Highly reversible extrinsic electrocaloric effects over a wide temperature range in epitaxially strained SrTiO3 films.

Electrocaloric effects have been experimentally studied in ferroelectrics and incipient ferroelectrics, but not incipient ferroelectrics driven ferroelectric using strain. Here we use optimally oriented interdigitated surface electrodes to investigate extrinsic electrocaloric effects in low-loss epitaxial SrTiO3 films near the broad second-order 243 K ferroelectric phase transition created by biaxial in-plane coherent tensile strain from DyScO3 substrates. Our extrinsic electrocaloric effects are an order of magnitude larger than the corresponding effects in bulk SrTiO3 over a wide range of temperatures including room temperature, and unlike electrocaloric effects associated with first-order transitions they are highly reversible in unipolar applied fields. Additionally, the canonical Landau description for strained SrTiO3 films works well if we set the low-temperature zero-field polarization along one of the in-plane pseudocubic <100> directions. In future, similar strain engineering could be exploited for other films, multilayers and bulk samples to increase the range of electrocaloric materials for energy efficient cooling.

Microarray based gene expression profiling of advanced gall bladder cancer.

BACKGROUND: Gall bladder cancer (GBC) is an aggressive cancer with specific predilection like female gender and specific geographical areas, however the molecular mechanisms and factors contributing to the clinical or biological behavior are not understood. AIM: The aim of this study was to perform a comprehensive analysis of differentially expressed genes in advanced GBC and chronic cholecystitis (CC) cases. MATERIALS AND METHODS: Microarray was planned on fresh specimens of advanced GBC and CC cases using single color cRNA based microarray technique (8X60K format; Agilent Technologies, USA). Twelve advanced GBC and four CC patients were included in the study. RESULTS: Of the total of 1307 differentially expressed genes, 535 genes were significantly upregulated, while 772 genes were significantly downregulated in advanced GBC vs CC samples. Differentially expressed genes were associated with biological processes (55.03%), cellular components (31.48%), and molecular functions (13.49%) respectively. The important pathways or key processes affected were cell cycle, DNA replication, oxidative stress, gastric cancer pathway. Using in silico analysis tools, three differentially expressed genes i.e. TPX2, Cdc45 and MCM4 were selected (for their significant role in DNA replication and microtubule function) and were further validated in 20 advanced GBC cohort by immunohistochemistry. Significant positive association of Cdc45 and MCM4 proteins was found in advanced GBC cases (p = 0.043), suggesting the probable oncogenic role of Cdc45 and MCM4 proteins in advanced GBC. CONCLUSION: Our data demonstrate the potential regulation of Cdc45-MCM4 axis in advanced GBC tumors. Additionally, our study also revealed a range of differentially expressed genes (e.g. TPX2, AKURA etc.) between GBC and CC, and further validation of these genes might provide a potential diagnostic or therapeutic target in future.

Caloric materials for cooling and heating.

Magnetically driven thermal changes in magnetocaloric materials have, for several decades, been exploited to pump heat near room temperature. By contrast, their electrocaloric and mechanocaloric counterparts have only been intensively studied and exploited for little more than a decade. These different caloric strands have recently been unified to yield a single field of research that could help combat climate change by generating better heat pumps for both cooling and heating. Here we outline the timeliness of the present activity and discuss recent advances in caloric measurements, materials, and prototypes.

Large magnetoelectric coupling in multiferroic oxide heterostructures assembled via epitaxial lift-off.

Epitaxial films may be released from growth substrates and transferred to structurally and chemically incompatible substrates, but epitaxial films of transition metal perovskite oxides have not been transferred to electroactive substrates for voltage control of their myriad functional properties. Here we demonstrate good strain transmission at the incoherent interface between a strain-released film of epitaxially grown ferromagnetic La0.7Sr0.3MnO3 and an electroactive substrate of ferroelectric 0.68Pb(Mg1/3Nb2/3)O3-0.32PbTiO3 in a different crystallographic orientation. Our strain-mediated magnetoelectric coupling compares well with respect to epitaxial heterostructures, where the epitaxy responsible for strong coupling can degrade film magnetization via strain and dislocations. Moreover, the electrical switching of magnetic anisotropy is repeatable and non-volatile. High-resolution magnetic vector maps reveal that micromagnetic behaviour is governed by electrically controlled strain and cracks in the film. Our demonstration should inspire others to control the physical/chemical properties in strain-released epitaxial oxide films by using electroactive substrates to impart strain via non-epitaxial interfaces.

Voltage-driven annihilation and creation of magnetic vortices in Ni discs.

Using photoemission electron microscopy (PEEM) to image ferromagnetism in polycrystalline Ni disks, and ferroelectricity in their single-crystal BaTiO3 substrates, we find that voltage-driven 90° ferroelectric domain switching serves to reversibly annihilate each magnetic vortex via uniaxial compressive strain, and that the orientation of the resulting bi-domain reveals the chirality of the annihilated vortex. Micromagnetic simulations reveal that only 60% of this strain is required for annihilation. Voltage control of magnetic vortices is novel, and should be energetically favourable with respect to the use of a magnetic field or an electrical current. In future, stray field from bi-domains could be exploited to read vortex chirality. Given that core polarity can already be read via stray field, our work represents a step towards four-state low-power memory applications.

Large electrocaloric effects in oxide multilayer capacitors over a wide temperature range.

Heat pumps based on magnetocaloric and electrocaloric working bodies-in which entropic phase transitions are driven by changes of magnetic and electric field, respectively-use displaceable fluids to establish relatively large temperature spans between loads to be cooled and heat sinks1,2. However, the performance of prototypes is limited because practical magnetocaloric working bodies driven by permanent magnets3-5 and electrocaloric working bodies driven by voltage6-16 display temperature changes of less than 3 kelvin. Here we show that high-quality multilayer capacitors of PbSc0.5Ta0.5O3 display large electrocaloric effects over a wide range of starting temperatures when the first-order ferroelectric phase transition is driven supercritically (as verified by Landau theory) above the Curie temperature of 290 kelvin by electric fields of 29.0 volts per micrometre. Changes of temperature in the large central area of the capacitor peak at 5.5 kelvin near room temperature and exceed 3 kelvin for starting temperatures that span 176 kelvin (complete thermalization would reduce these values from 5.5 to 3.3 kelvin and from 176 to 73 kelvin). If magnetocaloric working bodies were to be replaced with multilayer capacitors of PbSc0.5Ta0.5O3, then the established design principles behind magnetocaloric heat pumps could be repurposed for better performance without bulky and expensive permanent magnets.

Shear-strain-mediated magnetoelectric effects revealed by imaging.

Large changes in the magnetization of ferromagnetic films can be electrically driven by non-180° ferroelectric domain switching in underlying substrates, but the shear components of the strains that mediate these magnetoelectric effects have not been considered so far. Here we reveal the presence of these shear strains in a polycrystalline film of Ni on a 0.68Pb(Mg1/3Nb2/3)O3-0.32PbTiO3 substrate in the pseudo-cubic (011)pc orientation. Although vibrating sample magnetometry records giant magnetoelectric effects that are consistent with the hitherto expected 90° rotations of a global magnetic easy axis, high-resolution vector maps of magnetization (constructed from photoemission electron microscopy data, with contrast from X-ray magnetic circular dichroism) reveal that the local magnetization typically rotates through smaller angles of 62-84°. This shortfall with respect to 90° is a consequence of the shear strain associated with ferroelectric domain switching. The non-orthogonality represents both a challenge and an opportunity for the development and miniaturization of magnetoelectric devices.

Colossal barocaloric effects near room temperature in plastic crystals of neopentylglycol.

There is currently great interest in replacing the harmful volatile hydrofluorocarbon fluids used in refrigeration and air-conditioning with solid materials that display magnetocaloric, electrocaloric or mechanocaloric effects. However, the field-driven thermal changes in all of these caloric materials fall short with respect to their fluid counterparts. Here we show that plastic crystals of neopentylglycol (CH3)2C(CH2OH)2 display extremely large pressure-driven thermal changes near room temperature due to molecular reconfiguration, that these changes outperform those observed in any type of caloric material, and that these changes are comparable with those exploited commercially in hydrofluorocarbons. Our discovery of colossal barocaloric effects in a plastic crystal should bring barocaloric materials to the forefront of research and development in order to achieve safe environmentally friendly cooling without compromising performance.

Enterogenous Cyst Presenting as Mediastinal Mass in a Newborn.

Duplication cyst is a rare congenital malformation. Enterogenous cyst are foregut duplication cyst with or without a vertebral defect. We report a case of a 36hr old neonate with mediastinal enterogenous cyst associated with vertebral defects. The embryology, differentials, and management of enterogenous cyst in the newborn have been discussed.

Blood Procalcitonin Levels and Duration of Antibiotics in Neonatal Sepsis.

OBJECTIVE: To determine the time to normalization of procalcitonin (PCT) levels and duration of antibiotics in neonatal sepsis. METHODS: A prospective observational study design was used. The participants included were neonates with sepsis. The primary outcome measure was time to normalization of PCT levels and duration of antibiotics following clinical resolution. RESULTS: Time to normalization of PCT levels was 9.6 ± 4.2 days in neonates with septic shock, 6.2 ± 2.5 days in neonates without shock, 9.6 ± 3.1 days in neonates with culture-positive sepsis and 6.4 ± 3.1 days in neonates with culture-negative sepsis. Time to normalization of PCT levels according to the stage of systemic inflammatory response syndrome was 5.8 ± 2.8 days in neonates with sepsis, 6.1 ± 3.1 days in those with sepsis syndrome, 6.3 ± 3.3 days in those with early septic shock and 9.4 ± 3.6 days in those with multiorgan dysfunction syndrome. There was no morbidity and mortality in any neonate in the 4-week follow-up. CONCLUSION: The duration of antibiotics can be determined by observing the time to normalization of PCT following clinical resolution of sepsis.

Comparison of Four Days Versus Seven Days Duration of Antibiotic Therapy for Neonatal Pneumonia: A Randomized Controlled Trial.

OBJECTIVE: To compare the effect of 4 day course (study group) with 7 day course (control group) of antibiotic treatment in neonatal pneumonia, on treatment success rate. METHODS: This randomized controlled trial was conducted in a tertiary teaching hospital. Seventy, term and near-term neonates with pneumonia who had clinical remission by 48 h of antibiotic therapy were included. The neonates were randomized to receive a total of 4 d of antibiotics (Group 1) or 7 d of antibiotics (Group 2). The outcome measure was treatment failure in each group within 3 d of discharge. RESULTS: The treatment success rate of both the groups was 100%. There was a significant reduction in the duration of hospital stay (p < 0.001), antibiotic usage (p < 0.001), and cost (p < 0.001) in the 4 d group. On follow up till 28 d of enrollment, no infective morbidity was found in either group. CONCLUSIONS: For term and near-term neonates who become clinically asymptomatic within 48 h of antibiotic therapy, 4 d of antibiotic therapy is as effective and safe as 7 d of antibiotic therapy, with significant reduction in hospital stay, antibiotic usage and cost.

Scaling up a tobacco control intervention in low resource settings: a case example for school teachers in India.

Research on processes of bringing effective tobacco control interventions to scale to increase quit rates among tobacco users is uncommon. This study examines processes to bring to scale one such intervention for school teachers, i.e. Tobacco Free Teacher-Tobacco Free Society (TFT-TFS). This intervention provides a foundation for an effective and low cost approach to promote cessation through schools. The present study was conducted in the states of Bihar and Maharashtra in 2014 using quantitative and qualitative methods. Focus group discussions (FGDs) were analysed using immersion crystallization method. The data presented are from a survey of 291 principals and seven FGDs. This study examined characteristics of principals and teachers, organizational environment, external environmental factors and program characteristics to determine facilitators and barriers for successful dissemination and implementation of the TFT-TFS program. Some facilitators were, incorporation of the program in existing channels like staff meetings and trainings, certification and recognition by the department of education; while some barriers were routine time bound duties (mainly teaching) of teachers and prevalence of tobacco use among teachers and administrators. Principals and teachers expressed a need and high level of interest in the adoption and implementation of the TFT-TFS program in their schools.

Enhanced electrocaloric efficiency via energy recovery.

Materials that show large and reversible electrically driven thermal changes near phase transitions have been proposed for cooling applications, but energy efficiency has barely been explored. Here we reveal that most of the work done to drive representative electrocaloric cycles does not pump heat and may therefore be recovered. Initially, we recover 75-80% of the work done each time BaTiO3-based multilayer capacitors drive electrocaloric effects in each other via an inductor (diodes prevent electrical resonance while heat flows after each charge transfer). For a prototype refrigerator with 24 such capacitors, recovering 65% of the work done to drive electrocaloric effects increases the coefficient of performance by a factor of 2.9. The coefficient of performance is subsequently increased by reducing the pumped heat and recovering more work. Our strategy mitigates the advantage held by magnetocaloric prototypes that exploit automatic energy recovery, and should be mandatory in future electrocaloric cooling devices.

Zinc as an adjunct treatment for reducing case fatality due to clinical severe infection in young infants: study protocol for a randomized controlled trial.

BACKGROUND: An estimated 2.7 of the 5.9 million deaths in children under 5 years of age occur in the neonatal period. Severe infections contribute to almost a quarter of these deaths. Mortality due to severe infections in developing country settings is substantial despite antibiotic therapy. Effective interventions that can be added to standard therapy for severe infections are required to reduce case fatality. METHODS/DESIGN: This is a double-blind randomized placebo-controlled parallel group superiority trial to investigate the effect of zinc administered orally as an adjunct to standard therapy to infants aged 3 days up to 2 months (59 days) hospitalized with clinical severe infection, that will be undertaken in seven hospitals in Delhi, India and Kathmandu, Nepal. In a 1:1 ratio, we will randomly assign young infants to receive 10 mg of elemental zinc or placebo orally in addition to the standard therapy for a total of 14 days. The primary outcomes hospital case fatality, which is death due to any cause and at any time after enrolment while hospitalized for the illness episode, and extended case fatality, which encompasses the period until 12 weeks after enrolment. DISCUSSION: A previous study showed a beneficial effect of zinc in reducing the risk of treatment failure, as well as a non-significant effect on case fatality. This study was not powered to detect an effect on case fatality, which this current study is. If the results are consistent with this earlier trial, we would have provided strong evidence for recommending zinc as an adjunct to standard therapy for clinical severe infection in young infants. TRIAL REGISTRATION: Universal Trial Number: U1111-1187-6479, Clinical Trials Registry - India: CTRI/2017/02/007966 : Registered on February 27, 2017.

Elastic and anelastic relaxation behaviour of perovskite multiferroics II: PbZr0.53Ti0.47O3 (PZT)-PbFe0.5Ta0.5O3 (PFT).

Elastic and anelastic properties of ceramic samples of multiferroic perovskites with nominal compositions across the binary join PbZr0.53Ti0.47O3-PbFe0.5Ta0.5O3 (PZT-PFT) have been assembled to create a binary phase diagram and to address the role of strain relaxation associated with their phase transitions. Structural relationships are similar to those observed previously for PbZr0.53Ti0.47O3-PbFe0.5Nb0.5O3 (PZT-PFN), but the magnitude of the tetragonal shear strain associated with the ferroelectric order parameter appears to be much smaller. This leads to relaxor character for the development of ferroelectric properties in the end member PbFe0.5Ta0.5O3. As for PZT-PFN, there appear to be two discrete instabilities rather than simply a reorientation of the electric dipole in the transition sequence cubic-tetragonal-monoclinic, and the second transition has characteristics typical of an improper ferroelastic. At intermediate compositions, the ferroelastic microstructure has strain heterogeneities on a mesoscopic length scale and, probably, also on a microscopic scale. This results in a wide anelastic freezing interval for strain-related defects rather than the freezing of discrete twin walls that would occur in a conventional ferroelastic material. In PFT, however, the acoustic loss behaviour more nearly resembles that due to freezing of conventional ferroelastic twin walls. Precursor softening of the shear modulus in both PFT and PFN does not fit with a Vogel-Fulcher description, but in PFT there is a temperature interval where the softening conforms to a power law suggestive of the role of fluctuations of the order parameter with dispersion along one branch of the Brillouin zone. Magnetic ordering appears to be coupled only weakly with a volume strain and not with shear strain but, as with multiferroic PZT-PFN perovskites, takes place within crystals which have significant strain heterogeneities on different length scales.

Long Spin Diffusion Length in Few-Layer Graphene Flakes.

We report a spin valve with a few-layer graphene flake bridging highly spin-polarized La_{0.67}Sr_{0.33}MnO_{3} electrodes, whose surfaces are kept clean during lithographic definition. Sharp magnetic switching is verified using photoemission electron microscopy with x-ray magnetic circular dichroism contrast. A naturally occurring high interfacial resistance ∼12 MΩ facilitates spin injection, and a large resistive switching (0.8 MΩ at 10 K) implies a 70-130 µm spin diffusion length that exceeds previous values obtained with sharp-switching electrodes.

Large electrocaloric effects in single-crystal ammonium sulfate.

Electrocaloric (EC) effects are typically studied near phase transitions in ceramic and polymer materials. Here, we investigate EC effects in an inorganic salt, namely ammonium sulfate (NH4)2SO4, with an order-disorder transition whose onset occurs at 223 K on cooling. For a single crystal thinned to 50 µm, we use a Maxwell relation to find a large isothermal entropy change of 30 J K(-1) kg(-1) in response to a field change of 400 kV cm(-1) The Clausius-Clapeyron equation implies a corresponding adiabatic temperature change of 4.5 K.This article is part of the themed issue 'Taking the temperature of phase transitions in cool materials'.

Adoption and Implementation of Tobacco Control Policies in Schools in India: Results of the Bihar School Teachers Study.

Implementation of no tobacco policies in schools is associated with lower tobacco use among teachers and students. In this study we assessed the extent that a school-based intervention for teachers resulted in adoption and implementation of tobacco control policies. From a random sample of government schools (8th-10th), 72 were randomized into intervention and control conditions. Intervention included health education programs for teachers and support for tobacco control policy implementation. Adoption and implementation of policies were assessed at baseline and immediately after intervention. All 36 intervention and one control school adopted a tobacco-control policy. Higher enforcement of tobacco-control policy was at post intervention (OR=3.26; CI: 2.35, 4.54) compared to baseline in intervention schools. Some 64% of intervention and 28% control schools showed "improvement" in policy implementation. Adoption and implementation of no tobacco policies was positively impacted by intervention. This study provides support for scaling up of school-based tobacco control interventions to promote school tobacco control policies.

Assessment of Adequacy of Supplementation of Vitamin D in Very Low Birth Weight Preterm Neonates: A Randomized Controlled Trial.

OBJECTIVES: To compare the effect of 400 IU and 1000 IU vitamin D for 6 weeks in very low birth weight preterm neonates. DESIGN: Randomized, double-blinded controlled trial in a teaching hospital. PARTICIPANTS: Fifty very low birth weight preterm neonates. INTERVENTION: Vitamin D 400 IU/day (Group 1) or 1000 IU/day (Group 2). OUTCOME MEASURES: Change in serum calcium, phosphate, alkaline phosphatase (ALP), 25-hydroxy vitamin D (25-OHD), parathormone, incidence of skeletal hypomineralization and growth. RESULTS: After 6 weeks of supplementation, the mean serum calcium and 25-OHD levels were significantly higher (p < 0.001 each), while ALP and parathormone levels significantly lower (p < 0.001 each) in group 2. Skeletal hypomineralization was lesser and growth better in group 2. CONCLUSION: Vitamin D supplementation in a dose of 1000 IU/day is more effective in maintaining serum calcium, phosphate, ALP, 25-OHD and parathormone levels with lower incidence of skeletal hypomineralization and better growth.

Photo-convertible fluorescent proteins as tools for fresh insights on subcellular interactions in plants.

Optical highlighters comprise photo-activatable, photo-switchable and photo-convertible fluorescent proteins and are relatively recent additions to the toolbox utilized for live cell imaging research. Here, we provide an overview of four photo-convertible fluorescent proteins (pcFP) that are being used in plant cell research: Eos, Kaede, Maple and Dendra2. Each of these proteins has a significant advantage over other optical highlighters since their green fluorescent nonconverted forms and red fluorescent converted forms are generally clearly visible at expression levels that do not appear to interfere with subcellular dynamics and plant development. These proteins have become increasingly useful for understanding the role of transient and sustained interactions between similar organelles. Tracking of single organelles after green-to-red conversion has provided novel insights on plastids and their stroma-filled extensions and on the formation of mega-mitochondria. Similarly colour recovery after photo-conversion has permitted the estimation of nuclear endo-reduplication events and is being developed further to image protein trafficking within the lumen of the endoplasmic reticulum. We have also applied photo-convertible proteins to create colour-differentiation between similar cell types to follow their development. Both the green and red fluorescent forms of these proteins are compatible with other commonly used single coloured FPs. This has allowed us to develop simultaneous visualization schemes for up to five types of organelles and investigate organelle interactivity. The advantages and caveats associated with the use of photo-convertible fluorescent proteins are discussed.