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We examine the relationship between institutional investor ownership and dividend payouts using a large sample of NSE-listed non-financial firms during the period 2001 to 2016. Consistent with the evidence from the US market, institutional investors, on average, have larger holdings in dividend-paying firms and are seen to prefer dividend payers over non-payers among larger firms. However, among smaller firms, institutional investors seem to prefer non-paying firms. Consistent with it, logistic regression results reveal that institutional investors do improve a firms’ propensity to pay dividends, primarily across large firms. Further, among dividend-paying firms, institutional investors, on average, are observed to have relatively lesser holdings in firms with higher payouts than those with lower payouts. In line with these observations, regression analysis also provides no evidence to support a positive relationship between total institutional ownership and payout level. However, across investor categories, we do find evidence for domestic institutional investors (DII) in improving payouts. Further, we use a dynamic panel GMM estimator to correct for endogeneity and find that the relationship is robust among large firms. Our results highlight the role of DII in improving dividend payout and provide support to models that predict a positive relationship. JEL Classification: G23, G32, G34, G35

Coronavirus Disease 2019 is a rapidly progressing pandemic that has affected 12.3 million individuals while causing 5,54,061 deaths worldwide till date. In India, approx 7,94,000 individuals (including approximately 4,96,000 recovered patients) have been affected with approximately 21,604 deaths. The sheer extent of the disease makes it imperative to increase awareness among our professional peers regarding the nature of the disease and its transmissibility while formulating standard operating procedures to mitigate the same. The present article disseminates the evidence to date and is based on available literature, brief working experiences, and relevant recommendations that can be implemented at various dental centers and units at all levels.

Manipulation in micro or nanoscale with robotic manipulators under observation of electron microscopes is a widely used strategy for fabrication of nanodevices and nanoscale material property characterization. These types of manipulation systems can handle the relatively larger scale of objects. However, the complexity of manipulation increases highly for 3D manipulation. Since the manipulation system consists of multiple components including manipulator, microscope, and also some end-effector tools, a proper offline visualization of the system is necessary for operation. Therefore, we propose a web-based virtual interface between the user and the actual manipulator operated under digital microscope initially. It gives the operator 3D positional feedback from the virtual model by mapping data read during remote operation. The same interface is used for remote operation of the manipulator within the SEM chamber and a manipulation task is performed.

We report the creation of chromium-coated optical fiber meta-tip using Focused-Ion-Beam Lithography. A 2D nano array is designed and fabricated on standard optical fiber tip and supports the localized surface plasmon resonance.

We report a simple and inexpensive way for the preparation of highly transparent ZnO thin films and their application as active layer in UV ray sensor devices. ZnO thin films were deposited on glass substrates by thermal evaporation of pure ZnO powder. The as-deposited films were then annealed at different temperatures (100, 200, 300 and 400 °C) for various time durations (5, 15, 25 and 35 min) to make optically transparent in the visible region. The films annealed at 300 °C for 15 min show very good visible transparency and other material properties. These films were used as the active material for Ag/ZnO/Ag UV sensor devices. The sensor devices are photo conductive type and only sensitive in the UV region of the electromagnetic spectrum. Maximum photo-current gain of the UV sensor device is ∼2. Possible sensing mechanism has been discussed.

Objective: Patients with chronic diseases are more prone to develop drug-related problems (DRPs), which can further worsen their quality of life. The aim of this study was to determine factors and medications associated with DRPs in patients with chronic disease.Methods: This prospective interventional study was conducted for a duration of 6 mo in the in-patients of general medicine department of PSG Hospital, Coimbatore. DRPs were identified, assessed and recorded as per pharmaceutical care network Europe (PCNE) V5.01 criteria. Chi-square and correlation test were used to analyze the data for identifying factors associated with DRPs.Results: A total of 137 patients were enrolled for the study, of which 66 patients developed DRPs. The most prevalent DRP was found to be drug choice problem. The major causes of DRPs were found to be drug and dose selection. Antidiabetic drugs were found to be more associated with drug-related problems. The incidence of drug-related problems was high in patients aged between 50 to 59 y. Association between gender, length of hospital stays and polypharmacy with DRPs was found to be statistically significant. 58.33% of the total drug-related problems were completely solved and 19.05% were partially solved.Conclusion: The incidence of DRPs in the General Medicine department of the hospital was high. The use of an appropriate tool such as PCNE may assist pharmacists and other healthcare professionals to systematically identify, categorize and report drug-related problems.

β-SiC nanowires have been synthesized on etch-patterned wafers in a chemical vapor deposition (CVD) system without using any metal catalyst. The nanowires were grown selectively inside the ‘V-groove’ of etch-patterned silicon (110) substrate which was used as a template for nanostructure growth. Nanowire growth was hardly found on the sample which was not previously etched. The nanowires have a core-sheath structure with the SiC core surrounded by an amorphous SiO2 sheath layer. The etching of the patterned Si (110) wafers was carried out by a 50 % aqueous KOH solution. The SiC growth was performed in a resistively heated atmospheric pressure chemical vapor deposition (APCVD) system by using hexamethyldisilane (HMDS) as the single source for Si and C at 1150oC. The as-grown samples and the patterned wafers were characterized by field emission electron microscopy, energy dispersive x-ray spectroscopy, X-ray diffraction, micro-Raman spectroscopy and Fourier transform infrared spectroscopy. Etching is one of the key factors for nanostructure growth and the patterning in the wafer provides selectivity. The growth process was governed by vapor-solid (VS) mechanism.

Many studies have been done on low energy (1–200 keV) and high dose (1016–1017) implantation of Mn in GaAs. This study is an attempt to incorporate Mn ions in GaAs through implantation of 1 MeV Mn+1 ions in semi-insulating GaAs substrates at doses of 3×1015/cm2 and subsequent annealing. This was done to find out if any alloy of Mn–Ga–As, or binary compounds of Mn–Ga or Mn–As form due to annealing of Mn+1 ions implanted in GaAs substrates. High Resolution XRD (HRXRD) performed before annealing shows a possibility of Ga–Mn–As alloy formation, and after annealing at 800°C, except for GaAs main peaks no other phase peaks were detected. Scanning electron microscopy (SEM) shows nanostructures of various dimensions which are thought to be formed due to the defects generated due to implantation. Fourier Transform Infrared (FTIR) study shows the shift in bandgap due to Mn doping. Raman spectroscopy shows the red shift in LO and TO peak positions of GaAs after annealing, which indicates the presence of disorder and damage due to implantation. Resistivity measurement shows a thermally activated semiconductor character of charge conduction with an activation energy of 51 meV and this activation may have occurred through the transitions from impurity band to valence band. Large positive (∼25%) magnetoresistance and a mixture of ferromagnetic and paramagnetic behavior obtained in the magnetization measurement indicate the presence of ferromagnetic MnAs nanoclusters embedded in paramagnetic GaAs:Mn matrix.

This paper discusses the growth and characterization of 3C-SiC films on Si (100) and (111) substrates using hexamethyldisilane (HMDS) as the source material in a resistance-heated furnace as well as the formation and microstructure of various types of unusual defects. Apart from common triangular and square voids, some unusual shaped voids like hexagonal, truncated octahedron, etc. and some irregular features (like hockey stick or pipes) were observed regularly, which are related to voids. SiC whiskers and wires with a wide range of diameters (nm to @mm) were formed inside cracked regions as well as within voids. Optical microscopy, scanning electron microscopy (SEM) and Raman spectroscopy were used to study these features. ures.

This review article attempts to present a comprehensive picture of the progress in selective epitaxial growth (SEG) of cubic silicon carbide (3C-SiC) to make it a cheap and practical material for high temperature and high power, high frequency and MEMS (Micro Electromechanical Systems) applications. Selective epitaxial growth followed by epitaxial lateral overgrowth (ELO) is a suitable approach to minimize the interfacial defects and other planar defects in case of thin film growth. Different techniques of SEG and its application to Si, GaAs and III–V nitrides are reviewed briefly in the first section of this article. Various SEG techniques like epitaxial lateral overgrowth, pyramidal growth and pendeo epitaxial growth, etc. have been discussed extensively for growing 3C-SiC on Si, together with the characterization of the grown films. The influence of various experimental parameters such as temperature of growth, choice of mask material, influence of an etchant, pattern shape and size, etc. is also discussed. On the basis of these data, it is believed that SEG and related techniques are a promising approach for heteroepitaxial growth of 3C-SiC films useful for devices and MEMS applications.

Generally, GaN-based devices are grown on silicon carbide or sapphire substrates. But these substrates are costly and insulating in nature and also are not available in large diameter. Silicon can meet the requirements for a low cost and conducting substrate and will enable integration of optoelectronic or high power electronic devices with Si based electronics. But the main problem that hinders the rapid development of GaN devices based on silicon is the thermal mismatch of GaN and Si, which generates cracks. In 1998, the first MBE grown GaN based LED on Si was made and now the quality of material grown on silicon is comparable to that on sapphire substrate. It is only a question of time before Si based GaN devices appear on the market. This article is a review of the latest developments in GaN based devices on silicon.

Selective growth and reduction of defects of cubic silicon carbide (3C-SiC) crystals grown within windows and laterally over SiO2 masks patterned on Si substrates are presented. The growth has been performed via chemical vapor deposition using hexachlorodisilane and propane, as well as hexamethyldisilane. Lateral epitaxial overgrowth (LEO) was achieved at selected areas where windows are square or array of stripes. The LEO process was characterized mainly by atomic force microscopy. 3C-SiC grew epitaxially on Si inside the window of SiO2 mask, and after filling up the window area, SiC grew laterally onto the SiO2 mask. The LEO begins with appearance and growth of (1 1 2) facets of 3C-SiC, and finally, the fronts of laterally overgrown SiC from the opposite sides of windows coalesce with each other. If the mask is an array of rectangular stripes, the coalescence point becomes a seam. Cathodoluminescence micrographs showed the absence of dislocations in the LEO region and the presence at the seam lines. Although many rectangular-shaped pits are observed in the area of epitaxially grown 3C-SiC, they disappeared in the LEO regions. This suggests the pits being originated upon epitaxy of 3C-SiC on Si and expanded to form rectangular shape on the final surface.

The basic objective of this work was to investigate a suitable ohmic metallization to 3C-SiC epitaxial layer with relatively low process temperature, which is important for on-chip circuit integration. In this study, the ohmic contacts are associated with the catalytic-metal/SiC Schottky diode gas sensors operable at 400 °C. Therefore, the contacts must be reliable for efficient operation of the sensors at this temperature in air ambient. Several metallization schemes were studied and the observed electrical characteristics were correlated to the interface properties by secondary ion mass spectrometry. Nickel contacts to moderately doped (∼10 17 cm −3 ) 3C-SiC epilayer did not exhibit linear current–voltage relationship even after annealing at 600 °C. On the other hand, aluminum exhibited considerably low intercontact resistance in the as-deposited condition. But with increase in annealing temperature the current flow between a couple of Al contacts was impeded presumably due to very high affinity of this metal for oxygen. Titanium exhibited good ohmic properties after annealing at 400 °C. However, higher temperature (600 °C) annealing in air ambient (intended to examine its stability limit) caused surface oxidation of the Ti layer. This problem was minimized by deposition of 100 nm Au overlayer (on top of 400 nm Ti) which would increase the surface conductivity of the ohmic contacts and ensure stable wire bonding.

The heteroepitaxial growth of 3C–SiC on Si and other substrates has indicated the potential for high mobility devices. However, the high density of interfacial defects (misfit dislocations, voids) as well as other defects (threading dislocations, twins, stacking faults) result in the growth of lower quality material. A suitable approach towards solving this problem is the use of selective epitaxial growth on patterned silicon substrates followed by epitaxial lateral overgrowth. The substrates used were patterned silicon substrates prepared by depositing a SiO 2 layer as the mask, followed by conventional lithographic techniques. The windows are of different shapes (square, circular, hexagonal, parallel lines) with their edges oriented mostly along the 〈1 1 0〉 direction. Selective growth was carried out at the substrate temperature of 1150°C using hexachlorodisilane (HCDS) and propane. Lateral overgrowth was observed in these films. The selectivity was a function of temperature. An additional factor influencing selectivity was the concentration of the precursors. Coalescence of the epilayer on the windows strongly depended on the shape of the windows. Complete coalescence of the islands was not observed on windows with square and circular shapes. However, it was observed on the hexagonal windows as the growth fronts continued to maintain their linearity as growth proceeded.

This article reports the formation of Schottky nanocontacts on single crystalline ZnO nanorods (NR) using atomic force microscopy (AFM) with a PtIr-coated Si cantilever in a contact mode. ZnO NRs were synthesized by thermal evaporation of metallic zinc thin film followed by annealing. The NRs are [11 $$ \overline{2} $$ 0] directed (i.e., along a-axis) which is quite unusual for wurtzite ZnO. The appearance of an intense visible emission band in room-temperature photoluminescence indicates the presence of a high density of intrinsic defects confirming n-type ZnO. The PtIr tip/ZnO Schottky nanocontacts with an ultra fine effective contact radius ~0.5 nm on horizontally dispersed NRs show an ideality factor of ~7, turn on voltage of ~1.0 V, Schottky barrier height of ~0.65 eV, breakdown voltage of ~−4.7 V, and ON to OFF current ratio of ~500 at ±2 V. The junction corresponds to a nanoscale Schottky contact with satisfactory properties which is comparable to the other PtIr/ZnO or Pt/ZnO reports at higher loading forces. Single crystallinity and contact on the side faces of the horizontally dispersed NRs are primarily thought to be the key factors for higher device performances.

The sympathetic skin response (SSR) is an evoked change in electrical skin potential and is an index of the function of sympathetic pathways. We studied the SSR evoked by electrical stimulation of the median nerve and recording from the contralateral hands in 30 patients with carpal tunnel syndrome (CTS) without clinical autonomic signs and compared the results to the SSR in 30 normal controls. The SSR was absent in the affected hands in seven (23%) patients. In the other carpal tunnel syndrome patients (77%), a significant reduction in the SSR area was seen in the records from the affected hands. Subclinical sympathetic nerve fibre involvement occurs in the affected median nerves in CTS.

Introduction: Tongue cleaning has been shown to be effective in preventing plaque formation and reducing oral mutans streptococci (MS) when used in combination with other oral hygiene procedures. However, correlation between MS counts and plaque levels remains to be demonstrated. Aim: To evaluate the effect of tongue scraping and tongue brushing on salivary MS and plaque levels. Materials and Methods: A triple-blind three arm randomized controlled parallel-group trial was carried out among 54, 12–15-year-old boys in a residential school in Bengaluru city. The study participants were randomly allocated into Group A (toothbrushing and tongue scraping; n = 19), Group B (toothbrushing and tongue brushing; n = 18) and Group C (only toothbrushing; n = 17). The clinical procedure included a collection of saliva and recording of plaque index at baseline, 10th and 21st day. Salivary MS counts were determined using mitis salivarius bacitracin Agar media. ANOVA, Wilcoxon's signed-rank sum test, Mann–Whitney U-test and Spearman's correlation test were performed on log-transformed CFU/mL of MS. Results: The tongue scraping and tongue brushing groups showed statistically significant reductions in salivary MS counts after 10 days (4.76 ± 0.54) (4.79 ± 0.44) and 21 days (4.50 ± 0.44) (4.41 ± 0.57) respectively when performed along with toothbrushing. However, differences between the interventions were not statistically significant. Furthermore, there was no statistically significant reduction in plaque levels after 10 and 21 days. Conclusions: Tongue scraping and tongue brushing were equally effective in reducing salivary MS counts when used in combination with toothbrushing, however, their effect on reducing plaque levels was not significant. Hence, tongue cleaning is recommended as an adjunct to toothbrushing.

Epitaxial growth of 3C-SiC on Si substrates has been studied for many years, however an important issue is how to reduce the high density of interfacial defects. Channel epitaxy is the growth of a film on small channeled windows and is related to selective growth. Channel epitaxy of 3C-SiC grown on the seed 3C-SiC previously deposited on patterned Si substrates was achieved via CVD using hexamethyldisilane (HMDS). The proper selection of mask materials was also key to achieve channel epitaxy. Thermal oxide, silicon nitride and thin SiC masks were tried. Thin SiC was an effective mask to achieve selective growth at 1350°C. Smooth surface morphology was observed on both the channel regions and the mask regions at the growth temperature of 1350°C. Scanning electron microscopy revealed coalescence of the laterally grown regions via channel epitaxial growth of 3C-SiC.

High quality SiC and AlN films allow the fabrication of metal/AlN/SiC MIS structures and SiC/AlN heterostructures that require a low lattice mismatch and excellent thermal stability. Epitaxial SiC on AlN/sapphire was grown using hexamethyldisilane (HMDS) by MOVPE. 2HAlN is epitaxially grown on sapphire by MOCVD, and subsequently SiC is deposited on it. The growth of high quality SiC was achieved in a one step process without any nucleation step using dilute hydrogen in argon (12% H2 + Ar) as the carrier gas, which is less explosive than pure H2. The effect of growth temperature and thickness of AlN on the SiC crystal quality and the surface smoothness were studied. All films were analyzed using reflection high energy electron diffraction (RHEED), Nomarski differential interference contrast microscopy (NDIC), X-ray diffraction (XRD), and atomic force microscopy (AFM). Optimum temperature for SiC growth was between 1300°C and 1350°C. At these temperatures, the grown films show strong epitaxial relationship with AlN and very smooth surfaces (RMS ∼ 0.1- 0.75 nm). At temperatures below 1300°C, the film becomes polycrystalline. At 1400°C, the films show highly textured features, observed by XRD. In the RHEED, however, weak rings appear superimposed on the spot pattern, which implies the grown films are polycrystalline but highly textured. In order to evaluate the effect of underlying AlN thickness on the SiC film, layers with various thicknesses (50, 200, 400 nm) have been used at 1350°C. The SiC film on a 50 nm thick AlN layer shows a very smooth surface (RMS ∼ 0.1 nm) compared to the SiC film on a 400 nm (RMS ∼ 0.7 nm) AlN layer. This seems to be caused by the increasing roughness of the underlying AlN, as it becomes thicker. However, all the films show highly epitaxial growth features, which implies that 50 nm is sufficient to relieve the mismatch strain of the underlying AlN/sapphire.

Together with sapphire, SiC is the most common substrate material for GaN epitaxial growth. In fact, SiC has advantages over sapphire because of its better thermal conductivity and lower film substrate lattice mismatch (∼3.5%). However, nucleation of GaN on SiC is rather difficult because of the low surface energy of SiC and the sensitivity of substrate preparation. This latter point makes it essential to use a very careful cleaning step, and also to pre-treat the substrate surface by growing a thick buffer layer of AlN at a relatively high temperature. In this study, several pre-treatment steps of SiC for GaN deposition were tested including (a) nitration with NH3 for 0.5-20 minutes, (b) pre-adsorption of trimethyl gallium (TMG) or trimethyl aluminum (TMA) for 0.5-5 minutes, and (c) deposition of an AlN buffer layer at ∼1150°C. After each pre-treatment, GaN was deposited by MOCVD using dilute H2(Ar+12%H2), NH3 and TMG. All the films were characterized by XRD and cross-sectional TEM. After nitration of SiC, the deposited GaN film was found to be polycrystalline. In case of pre-adsorption of TMG, epitaxial but island-like GaN formed on the substrate. In the third case, with an ultra-thin (∼1.5nm) coverage of AlN on SiC (by pre-adsorption of TMA or by 50 seconds deposition of AlN), GaN epilayers were successfully deposited on SiC. However, when AlN was deposited for longer than 3 minutes (up to 10 minutes), only polycrystalline GaN was obtained. With this technique of covering the surface with an ultra-thin layer of AlN, epitaxial GaN has been successfully deposited on 6H-SiC (0001), on 4H-SiC(0001), and on 3C-SiC/Si(111) substrates. The effect of the different pre-treatments of SiC on the quality of the deposited GaN films will be discussed and compared, and the optimal conditions for GaN deposition for each substrate will be presented.