Timescape cosmology with radiation fluid

The timescape cosmology represents a potentially viable alternative to the standard homogeneous cosmology, without the need for dark energy. Although average cosmic evolution in the timescape scenario only differs substantially from that of Friedmann-Lemaitre model at relatively late epochs when the contribution from the energy density of radiation is negligible, a full solution of the Buchert equations to incorporate radiation is necessary to smoothly match parameters to the epoch of photon decoupling and to obtain constraints from cosmic microwave background data. Here we extend the matter-dominated solution found in earlier work to include radiation, providing series solutions at early times and an efficient numerical integration strategy for generating the complete solution. The numerical solution is used to directly calculate the scale of the sound horizon at decoupling, and at the baryon drag epoch. The constraints on these scales from the Planck satellite data yield bounds on the timescape cosmological parameters, which are found to also agree with the best-fit values from a recent analysis of SDSS-II supernova data, while avoiding the problem of a primordial lithium-7 abundance anomaly.Comment: 21 pages, 6 figures; v2: small additions, accepted by Class. Quantum Gra

Creating excitonic entanglement in quantum dots through the optical Stark effect

We show that two initially non-resonant quantum dots may be brought into resonance by the application of a single detuned laser. This allows for control of the inter-dot interactions and the generation of highly entangled excitonic states on the picosecond timescale. Along with arbitrary single qubit manipulations, this system would be sufficient for the demonstration of a prototype excitonic quantum computer.Comment: 4 pages, 3 figures; published version, figure 3 improved, corrections to RWA derive

Radical Chemistry in a Femtosecond Laser Plasma: Photochemical Reduction of Ag+ in Liquid Ammonia Solution

Plasmas with dense concentrations of reactive species such as hydrated electrons and hydroxyl radicals are generated from focusing intense femtosecond laser pulses into aqueous media. These radical species can reduce metal ions such as Au3+ to form metal nanoparticles (NPs). However, the formation of H2O2 by the recombination of hydroxyl radicals inhibits the reduction of Ag+ through back-oxidation. This work has explored the control of hydroxyl radical chemistry in a femtosecond laser-generated plasma through the addition of liquid ammonia. The irradiation of liquid ammonia solutions resulted in a reaction between NH3 and OH·, forming peroxynitrite and ONOO−, and significantly reducing the amount of H2O2 generated. Varying the liquid ammonia concentration controlled the Ag+ reduction rate, forming 12.7 ± 4.9 nm silver nanoparticles at the optimal ammonia concentration. The photochemical mechanisms underlying peroxynitrite formation and Ag+ reduction are discussed

Expedited biodegradation of organic pollutants and refractory compounds using bioelectrochemical systems

Biodegradation of xenobiotics is often considered to be a slow process. This is especially true if the xenobiotic in question is polymeric in nature, contains many chemical substituent groups or generally exhibits high level of toxicity to environmental microbiota. Due to this observed slow kinetics of degradation, removal of many xenobiotics from contaminated environments using conventional bioremediation technologies is a difficult problem. To alleviate this, alternative technologies showing improved kinetics of biodegradation are sought by the scientific community. One such promising approach is the usage of the novel technology of bio-electrochemical systems for improved degradation of xenobiotics. Due to the newness of this technology and affiliated methods, not much information about its usage for biodegradation of xenobiotics is available in literature. Therefore, this chapter aims to address that gap and bring about a comprehensive analysis on the usage of bio-electrochemical systems for rapid removal of xenobiotic contaminants from the environment

Vibronic resonances facilitate excited state coherence in light harvesting proteins at room temperature

Until recently it was believed that photosynthesis, a fundamental process for life on earth, could be fully understood with semi-classical models. However, puzzling quantum phenomena have been observed in several photosynthetic pigment-protein complexes, prompting questions regarding the nature and role of these effects. Recent attention has focused on discrete vibrational modes that are resonant or quasi-resonant with excitonic energy splittings and strongly coupled to these excitonic states. Here we unambiguously identify excited state coherent superpositions in photosynthetic light-harvesting complexes using a new experimental approach. Decoherence on the timescale of the excited state lifetime allows low energy (56 cm-1) oscillations on the signal intensity to be observed. In conjunction with an appropriate model, these oscillations provide clear and direct experimental evidence that the persistent coherences observed require strong vibronic mixing among excited states

Electron Counting Statistics for Non-Additive Environments

Molecular electronics is a rapidly developing field focused on using molecules as the structural basis for electronic components. It is common in such devices for the system of interest to couple simultaneously to multiple environments. Here we consider a model comprised of a double quantum dot (or molecule) coupled strongly to vibrations and weakly to two electronic leads held at arbitrary bias voltage. The strong vibrational coupling invalidates treating the bosonic and electronic environments simply as acting additively, as would be the case in the weak coupling regime or for flat leads at infinite bias. Instead, making use of the reaction coordinate framework we incorporate the dominant vibrational coupling effects within an enlarged system Hamiltonian. This allows us to derive a non-additive form for the lead couplings that accounts properly for the influence of strong and non-Markovian coupling between the double dot system and the vibrations. Applying counting statistics techniques we track electron flow between the double dot and the electronic leads, revealing both strong-coupling and non-additive effects in the electron current, noise and Fano factor.Comment: 16 pages, 6 figures. v2 - close to published versio

Residual entropy in a model for the unfolding of single polymer chains

We study the unfolding of a single polymer chain due to an external force. We use a simplified model which allows to perform all calculations in closed form without assuming a Boltzmann-Gibbs form for the equilibrium distribution. Temperature is then defined by calculating the Legendre transform of the entropy under certain constraints. The application of the model is limited to flexible polymers. It exhibits a gradual transition from compact globule to rod. The boundary line between these two phases shows reentrant behavior. This behavior is explained by the presence of residual entropy.Comment: 5 pages, 4 figures, extended version of arXiv:cond-mat/061225

Integrating dentistry into palliative medicine - Novel insights and opportunities

Palliative care is a global human right, to be provided in a systematic way. The dentist can help the patient right from the initial diagnosis of the condition up to the relief of pain in the terminal stages of the diseases. This inquiry into the oral physician‘s role on elderly care and special needs would be of benefit to researchers of Palliative Dentistry; particularly in multidisciplinary contexts. This text proposes to discussintegrated oral care, oral health care delivery system, and a flow of educational actions, resources, research, conceptual framework, guidelines and dissemination of newer trends in oral palliative care

Evaluation of Renoprotective Effects of Ethanolic Extract of Morinda citrifolia L. in a Murine Model of Gentamicin-induced Nephrotoxicity

AIM: The present study was undertaken to evaluate noni fruit juice for its protective effects on gentamicin-induced nephrotoxicity in rats. METHODS:Wistar albino rats of either sex, weighing 150-200g were divided into 4 groups; normal saline, gentamicin 80 mg/kg, i.p.,i for 8 days, noni fruit juice 5 and 10 mg/kg, p.o., for 8 days, noni fruit juice 3 days prior and concurrently with gentamicin for 5 days. Blood urea, serum creatinine, serum uric acid and blood urea nitrogen analyses and microscopic examination of kidney were performed after the treatment. RESULTS: Gentamicin treatment caused nephrotoxicity as evidenced by marked elevation in blood urea and serum creatinine. Serum urea, serum uric acid, serum creatinine and blood urea nitrogen were increased with gentamicin compared to saline-treated animals (162.33 ± 9.92mg/dl, 3.13 ± 0.12 mg/dl, 6.85 ± 0.35 mg/dl and 75.86 ± 4.64 mg/dl respectively).Co-administration of noni fruit juice with gentamicin decreased the rise in in these parameters in a dose dependent manner. Study of renal morphology by light microscope showed epithelial loss with intense granular degeneration involving \u3e50% renal cortex in gentamicin treated rats, whereas in noni fruit juice plus gentamicin treated rat revealed insignificant changes in tubular epithelium. CONCLUSION: To conclude, our data suggest that supplementation of noni fruit juice may be useful in reducing gentamicin nephrotoxicity in rats

Tunneling of a composite particle: Effects of intrinsic structure

We consider simple models of tunneling of an object with intrinsic degrees of freedom. This important problem was not extensively studied until now, in spite of numerous applications in various areas of physics and astrophysics. We show possibilities of enhancement for the probability of tunneling due to the presence of intrinsic degrees of freedom split by weak external fields or by polarizability of the slow composite object.Comment: 6 pages, 3 figures, version to be published in Journal of Physics