Flexible perylenediimide/GaN organic-inorganic hybrid system with exciting optical and interfacial properties

We report the band gap tuning and facilitated charge transport at perylenediimide (PDI)/GaN interface in organic-inorganic hybrid nanostructure system over flexible titanium (Ti) foil. Energy levels of the materials perfectly align and facilitate high efficiency charge transfer from electron rich n-GaN to electron deficient PDI molecules. Proper interface formation resulted in band gap tuning as well as facilitated electron transport as evident in I-V characteristics. Growth of PDI/GaN hybrid system with band gap tuning from ultra-violet to visible region and excellent electrical properties open up new paradigm for fabrication of efficient optoelectronics devices on flexible substrates

Influence of growth temperature on structural and optical properties of laser MBE grown epitaxial thin GaN films on a-plane sapphire

Epitaxial thin GaN films (similar to 60 nm) have been grown on a-plane sapphire substrates at different growth temperatures (500-700 degrees C) using laser molecular beam epitaxy (LMBE). The effect of growth temperatures on the structural and optical properties of GaN layers grown on low temperature (LT) GaN buffer on prenitridated a-sapphire have been studied systematically. The in situ reflection high energy electron diffraction pattern revealed the three-dimensional epitaxial growth of GaN films on a-sapphire under the adopted growth conditions. The full width at half maximum (FWHM) value of x-ray rocking curves (XRCs) along GaN (0002) and (10-12) planes decreases with increasing growth temperature. The FWHM values of (0002) and (10-12) XRC for the 700 degrees C grown GaN film are 1.09 degrees and 1.08 degrees, respectively. Atomic force microscopy characterization showed that the grain size of GaN increases from 30-60 to 70-125 nm with the increase in growth temperature as GaN coalescence time is shorter at high temperature. The refractive index value for the dense GaN film grown at 600 degrees C is obtained to be similar to 2.19 at the wavelength of 632 nm as deduced by spectroscopic ellipsometry. Photoluminescence spectroscopy confirmed that the epitaxial GaN layers grown on a-sapphire at 600-700 degrees C possess near band edge emission at similar to 3.39 eV, close to bulk GaN. The GaN growth at 700 degrees C without a buffer still produced films with better crystalline and optical properties, but their surface morphology and coverage were inferior to those of the films grown with LT buffer. The results show that the growth temperature strongly influences the structural and optical quality of LMBE grown epitaxial GaN thin films on a-plane sapphire, and a growth temperature of >600 degrees C is necessary to achieve good quality GaN films. Published by the AVS

High frequency plant regeneration with histological analysis of organogenic callus from internode explants of Asteracantha longifolia Nees

Asteracantha longifolia Nees is an ayurvedic medicinal herb. The internode explants of this plant were used for high frequency plant regeneration on Murashige and Skoog (MS) medium supplemented with various plant growth regulators (PGRs) in different concentrations. Apical meristem and leaf primordium formations were confirmed through microscopic analysis of histological sections of the organogenic callus tissues. The synergistic effect of α-naphthaleneacetic acid (NAA) 0.5 mg/l with N6 benzyladenine (BA) 0.25 mg/l increased the percentage of explants response for callus induction while comparing other treatments. Various concentrations of NAA were also found to be best for explants response to callus induction than 2,4-dichlorophenoxyacetic acid (2,4-D). The callus morphology (color and texture) was different according to the growth regulators and their concentrations. The highest percentage of response per culture for shoot bud regeneration was noted for the concentration of NAA 0.5 mg/l with BA 2.0 mg/l, the same concentration effectively increased the number of shoots per culture. Different concentrations of indol-3-butyric acid (IBA) and NAA were used in half strength MS medium for in vitro rooting of regenerated shoots. The maximum percentage of shoot response for rooting and the highest number of root formations per shoot were observed on the medium containing 0.5 mg/l of IBA. The survival rate (86.7%) of the regenerated plants was noted after 20 days of transplantation

On the synthesis and characterization of ZnO/MgO nanocomposite by thermal evaporation technique

ZnO/MgO nanocomposites have been synthesized by an easy and cost effective thermal evaporation technique. Various growth temperatures ranging from 800 to 900 degrees C were tried. It is observed that the process temperature plays a key role in the formation of ZnO/MgO nanocomposite and the proper formation of ZnO/MgO nanocomposite occurs at 875 degrees C temperature as confirmed by X-ray diffraction studies. Scanning electron microscopic images indicate that the ZnO/MgO nanocomposite is formed as agglomerated nanoparticles distributed over a large area. Energy dispersive X-ray analyses also reveal that the Mg composition in the synthesized nanocomposite strongly depends on the process temperature. Photoluminescence (PL) spectrum exhibits a blue shift for the ZnO/MgO nanocomposite synthesized at 875 degrees C indicating the incorporation of Mg into the ZnO crystal lattice. A higher PL intensity ratio of band-edge to deep band emission has been observed for this sample indicating the presence of low crystalline defects

Hemodynamically stable very low birth neonates weight gain is affected by the early initiation of full enteral feedings compared to standard feeding

BACKGROUND: Premature babies need to develop similarly to fetuses of the same gestational age. The majority of premature neonates experience a growth-restricted status while in the patent ductus arteriosus (PDA). Extrauterine growth failure is a significant barrier for infants with very low birth weight (VLBW). MATERIALS AND METHODS: The study was conducted for six months at the Neonatology Unit, Department of Pediatrics, Coimbatore Medical College Hospital, Coimbatore, Tamil Nadu, India. Neonates with VLBW who met the inclusion criteria were assigned randomly to one of two feeding strategies, that is, full enteral feeding or partial feeding, based on the randomization sequence discovered by opening the sealed cover. The duration of stay, weight variation, neonatal variables, feeding intolerance, necrotizing enterocolitis (NEC), septicemia, apnea, newborn hyperbilirubinemia, PDA, hypoglycemia, intracranial bleeding, and mortality of neonatal recruits were all carefully evaluated. RESULTS: Two thousand two hundred eighty-four neonates were hospitalized throughout the six-month trial period, and 408 had low birth weight. Three hundred forty-two babies were eliminated from the study due to hemodynamic instability, persistent respiratory distress, infections, metabolic issues, and congenital abnormalities. Sixty-six babies met the study's inclusion criteria, and thus participated in the study. Sixty-six newborns weighed between 1.251 and 1.500 kg. Randomly assigning intervention and control groups. Thirty-three newborns were assigned to group A (intervention) and another 33 to group B (control). CONCLUSIONS: The study concluded that enteral feeding was effective, inexpensive, secure, and feasible. Early full enteral feeding reduced septicemia and infant hyperbilirubinemia. Thus, we must start enteral feeding as soon as possible to avoid inadequate nutrition in neonates with VLBW during a crucial growth period