Frustrated spin ladder with alternating spin-1 and spin-1/2 rungs

We study the impact of the diagonal frustrating couplings on the quantum phase diagram of a two-leg ladder composed of alternating spin-1 and spin-1/2 rungs. As the coupling strength is increased the system successively exhibits two gapped paramagnetic phases (a rung-singlet and a Haldane-like non-degenerate states) and two ferrimagnetic phases with different ferromagnetic moments per rung. The first two states are similar to the phases studied in the frustrated spin-1/2 ladder, whereas the magnetic phases appear as a result of the mixed-spin structure of the model. A detailed characterization of these phases is presented using density-matrix renormalization-group calculations, exact diagonalizations of periodic clusters, and an effective Hamiltonian approach inspired by the analysis of numerical data. The present theoretical study was motivated by the recent synthesis of the quasi-one-dimensional ferrimagnetic material Fe$^{II}$Fe$^{III}$ (trans-1,4-cyclohexanedicarboxylate) exhibiting a similar ladder structure.Comment: 10 pages, 8 figure

Giant magnetothermal conductivity and magnetostriction effect in charge ordered Nd0.8_{0.8}Na0.2_{0.2}MnO3_{3} compound

We present results on resistivity ($\rho$), magnetization ($M$), thermal conductivity ($\kappa$), magnetostriction ($\frac{\Delta L}{L(0)}$) and specific heat ($C_{p}$) of charge-orbital ordered antiferromagnetic Nd$_{0.8}$Na$_{0.2}$MnO$_{3}$ compound. Magnetic field-induced antiferromagnetic/charge-orbital ordered insulating to ferromagnetic metallic transition leads to giant magnetothermal conductivity and magnetostriction effect. The low-temperature irreversibility behavior in $\rho$, $M$, $\kappa$ and $\frac{\Delta L}{L(0)}$ due to field cycling together with striking similarity among the field and temperature dependence of these parameters manifest the presence of strong and complex spin-charge-lattice coupling in this compound. The giant magnetothermal conductivity is attributed mainly to the suppression of phonon scattering due to the destabilization of spin fluctuations and static/dynamic Jahn-Teller distortion by the application of magnetic field.Comment: 4 Pages, 4 Figure

Prescription audit for evaluation of present prescribing trends in a rural tertiary care hospital in South India: an observational study

Background: Prescription is a written order from the physician to pharmacist which contains name of the drug, its dose and its method of dispensing and advice over consuming it. The quality of life can be improved by enhancing the standards of the medical treatment at all levels of the health care delivery system. Prescription audit aims to provide precise information to a particular setting which enables rational policy decisions to be made. The present study was undertaken to find errors in current prescription practices in a tertiary care hospital situated in B G Nagara, Nagamangala, India.Methods: An observational study in Adichunchanagiri Institute of Medical Sciences, B G Nagara, Nagamangala, India was conducted during October 2015. 113 prescriptions were analyzed. Information regarding the patient, doctor, drug and legibility of the prescription were obtained.Results: Regarding patient details, name was present in all prescriptions with absence of height and weight in all prescriptions. Regarding prescriber details name, qualifications, address, phone number were not found in any prescriptions, but with 100% presence of signature. Regarding drug details generic name was found in 9.7%, and dose and frequency were found in 96.45% and 95.5% respectively. 96.4% of the prescriptions were found to be legible.Conclusions: Irrational prescribing is a global problem. The rationality of prescribing pattern is of utmost importance because bad prescribing habits including misuse, overuse and underuse of medicines can lead to unsafe treatment, exacerbation of the disease, health hazards, economic burden on the patients and wastage. Computerised prescription ordering eliminates some of the subjective features of prescribing. Thus, if the proper information is entered correctly in the electronic system, medication errors due to illegible handwriting, incorrect dose, incorrect medication for medical condition, and drug interactions can be reduced, because each prescription can be linked to high-quality drug databases that check that the information on the prescription is appropriate for the patient (e.g., age, weight, gender, condition, lab values, disease being treated, concurrent medications) and that known warnings and potential problems are brought to the attention of the physician, pharmacist and patient

DANTE: Deep AlterNations for Training nEural networks

We present DANTE, a novel method for training neural networks using the alternating minimization principle. DANTE provides an alternate perspective to traditional gradient-based backpropagation techniques commonly used to train deep networks. It utilizes an adaptation of quasi-convexity to cast training a neural network as a bi-quasi-convex optimization problem. We show that for neural network configurations with both differentiable (e.g. sigmoid) and non-differentiable (e.g. ReLU) activation functions, we can perform the alternations effectively in this formulation. DANTE can also be extended to networks with multiple hidden layers. In experiments on standard datasets, neural networks trained using the proposed method were found to be promising and competitive to traditional backpropagation techniques, both in terms of quality of the solution, as well as training speed.Comment: 19 page

PROTOTYPE SELF EMULSIFYING SYSTEM OF ETRAVIRINE: DESIGN, FORMULATION AND IN VITRO EVALUATION

Objective: Lipid-based formulations have gained much attention, particularly on self-emulsifying drug delivery systems (SEDDS), to improve the oral bioavailability of lipophilic drugs. In the present study, an attempt was made to develop and evaluate prototype SEDDS of poorly soluble antiviral BCS class IV drug etravirine.Methods: Various oils, surfactants and co-surfactants were screened for their suitability in the formulation of SEDDS. Based on the screening, gelucire 44/14, as the oil, labrasol as a surfactant and transcutol HP as the co-surfactant were selected. SEDDS with drug etravirine was formulated and evaluated for emulsifying ability, dilution potential and microscopic properties. The emulsion area for each of the combination of oil and surfactant co-surfactant mixture (Smix) was determined by the construction of pseudo-ternary phase diagrams.Results: The optimized formulation with oil (gelucire 44/14) and Smix (labrasol: transcutol HP, 6:1) in a ratio of 2:8 exhibited a rapid emulsification rate and a good polydispersibility index of 0.103±0.012 indicating uniformity of the formed droplets. The size of the droplets was determined by zetasizer and was found to be in 200 nm range. The drug release from the final formulation after 2hr was found to be 41.15%±0.5 compared to 19.3%±3.8 of pure drug indicating enhanced dissolution profile of the drug.Conclusion: In vitro study illustrated enhanced dissolution rate of formulated prototype SEDDS of BCS class IV drug etravirine for oral delivery

SARAS 2: A Spectral Radiometer for probing Cosmic Dawn and the Epoch of Reionization through detection of the global 21 cm signal

The global 21 cm signal from Cosmic Dawn (CD) and the Epoch of Reionization (EoR), at redshifts $z \sim 6-30$, probes the nature of first sources of radiation as well as physics of the Inter-Galactic Medium (IGM). Given that the signal is predicted to be extremely weak, of wide fractional bandwidth, and lies in a frequency range that is dominated by Galactic and Extragalactic foregrounds as well as Radio Frequency Interference, detection of the signal is a daunting task. Critical to the experiment is the manner in which the sky signal is represented through the instrument. It is of utmost importance to design a system whose spectral bandpass and additive spurious can be well calibrated and any calibration residual does not mimic the signal. SARAS is an ongoing experiment that aims to detect the global 21 cm signal. Here we present the design philosophy of the SARAS 2 system and discuss its performance and limitations based on laboratory and field measurements. Laboratory tests with the antenna replaced with a variety of terminations, including a network model for the antenna impedance, show that the gain calibration and modeling of internal additives leave no residuals with Fourier amplitudes exceeding 2~mK, or residual Gaussians of 25 MHz width with amplitudes exceeding 2~mK. Thus, even accounting for reflection and radiation efficiency losses in the antenna, the SARAS~2 system is capable of detection of complex 21-cm profiles at the level predicted by currently favoured models for thermal baryon evolution.Comment: 44 pages, 17 figures; comments and suggestions are welcom

Antiferromagnetic sawtooth chain with spin-½ and spin-1 sites

We study the low-energy properties of a sawtooth chain with spin-1's at the bases of the triangles and spin-½'s at the vertices of the triangles. The spins have Heisenberg antiferromagnetic interactions between nearest neighbors, with a coupling J2 between a spin-1 and a spin-½, and a coupling J1=1 between two spin-1's. Analysis of the exact diagonalization data for periodic chains containing up to N=12 unit cells shows that the ground state is a singlet for exchange couplings up to approximately J2=3.8, whereas for larger J2 the system exhibits a ferrimagnetic ground state characterized by a net ferromagnetic moment per unit cell of ½. In the region of small interactions J2, the mixed spin sawtooth chain maps on to an effective isotropic spin model representing two weakly interacting and frustrated spin-½ Heisenberg chains composed of spin-½ sites at odd and even vertices, respectively. Finally, we study the phenomenon of a macroscopic magnetization jump which occurs if a magnetic field is applied with a value close to the saturation field for J2=2

Strategies Towards the Synthesis of Staurosporine Indolocarbazole Alkaloid and Its Analogues

In this Chapter we revisit the main strategies used for years in synthesizing staurosporine indolocarbazole alkaloid and its analogues, which are promising compounds for treating cancer. In addition to describing the details of the synthesis strategies, including the key challenges that had to be faced, we offer a historical perspective of the development in the field