Finite element study on the effect of abutment length and material on implant bone interface against dynamic loading

Manish Mishra,Shogo Ozawa,Tatsuhiko Masuda,Fumi Yoshioka,Yoshinobu Tanaka 대한치과보철학회 2011 The Journal of Advanced Prosthodontics Vol.3 No.3

PURPOSE Finite element study on the effect of abutment length and material on implant bone interface against dynamic loading. MATERIALS AND METHODS Two dimensional finite element models of cylinderical implant, abutments and bone made by titanium or polyoxymethylene were simulated with the aid of Marc/Mentat software. Each model represented bone, implant and titanium or polyoxymethylene abutment. Model 1: Implant with 3 mm titanium abutment, Model 2: Implant with 2 mm polyoxymethylene resilient material abutment, Model 3: Implant with 3 mm polyoxymethylene resilient material abutment and Model 4: Implant with 4 mm polyoxymethylene resilient material abutment. A vertical load of 11 N was applied with a frequency of 2 cycles/sec. The stress distribution pattern and displacement at the junction of cortical bone and implant was recorded. RESULTS When Model 2, 3 and 4 are compared with Model 1, they showed narrowing of stress distribution pattern in the cortical bone as the height of the polyoxymethylene resilient material abutment increases. Model 2, 3 and 4 showed slightly less but similar displacement when compared to Model 1. CONCLUSION Within the limitation of this study, we conclude that introduction of different height resilient material abutment with different heights i.e. 2 mm, 3 mm and 4 mm polyoxymethylene, does not bring about significant change in stress distribution pattern and displacement as compared to 3 mm Ti abutment. Clinically, with the application of resilient material abutment there is no significant change in stress distribution around implant-bone interface.

Physico-chemical and catalytic properties of Mg–Al hydrotalcite and Mg–Al mixed oxide supported copper catalysts

Manish Dixit,Manish Mishra,P.A. Joshi,D.O. Shah 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.2

The Mg–Al hydrotalcite (HT) and Mg–Al mixed oxide supported copper catalysts containing 3–3.5 wt.%copper in finely dispersed form were synthesized and characterized. The effect of support nature on physico-chemical and catalytic properties of supported copper species were studied. The loading of copper on the supports was observed to be influencing the surface acidic, basic and reducibility properties, and catalytic behavior in dehydrogenation of benzyl alcohol. The high basicity and intercalated copper ions in Mg–Al hydrotalcite supported copper sample showed multifunctional activity in catalytic transformations of alcohols (primary, secondary and aromatic alcohols).

Solvent Free N-Heterocyclization of Primary Amines to N-Substituted Azacyclopentanes Using Hydrotalcite as Solid Base Catalyst

Manish Dixit,Manish Mishra,P.A. Joshi,D.O. Shah 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.5

An ecofriendly catalytic route for selective synthesis of N-substituted azacyclopentanes, nitrogen-containing heterocyclic intermediates for many bioactive compounds, was established by carrying out N-heterocyclization (di N-alkylation) of primary amines with 1,4-dichloro butane (as dialkylating agent) using catalytic amount of hydrotalcite as solid base catalyst. The hydrotalcite was found to be efficient solid base catalyst for di Nalkylation of different primary amines (aniline, benzyl amine, cyclohexyl amine and n-butyl amine) giving 82 to 96% conversion (at optimized reaction condition) of 1,4-dichloro butane and > 99% selectivity of respective N-substituted azacyclopentanes within 30 min. under solvent free condition. The reaction parameters significantly influence the conversion of 1,4-dichloro butane to N-substituted azacyclopentanes. The nature of substituent present on amino group affects the reactivity of amine substrates for di N-alkylation reaction with 1,4-dichloro butane. The 1,4-dichloro butane was found to be highly reactive alkylating agent for di Nalkylation of amines as compared to 1,4-dihydroxy butane. The reusability of the catalyst and its chemical stability in the reaction was demonstrated.

Novel conducting lithium ferrite/chitosan nanocomposite: Synthesis, characterization, magnetic and dielectric properties

Manish Srivastava,Jay Singh,Rajneesh K. Mishra,Manish K. Singh,Animesh K. Ojha,Madhu Yashpal,Srivastava Sudhanshu 한국물리학회 2014 Current Applied Physics Vol.14 No.7

A study on Lithium ferrite/chitosan nanocomposite (LFCN), easily moldable into arbitrary shapes, as the conducting polymer and ferromagnetic characteristics is presented. The composite material is produced in the presence of Li0.5Cr0.1Fe2.4O4 and Li0.5Co0.1Fe2.4O4 nanoparticle by ex-situ polymerizations process. Various characterizations techniques have been used to explore the characteristic of the synthesized products. The frequency dependent dielectric properties and electrical conductivity of all the samples have been measured through complex impedance plot in the frequency range of 1 kHze6 MHz at room temperature. It was observed that in case of (LFCN), fluctuation in value of (ε 0) and (ε 00) is ceased over the frequency range of 4 Mz which can be attributed to the steady storage and dissipation of energy in the nanocomposite system. Moreover, it is also observed that electrical conductivity of (LFCN) increases with frequency and its value was found to be (0.032e0.048) (ohm-cm)1 in frequency range of 1 kHze6 MHz. Due to its low cost, a simple synthesis process and high flexibility, the proposed LFCN may find applications in various types of electronic components.

Solvent Free N-Heterocyclization of Primary Amines to N-Substituted Azacyclopentanes Using Hydrotalcite as Solid Base Catalyst

Dixit, Manish,Mishra, Manish,Joshi, P.A.,Shah, D.O. Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.5

An ecofriendly catalytic route for selective synthesis of $N$-substituted azacyclopentanes, nitrogen-containing heterocyclic intermediates for many bioactive compounds, was established by carrying out $N$-heterocyclization (di $N$-alkylation) of primary amines with 1,4-dichloro butane (as dialkylating agent) using catalytic amount of hydrotalcite as solid base catalyst. The hydrotalcite was found to be efficient solid base catalyst for di $N$-alkylation of different primary amines (aniline, benzyl amine, cyclohexyl amine and n-butyl amine) giving 82 to 96% conversion (at optimized reaction condition) of 1,4-dichloro butane and > 99% selectivity of respective $N$-substituted azacyclopentanes within 30 min. under solvent free condition. The reaction parameters significantly influence the conversion of 1,4-dichloro butane to $N$-substituted azacyclopentanes. The nature of substituent present on amino group affects the reactivity of amine substrates for di $N$-alkylation reaction with 1,4-dichloro butane. The 1,4-dichloro butane was found to be highly reactive alkylating agent for di $N$-alkylation of amines as compared to 1,4-dihydroxy butane. The reusability of the catalyst and its chemical stability in the reaction was demonstrated.

SnO2 quantum dots decorated on RGO: a superior sensitive, selective and reproducible performance for a H2 and LPG sensor.

Mishra, R K,Upadhyay, S B,Kushwaha, Ajay,Kim, Tae-Hyung,Murali, G,Verma, Ranjana,Srivastava, Manish,Singh, Jay,Sahay, P P,Lee, Seung Hee RSC Pub 2015 Nanoscale Vol.7 No.28

<P>We report the H2 and LPG gas sensing behavior of RGO/SnO2 QDs synthesized by a surfactant assisted hydrothermal method. The RGO/SnO2 QD based sensor shows a high response of 89.3% to H2 and 92.4% to LPG for 500 ppm test gas concentration at operating temperatures of 200 C and 250 C, respectively. Further, the RGO/SnO2 QD based sensor shows good selectivity for H2 and LPG in the presence of other interfering gases such as ammonia, chloroform, toluene, benzene, acetone, n-butylacetate, acetic acid and formic acid. We observed that the gas response to H2 is 29.8 times higher than that to acetic acid whereas the gas response to LPG is 17.8 times higher than that to formic acid. Long-term analyses have also been performed to demonstrate the reproducible nature of the RGO/SnO2 QD based sensor over passing time which shows excellent reproducibility.</P>

Cloning, Characterization of Pichia etchellsii β-Glucosidase II and Effect of Media Composition and Feeding Strategy on its Production in a Bioreactor

Saroj Mishra,Benu Sethi,Monika Jain,Manish Chowdhary,Yogesh Soni,Yukti Bhatia,Vikram Sahai 한국생물공학회 2002 Biotechnology and Bioprocess Engineering Vol.7 No.1

The cloning and expression of β-glucosidase II, encoded by the gene bglu2, from thermo- tolerant yeast Pichia etchellsii into Escherichia coli is described. Cloning of the 7.3 kb BamHI/SalI yeast insert containing bglu2 in pUC18, which allowed for reverse orientation of the insert, resulted in better enzyme expression. Transformation of this plasmid into E. coli JM109 resulted in accumulation of the enzyme in periplasmic space. At 50oC, the highest hydrolytic activity of 1686 IU/g protein was obtained on sophorose. Batch and fed-batch techniques were employed for enzyme production in a 14 L bioreactor. Exponential feeding rates were determined from mass balance equations and these were employed to control specific growth rate and in turn maximize cell growth and enzyme production. Media optimization coupled with this strategy resulted in increased enzyme units of 1.2 kU/L at a stabilized growth rate of 0.14 h-1. Increased enzyme production in bioreactor was accompanied by formation of inclusion bodies.

Object-oriented integrated algorithms for efficient water pipe network by modified Hardy Cross technique

Kailash Jha,Manish Kumar Mishra 한국CDE학회 2020 Journal of computational design and engineering Vol.7 No.1

In this work, object-oriented integrated algorithms for an efficient flow analysis of the water pipe network are developed. This is achieved by treating the pipe network as a graph data structure with its nodes as the graph’s nodes and the pipes as the edges. The algorithm for cycle (real cycle or pseudo-cycle) extraction has been developed using nested breadth-first search that gives ordered cycles. Pseudo-loops are found using the shortest path algorithm between the nodes. Pipes are initialized loop by loop using conservation of mass at nodes. A modified Hardy Cross method is used in the proposed work with third-order convergence. The friction factor is updated for every change in discharges. The pressure calculation has been done by the graph traversal algorithm between the reference nodes and node where the pressure is to be calculated using the energy equation. The pressure at all intermediate nodes is obtained in the course of the traversal. Balanced discharges and nodal pressure in the pipe network are compared with the simultaneous loop flow adjustment method and EPANET software. The proposed work gives more efficient flow analysis than the traditional Newton–Raphson-based techniques for complex networks.

Microwave assisted solvent free synthesis of a,a9 -bis (arylidene) cycloalkanones by sulfated zirconia catalyzed cross aldol condensation of aromatic aldehydes and cycloalkanones

Kirat Rawal,Manish Dixit,Meka Srinivasarao,Manish Kumar Mishra 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.4

The catalytic application of sulfated zirconia as solid Brønsted acid catalyst was explored for cross aldol condensation reactions (Claisen Schmidt reaction). The synthesized catalyst was highly active for solvent free synthesis of a,a9 -bis(arylidene)cycloalkanones by cross aldol condensation of aromatic aldehydes with cycloalkanones. The microwave assisted synthesis resulted increased yields of the products (79–99%) at significantly lower reaction temperature (120–140 8C) and reaction time (20 min) as compared to the synthesis by thermal heating (63–96% yield at 170 8C after 4 h). The microwave irradiation afforded selectively cross aldol products. The catalyst could be easily regenerated and reused several times with similar efficiency.

Microsatellite instability and its correlation with clinicopathological features in a series of thyroid tumors prevalent in iodine deficient areas

Minal Vaish,Anjali Mishra,Manish Kaushal,Saroj K Mishra,Balraj Mittal 생화학분자생물학회 2004 Experimental and molecular medicine Vol.36 No.2

Thyroid tumors display diverse spectrum of his-topathological groups with geographic variation in its prevalence. Influence of iodine deficiency (a major causative factor) in its etiology, prevalence, or aggressiveness is debatable which reflects the existence of various genetic events in pathoge-nesis. The present study was undertaken to study the role of Microsatellite instability (MSI) or LOH (loss of heterozygosity), an indicator of defective mismatch repair system as a genetic change and tumors. Tumor tisues from total thyroidectomy surgical specimens and blood (matched control) of 36 patients from iodine deficient areas (10 benign; 26 malignant) were obtained after their consent. Urinary iodine analysis was done by alkali ash method for which 10 ml of urine was colected from 18 patients before surgery. Genomic DNA, isolated from tumor tissue and blod was am-plified by polymerase chain reaction (PCR) using mono and dinucleotide markers - BAT-26, BAT-40, TGF(RII, IGFIIR, hMSH3, BAX, D2S123, D9S283, on 8% denaturing polyacrylamide gel folowed by autoradiography. Of total, 66.6% of tumors [70% (7/10) benign and 65.4% malignant cases (17/26)] showed MSI/LOH. Strong asociation of MSI/LOH with low iodine (P = 0.01) and with AMES risk groups i.e. age (P= 0.02), tumor size (P= 0.04) and metastases (P = 0.002) in thyroid tumors was observed. This may help in predicting the biolo-gical behaviour and strengthening the hypothesis thyroid tumors. Our results further substantiate the risk group clasification and help in deciding the treatment modality in particular patient.