-based classical and quantum communication applications.

Formation of G-wires, bimolecular and tetramolecular quadruplex: Cation-induced structural polymorphs of G-rich DNA sequence of human SYTX gene.

An exceptional property of auto-folding into a range of intra- as well as intermolecular quadruplexes by guanine-rich oligomers (GROs) of promoters, telomeres and various other genomic locations is still one of the most attractive areas of research at present times. The main reason for this attention is due to their established in vivo existence and biological relevance. Herein, the structural status of a 20-nt long G-rich sequence with two G5 stretches (SG20) is investigated using various biophysical and biochemical techniques. Bioinformatics analysis suggested the presence of a 17-nt stretch of this SG20 sequence in the intronic region of human SYTX (Synaptotagmin 10) gene. The SYTX gene helps in sensing out the Ca2+ ion, causing its intake in the pre-synaptic neuron. A range of various topologies like bimolecular, tetramolecular and guanine-wires (nano-wires) was exhibited by the studied sequence, as a function of cations (Na+ /K+ ) concentration. UV-thermal denaturation, gel electrophoresis, and circular dichroism (CD) spectroscopy showed correlations and established a cation-dependent structural switch. The G-wire formation, in the presence of K+ , may further be explored for its possible relevance in nano-biotechnological applications.

Structural polymorphism of a cytosine-rich DNA sequence forming i-motif structure: Exploring pH based biosensors.

Sequence recognition and conformational polymorphism enable DNA to emerge out as a substantial tool in fabricating the devices within nano-dimensions. These DNA associated nano devices work on the principle of conformational switches, which can be facilitated by many factors like sequence of DNA/RNA strand, change in pH or temperature, enzyme or ligand interactions etc. Thus, controlling these DNA conformational changes to acquire the desired function is significant for evolving DNA hybridization biosensor, used in genetic screening and molecular diagnosis. For exploring this conformational switching ability of cytosine-rich DNA oligonucleotides as a function of pH for their potential usage as biosensors, this study has been designed. A C-rich stretch of DNA sequence (5'-TCCCCCAATTAATTCCCCCA-3'; SG20c) has been investigated using UV-Thermal denaturation, poly-acrylamide gel electrophoresis and CD spectroscopy. The SG20c sequence is shown to adopt various topologies of i-motif structure at low pH. This pH dependent transition of SG20c from unstructured single strand to unimolecular and bimolecular i-motif structures can further be exploited for its utilization as switching on/off pH-based biosensors.

Structural switch from a multistranded G-quadruplex to single strands as a consequence of point mutation in the promoter of the human GRIN1 gene.

A huge number of G-rich sequences forming quadruplexes are found in the human genome, especially in telomeric regions, UTRs, and the promoter regions of a number of genes. One such gene is GRIN1 encoding the NR1 subunit of the N-methyl-d-aspartate receptor (NMDA). Several lines of reports have implicated that attenuated function of NMDA results in schizophrenia, a genetic disorder characterized by hallucinations, delusions, and psychosis. Involvement of the GRIN1 gene in the pathogenesis of schizophrenia has been extensively analysed. Recent reports have demonstrated that polymorphism in the promoter region of GRIN1 at position -855 (G/C) has a possible association with schizophrenia. The binding site for the NF-κB transcription factor gets altered due to this mutation, resulting in reduced gene expression as well as NMDA activity. By combining gel electrophoresis (PAGE), circular dichroism (CD) and CD melting techniques, the G → C single nucleotide polymorphism (SNP) at the G-rich sequence (d-CTTAGCCCGAGGAG[combining low line]GGGGGTCCCAAGT; GRIN1) was investigated. We report that the GRIN1 sequence can form an octameric/multistranded quadruplex structure with parallel conformation in the presence of K+ as well as Na+. CD and gel studies are in good correlation in order to detect molecularity and strand conformation. The parallel G-quadruplex species was hypothesized to be octameric in K+/Na+ salts. The mutated sequence (d-CTTAGCCCGAGGAC[combining low line]GGGGGTCCCAAGT; GRIN1M) remained single stranded under physiological conditions. CD melting studies support the formation of an interstranded G-quadruplex structure by the GRIN1 sequence. Two structural models are propounded for a multistranded parallel G-quadruplex conformation which might be responsible for regulating the gene expression normally underlying memory and learning.

Molecular mapping of the grain iron and zinc concentration, protein content and thousand kernel weight in wheat (Triticum aestivum L.).

Genomic regions responsible for accumulation of grain iron concentration (Fe), grain zinc concentration (Zn), grain protein content (PC) and thousand kernel weight (TKW) were investigated in 286 recombinant inbred lines (RILs) derived from a cross between an old Indian wheat variety WH542 and a synthetic derivative (Triticum dicoccon PI94624/Aegilops squarrosa [409]//BCN). RILs were grown in six environments and evaluated for Fe, Zn, PC, and TKW. The population showed the continuous distribution for all the four traits, that for pooled Fe and PC was near normal, whereas, for pooled Zn, RILs exhibited positively skewed distribution. A genetic map spanning 2155.3cM was constructed using microsatellite markers covering the 21 chromosomes and used for QTL analysis. 16 quantitative trait loci (QTL) were identified in this study. Four QTLs (QGFe.iari-2A, QGFe.iari-5A, QGFe.iari-7A and QGFe.iari-7B) for Fe, five QTLs (QGZn.iari-2A, QGZn.iari-4A, QGZn.iari-5A, QGZn.iari-7A and QGZn.iari-7B) for Zn, two QTLs (QGpc.iari-2A and QGpc.iari-3A) for PC, and five QTLs (QTkw.iari-1A, QTkw.iari-2A, QTkw.iari-2B, QTkw.iari-5B and QTkw.iari-7A) for TKW were identified. The QTLs together explained 20.0%, 32.0%, 24.1% and 32.3% phenotypic variation, respectively, for Fe, Zn, PC and TKW. QGpc.iari-2A was consistently expressed in all the six environments, whereas, QGFe.iari-7B and QGZn.iari-2A were identified in two environments each apart from pooled mean. QTkw.iari-2A and QTkw.iari-7A, respectively, were identified in four and three environments apart from pooled mean. A common region in the interval of Xgwm359-Xwmc407 on chromosome 2A was associated with Fe, Zn, and PC. One more QTL for TKW was identified on chromosome 2A but in a different chromosomal region (Xgwm382-Xgwm359). Two more regions on 5A (Xgwm126-Xgwm595) and 7A (Xbarc49-Xwmc525) were found to be associated with both Fe and Zn. A QTL for TKW was identified (Xwmc525-Xbarc222) in a different chromosomal region on the same chromosome (7A). This reflects at least a partly common genetic basis for the four traits. It is concluded that fine mapping of the regions of the three chromosomes of A genome involved in determining the accumulation of Fe, Zn, PC, and TKW in this mapping population may be rewarding.

Structure-Specific Ligand Recognition of Multistranded DNA Structures.

Structural polymorphism is an extremely significant phenomenon of nucleic acids, in which DNA and RNA oligonucleotide sequences are able to adapt various canonical, alternative and multistranded structures. These alternative forms of DNA and RNA have an enormous potential of participating in various cellular processes by recognizing ligands such as proteins, drugs and metal ions in a sequence and structure-specific manner. Such DNA-ligand interactions prove to be highly beneficial when exploited for therapeutic purposes. Many of these DNA/ RNA structures recognizing drugs have already proved their potential as anticancer, antibacterial, anthelmintic and antiviral properties. Over the last 2-3 decades, many mechanisms of DNA-drug interactions have been documented, but still many other new mechanisms are being explored. Designing new drugs with improved efficacy and specificity is of prime concern for all researchers which not only deals with the experiments related to synthesizing drugs, but also takes care of searching novel routes or agents for administration or delivery of these therapeutic agents by increasing their nuclear and cellular uptake. This review aims at explaining the structural polymorphs/ multistranded DNA structures and their interactions with pharmaceutical drugs in a structure-specific manner, along with their modes of interactions and biological relevance. This detailed overview of multistranded DNA structures and interacting drugs might further facilitate our understanding about molecular targets and drug development in a more precise manner for the larger benefit of mankind.

A bouquet of DNA structures: Emerging diversity.

Structural polymorphism of DNA has constantly been evolving from the time of illustration of the double helical model of DNA by Watson and Crick. A variety of non-canonical DNA structures have constantly been documented across the globe. DNA attracted worldwide attention as a carrier of genetic information. In addition to the classical Watson-Crick duplex, DNA can actually adopt diverse structures during its active participation in cellular processes like replication, transcription, recombination and repair. Structures like hairpin, cruciform, triplex, G-triplex, quadruplex, i-motif and other alternative non-canonical DNA structures have been studied at length and have also shown their in vivo occurrence. This review mainly focuses on non-canonical structures adopted by DNA oligonucleotides which have certain prerequisites for their formation in terms of sequence, its length, number and orientation of strands along with varied solution conditions. This conformational polymorphism of DNA might be the basis of different functional properties of a specific set of DNA sequences, further giving some insights for various extremely complicated biological phenomena. Many of these structures have already shown their linkages with diseases like cancer and genetic disorders, hence making them an extremely striking target for structure-specific drug designing and therapeutic applications.

Genetic interaction and mapping studies on the leaflet development (lld) mutant in Pisum sativum.

In Pisum sativum, the completely penetrant leaflet development (lld) mutation is known to sporadically abort pinnae suborgans in the unipinnate compound leaf. Here, the frequency and morphology of abortion was studied in each of the leaf suborgans in 36 genotypes and in presence of auxin and gibberellin, and their antagonists. Various lld genotypes were constructed by multifariously recombining lld with a coch homeotic stipule mutation and with af, ins, mare, mfp, tl and uni-tac leaf morphology mutations. It was observed that the suborgans at all levels of pinna subdivisions underwent lld-led abortion events at different stages of development. As in leafblades, lld aborted the pinnae in leaf-like compound coch stipules. The lld mutation interacted with mfp synergistically and with other leaf mutations additively. The rod-shaped and trumpet-shaped aborted pea leaf suborgans mimicked the phenotype of aborted leaves in HD-ZIP-III-deficient Arabidopsis thaliana mutants. Suborganwise aborted morphologies in lld gnotypes were in agreement with basipetal differentiation of leaflets and acropetal differentiation in tendrils. Altogether, the observations suggested that LLD was the master regulator of pinna development. On the basis of molecular markers found linked to lld, its locus was positioned on the linkage group III of the P. sativum genetic map.

COCHLEATA controls leaf size and secondary inflorescence architecture via negative regulation of UNIFOLIATA (LEAFY ortholog) gene in garden pea Pisum sativum.

UNIFOLIATA [(UNI) or UNIFOLIATA-TENDRILLED ACACIA (UNI-TAC)] expression is known to be negatively regulated by COCHLEATA (COCH) in the differentiating stipules and flowers of Pisum sativum. In this study, additional roles of UNI and COCH in P. sativum were investigated. Comparative phenotyping revealed pleiotropic differences between COCH (UNI-TAC and uni-tac) and coch (UNI-TAC and uni-tac) genotypes of common genetic background. Secondary inflorescences were bracteole-less and bracteolated in COCH and coch genotypes, respectively. In comparison to the leaves and corresponding sub-organs and tissues produced on COCH plants, coch plants produced leaves of 1.5-fold higher biomass, 1.5-fold broader petioles and leaflets that were 1.8-fold larger in span and 1.2-fold dorso-ventrally thicker. coch leaflets possessed epidermal cells 1.3-fold larger in number and size, 1.4-fold larger spongy parenchyma cells and primary vascular bundles with 1.2-fold larger diameter. The transcript levels of UNI were at least 2-fold higher in coch leaves and secondary inflorescences than the corresponding COCH organs. It was concluded that COCH negatively regulated UNI in the differentiating leaves and secondary inflorescences and thereby controlled their sizes and/or structures. It was also surmised that COCH and UNI (LFY homolog) occur together widely in stipulate flowering plants.