Voltage bias induced modification of all oxide Pr0.5Ca0.5MnO3/SrTi0.95Nb.05O3 junctions

In this paper we report what happens to a pristine oxide junction Pr0.5Ca0.5MnO3/SrTi0.95Nb.05O3 (PCMO/Nb:STO), when it is subjected to cycling of voltage bias of moderate value ({\pm}4V). It is found that the initial cycling leads to formation of a permanent state of lower resistance where the lower resistance arises predominantly due to development of a shunt across the device film (PCMO). On successive voltage cycling with increasing magnitude, this state transforms into states of successive lower resistance that can be transformed back to the initial stable state on cycling to below a certain bias. A simple model based on p-n junction with shunt has been used to obtain information on the change of the junction on voltage cycling. It has been shown that the observation can be explained if the voltage cycling leads to lowering of barrier at the interface and also reduction in series resistance. It is suggested that this lowering can be related to the migration of oxygen ions and vacancies at the junction region. Cross-sectional imaging of the junction shows formation of permanent filamentary bridges across the thickness of the PCMO after the pristine p-n junction is first taken through a voltage cycle, which would explain appearance of a finite shunt across the p-n junction.Comment: 12 pages,7figure

The Invader of the Maxillary Sinus

This report aims to present the case of a 21 year old boy with oroantral communication associated with sinonasal symptom. The aetiology was the presence of ectopic third molar in the sinus. Closure of the communication and surgical removal of the tooth via Caldwell-Luc procedure resulted in resolution of the symptoms. The oroantral communication was surprisingly caused by the chronic sinusitis resulting from the presence of the tooth in the maxillary sinus. Keywords: oroantral communication, maxillary sinus, ectopic maxillary third mola

Crystal structure and physical properties of half-doped manganite nanocrystals with size < 100nm

In this paper we report the structural and property (magnetic and electrical transport) measurements of nanocrystals of half-doped $\mathrm{La_{0.5}Ca_{0.5}MnO_3}$(LCMO) synthesized by chemical route, having particle size down to an average diameter of 15nm. It was observed that the size reduction leads to change in crystal structure and the room temperature structure is arrested so that the structure does not evolve on cooling unlike bulk samples. The structural change mainly affects the orthorhombic distortion of the lattice. By making comparison with observed crystal structure data under hydrostatic pressure it is suggested that the change in the crystal structure of the nanocrystals occurs due to an effective hydrostatic pressure created by the surface pressure on size reduction. This not only changes the structure but also causes the room temperature structure to freeze-in. The size reduction also does not allow the long supercell modulation needed for the Charge Ordering, characteristic of this half-doped manganite, to set-in. The magnetic and transport measurements also show that the Charge Ordering (CO) does not occur when the size is reduced below a critical size. Instead, the nanocrystals show ferromagnetic ordering down to the lowest temperatures along with metallic type conductivity. Our investigation establishes a structural basis for the destabilization of CO state observed in half-doped manganite nanocrystals.Comment: 11 pages, 13 Figure

DURATION DEPENDENT ANTIAPOPTOTIC EFFICACY OF CAMELLIA SINENSIS (GREEN TEA) ON STREPTOZOTOCIN INDUCED DIABETES LINKED TESTICULAR HYPOFUNCTION IN ALBINO RAT: GENOMIC AND FLOW CYTOMETRIC ASSESSMENT

Objective: The study has been conducted to search out the threshold duration of treatment of ethyl acetate fraction of methanolic extract of leaves of Camellia sinensis (L.) Kuntze at the dose of 100 mg/kg body weight for the management of diabetes-induced testicular impairment in streptozotocin-induced diabetic rat in a duration dependent fashion. Methods: In this respect, the glycemic, androgenic,&nbsp;oxidative stress sensors, gene expression of testicular androgenic key enzymes along with apoptotic&nbsp;markers were evaluated in&nbsp;a duration dependent way&nbsp;(14, 28 and 56 d). Results: A significant correction was noted in the levels of glycated haemoglobin (HbA1C), testicular&nbsp;thiobarbituric acid reactive substances (TBARS), conjugated diene (CD), sperm viability, sperm mitochondrial status, serum testosterone, and genomic expression of testicular Δ5,&nbsp;3β-hydroxysteroid dehydrogenase (HSD), 17β-HSD, Bax, Bcl-2 after treatment for different duration with the said fraction in diabetic groups in compare to respective vehicle-treated diabetic group without any toxicity induction in general. Thin layer chromatography (TLC) study of the fraction showed two spots with retention factors (Rf) of 0.78 and 0.51. Conclusion: The results showed that 28 d treatment was threshold duration of treatment for the correction of diabetes-induced testicular impairment

The Importance of Creating Value in Seismic Design

Major earthquakes have resulted in devastating consequences in terms of human and economic loss. In almost all the earthquakes we observe the failure of structures, sometimes due to poor construction but also due to designers not identifying the specific geo-hazards (iIntensity of ground motion, faults, liquefaction, slopes etc) which affect these structures. In many cases these damages could have been avoided if the original design had correctly identified the geohazards at the site and incorporated the philosophy of performance based design. In this paper several examples will be presented where the different stages of risk assessment will be identified and possible solutions incorporated in the final design. The paper provides examples where existing studies and codes in certain countries may be storing up problems for the future.This paper also highlights some gaps in existing knowledge where more research is needed. Design examples will also cover the advantages of performing detailed design accounting for soil structure interaction effects. In many cases these will offer potential saving to the clients and thus provide value in seismic design. Examples are shown where structures which have accounted for the geohazards will be shown to perform satisfactorily during past earthquakes

Growth and physical property study of single nanowire (diameter ~ 45nm) of half doped Manganite

We report here the growth and characterization of functional oxide nanowire of hole doped manganite of La0.5Sr0.5MnO3 (LSMO). We also report four probe electrical resistance measurement of single nanowire of LSMO (diameter ~ 45nm) using FIB fabricated electrodes. The wires were fabricated by hydrothermal method using autoclave at a temperature of 270 oC. The elemental analysis and physical property like electrical resistivity were studied at individual nanowire level. The quantitative determination of Mn valency and elemental mapping of constituent elements was done by using Electron Energy Loss Spectroscopy (EELS) in the Scanning Transmission Electron Microscopy (STEM) mode. We addressed the important issue of whether as a result of size reduction the nanowires can retain the desired composition, structure and physical properties. The nanowires used were found to have a ferromagnetic transition (TC) at around 325 K which is very close to the bulk value of around 330 K found in single crystal of the same composition confirming that the functional behavior is likely to be retained even after size reduction of the nanowires to a diameter of 45 nm. The electrical resistivity shows insulating behavior within the temperature range measured, which is very much similar to the bulk system.Comment: 11 pages, 7 figures, accepted in Journal of Nanomaterial

Frequency dependence of dielectric anomaly around Neel temperature in bilayer manganite Pr(Sr0.1Ca0.9)2Mn2O7

A novel frequency dependence of anomaly in dielectric constant versus temperature plot, around the Neel temperature T_N (~150 K), has been observed in a single crystal of bilayer manganite Pr(Sr0.1Ca0.9)2Mn2O7. The anomaly in the permittivity (epsilon'||c) occurs at a temperature T_f which moves within a temperature window (delT_f) of ~40 K around T_N for a frequency range 50 kHz-5 MHz. The capacitive component Cp of the dielectric response exhibits a clear yet broad feature around T_N which establishes the intrinsic capacitive nature of the anomaly.Comment: 15 pages with 4 figures; pdf onl

Functionalization of manganite nanoparticles and their interaction with biologically relevant small ligands: picosecond time-resolved FRET studies

We report molecular functionalization of the promising manganite nanoparticles La0.67Sr0.33MnO3 (LSMO) for their solubilization in aqueous environments. The functionalization of individual NPs with the biocompatible citrate ligand, as confirmed by Fourier transform infrared (FTIR) spectroscopy, reveals that citrates are covalently attached to the surface of the NPs. UV-VIS spectroscopic studies on the citrate functionalized NPs reveals an optical band in the visible region. Uniform size selectivity (2.6 nm) of the functionalization process is confirmed from high resolution transmission electron microscope (HRTEM). In the present study we have used the optical band of the functionalized NPs to monitor their interaction with other biologically important ligands. Forster resonance energy transfer (FRET) of a covalently attached probe 4-nitrophenylanthranilate (NPA) with the capped NPs confirm the attachment of the NPA ligands to the surface functional group (-OH) of the citrate ligand. The FRET of a DNA base mimic, 2-aminopurine (2AP), with the NPs confirms the surface adsorption of 2AP. Our study may find relevance in the study of the interaction of individual manganite NPs with drug/ligand molecules

A case series of congenital nevus and their various manifestations

A nevus is characterized by collection of partially differentiated or well-differentiated cells normally found in the skin. Some nevi are associated with disorders such as autism, epilepsy, ophthalmogical disorders, intracranial abnormalities, and others. In this case series, we aim to analyze six cases with congenital nevus, matched our findings with case reports published and reviewed the literature, to come to a conclusion that would help the clinician to do focused clinical examination and investigations when they come across such nevi. Furthermore, as these sort of skin lesions cause psychological morbidity to both parents and patients, proper counseling is required along with dermatological therapy and treatment of comorbid conditions. As well as regular follow-up with monitoring of the lesions. The following are the cases: Case-1, is a case of congenital melanocytic nevi who presented with delayed milestone, epilepsy and neuroimaging revealed intracranial melanosis. Case-2 nevus of Ota on face with scleral nevus and glaucoma in the left eye. In Case-3: Nevus achromicus was present over the abdomen and scalp in a child who presented with status epilepticus and there was focal cortical dysplasia of left frontal cortex on imaging. Nevus sebaceous was present in case-4 who had seizure disorder but neuroimaging was normal. Case-5 child had nevus spilus over left frontal area with melanocytic satellite nevi who presented with febrile convulsion but normal neuroimaging. The sixth case is a 5-year-old male child with linear nevus without any other association