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Performance Improvement of Multiband Triangular Microstrip Patch Antenna Using Frequency Selective Surface

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Journal of Shanghai Jiaotong university(Science) 2024年第2期29卷 316-321页

作者： MAHENDRAN krishnakumar GAYATHRI Rajaraman Department of Electronics and Communication Engineering Annamalai UniversityChidambaram 608002India

Today's antennas have to operate in multiple resonant frequencies to satisfy the need of recent advances in communication *** paper presents split ring resonator based triangular multiband antenna whose antenna performance is enhanced with the help of frequency selective surfaces(FSSs).The antenna has multiple resonances at S,C,and X *** array of 4×3 crisscross-shaped unit cells are arranged to form the FSS *** antenna is fed with a microstrip line feeding *** proposed antenna operates at 3.5 GHz,4.1 GHz,5.5GHz,9.4GHz,and 9.8 GHz with a better return loss and *** and measured results yield a good match.

关键词： triangular microstrip antenna split ring resonator frequency selective surface(FSS) metamaterial

Management of multiple and displaced mandibular fractures in a pediatric patient sans mandibular immobilization,sans open reduction and internal fixation

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Chinese Journal of Traumatology 2024年第5期27卷 284-287页

作者： Elavenil Panneerselvam Chandini Ravikumar Trishala Annamalai Rajan Sasikala Balasubramanian krishnakumar Raja V.B. Department of Oral and Maxillofacial Surgery SRM Dental College and HospitalRamapuramChennai600089Tamil NaduIndia

Maxillofacial fractures in the pediatric population are generally managed by conservative approaches such as soft diet and medication or semi-invasive procedures namely inter-maxillary fixation or circummandibular *** approaches are preferred over any invasive treatment to minimize injury to the growing skeleton and tooth *** fractures that cause functional problems such as restricted mouth opening,malocclusion or impaired breathing,mandate open reduction and internal ***,surgical management is associated with morbidity related to general anesthesia,risk of injury to vital structures,and potential,skeletal or dental growth *** case report describes a non-invasive method of managing displaced,multiple fractures of the mandible in a pediatric patient,with the use of low intensity pulsed ultrasound to achieve favorable clinical outcomes and nil *** immobilization of the mandible with inter-maxillary fixation nor open reduction and internal fixation was *** intensity pulsed ultrasound therapy is painless and patient-friendly.

关键词： Pediatric fractures Parasymphysis Ramus Composite splinting

Solar active fire clay based hetero-Fenton catalyst over a wide pH range for degradation of Acid Violet 7

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Journal of Environmental Sciences 2012年第3期24卷 529-535页

作者： Inbasekaran Muthuvel Balu krishnakumar Meenakshisundaram Swaminathan Department of Chemistry Annamalai UniversityAnnamalainagar 608002India.

Fe（III） immobilized fire clay （Fe-FC） was prepared using ferric nitrate by solid state dispersion method and this hetero-Fenton catalyst was applied for the degradation of Acid Violet 7 （AV 7） under natural sunlight. The 26% ferric nitrate loaded fire clay was found to be most efficient. The experimental conditions such as solution pH, H2O2 concentration for efficient degradation of AV 7 have been determined. Unlike Fenton catalyst, Fe-FC is photoactive over a wide pH range of 3-7. This catalyst was found to be stable and reusable. The GC-MS analysis of experimental solutions during irradiation revealed the formation of 2,8-diaminonaphthalene-1,3,6- triol, 8-aminonaphthalene-1,2,3,6-tetrol, 2-aminonaphthalene-1,3,6,8-tetrol and 2-aminobenzene-1,3-diol/5-aminonbenzene-1,3-diol/ 2-aminobenzene-1,4-diol as intermediates. The 26% ferric nitrate loaded fire clay was characterized by XRD, ICP-AES, BET surface area, FT-IR, SEM-EDS and UV-DRS studies.

关键词： hetero-Fenton degradation Acid Violet 7 fire clay wastewater treatment solar light

Geographic Drone-based Route Optimization Approach for Emergency Area Ad-Hoc Network

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Computer Systems Science & Engineering 2023年第4期45卷 985-1000页

作者： V.krishnakumar R.Asokan Department of Electronics and Communication Engineering Kongunadu College of Engineering and TechnologyThottiamTrichy621215India

Wireless sensor Mobile ad hoc networks have excellent potential in moving and monitoring disaster area networks on real-time *** recent challenges faced in Mobile Ad Hoc Networks(MANETs)include scalability,localization,heterogeneous network,self-organization,and self-sufficient *** this background,the current study focuses on specially-designed communication link establishment for high connection stability of wireless mobile sensor networks,especially in disaster area *** protocols focus on location-dependent communications and use networks based on typically-used Internet Protocol(IP)***,IP-based communications have a few limitations such as inefficient bandwidth utilization,high processing,less transfer speeds,and excessive memory *** overcome these challenges,the number of neighbors(Node Density)is minimized and high Mobility Nodes(Node Speed)are *** proposed Geographic Drone Based Route Optimization(GDRO)method reduces the entire overhead to a considerable level in an efficient manner and significantly improves the overall performance by identifying the disaster *** drone communicates with anchor node periodically and shares the information to it so as to introduce a drone-based disaster network in an *** routing is a promising approach to enhance the routing efficiency in *** algorithm helps in reaching the anchor(target)node with the help of Geographical Graph-Based Mapping(GGM).Global Positioning System(GPS)is enabled on mobile network of the anchor node which regularly broadcasts its location information that helps in finding the *** first step,the node searches for local and remote anticipated Expected Transmission Count(ETX),thereby calculating the estimated *** Signal Strength Indicator(RSSI)results are stored in the local memory of the ***,the node calculates the least remote anticipated ETX,Link Loss Rate,and information to the new location.

关键词： Mobile ad hoc networks(MANETs) geographical graph-based mapping(GGM) geographic drone based route optimization data speed anchor node’s

New approaches to water purification for resource- constrained settings： Production of activated biochar by chemical activation with diammonium hydrogenphosphate

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Frontiers of Chemical Science and Engineering 2018年第1期12卷 194-208页

作者： Mohit Nahata Chang Y. Seo Pradeep krishnakumar Johannes Schwank Department of Chemical Engineering University of Michigan-Ann Arbor Ann Arbor MI 48109 USA

A significant portion of the world＇s population does not have access to safe drinking water. This problem is most acute in remote, resource-constrained rural settings in developing countries. Water filtration using activated carbon is one of the important steps in treating con- taminated water. Lignocellulosic biomass is generally available in abundance in such locations, such as the African rain forests. Our work is focused on developing a simple method to synthesize activated biochar from locally available materials. The preparation of activated biochar with diammonium hydrogenphosphate （DAP） as the activating agent is explored under N2 flow and air. The study, carried out with cellulose as a model biomass, provides some insight into the interaction between DAP and biomass, as well as the char forming mechanism. Various characterization techniques such as N2 physisorption, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and Raman spectroscopy are utilized to compare the properties between biochar formed under nitrogen and partial oxidative conditions. At a temperature of 450 ℃, the loading of DAP over cellulose is systematically varied, and its effect on activation is examined. The activated biochar samples are predominantly microporous in the range of concentrations studied. The interaction of DAP with cellulose is investigated and the nature of bonding of the heteroatoms to the carbonaceous matrix is elucidated. The results indicate that the quality of biochar prepared under partial oxidation condition is comparable to that ofbiochar prepared under nitrogen, leading to the possibility of an activated biochar production scheme on a small scale in resource-constrained settings.

关键词： cellulose DAP activation heteroatom,microporous

Molt and reproduction enhancement together with hemolymph ecdysteroid elevation under eyestalk ablation in the female fiddler crab,Uca triangularis(Brachyura:Decapoda)

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Chinese Journal of Oceanology and Limnology 2017年第3期35卷 645-657页

作者： SUPRIYA Nagathinkal T SUDHA Kappalli krishnakumar Velayudhannair ANILKumaR Gopinathan Post Graduate Department of Zoology and Research Centre Sree Narayana CollegeKannurKerala 670007India Department of Zoology University of MadrasGuindy CampusChennai-600 025India School of Biotechnology Chemical and Biomedical EngineeringVIT UniversityVellore 632014India

We present the results of eyestalk extirpation experiments performed on the fiddler crab, Uca triangularis at seasons of molting and reproduction, with a view to have a better understanding of the regulatory mechanisms of these two highly energy-demanding processes. Bilateral eyestalk ablation resulted in precocious acceleration of both molting and reproduction, irrespective of the season at which each experiment was conducted. The rate of accelerated ovarian growth, however, was maximum if the eyestalk ablation was conducted during August-January, the breeding season in the wild, or in February- May （molting-reproductive season）, wherein a section of the wild population would be engaged in molting and another section in breeding. The highest degree of precocious molt acceleration, on the other hand, was obtained during June-July when the population was primarily engaged in molting, but with no reproductive activity. The precocious oocyte maturation （due to de-eyestalking） was minimal in June--July. Significantly, the eyestalk ablation also resulted in a dramatic increase in the hemolymph ecdysteroid titer, revealing that a high ecdysteroid titer would have no restraining influence on vitellogenesis. No spawning was, however, observed among de-eyestalked females, even though their final oocyte size surpassed the size of the normal mature oocytes, implying that spawning is not exclusively under the control of eyestalk hormones. A comparative study performed on the viteUine components of the experimentals and the controls revealed that the precociously incorporated yolk under eyestalk ablation was biochemically impoverished. These results indicate that throughout the annual cycle, both the somatic and the reproductive growth of U. triangularis are under the influence of inhibitory principles from the eyestalks. It is also revealing that mere deprival of the inhibitory principles does not culminate into successful vitellogenesis. Arguably, the inhibitory influence from

关键词： crab molt reproduction eyestalk principles ecdysteroids

Gut microbiome in acute pancreatitis:A review based on current literature

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World Journal of Gastroenterology 2021年第30期27卷 5019-5036页

作者： Bharati Kadamb Patel Kadamb H Patel Madhav Bhatia Shridhar Ganpati Iyer krishnakumar Madhavan Shabbir M Moochhala Department of Surgery National University of SingaporeSingapore 119228Singapore School of Applied Sciences Temasek PolytechnicSingapore 529757Singapore Department of Pathology University of OtagoChristchurch 8140New Zealand Department of Surgery Yong Loo Lin School of MedicineNational University of SingaporeSingapore 119228Singapore National University Hospital National University of SingaporeSingapore 119228Singapore Department of Pharmacology Yong Loo Lin School of MedicineNational University of SingaporeSingapore 119228Singapore

The gut microbiome is a complex microbial community,recognized for its potential role in physiology,health,and *** available evidence supports the role of gut dysbiosis in pancreatic disorders,including acute pancreatitis(AP).In AP,the presence of gut barrier damage resulting in increased mucosal permeability may lead to translocation of intestinal bacteria,necrosis of pancreatic and peripancreatic tissue,and infection,often accompanied by multiple organ dysfunction *** gut microbial homeostasis may reduce the systemic effects of AP.A growing body of evidence suggests the possible involvement of the gut microbiome in various pancreatic diseases,including *** review discusses the possible role of the gut microbiome in *** highlights AP treatment and supplementation with prebiotics,synbiotics,and probiotics to maintain gastrointestinal microbial balance and effectively reduce hospitalization,morbidity and mortality in an early *** also addresses novel therapeutic areas in the gut microbiome,personalized treatment,and provides a roadmap of human microbial contributions to AP that have potential clinical benefit.

关键词： Acute pancreatitis Gut microbiota Biomarkers Diagnostics Dysbiosis

General Variance Covariance Structures in Two-Way Random Effects Models

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Applied Mathematics 2013年第4期4卷 614-623页

作者： Carlos De Porres Jaya krishnakumar Department of Economics University of Geneva Geneva Switzerland

This paper examines general variance-covariance structures for the specific effects and the overall error term in a two-way random effects (RE) model. So far panel data literature has only considered these general structures in a one-way model and followed the approach of a Cholesky-type transformation to bring the model back to a “classical” one-way RE case. In this note, we first show that in a two-way setting it is impossible to find a Cholesky-type transformation when the error components have a general variance-covariance structure (which includes autocorrelation). Then we propose solutions for this general case using the spectral decomposition of the variance components and give a general transformation leading to a block-diagonal structure which can be easily handled. The results are obtained under some general conditions on the matrices involved which are satisfied by most commonly used structures. Thus our results provide a general framework for introducing new variance-covariance structures in a panel data model. We compare our results with [1] and [2] highlighting similarities and differences.

关键词： Error Components Matrix Decompositions Panel Data Spectral Decompositions

Passage of nasogastric tube through tracheo-esophageal fistula into stomach: A rare event

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World Journal of Clinical Cases 2014年第7期2卷 309-310页

作者： Ravikiran Shankar Kamble Rahulkumar Gupta Abhaya Gupta Paras Kothari K Vishesh Dikshit krishnakumar Kesan Kedar Mudkhedkar Department of Pediatric Surgery Lokamany Tilak Municipal Medical College and Government HospitalMaharashtra 400022India

Esophageal atresia with tracheo-oesophageal fistula(TEF) occurs in 1 in 3500 live births. Anorectal malformation is found to be associated with 14% of TEF. Esophageal atresia with TEF is a congenital anomaly which classically presents as excessive frothing from the mouth and respiratory distress. Rarely gastric position of the feeding tube in a case of TEF can be obtained delaying the diagnosis of TEF. We had an uncommon situation where a nasogastric tube reached the stomach through the trachea and tracheo-esophageal fistula, leading to misdiagnosis in a case of esophageal atresia with tracheoesophageal fistula. By using a stiff rubber catheter instead of a soft feeding tube for the diagnosis of esophageal atresia and TEF, such situation can be avoided.

关键词： Esophageal atresia Tracheoesophageal fistula Nasogastric tube Red rubber catheter Misdiagnosis