Dark Matter from Evaporating PBH dominated in the Early Universe

Primordial Black Holes (PBH) could dominate in the early universe and, evaporating before Big bang Nucleosynthesis, can provide new freeze in mechanism of dark matter (DM) production. The proposed scenario is considered for two possible mechanisms of PBH formation and the corresponding continuous PBH mass spectra so that the effect of non-single PBH mass spectrum is taken into account in the results of PBH evaporation, by which PBH dominance in the early universe ends. We specify the conditions under which the proposed scenario can explain production of dark matter in very early Universe.Comment: 21 pages; 6 figure

Strong Hilbert space fragmentation via emergent quantum drums in two dimensions

We introduce a disorder-free model of $S=1/2$ spins on the square lattice in a constrained Hilbert space where two up-spins are not allowed simultaneously on any two neighboring sites of the lattice. The interactions are given by ring-exchange terms on elementary plaquettes that conserve both the total magnetization as well as dipole moment. We show that this model provides a tractable example of strong Hilbert space fragmentation in two dimensions with typical initial states evading thermalization with respect to the full Hilbert space. Given any product state, the system can be decomposed into disjoint spatial regions made of edge and/or vertex sharing plaquettes that we dub as ``quantum drums''. These quantum drums come in many shapes and sizes and specifying the plaquettes that belong to a drum fixes its spectrum. The spectra of some small drums is calculated analytically. We study two bigger quasi-one-dimensional drums numerically, dubbed ``wire'' and a ``junction of two wires'' respectively. We find that these possess a chaotic spectrum but also support distinct families of quantum many-body scars that cause periodic revivals from different initial states. The wire is shown to be equivalent to the one-dimensional PXP chain with open boundaries, a paradigmatic model for quantum many-body scarring; while the junction of two wires represents a distinct constrained model.Comment: v3: 57 pages, 30 figs; resubmission to SciPost Physic

Radiation Effect on Boundary Layer Flow of a Nanofluid over a Nonlinearly Permeable Stretching Sheet

We analyze the influence of thermal radiation on boundary layer flow of a nanofluid past a nonlinearly permeable stretching sheet. The governing partial differential equations are reduced into a system of ordinary differential equations using similarity transformation and then solved by using shooting technique. Effects of thermal radiation parameter, Brownian motion parameter, Suction parameter and Thermophoresis parameter on the flow, concentration and heat transfer characteristics are thoroughly investigated. The local Nusselt number and the local Sherwood numbers are presented and compared with existed results. Keywords: Heat transfer, Nanofluid, Thermal radiation, Boundary layer flow, Stretching/Shrinking sheet

Dual role of nanoparticles as drug carrier and drug.

The conventional chemotherapeutic agents used in the treatment of human malignancies are directed nonspecifically against both malignant and nonmalignant cells, often limiting their efficacy with having serious side effects. Recent development of drug delivery vehicles has opened up the possibility of targeted drug delivery systems with the potential of achieving maximum efficacy with minimal toxicity. The possibility of using a nanomaterial as a combinational drug component is intuitively evident as it would compensate the toxicity level by enhancing drug delivery efficiency. Additionally, cell-specific cytotoxicity (reported earlier by our group) of the nanovehicle itself may potentiate a more effective targeted cell killing. In this paper, we explore the possibility of using gold nanoparticles playing the dual role of an anticancer agent and a carrier of a chemotherapeutic drug. This is demonstrated using vincristine sulfate (VS), salt of an alkaloid often used in the treatment of multiple myeloma (MM), and U266 as a test MM cell line. The drug VS shows the expected G2-M-phase arrest of cells. Notably, bare gold nanoparticle shows arrest of the S phase cells that may be particularly important in case of slow-growing malignancies like MM where most of the cells remain in G1 phase of the cell cycle. The VS conjugated gold retains the activity of both gold nanoparticle and VS leading to a synergistic rise of the apoptotic cell population

AQUEOUS BARK EXTRACT OF TERMINALIA ARJUNA PROTECTS AGAINST PHENYLHYDRAZINE INDUCED OXIDATIVE DAMAGE IN GOAT RED BLOOD CELL MEMBRANE BOUND AND METABOLIC ENZYMES

Objective: The objective of the present study is to determine the phenylhydrazine (PHZ) induced oxidative stress mediated alteration in the metabolic status and morphology of the red blood cells (RBC) and amelioration of the same by aqueous bark extract of Terminalia arjuna (TA).Methods: Fresh goat blood collected from local Kolkata Corporation approved slaughter house, was used for the present study. Packed cells were prepared from the freshly collected goat blood and were divided into four groups as follows for further studies i. e Group I: Control (CON), Group II: TA bark extract treated, named T5C (5 mg/ml, incubation mixture; positive control), Group III: PHZ treated (1 mM), Group IV: PHZ treated+TA bark extract at a dose of 5 mg/ml, named as P+T5. ROS, superoxide anion radical, and hydroxyl radical scavenging activity were determined. Intracellular iron and intracellular nitrate concentration were estimated. Activities of various membrane-bound enzymes like Na+/K+-ATPase, Mg2+-ATPase and Ca2+-ATPase and Ach-E were determined. Moreover, the activities of some metabolic enzymes like glucose 6-phosphate dehydrogenase (G6PDH), hexokinase, aldolase, lactase dehydrogenase were also studied. In addition, the morphological structure of RBCs was also determined.Results: PHZ treatment caused significant alterations in RBC morphology as well as altered the activities of membrane-bound as well as metabolic enzymes. All these changes following oxidative stress were found to be ameliorated when the RBCs were co-treated with PHZ and aqueous bark extract of TA. However, aqueous bark extract of TA alone did not exhibit any such changes in RBC.Conclusion: The aqueous bark extract of TA ameliorates PHZ-induced oxidative damages in goat RBC possibly by an antioxidant mechanism(s). The aqueous bark extract of TA may have future therapeutic relevance in oxidative stress-induced damages in RBCs.Keywords: Antioxidant enzymes, Aqueous bark extract, Oxidative stress, Phenylhydrazine, Red blood cells, Terminalia arjun

Neutron star-black hole mergers in next generation gravitational-wave observatories

Observations by the current generation of gravitational-wave detectors have been pivotal in expanding our understanding of the universe. Although tens of exciting compact binary mergers have been observed, neutron star-black hole (NSBH) mergers remained elusive until they were first confidently detected in 2020. The number of NSBH detections is expected to increase with sensitivity improvements of the current detectors and the proposed construction of new observatories over the next decade. In this work, we explore the NSBH detection and measurement capabilities of these upgraded detectors and new observatories using the following metrics: network detection efficiency and detection rate as a function of redshift, distributions of the signal-to-noise ratios, the measurement accuracy of intrinsic and extrinsic parameters, the accuracy of sky position measurement, and the number of early-warning alerts that can be sent to facilitate the electromagnetic follow-up. Additionally, we evaluate the prospects of performing multi-messenger observations of NSBH systems by reporting the number of expected kilonova detections with the Vera C. Rubin Observatory and the Nancy Grace Roman Space Telescope. We find that as many as $\mathcal{O}(10)$ kilonovae can be detected by these two telescopes every year, depending on the population of the NSBH systems and the equation of state of neutron stars.Comment: 30 pages, 15 figure

Gestation-wise Reference Ranges of Neutrophil Counts in Indian Newborns

Objectives: Blood counts are commonly performed tests in neonatal intensive care units with the results having various clinical ramifications. Interpreting blood counts as normal or abnormal requires reference ranges as per gestation. Studies on reference ranges for neonatal neutrophil counts are already scarce, and data is lacking in the Asian context. We sought to formulate gestation-wise reference ranges of neutrophil counts in an Indian setting. Methods: Healthy, newborn babies of either gender, aged between 30 to 41 weeks gestation were included in the study. Gestational age was corroborated through first trimester dating scan and postnatally by the New Ballard Score. Single venous blood samples were drawn on day three and day five for estimation of total leukocyte count, differential count (neutrophils, lymphocytes), and peripheral blood smear examination. Results: We evaluated the data of 420 newborns. The normative values were compiled week-wise for gestational ages of 30 to 41 weeks at birth. We observed a clustering of neutrophil count values below 8000 cells/μL on day three and below 5000 cells/μL on day five. No gender-based differences in counts were observed. We were able to generate reference range curves for neutrophil counts as per gestational age. Conclusions: The absolute neutrophil counts of term and preterm Indian newborns are higher than the values depicted in the standard reference chart used currently. This indicates that a different standard chart as per gestation should be used in Indo-Asian countries to differentiate ‘normal’ from ‘abnormal’

SILYMARIN PROTECTS AGAINST COPPER-ASCORBATE INDUCED INJURY TO GOAT CARDIAC MITOCHONDRIA IN VITRO: INVOLVEMENT OF ANTIOXIDANT MECHANISM(S)

Silymarin, 'one of the component of the Milk thistle seeds Silybum marianum (L.) is used in traditional food and medicine in India. In the present study, we investigated the antioxidant activities of Silymarin against copper-ascorbate induced toxic injury to mitochondria obtained from goat heart, in vitro. Incubation of isolated cardiac mitochondria with copper-ascorbate resulted in elevated levels of lipid peroxidation and protein carbonylation of the mitochondrial membrane, a reduced level of mitochondrial GSH and altered status of antioxidant enzymes as well as decreased activities of pyruvate dehydrogenase and the Kreb's cycle enzymes, altered mitochondrial morphology, mitochondrial swelling and di-tyrosine level. All these changes were found to be ameliorated when the cardiac mitochondria were co-incubated with copper-ascorbate and Silymarin, in vitro. Silymarin, in our in vitro experiments, was found to scavenge hydrogen peroxide, superoxide anion free radicals, hydroxyl radicals and DPPH radical, in a chemically defined system, indicating that this compound may provide protection to cardiac mitochondria against copper-ascorbate induced toxic injury through its antioxidant activities. The results of this study suggest that Silymarin may be considered as a future therapeutic antioxidant and may be used singly or as a co-therapeutic in the treatment of diseases associated with mitochondrial oxidative stress