EXtraction or PREServation? EXPRESS survey of patients' preference for toothache in public health facilities of Eastern India

OBJECTIVE

To investigate patients' preference for extraction or preservation for toothache and hypothetical anterior tooth pain along with the specific reason for their choice.

BASIC RESEARCH DESIGN

Cross-sectional analytical semi-structured interview study.

PARTICIPANTS

A sample of 703 adult dental outpatients visiting secondary and tertiary government health centres with toothache due to dental caries in Eastern India.

MAIN OUTCOME MEASURES

Patients preferring restorative or extraction services for toothache, specific reason, and socio-demographic background factors for anterior and posterior teeth.

RESULTS

Half (50.1%) choose preservation for present toothache and 79.9% for hypothetical front tooth pain. Immediate relief from toothache for extraction and the motive to preserve natural teeth for preservation were the main reasons expressed. In logistic regression, participants preferring extraction were more likely to be aged 25-34 years (OR = 1.94), 55+ years (OR=33.32), have primary and below education level (OR=1.99), have had a previous extraction (OR=1.99) and be unaware of preservation options (OR=2.34). For assumed anterior tooth pain, those between 25-34 years (OR=0.39) were more likely to choose preservation. Participants with primary and below education levels (OR=1.99) and unaware of preservation options (OR=1.95) chose extraction of the front tooth irrespective of their choice of treatment for the present toothache.

CONCLUSION

Notable differences between the choices to preserve or extract a posterior tooth were not found. There was greater preference towards preserving anterior teeth. Future research should identify additional barriers to the preference and utilization of restorative services.

Evidence of a Hardening in the Cosmic Ray Proton Spectrum at around 166 TeV Observed by the GRAPES-3 Experiment

We present the measurement of the cosmic ray proton spectrum from 50 TeV to 1.3 PeV using 7.81×10^{6} extensive air shower events recorded by the ground-based GRAPES-3 experiment between 1 January 2014 and 26 October 2015 with a live time of 460 day. Our measurements provide an overlap with direct observations by satellite and balloon-based experiments. The electromagnetic and muon components in the shower were measured by a dense array of plastic scintillator detectors and a tracking muon telescope, respectively. The relative composition of the proton primary from the air shower data containing all primary particles was extracted using the multiplicity distribution of muons which is a sensitive observable for mass composition. The observed proton spectrum suggests a spectral hardening at ∼166  TeV and disfavors a single power law description of the spectrum up to the Knee energy (∼3  PeV).

Identification of starvation-mimetic bioactive phytocomponent from Withania somnifera using in-silico molecular modelling and flow cytometry-based analysis for the management of malaria

Multidrug resistance episodes in malaria increased from 3.9% to 20% from 2015 to 2019. Synchronizing the clinical manifestation in chronological sequence led to a unique impression on glucose demand (increased up to 100-fold) by the parasite-infected RBCs. Hence, restriction in the glucose uptake to parasite-infected RBCs could be an alternative approach to conquer the global burden of malaria to a greater extent. A C28 steroidal lactone Withaferin A (WS-3) isolated from Withania somnifera leave extract shows better thermodynamically stable interactions with the glucose transporters (GLUT-1 and PfHT) to standard drugs metformin and lopinavir. MD simulations for a trajectory period of 100 ns reflect stable interactions with the interactive amino acid residues such as Pro141, Gln161, Gln282, Gln283, Trp388, Phe389, and Phe40, Asn48, Phe85, His168, Gln169, Asn311 which potentiating inhibitory activity of WS-3 against GLUT-1 and PfHT respectively. WS-3 was non-hemotoxic (%hemolysis <5%) for a high concentration of up to 1 mg/ml in the physiological milieu. However, the %hemolysis significantly increased up to 30.55 ± 0.929% in a parasitophorous simulated environment (pH 5.0). Increased hemolysis of WS-3 could be due to the production of ROS in an acidic environment. Further, the inhibitory activity of WS-3 against both glucose transporters was supported with flow cytometry-based analysis of parasite-infected RBCs. Results show that WS-3 has low mean fluorescence intensities for both target proteins compared to conventional drugs, suggesting a potential sugar transporter inhibitor against GLUT-1 and PfHT for managing malaria. Communicated by Ramaswamy H. Sarma.

Combined Quantum Mechanical and Quasi-Classical State-to-State Dynamical Study on the Isotopic Effect in H/D + LiH+/LiD+ → H2/HD/D2 + Li+ Reactions

Coriolis-coupled quantum mechanical (QM-CC) and quasi-classical trajectory (QCT) calculations are carried out to investigate the dynamics of the H(D) + LiH+(v = 0, j = 0) → H2(HD) (v', j') + Li+ reactions on the ground electronic state potential energy surface reported by Martinazzo et al. (Martinazzo et al., J. Chem. Phys. 2003, 119, 11241). The QM-CC and QCT results at the initial state-selected and state-to-state levels are used to investigate the validity and accuracy of the QCT method for these exoergic barrierless reactions. Furthermore, the QCT method is used to understand the isotopic effects on reaction observables like total and state-to-state integral cross section, differential cross section, product energy disposal, and rate constants of H(D) + LiH+(v = 0, j = 0) → H2(HD) (v', j') + Li+ and H(D) + LiD+(v = 0, j = 0) → HD(D2) (v', j') + Li+ reactions. Attempts are also made to understand the impact of the isotopic substitution on the reaction mechanism. It is observed that QM-CC and QCT results closely follow each other at the initial state-selected and state-to-state levels. Noticeable kinematic effects of reagents on the reactivity and mechanism of the reactions are also observed.

Electronic nonadiabatic effects in the state-to-state dynamics of the H + H2 → H2 + H exchange reaction with a vibrationally excited reagent

Out of the many major breakthroughs that the hydrogen-exchange reaction has led to, electronic nonadiabatic effects that are mainly due to the geometric phase has intrigued many. In this work we investigate such effects in the state-to-state dynamics of the H + H2 (v = 3, 4, j = 0) → H2 (v', j') + H reaction with a vibrationally excited reagent at energies corresponding to thermal conditions. The dynamical calculations are performed by a time-dependent quantum mechanical method both on the lower adiabatic potential energy surface (PES) and also using a two-states coupled diabatic theoretical model to explicitly include all the nonadiabatic couplings present in the 1E' ground electronic manifold of the H3 system. The nonadiabatic couplings are considered here up to the quadratic term; however, the effect of the latter on the reaction dynamics is found to be very small. Adiabatic population analysis showed a minimal participation of the upper adiabatic surface even for the vibrationally excited reagent. A strong nonadiabatic effect appears in the state-to-state reaction probabilities and differential cross sections (DCSs). This effect is manifested as "out-of-phase" oscillations in the DCSs between the results of the uncoupled and coupled surface situations. The oscillations persist as a function of both scattering angle and collision energy in both the backward and forward scattering regions. The origins of these oscillations are examined in detail. The oscillations that appear in the forward direction are found to be different from those due to glory scattering, where the latter showed a negligibly small nonadiabatic effect. The nonadiabatic effects are reduced to a large extent when summed over all product quantum states, in addition to the cancellation due to integration over the scattering angle and partial wave summation.

Asymmetric comb waveguide for strong interactions between atoms and light

Coupling quantum emitters and nanostructures, in particular cold atoms and optical waveguides, has recently raised a large interest due to unprecedented possibilities of engineering light-matter interactions. In this work, we propose a new type of periodic dielectric waveguide that provides strong interactions between atoms and guided photons with an unusual dispersion. We design an asymmetric comb waveguide that supports a slow mode with a quartic (instead of quadratic) dispersion and an electric field that extends far into the air cladding for an optimal interaction with atoms. We compute the optical trapping potential formed with two guided modes at frequencies detuned from the atomic transition. We show that cold Rubidium atoms can be trapped as close as 100 nm from the structure in a 1.3-mK-deep potential well. For atoms trapped at this position, the emission into guided photons is largely favored, with a beta factor as high as 0.88 and a radiative decay rate into the slow mode 10 times larger than the free-space decay rate. These figures of merit are obtained at a moderately low group velocity of c/50.

Multi-state and Multi-mode Vibronic Coupling Effects in the Photoionization Spectroscopy of Acetaldehyde

Multi-state and multi-mode vibronic dynamics in the seven energetically low-lying (X~2A', A~2A″, B~2A', C~2A', D~2A″, E~2A', and F~2A') electronic states of the acetaldehyde radical cation is theoretically studied in this article. Adiabatic energies of these electronic states are calculated by ab initio quantum chemistry methods. A vibronic coupling model of seven electronic states is constructed in a diabatic electronic basis to carry out the first-principles nuclear dynamics study. The vibronic spectrum is calculated and compared with the experimental findings reported in the literature. The progressions of vibrational modes found in the spectrum are assigned. The findings reveal that the X~2A' and F~2A' electronic states are energetically well-separated from the other electronic states and the remaining states (A~2A″ to E~2A') are energetically very close or even quasi-degenerate at the equilibrium geometry of the reference electronic ground state of acetaldehyde. The energetic proximity of A~2A″ to E~2A' electronic states results in multiple multi-state conical intersections. The impact of electronic nonadiabatic interactions due to conical intersections on the vibronic structure of the photoionization band and nonradiative internal conversion dynamics is discussed.

Optimal control of photodissociation of phenol using genetic algorithm

Photodissociation dynamics of the OH bond of phenol is studied with an optimally shaped laser pulse. The theoretical model consists of three electronic states (the ground electronic state, ππ* state, and πσ* state) in two nuclear coordinates (the OH stretching coordinate as a reaction coordinate, r, and the CCOH dihedral angle as a coupling coordinate, θ). The optimal UV laser pulse is designed using the genetic algorithm, which optimizes the total dissociative flux of the wave packet. The latter is calculated in the adiabatic asymptotes of the S0 and S1 electronic states of phenol. The initial state corresponds to the vibrational levels of the electronic ground state and is defined as | n r, n θ⟩, where n r and n θ represent the number of nodes along r and θ, respectively. The optimal UV field excites the system to the optically dark πσ* state predominantly over the optically bright ππ* state with the intensity borrowing effect for the |0, 0⟩ and |0, 1⟩ initial states. For the |0, 0⟩ initial condition, the photodissociation to the S1 asymptotic channel is favored slightly over the S0 asymptotic channel. Addition of one quantum of energy along the coupling coordinate increases the dissociation probability in the S1 channel. This is because the wave packet spreads along the coupling coordinate on the πσ* state and follows the adiabatic path. Hence, the S1 asymptotic channel gets more ([Formula: see text]11%) dissociative flux as compared to the S0 asymptotic channel for the |0, 1⟩ initial condition. The |1, 0⟩ and |1, 1⟩ states are initially excited to both the ππ* and πσ* states in the presence of the optimal UV pulse. For these initial conditions, the S1 channel gets more dissociative flux as compared to the S0 channel. This is because the high energy components of the wave packet readily reach the S1 channel. The central frequency of the optimal UV pulse for the |0, 0⟩ and |0, 1⟩ initial states has a higher value as compared to the |1, 0⟩ and |1, 1⟩ initial states. This is explained with the help of an excitation mechanism of a given initial state in relation to its energy.

Quantum interference in the mechanism of H + LiH+ → H2 + Li+ reaction dynamics

In this work, the detailed reaction mechanism of the astrochemically relevant exoergic and barrierless H + LiH⁺ → H₂ + Li⁺ reaction is investigated by both time-dependent wave packet and quasi-classical trajectory (QCT) methods on the ab initio electronic ground state potential energy surface reported by Martinazzo et al. [Martinazzo et al., J. Chem. Phys., 2003, 119, 11241]. The interference terms due to the coherence between the partial waves are quantified. When plotted along the scattering angle they reveal interference of constructive or destructive nature. Significant interference was found in the differential cross-section (DCS) which is a symbolic of the non-statistical nature of the reaction. This is further complemented by calculating the lifetime of the collision complex by the QCT method. It is found that the reaction follows a direct stripping mechanism at higher collision energies and yields forward scattered products from collisions involving high total angular momentum. At low collision energies, the reaction follows a mixed direct/indirect mechanism but with a dominant indirect contribution. The product state-resolved DCSs reveal that two opposite mechanisms co-exist, both at low and high collision energies. The microscopic scattering mechanism of the reaction is found to be unaffected by the ro-vibrational excitation of the reagent diatom.

SARS COV-2- IgG antibodies in blood donors in pandemic - A game changer for policy makers

BACKGROUND

A novel beta coronavirus, named Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2), has been identified as the causative pathogen for the present pandemic. The objective of the study was to measure the levels of IgG antibodies targeting the SARS-CoV-2 during the peak period of the COVID-19 pandemic in Odisha State, India to know the magnitude of SARS-CoV-2 exposure, the prevalence of herd immunity in the population, the distribution of IgG-positive cases examined according to ABO blood groups and the number of blood donors with higher neutralizing IgG antibody titre who later on were converted into Plasma Donors donating Convalescent Plasma (CP).

METHOD

This observational prospective study was conducted for a duration of three months on 1032 number of Blood donors consisting of 1025 number of males and 07 number of females. The samples of donors were subjected to Electro- chemiluminescence immunoassay (ECLIA) to detect SARS-CoV-2 IgG antibodies.

RESULT

Out of 1032 Donors, 370(35.9%) were SARS-COV-2 IgG positive which included 303 donors (29.36%) with neutralizing antibody titre of SARS-COV2 IgG antibodies above 1:80. SARS-COV-2 IgG positive cases consisted of 367(35.8%) male and 3(42.9%) female donors. The number of IgG positive cases were highest in 21-40 years' age group i.e. 323 out of 869(37.2%). In terms of Blood group, 145(42.4%) out of 342 were from B RhD positive group. Out of 22 donors who were positive with COVID 19 in the past with neutralizing IgG antibody titre more than 1:80, 6(27.3%) persons came for voluntary convalescent plasma(CP) donation.

CONCLUSION

A high prevalence of SARS-CoV-2 antibodies was detected among blood donors which indicated a high level of exposure to the virus within the population and development of innate immunity against the virus. Policy makers can add the protocol of antibody testing in the screening of blood donors to enhance the number of Plasma Donation cases for the treatment of serious COVID patients.

Integrated multiplex network based approach for hub gene identification in oral cancer

Background: The incidence of Oral Cancer (OC) is high in Asian countries, which goes undetected at its early stage. The study of genetics, especially genetic networks holds great promise in this endeavor. Hub genes in a genetic network are prominent in regulating the whole network structure of genes. Thus identification of such genes related to specific cancer types can help in reducing the gap in OC prognosis. Methods: Traditional study of network biology is unable to decipher the inter-dependencies within and across diverse biological networks. Multiplex network provides a powerful representation of such systems and encodes much richer information than isolated networks. In this work, we focused on the entire multiplex structure of the genetic network integrating the gene expression profile and DNA methylation profile for OC. Further, hub genes were identified by considering their connectivity in the multiplex structure and the respective protein-protein interaction (PPI) network as well. Results: 46 hub genes were inferred in our approach with a high prediction accuracy (96%), outstanding Matthews coefficient correlation value (93%) and significant biological implications. Among them, genes PIK3CG, PIK3R5, MYH7, CDC20 and CCL4 were differentially expressed and predominantly enriched in molecular cascades specific to OC. Conclusions: The identified hub genes in this work carry ontological signatures specific to cancer, which may further facilitate improved understanding of the tumorigenesis process and the underlying molecular events. Result indicates the effectiveness of our integrated multiplex network approach for hub gene identification. This work puts an innovative research route for multi-omics biological data analysis.

Theoretical Study of the Energy Disposal Mechanism and the State-Resolved Quantum Dynamics of the H + LiH+ → H2 + Li+ Reaction

Despite several studies in the literature, the detailed quantum state-to-state level mechanism of the astrophysically important exoergic barrierless H + LiH⁺ → H₂ + Li⁺ reaction is yet to be understood. In this work, we have investigated the energy disposal mechanism of the reaction in terms of integral reaction cross section, product internal state distributions, differential cross section, and rate constant. Fully converged and Coriolis coupled quantum mechanical calculations based on a time-dependent wave packet method have been performed at the state-to-state level on the ab initio electronic ground state potential energy surface (PES) constructed by Martinazzo et al. (J. Chem. Phys. 2003, 119, 11241-11248). The agreement between the present quantum mechanical and previous quasi-classical results is found even at very low relative translational energies of reagents. A non-statistical inverse Boltzmann vibrational distribution for the product is found. This is attributed to the "attractive" nature of the underlying PES, which facilitates the excess energy release mostly as product vibration (60-80%). The energy disposal in products is found to be unaffected by the rovibrational excitation of the reagent diatom due to the weak coupling between the vibrational modes of the reagent and the product. The mild effect of collision energy on the product energy disposal is ascribed to the effective coupling between the translational modes of the reagent and the product. It is found that the collisions lead to the formation of the product H₂ in its rovibrationally excited levels.

Constraints and challenges in convalescent plasma collection amidst the Covid 19 pandemic- strategies and recommendations to overcome these

Background

COVID 19 is an acute respiratory disease caused by infection by the virus SARS-COV-2 and has been declared as a pandemic whose specific treatment is still not established. One of the options in the treatment is Convalescent plasma (CP) therapy when there is presence of required amount of neutralizing antibodies in the plasma of recovered COVID patients. Our objective was to analyze the challenges and the constraints encountered in motivation of COVID 19 recovered persons to come for the screening procedures and to convince the selected persons to come for Plasma donation voluntarily.

Material & methods

The present retrospective observational study was conducted for a period of five and half months. Out of 1515 number of persons contacted telephonically for Plasma donation, 1291 persons came for screening of whom 1028 persons were eligible for donation, 263 cases were deferred and 966 persons finally donated.

Results

Maximum number of acceptance cases were from males-(98.7%). Of the accepted cases, (41.73%) were from the 18-30 years’ age group. 33.94% were from blood group ‘O’ Rh D positive giving maximum contribution from any blood group. 38.3% of the accepted cases had resolution of all COVID symptoms within time period of 28-40 days. Maximum number of accepted individuals (39.75%) had suffered from multiple symptoms followed by 39.02% of asymptomatic persons. Highest number of Plasma donation was contributed by Odisha Government Police personnel (51.56%).

Discussion

In this global ongoing pandemic, the “Fear Factor of contracting the disease” has acted as a major challenge in motivating and convincing a COVID recovered patient for plasma donation. The challenge before the medical professionals was to motivate, educate and convince the potential donors and the society about the likely benefits of convalescent plasma. This could be finally overcome with the help of positive orientation through social and conventional media as well as mass appeal from government side on the benefits of plasma therapy in saving lives in the present pandemic.

Femtosecond Transfer and Manipulation of Persistent Hot-Trion Coherence in a Single CdSe/ZnSe Quantum Dot

Ultrafast transmission changes around the fundamental trion resonance are studied after exciting a p-shell exciton in a negatively charged II-VI quantum dot. The biexcitonic induced absorption reveals quantum beats between hot-trion states at 133 GHz. While interband dephasing is dominated by relaxation of the P-shell hole within 390 fs, trionic coherence remains stored in the spin system for 85 ps due to Pauli blocking of the triplet electron. The complex spectrotemporal evolution of transmission is explained analytically by solving the Maxwell-Liouville equations. Pump and probe polarizations provide full control over amplitude and phase of the quantum beats.

Vibronic coupling in the first six electronic states of pentafluorobenzene radical cation: Radiative emission and nonradiative decay

Nuclear dynamics in the first six vibronically coupled electronic states of pentafluorobenzene radical cation is studied with the aid of the standard vibronic coupling theory and quantum dynamical methods. A model 6 × 6 vibronic Hamiltonian is constructed in a diabatic electronic basis using symmetry selection rules and a Taylor expansion of the elements of the electronic Hamiltonian in terms of the normal coordinate of vibrational modes. Extensive ab initio quantum chemistry calculations are carried out for the adiabatic electronic energies to establish the diabatic potential energy surfaces and their coupling surfaces. Both time-independent and time-dependent quantum mechanical methods are employed to perform nuclear dynamics calculations. The vibronic spectrum of the electronic states is calculated, assigned, and compared with the available experimental results. Internal conversion dynamics of electronic states is examined to assess the impact of various couplings on the nuclear dynamics. The impact of increasing fluorination of the parent benzene radical cation on its radiative emission is examined and discussed.

Effect of Reagent Vibration and Rotation on the State-to-State Dynamics of the Hydrogen Exchange Reaction, H + H2 → H2 + H

State-to-state dynamics of the benchmark hydrogen exchange reaction H + H₂ (v = 0-4, j = 0-3) → H₂ (v', j') + H is investigated with the aid of the real wave packet approach of Gray and Balint-Kurti (J. Chem. Phys. 1998, 108, 950-962) and electronic ground BKMP2 potential energy surface of Boothroyd et al. (J. Chem. Phys. 1996, 104, 7139-7152). Initial state-selected and product state-resolved reaction probabilities, integral cross section, and product diatom vibrational and rotational level populations at a few collision energies are reported to elucidate the energy disposal mechanism. State-specific thermal rate constants are also calculated and compared with the available literature results. Coriolis coupling terms of the nuclear Hamiltonian are included, and calculations are parallelized over the helicity quantum number, Ω'. Attempts are made, in particular, to study the effect of reagent vibrational and rotational excitations on the dynamical attributes. It is found that the calculations become computationally expensive with reagent vibrational and rotational excitation. Reagent vibrational excitation is found to enhance the reactivity and has significant impact on the energy disposal to the vibrational and rotational degrees of freedom of the product. The interplay of reagent translational and vibrational energy on the product vibrational distribution unfolds an important aspect of the energy disposal mechanism. The effect of reagent rotation on the state-to-state dynamics is found not to be very significant, and the weak effect turns out to be specific to v'.

Multicolor femtosecond pump-probe system with single-electron sensitivity at low temperatures and high magnetic fields

We present an ultrafast spectroscopy system designed for temporal and spectral resolution of transient transmission changes after excitation of single electrons in solid-state quantum structures. The system is designed for optimum long-term stability, offering the option of hands-off operation over several days. Pump and probe pulses are generated in a versatile Er:fiber laser system where visible photon energies may be tuned independently from 1.90 eV to 2.51 eV in three parallel branches. Bandwidth-limited pulse durations between 100 fs and 10 ps are available. The solid-state quantum systems under investigation are mounted in a closed-cycle superconducting magnet cryostat providing temperatures down to 1.6 K and magnetic fields of up to 9 T. The free-standing cryomagnet is coupled to the laser system by means of a high-bandwidth active beam steering unit to eliminate residual low-frequency mechanical vibrations of the pulse tube coolers. High-NA objective lenses inside the sample chamber are employed for focusing femtosecond laser pulses onto the sample and recollection of the transmission signal. The transmitted probe light is dispersed in a grating monochromator equipped with a liquid nitrogen-cooled CCD camera, enabling a frame rate of 559 Hz. In order to eliminate spurious background effects due to low-frequency changes in the thermal equilibrium of the sample, we operate with a lock-in scheme where, instead of the pump amplitude, the pump-probe timing is modulated. This feature is provided without any mechanical action by an electro-optic timing unit inside the femtosecond Er:fiber system. The performance of the instrument is tested with spectrally resolved pump-probe measurements on a single negatively charged CdSe/ZnSe quantum dot under a magnetic field of 9 T. Selective initialization and readout of charge and spin states is carried out via two different femtosecond laser pulses. High-quality results on subpicosecond intraband relaxation dynamics after single-electron excitation motivate a broad variety of future experiments in ultrafast quantum optics and few-fermion quantum dynamics.

Controlled intramolecular H-transfer in malonaldehyde in the electronic ground state mediated through the conical intersection of 1nπ* and 1ππ* excited electronic states

We report photo-isomerization of malonaldehyde in its electronic ground state (S0), mediated by coupled 1nπ*(S1)-1ππ*(S2) excited electronic states, accomplished with the aid of optimally designed ultraviolet (UV)-laser pulses. In particular, control of H-transfer from a configuration predominantly located in the left well (say, reactant) to that in the right well (say, product) of the electronic ground S0 potential energy surface is achieved by a pump-dump mechanism including the nonadiabatic interactions between the excited S1 and S2 states. An interplay between the nonadiabatic coupling due to the conical intersection of the S1 and S2 states and the laser-molecule interaction is found to be imprinted in the time-dependent electronic population. The latter is also examined by employing optimal fields of varying intensities and frequencies of the UV laser pulses. For the purpose of the present study, we constructed a three-state and two-mode coupled diabatic Hamiltonian with the help of adiabatic electronic energies and transition dipole moments calculated by ab initio quantum chemistry methods. The electronic diabatic model is developed using the calculated adiabatic energies of the two excited electronic states (S1 and S2) in order to carry out the dynamics study. The optimal fields for achieving the controlled isomerization are designed within the framework of optimal control theory employing the optimization technique of a multitarget functional using the genetic algorithm. The laser-driven dynamics of the system is treated by numerically solving the time-dependent Schrödinger equation within the dipole approximation. A time-averaged yield of the target product of ∼40% is achieved in the present treatment of dynamics with optimal laser pulses.

An alternative laser driven photodissociation mechanism of pyrrole via πσ*1∕S0 conical intersection

A first principles quantum dynamics study of N-H photodissociation of pyrrole on the S₀-¹πσ^*(A21) coupled electronic states is carried out with the aid of an optimally designed UV-laser pulse. A new photodissociation path, as compared to the conventional barrier crossing on the πσ*1 state, opens up upon electronic transitions under the influence of pump-dump laser pulses, which efficiently populate both the dissociation channels. The interplay of electronic transitions due both to vibronic coupling and the laser pulse is observed in the control mechanism and discussed in detail. The proposed control mechanism seems to be robust, and not discussed in the literature so far, and is expected to trigger future experiments on the πσ*1 photochemistry of molecules of chemical and biological importance. The design of the optimal pulses and their application to enhance the overall dissociation probability is carried out within the framework of optimal control theory. The quantum dynamics of the system in the presence of pulse is treated by solving the time-dependent Schrödinger equation in the semi-classical dipole approximation.

Dephasing rates for weak localization and universal conductance fluctuations in two dimensional Si:P and Ge:P δ-layers

We report quantum transport measurements on two dimensional (2D) Si:P and Ge:P δ-layers and compare the inelastic scattering rates relevant for weak localization (WL) and universal conductance fluctuations (UCF) for devices of various doping densities (0.3–2.5 × 10¹⁸ m⁻²) at low temperatures (0.3–4.2 K). The phase breaking rate extracted experimentally from measurements of WL correction to conductivity and UCF agree well with each other within the entire temperature range. This establishes that WL and UCF, being the outcome of quantum interference phenomena, are governed by the same dephasing rate.

Purification and development of ELISAs for two forms of vitellogenin in Indian walking catfish, Clarias batrachus (L.)

Two forms of vitellogenin (Vg: Vg1 and Vg2) were purified from the plasma of estradiol-17β (E₂)-treated Indian walking catfish, Clarias batrachus, by gel filtration and adsorption chromatography. Native Vg1 and Vg2 had apparent molecular masses of 375 and 450 kDa, respectively, and both Vgs resolved into two similar major bands (95 and 67 kDa) in SDS-PAGE under reducing condition. Polyclonal antisera raised against each form of Vg were absorbed with a combination of hypophysectomized male catfish serum proteins and alternate Vg to ensure specificity. Immunological analyses verified the presence of Vg1 and Vg2 in the plasma of female catfish. Homologous ELISAs were developed for Vg1 and Vg2 using their respective harvested antisera, which exhibited the detection limit of 100 ng ml^-1 for Vg1 and 40 ng ml^-1 for Vg2, and low level of cross-reactivity (not parallel to the standard) was found with alternate Vg in each assay. Treatment of male catfish with E₂ induced both Vgs showing a proportionate ratio of Vg1 to Vg2 at 5.6:1. Plasma concentrations of both Vgs measured by ELISAs at different reproductive phases of field collected female catfish increased in accordance with the ovarian development, keeping the proportionate ratio of Vg1 to Vg2 at about 2:1 in fish undergoing vitellogenesis during prespawning period and 1:20 during spawning period, suggesting that Vg1 may be the major Vg to contribute in yolk formation, whereas Vg2, besides its role in yolk formation, may facilitate other physiological functions. The present study, thus, demonstrates the occurrence of two unequally synthesized Vgs in the catfish.

The HIV/AIDS epidemic among young people in China between 2005 and 2012: results of a spatial temporal analysis

OBJECTIVES

Despite a recent increase in the HIV/AIDS epidemic among young people in China, youth-specific HIV data are limited.

METHODS

In total, 56 621 individuals with HIV/AIDS, aged 15-24 years, registered in the Case Reporting System of China between 2005 and 2012 and having complete spatial information were included in the present analysis. Spatial autocorrelation (general and local) and space-time scanning were performed using the ArcGIS 10.2 and SaTScan 9.3 software, respectively.

RESULTS

During 2005-2012, the number of reported HIV/AIDS cases and the proportion of HIV cases increased while the proportion of AIDS cases decreased. Sexual contact became the predominant route of transmission in later years. Spatial analysis showed marked geographical variations in HIV infection among young people throughout China during 2005-2012. The number of new hotspots increased over time. They were mainly localized to southeastern coastal areas, southwestern frontier provinces or autonomous regions (of Guangxi, Yunnan and Sichuan) and Beijing municipality. Later these hotspots disappeared and new hotspots were found in the northeast of the country. Significant clusters of HIV-positive cases were identified in three different time periods, which indicated high HIV transmission among young Chinese people in the recent past. The risk of HIV infection was highest in the first cluster (2009-2012; this cluster was the largest in size) covering the provinces of Guizhou and Yunnan, the Chongqing municipality, Guangxi, and the province of Sichuan. The second cluster (2010-2012) was mostly located in Shanghai, South Jiangsu, Zhejiang and South Anhui, while the third cluster (2010-2012) was located in Beijing and Tianjin.

CONCLUSIONS

Target-specific comprehensive behavioural interventions are urgently needed to contain the HIV epidemic among young people.

Theoretical Study on Molecules of Interstellar Interest. II. Radical Cation of Compact Polycyclic Aromatic Hydrocarbons

Radical cations of polycyclic aromatic hydrocarbons have been postulated to be molecular carriers of diffuse spectroscopic features observed in the interstellar medium. Several important observations made by stellar and laboratory spectroscopists motivated us to undertake a detailed theoretical study attempting to validate the recorded data. In continuation of our work on this subject, we here focus on a detailed theoretical study of the doublet ground (X̃) and low-lying excited (Ã, B̃, and C̃) electronic states of the radical cation of phenanthrene, pyrene, and acenaphthene molecule. A multistate and multimode theoretical model in a diabatic electronic basis is developed here through extensive ab initio quantum chemistry calculations. Employing this model, first-principles nuclear dynamics calculations are carried out to unravel the spectral assignment, time-dependent dynamics, and photostability of the mentioned electronic states of the radical cations. The theoretical results compare well with the observed experimental data.

A comparative account of quantum dynamics of the H⁺ + H₂ reaction at low temperature on two different potential energy surfaces

Rotationally resolved reaction probabilities, integral cross sections, and rate constant for the H(+) + H2 (v = 0, j = 0 or 1) → H2 (v' = 0, j') + H(+) reaction are calculated using a time-independent quantum mechanical method and the potential energy surface of Kamisaka et al. [J. Chem. Phys. 116, 654 (2002)] (say KBNN PES). All partial wave contributions of the total angular momentum, J, are included to obtain converged cross sections at low collision energies and rate constants at low temperatures. In order to test the accuracy of the KBNN PES, the results obtained here are compared with those obtained in our earlier work [P. Honvault et al., Phys. Rev. Lett. 107, 023201 (2011)] using the accurate potential energy surface of Velilla et al. [J. Chem. Phys. 129, 084307 (2008)]. Integral cross sections and rate constants obtained on the two potential energy surfaces considered here show remarkable differences in terms of magnitude and dependence on collision energy (or temperature) which can be attributed to the differences observed in the topography of the surfaces near to the entrance channel. This clearly shows the inadequacy of the KBNN PES for calculations at low collision energies.

Embolic occlusion of arteriovenous fistula due to infective endocarditis

A 45-year-old male on maintenance hemodialysis through right radio cephalic arteriovenous fistula (AVF) also had mitral regurgitation. He presented with fever and chills of 2 days duration along with pain and swelling at median cubital fossa of right upper limb. Local examination revealed warmth, redness, and tenderness at median cubital fossa. AVF thrill was absent. Echocardiography revealed vegetations on the mitral valve. An extensive search of literature did not reveal an instance of embolic occlusion of AVF due to vegetations of infective endocarditis.

Spontaneous breaking of time-reversal symmetry in strongly interacting two-dimensional electron layers in silicon and germanium

We report experimental evidence of a remarkable spontaneous time-reversal symmetry breaking in two-dimensional electron systems formed by atomically confined doping of phosphorus (P) atoms inside bulk crystalline silicon (Si) and germanium (Ge). Weak localization corrections to the conductivity and the universal conductance fluctuations were both found to decrease rapidly with decreasing doping in the Si:P and Ge:P delta layers, suggesting an effect driven by Coulomb interactions. In-plane magnetotransport measurements indicate the presence of intrinsic local spin fluctuations at low doping, providing a microscopic mechanism for spontaneous lifting of the time-reversal symmetry. Our experiments suggest the emergence of a new many-body quantum state when two-dimensional electrons are confined to narrow half-filled impurity bands.

Theoretical study on molecules of interstellar interest. I. Radical cation of noncompact polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbons (PAHs), in particular, their radical cation (PAH(+)), have long been postulated to be the important molecular species in connection with the spectroscopic observations in the interstellar medium. Motivated by numerous important observations by stellar as well as laboratory spectroscopists, we undertook detailed quantum mechanical studies of the structure and dynamics of electronically excited PAH(+) in an attempt to establish possible synergism with the recorded data. In this paper, we focus on the quantum chemistry and dynamics of the doublet ground (X̃) and low-lying excited (Ã, B̃, and C̃) electronic states of the radical cation of tetracene, pentacene, and hexacene molecule. This study is aimed to unravel photostability, spectroscopy, and time-dependent dynamics of their excited electronic states. In order to proceed with the theoretical investigations, we construct suitable multistate and multimode Hamiltonians for these systems with the aid of extensive ab initio calculations of their electronic energy surfaces. The diabatic coupling surfaces are derived from the calculated adiabatic electronic energies. First principles nuclear dynamics calculations are then carried out employing the constructed Hamiltonians and with the aid of time-independent and time-dependent quantum mechanical methods. The theoretical results obtained in this study are found to be in good accord with those recorded in experiments. The lifetime of excited electronic states is estimated from their time-dependent dynamics and compared with the available data.

Cav1.3 and Cav1.2 channels of adrenal chromaffin cells: emerging views on cAMP/cGMP-mediated phosphorylation and role in pacemaking

Voltage-gated Ca²⁺ channels (VGCCs) are voltage sensors that convert membrane depolarizations into Ca²⁺ signals. In the chromaffin cells of the adrenal medulla, the Ca²⁺ signals driven by VGCCs regulate catecholamine secretion, vesicle retrievals, action potential shape and firing frequency. Among the VGCC-types expressed in these cells (N-, L-, P/Q-, R- and T-types), the two L-type isoforms, Ca(v)1.2 and Ca(v)1.3, control key activities due to their particular activation-inactivation gating and high-density of expression in rodents and humans. The two isoforms are also effectively modulated by G protein-coupled receptor pathways delimited in membrane micro-domains and by the cAMP/PKA and NO/cGMP/PKG phosphorylation pathways which induce prominent Ca²⁺ current changes if opposingly regulated. The two L-type isoforms shape the action potential and directly participate to vesicle exocytosis and endocytosis. The low-threshold of activation and slow rate of inactivation of Ca(v)1.3 confer to this channel the unique property of carrying sufficient inward current at subthreshold potentials able to activate BK and SK channels which set the resting potential, the action potential shape, the cell firing mode and the degree of spike frequency adaptation during spontaneous firing or sustained depolarizations. These properties help chromaffin cells to optimally adapt when switching from normal to stress-mimicking conditions. Here, we will review past and recent findings on cAMP- and cGMP-mediated modulations of Ca(v)1.2 and Ca(v)1.3 and the role that these channels play in the control of chromaffin cell firing. This article is part of a Special Issue entitled: Calcium channels.