Classical route to ergodicity and scarring in collective quantum systems.

Ergodicity, a fundamental concept in statistical mechanics, is not yet a fully understood phenomena for closed quantum systems, particularly its connection with the underlying chaos. In this review, we consider a few examples of collective quantum systems to unveil the intricate relationship of ergodicity as well as its deviation due to quantum scarring phenomena with their classical counterpart. A comprehensive overview of classical and quantum chaos is provided, along with the tools essential for their detection. Furthermore, we survey recent theoretical and experimental advancements in the domain of ergodicity and its violations. This review aims to illuminate the classical perspective of quantum scarring phenomena in interacting quantum systems.

Association between levels of insulin-like growth factor-1 in serum and seminal plasma with fresh and frozen-thawed semen characteristics in Beetal bucks.

The aim of this study was to investigate the relationship between the levels of insulin-like growth factor-1 (IGF-1) in serum and seminal plasma and the characteristics of semen in Beetal bucks (Capra hircus). A total of 12 adult Beetal bucks were involved in the study, with each buck providing six ejaculates collected using a standard artificial vagina (n = 72 total). Only qualified semen samples (volume of 0.7 mL, a mass motility rating of 3+ or higher on a 0-+ scale, and individual progressive motility of 80% or more) divided into three fractions were processed for estimation of IGF-1 and other seminal parameters like motility, viability, acrosome integrity, sperm abnormality and superoxide dismutase (SOD) activity. The first and second fraction were diluted and extended with Optixcell extender (1:15 ratio). The first ejaculate fraction was processed for studying fresh semen parameters and the second fraction was cryopreserved for evaluating frozen semen parameters. French mini straws (0.25 mL) were used for semen filling, and polyvinyl alcohol powder of different colours was used for sealing the extended semen. The third fraction of each ejaculate was centrifuged at room temperature (1100 × g for 7 min) to separate the seminal plasma. Additionally, blood samples were taken from each buck on the same day as semen collection, resulting in a total of 36 blood samples. The results revealed a significant positive correlation (r = .4243; p < .05) between the concentration of IGF-1 in both serum and seminal plasma of the Beetal bucks. Furthermore, the concentration of IGF-1 in serum showed significant positive correlations with sperm viability (r = .554; p < .05), acrosome integrity (r = .527; p < .05), post-thaw sperm motility (r = .407; p < .01), post-thaw sperm viability (r = .426; p < .01) and post-thaw acrosome integrity (r = .333; p < .05). However, it had a significant negative correlation with SOD activity in fresh semen (r = -0.458; p < .01). Moreover, the concentration of IGF-1 in seminal plasma demonstrated significant positive correlations with individual progressive motility (r = .341; p < .05), sperm viability (r = .527; p < .05), acrosome integrity (r = .539; p < .05), sperm plasma membrane integrity (r = .464; p < .05), post-thaw sperm motility (r = .644; p < .01), post-thaw sperm viability (r = .643; p < .01), post-thaw acrosome integrity (r = .487; p < .01) and post-thaw sperm plasma membrane integrity (r = .521; p < .01). Additionally, it showed a significant negative correlation with SOD activity in both fresh semen (r = -0.714; p < .01) and frozen semen (r = -0.558; p < .01) of Beetal bucks. Based on these findings, IGF-1 in seminal plasma can be considered as a potential biomarker for the selection of bucks for breeding purposes.

Zinc oxide and selenium nanoparticles can improve semen quality and heat shock protein expression in cryopreserved goat (Capra hircus) spermatozoa.

BACKGROUND: Reactive oxygen species (ROS) are strongly linked with oxidative stress (OS) generated during the process of sperm cryopreservation. Indeed, cellular damage from ROS has been implicated during sperm cryopreservation which causes deterioration in sperm quality and antioxidant nanoparticles (NPs) have been successful in preventing such damage. The interaction of NPs with sperm cells has been less frequently explored in farm animals. OBJECTIVE: The present study explored the effect of NP supplementation on sperm ultrastructure, potential interaction with sperm membrane (plasma and acrosome membrane), heat shock protein (HSP) gene expression levels and sperm quality in cryopreserved buck semen. MATERIALS AND METHODS: Thirty-two (32) ejaculates were collected from four (4) adult male bucks and then diluted in Tris- citric acid- fructose- egg yolk (TCFY) extender containing the Zinc-oxide (ZnO) and Selenium (Se) NP treatments (T0: Control; TZn: 0.1 mg/mL ZnO NPs and TSe: 1 µg/mL Se NPs) after initial evaluation. Diluted semen was packed in 0.25 mL French mini straws and then stored in liquid nitrogen (LN2). Sperm parameters, lipid peroxidation (LPO) profile, sperm head morphology ultrastructural classification under transmission electron microscope (TEM), potential interaction of NPs with sperm membrane and expression of HSP genes were evaluated in the different treatment groups. RESULTS: We found a significant (p < 0.05) increase in the percentage of spermatozoa with intact plasma membrane, and intact acrosome in the ZnO (0.1 mg/mL) and Se (1 µg/mL) NP supplemented groups in comparison to the frozen control group. TEM assessment revealed no internalization of both ZnO and Se NPs into the sperm structure. Few occasional contacts of ZnO NPs with the sperm membrane and a few agglomerates of Se NPs around the area of damaged membranes were visualized. HSP70 and HSP90 mRNA levels were significantly (p < 0.001) higher in the NP supplemented groups in comparison to the control. HSP70 and HSP90 mRNA levels had a strong positive association with sperm motility and a weak to moderate association with other sperm parameters. CONCLUSIONS: Current findings indicated that ZnO NPs are more potent than Se NPs in ameliorating peroxidative damages during sperm cryopreservation, increases semen quality parameters possibly by increasing the expression levels of HSP genes in buck semen. Furthermore, NP supplementation may have a potential role in preserving sperm head ultrastructure by acting as an antioxidant and reducing OS during various degrees of cellular insults, which needs to be further explored.

In Vitro and In Vivo Studies on the Efficacy of Zinc-Oxide and Selenium Nanoparticle in Cryopreserved Goat (Capra hircus) Spermatozoa.

Different nanoparticles (NPs) are currently being investigated for their potential role as cryoprotectant during semen cryopreservation in several mammalian species. It may be possible to improve semen quality following cryopreservation by supplementation of NPs in the freezing extenders. The present study was carried out in semen collected from four (4) Assam Hill Goat bucks (10 ejaculates per buck) to investigate the effect of supplementing zinc oxide (ZnO) and selenium (Se) NPs in Tris-citric acid-fructose yolk (TCFY) extender on in vitro sperm quality and in vivo fertility rate after freeze-thawing. The size morphology and zeta potential of ZnO and Se NPs were evaluated prior to its incorporation in the freezing extender. Qualified semen samples (> 70% progressive motility) were divided into five (5) aliquots and then diluted in TCFY extender containing ZnO and Se NP supplementation at different concentrations (T0, control; T1, 0.1 mg/mL ZnO NPs; T2, 0.5 mg/mL ZnO NPs; T3, 0.5 µg/mL Se NPs; and T4, 1 µg/mL Se NPs). Diluted semen was packed in 0.25 mL straws and then stored in liquid nitrogen. After thawing, post-thaw in vitro sperm attributes were evaluated. Finally, the effect of NPs on in vivo fertility rate was checked in heat-synched does (n = 70) by artificial insemination (AI) using straws that showed superior results during the in vitro study. Results showed that ZnO and Se NPs were poly-crystalline in nature with particle size below 100 nm (nm). The evaluated post-thaw sperm in vitro attributes were significantly (p < 0.001) higher in T1 in comparison to T0. The antioxidant enzyme activities were significantly (p < 0.001) higher in T1. Lipid peroxidation (LPO) profile was significantly (p < 0.001) lower in T1. Sperm motility and mitochondrial membrane potential (MMP) had a highly significant (r = 0.580, p < 0.05) association in T1. No significant (p > 0.05) differences in pregnancy rates were recorded after AI in the different treatments. In conclusion, extender supplemented with 0.1 mg/mL ZnO NPs improved post-thaw semen quality of goat spermatozoa consequently by increasing activities of endogenous antioxidant enzymes thereby lowering LPO levels. However, improved in vitro outcomes might not correspond to improved field fertility outcomes.

Studies on nanomaterial-based p-type semiconductor gas sensors.

The development of various metal oxide semiconductor materials has resulted in better performance of the gas sensors in terms of selectivity, sensitivity, and response time. Different types of nanostructured materials, i.e., 2D materials, carbon nanotubes, and metal oxides, are used in the gas sensing applications. Generally, the metal oxide-based gas sensor operates at higher temperature to activate the adsorption process between the material surface and the target gas. The higher operating temperature of the gas sensor leads to more power consumption and produces defects in the grain boundary of metal oxide. To improve the selectivity and minimize the power consumption, nanoparticle-based p-type semiconductor materials are being developed. P-type metal oxide-based semiconductor materials have the ability to produce a hole accumulation layer which can chemisorb the oxygen molecules of higher concentration and these materials are not affected by humidity. The structure of p-type nanomaterial-based gas sensor depends upon the fabrication techniques which can affect the sensing properties of semiconductor materials. The hole accumulation layer is also known as conduction layer which is developed in the outer shell of p-type semiconductor material and the sensing mechanism is controlled by grain boundaries which is different from the n-type semiconductor material. This paper reviews the preparation methods, morphological analysis, and sensing mechanisms of nanomaterial-based p-type metal oxide-based gas sensors.

Quantum transitions, ergodicity, and quantum scars in the coupled top model.

We consider an interacting collective spin model known as coupled top (CT), exhibiting a rich variety of phenomena related to quantum transitions, ergodicity, and formation of quantum scars, discussed in our previous work [Mondal, Sinha, and Sinha, Phys. Rev. E 102, 020101(R) (2020)2470-004510.1103/PhysRevE.102.020101]. In this work, we present a detailed analysis of the different type of transitions in the CT model, and find their connection with the underlying collective spin dynamics. Apart from the quantum scarring phenomena, we also identify another source of deviation from ergodicity due to the presence of nonergodic multifractal states. The degree of ergodicity of the eigenstates across the energy band is quantified from the relative entanglement entropy as well as multifractal dimensions, which can be probed from nonequilibrium dynamics. Finally, we discuss the detection of nonergodic behavior and different types of quantum scars using "out-of-time-order correlators," which has relevance in the recent experiments.

Dynamical route to ergodicity and quantum scarring in kicked coupled top.

Unlike classical systems, understanding ergodicity from phase space mixing remains unclear for interacting quantum systems due to the absence of phase space trajectories. By considering an interacting spin model known as kicked coupled top, we elucidate the manifestation of phase space dynamics on local ergodic behavior of its quantum counterpart and quantum scarring phenomena. A transition to chaos occurs by increasing the kicking strength, and in the mixed phase space, the islands of regular motions within the chaotic sea clearly exhibit deviation from ergodicity, which we quantify from entanglement entropy and survival probability. Interestingly, the reminiscence of unstable orbits and fixed points can be identified as scars in quantum states, exhibiting athermal behavior and violation of Berry's conjecture for ergodic states. We also discuss the detection of quantum scars by a recently developed method of "out-of-time-order correlators," which has experimental relevance.

Fingerprint of chaos and quantum scars in kicked Dicke model: an out-of-time-order correlator study.

We investigate the onset of chaos in a periodically kicked Dicke model (KDM), using the out-of-time-order correlator (OTOC) as a diagnostic tool, in both the oscillator and the spin subspaces. In the large spin limit, the classical Hamiltonian map is constructed, which allows us to investigate the corresponding phase space dynamics and to compute the Lyapunov exponent. We show that the growth rate of the OTOC for the canonically conjugate coordinates of the oscillator is able to capture the Lyapunov exponent in the chaotic regime. The onset of chaos is further investigated using the saturation value of the OTOC, that can serve as an alternate indicator of chaos in a generic interacting quantum system. This is also supported by a system independent effective random matrix model. We further identify the quantum scars in KDM and detect their dynamical signature by using the OTOC dynamics. The relevance of the present study in the context of ongoing cold atom experiments is also discussed.

Chaos and Quantum Scars in Bose-Josephson Junction Coupled to a Bosonic Mode.

We consider a model describing Bose-Josephson junction (BJJ) coupled to a single bosonic mode exhibiting quantum phase transition (QPT). Onset of chaos above QPT is observed from semiclassical dynamics as well from spectral statistics. Based on entanglement entropy, we analyze the ergodic behavior of eigenstates with increasing energy density which also reveals the influence of dynamical steady state known as π-mode on it. We identify the imprint of unstable π-oscillation as many body quantum scar (MBQS), which leads to the deviation from ergodicity and quantify the degree of scarring. Persistence of phase coherence in nonequilibrium dynamics of such initial state corresponding to the π-mode is an observable signature of MBQS which has relevance in experiments on BJJ.

Chaos and quantum scars in a coupled top model.

We consider a coupled top model describing two interacting large spins, which is studied semiclassically as well as quantum mechanically. This model exhibits a variety of interesting phenomena such as a quantum phase transition (QPT), a dynamical transition, and excited-state quantum phase transitions above a critical coupling strength. Both classical dynamics and entanglement entropy reveal ergodic behavior at the center of the energy density band for an intermediate range of coupling strength above QPT, where the level spacing distribution changes from Poissonian to Wigner-Dyson statistics. Interestingly, in this model we identify quantum scars as reminiscent of unstable collective dynamics even in the presence of an interaction. The statistical properties of such scarred states deviate from the ergodic limit corresponding to the random matrix theory and violate Berry's conjecture. In contrast to ergodic evolution, the oscillatory behavior in the dynamics of the unequal time commutator and survival probability is observed as the dynamical signature of a quantum scar, which can be relevant for its detection.

Cortical source localization during facial emotion recognition in bipolar mania: An ERP study.

Facial emotion recognition has enormous value for humans in social cognition and thereby day to day functioning. Disturbances in the processing of emotional cues are seen in all the three phases of bipolar disorder and have been proposed as an etiology in the development of bipolar disorder. 30 consented patients with bipolar mania with psychotic symptoms and 30 age and sex matched healthy controls were taken for the study. Facial emotion ecognition task containing four basic emotions namely happy, sad, anger and fear were used. Sixty four (64) channel ERP recordings were done for all the subjects. Source localization was done using sLORETA selecting the window for late positive potentials (LPP). Statistically significant and reduced cortical sources were noted in the right insula (p = 0.004) at the peak of LPP during response to anger facial emotions in bipolar mania patients. Hypoactivation of right insular cortex during response to anger emotion may be due to the aberrant activation and possible failure of interoceptive prediction system during acute manic phase are discussed.

Dissipative Bose-Josephson junction coupled to bosonic baths.

We investigate the effect of dissipation in a Bose-Josephson junction (BJJ) coupled to baths of bosons at its two sites. Apart from the dynamical transition due to repulsive interactions, the BJJ undergoes a quantum phase transition by increasing the coupling strength with the bath modes. We analyze this system by mapping to an equivalent spin model coupled to the bosonic modes. The excitation energies and fluctuation of number imbalance are obtained within a Holstein-Primakoff approximation, which exhibits vanishing of the energy gap and enhanced quantum fluctuations at the critical point. We study the dynamics of BJJ using a time-dependent variational method and analyze stability of different types of steady states. As a special case we study in detail the phase space dynamics of BJJ coupled to a single mode, which reveals diffusive and incoherent behavior with increasing coupling to the bath mode. The dynamical steady states corresponding to the π oscillation and self-trapped state become unstable when their oscillation frequencies are in resonance with the bath modes. We study the Josephson dynamics in the presence of an Ohmic bath with Gaussian noise to incorporate the thermal fluctuations and obtain the Josephson oscillation frequency and damping analytically. We also observe the transition to the symmetry-broken state for strong coupling as well as decay of π oscillation and a self-trapped state to the ground state due to dissipation. Variation of the phase fluctuation with temperature of the bath shows similar behavior as observed in experiment. Finally we discuss the experimental setup to study the observable effects of dissipation in BJJ.

Understanding the molecular mechanism of improved proliferation and osteogenic potential of human mesenchymal stem cells grown on a polyelectrolyte complex derived from non-mulberry silk fibroin and chitosan.

The development of engineered bone tissue, as a promising alternative to conventional bone grafts, has so far not proven successful and still remains challenging. Thus, attempts have been made in the present study to synthesize polyelectrolyte complex (PEC) scaffolds by blending chitosan (CS) to silk fibroin (SF) derived from the non-mulberry silkworm (Antheraea pernyi) at three different pH values (5.0, 6.0, and 7.0), and to characterize them in terms of morphology, ultrastructure and mechanical properties with scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy, x-ray diffraction and tensile strength analyses. The prepared PEC scaffolds showed a mean pore size of 130 µm, as revealed by SEM analysis, and a comparatively higher compressive strength. The findings of in vitro cytocompatibility, in vivo biocompatibility and osteogenic marker (genes/proteins) analysis suggest that the PECs blended at pH 7.0 showed greater stability and enhanced growth and an osteogenic differentiation capability of human mesenchymal stem cells (MSCs). To aid our understanding of protein-polyion binding mechanisms, we employed a molecular docking and simulation study of SF macrodomains and CS oligomer using Schrödinger 14 and GROMACS (Groningen Machine for Chemical Simulations) software. The study involved analytical techniques for macromolecular solution characterization and theoretical simulations based on molecular dynamics. The computational studies confirmed the presence of an integral RGD sequence that played a vital role in superior cell-attachment, proliferation and osteogenic differentiation of MSCs grown on the developed SF-CS PEC scaffolds.

Medical and scientific writing: Time to go lean and mean.

The Lean Six Sigma methodology for process improvements and driving efficiency is old, but lean writing was adopted late by the pharmaceutical world in terms of size of the documents. The documents were lean earlier, and then became voluminous, and now we are about to complete a full circle in this regard, i.e., coming back to the lean documents again using e-formats and hyperlinking. Furthermore, writing has become more and more precise over time. The need for this lean and mean medical and scientific writing arose from voluminous research globally, both industry and academia which are abuzz with skyrocketing regulatory and scientific submission volumes. The quantum of literature is so much that reviewers or information seekers firmly believe that going through even selected and relevant literature has become highly challenging. Considering this, there has been much insistence on downsizing the medical writing documents, which could be tempting enough to be leveraged for scientific publications as well. Here, we present the need for lean and mean medical writing, discuss this concept in relation to the pharmaceutical industry, and how to apply this to key documents. Furthermore, presented is the proposed algorithm for lean and mean clinical study reports and manuscripts. These thoughts are aligned to the recently established concept of data transparency, and can be easily achieved by web links between the protocols and clinical trial results disclosed publicly, and the corresponding manuscripts.

Effect of thawing methods on frozen semen quality of yak (Poephagus grunniens L.) bulls.

AIM: To evaluate different thawing temperatures and duration on the post-thaw semen quality of Indian yaks bulls. MATERIALS AND METHODS: Semen ejaculates from four different yak bulls were collected using artificial vagina method and extended with tris extender containing 6.4% glycerol at 35°C, cooled gradually from 35°C to 5°C at 1°C/3 min and equilibrated at 4-5°C for 4 h and frozen in French mini straws using a programmable bio-freezer and finally stored in liquid nitrogen. Thawing of frozen semen straws was carried out using three methods i.e., 35°C for 60 s (thawing method I), 37°C for 30 s (thawing method II) and 75°C for 9 s (thawing method III). The post-thaw semen quality parameters assessed were sperm motility, percent live sperm, hypo-osmotic swelling test (HOST)-reacted sperm, acrosomal changes, and alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in the extracellular media. RESULTS: The percent sperm motility, total incidence of acrosomal changes, and extracellular release of AST varied significantly (p<0.01) between thawing methods but live sperm and HOST-reacted sperm did not vary significantly between thawing methods. The percent sperm motility of frozen yak semen for thawing method III was significantly (p<0.05) higher than that for thawing methods I and II, the difference between thawing methods I and II being non-significant. The critical difference test revealed that the total incidence of acrosomal changes and extracellular release of AST were significantly (p<0.05) lower when thawing was done using methods I and II than in method III. CONCLUSION: On the basis of the present experiment, we can conclude that barring the post-thaw sperm motility, thawing of frozen yak semen in water either at 35°C for 60 s or 37°C for 30 s gives better post-thaw semen quality than at 75°C for 09 s.