The fabrication of a superior-performance ultraviolet (UV) photodetector utilizing graphene quantum dots (GQDs) as a sensitization agent on a ZnO-nanorod/GaN-nanotower heterostructure has been realized. GQD sensitization displays substantial impact on the electrical as well as the optical performance of a heterojunction UV photodetector. The GQD sensitization stimulates charge carriers in both ZnO and GaN and allows energy band alignment, which is realized by a spontaneous time-correlated transient response. The fabricated device demonstrates an excellent responsivity of 3.2 × 10 3 A/W at −6 V and displays an enhancement of ∼265% compared to its bare counterpart. In addition, the fabricated heterostructure UV photodetector exhibits a very high external quantum efficiency of 1.2 × 10 6 %, better switching speed, and signal detection capability as low as ∼50 fW.
Diabetes mellitus is a metabolic disorder in the endocrine system. This dreadful disease is found in all parts of the world and becoming a serious threat of mankind health. There are lots of chemical agents available to control and to treat diabetic patients, but total recovery from diabetes has not been reported up to this date. In addition to adverse effects, drug treatments are not always satisfactory in maintaining euglycemia and avoiding late stage diabetic complications. Alternative to these synthetic agents, plants provided a potential source of hypoglycemic drugs and are widely used in several traditional systems of medicine to prevent diabetes. Several medicinal plants have been investigated for their beneficial effect in different type of diabetes. Other alternative therapies such as dietary supplements, acupuncture, hydrotherapy, and yoga therapies less likely to have the side effects of conventional approaches for diabetes.
Vertically aligned GaN nanotowers (NTs) were grown on the Si (111) substrate by plasma-assisted molecular beam epitaxy to design a highly responsive ultraviolet (UV) photodetector. The UV detector fabricated on a bare GaN-NT array yielded highly sensitive and repeatable device characteristics attributed by high responsivity (R), low noise equivalent power (NEP), and a high external quantum efficiency (EQE) of 484.77 A/W, 1.76 × 10 −13 W.Hz -1/2 , and 1.85 × 10 5 %, respectively. Furthermore, the developed UV photodetector demonstrated fast response with excellent stability when functionalized with Au nanoparticles and ZnO nanorods. This hybridized GaN-NT-based device with ZnO nanorods and Au nanoparticles significantly accelerated the performance of the device where a prominent threeorder reduction under dark current is observed along with gigantic R, lower NEP, and an extremely enhanced EQE of 7042 A/W, 1.84 × 10 −14 W.Hz -1/2 , and 2.7 × 10 6 %, respectively. The mechanism elaborating the enhanced device performance with a localized surface plasmon effect has been discussed through an energy band diagram. The fabricated highly sensitive device can lead the path toward future optoelectronic applications of integrated III-nitride technology.
The fabrication of unique taper-ended GaN-Nanotowers structure based highly efficient ultraviolet photodetector is demonstrated. Hexagonally stacked, single crystalline GaN nanocolumnar structure (nanotowers) grown on AlN buffer layer exhibits higher photocurrent generation due to high quality nanotowers morphology and increased surface/volume ratio which significantly enhances its responsivity upon ultraviolet exposure leading to outstanding performance from the developed detection device. The fabricated detector display low dark current (~ 12 nA), high ILight/IDark ratio (> 104), fast time-correlated transient response (~ 433 µs) upon ultraviolet (325 nm) illumination. A high photoresponsivity of 2.47 A/W is achieved in self-powered mode of operation. The reason behind such high performance could be attributed to built-in electric field developed from a difference in Schottky barrier heights will be discussed in detail. While in photoconductive mode, the responsivity is observed to be 35.4 A/W @ − 3 V along with very high external quantum efficiency (~ 104%), lower noise equivalent power (~ 10–13 WHz−1/2) and excellent UV–Vis selectivity. Nanotower structure with lower strain and dislocations as well as reduced trap states cumulatively contributed to augmented performance from the device. The utilization of these GaN-Nanotower structures can potentially be useful towards the fabrication of energy-efficient ultraviolet photodetectors.
The nanoplasmonic impact of chemically synthesized Au nanoparticles (Au NPs) on the performance of GaN nanostructure-based ultraviolet (UV) photodetectors is analyzed. The devices with uniformly distributed Au NPs on GaN nanostructures (nanoislands and nanoflowers) prominently respond toward UV illumination (325 nm) in both self-powered as well as photoconductive modes of operation and have shown fast and stable time-correlated response with significant enhancement in the performance parameters. A comprehensive analysis of the device design, laser power, and bias-dependent responsivity and response time is presented. The fabricated Au NP/GaN nanoflower-based device yields the highest photoresponsivity of ∼ 380 mA/W, detectivity of ∼ 1010 jones, reduced noise equivalent power of ∼ 5.5 × 10–13 W Hz–1/2, quantum efficiency of ∼ 145%, and fast response/recovery time of ∼40 ms. The report illustrates the mechanism where light interacts with the chemically synthesized nanoparticles guided by the surface plasmon to effectively enhance the device performance. It is observed that the Au NP-stimulated local surface plasmon resonance effect and reduced channel resistance contribute to the augmented performance of the devices. Further, the decoration of low-dimensional Au NPs on GaN nanostructures acts as a detection enhancer with a fast recovery time and paves the way toward the realization of energy-efficient optoelectronic device applications.
Objectives:This prescription-monitoring study was conducted to establish the drug-prescribing trend of anti-asthmatic drugs in various hospitals of Gorakhpur.Setting:The study covered three famous hospitals of Gorakhpur.Patients and Methods:Hundred patients were studied using a prescription auditing performa. Data was recorded from the patient's attending the out patient department using a chance random sample method for two months. Patients who co- operated were interviewed and information was filled in the performa.Results:The results suggested that b-agonist (40%) were the most frequently prescribed anti-asthmatic drugs followed by Methylxanthine (27%), corticosteroids (25%), leukotriene antagonist (4.4%) and anti-histaminics (3.6%) was the least prescribed. Analysis of prescription revealed that multiple drug therapy (81%) was opted for a significant number of patients as compared to single drug therapy (19%). Contrary to popular belief, oral dosage form tablets (56.3%) were preferred over inhalation (33.8%).Conclusion:It is concluded that the present prescribing pattern of anti-asthmatics in Gorakhpur does not completely meet standard guidelines of asthma treatment. Hence there is a need to encourage physicians of Gorakhpur to follow the guidelines while treating asthma.
The role of nonsteroidal anti-inflammatory drugs (NSAIDs) in prevention of Alzheimer's disease (AD) has been evaluated in many studies. We performed a meta-analysis to summarize the existing evidence on the relation between use of classical NSAIDs and AD. Randomized controlled trials (RCTs) evaluating the role of classical NSAIDs in AD was searched using different search engines. The RCTs in patients who had the degree of AD measured on Mini-Mental State Examination (MMSE) or AD Assessment Scale-Cognitive subscale (ADAS-cog) were included in the study. The RCTs and data (AD scores) were independently assessed by 2 reviewers, and data were included in meta-analysis only after a common consensus was reached. The pooled results from the ADAS-cog and MMSE scores failed to show any difference between the treatment and the placebo groups as opposed to findings from some observational studies. However, in view of heterogeneity of results, there is a need to conduct more RCTs to arrive at confirmatory findings.
This paper presents a new approach for third order quadrature oscillator (QO) realisation. It uses a high pass filter and differentiator connected in a feedback loop. A differential voltage current conveyor transconductance amplifier (DVCCTA) is employed to verify the proposed approach. Two circuit topologies of QO have been proposed. Both the topologies utilise two DVCCTA and three grounded capacitors. In addition, the first topology employs a single resistor while the second makes use of two resistors. The circuits exhibit orthogonal control on frequency and condition of oscillation. The quadrature current outputs are available at high output impedance and voltage outputs are also present. The theoretical proposition has been verified through SPICE simulations using 0.25 μm Taiwan semiconductor manufacturing company (TSMC) complementary metal oxide semiconductor (CMOS) technology parameters. Experimental results are also included which corroborate the theoretical propositions and simulated results.
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