Nanostructured Bulk Ceramics (Part I)

Han, Young-Hwan,Mukherjee, Amiya K. The Korean Ceramic Society 2009 한국세라믹학회지 Vol.46 No.3

The processing and characterization of ceramic nanocomposites, which produce bulk nanostructures with attractive mechanical properties, have been emphasized and introduced at Prof. Mukherjee's Lab at UC Davis. The following subjects will be introduced in detail in Part II, III, and IV. In Part II, the paper will describe a three-phase alumina-based nanoceramic composite demonstrating superplasticity at a surprisingly lower temperature and higher strain rate. The next part will show that an alumina-carbon nanotube-niobium nanocomposite produced fracture toughness values that are three times higher than that of pure nanocrystalline alumina. It was possible to take advantage of both fiber-toughening and ductile-metal toughening in this investigation. In the fourth section, discussed will be a silicon-nitride/silicon-carbide nanocomposite, produced by pyrolysis of liquid polymer precursors, demonstrating one of the lowest creep rates reported so far in ceramics at the comparable temperature of $1400^{\circ}C$. This was first achieved by avoiding the oxynitride glass phase at the intergrain boundaries. One important factor in the processing of these nanocomposites was the use of the electrical field assisted sintering method. This allowed the sintering to be completed at significantly lower temperatures and during much shorter times. These improvements in mechanical properties will be discussed in the context of the results from the microstructural investigations.

Nanostructured Bulk Ceramics (Part Ⅰ)

한영환,Amiya K. Mukherjee 한국세라믹학회 2009 한국세라믹학회지 Vol.46 No.3

The processing and characterization of ceramic nanocomposites, which produce bulk nanostructures with attractive mechanical properties, have been emphasized and introduced at Prof. Mukherjee’s Lab at UC Davis. The following subjects will be introduced in detail in Part ⅡI, Ⅲ, and Ⅳ. In Part Ⅱ, the paper will describe a three-phase alumina-based nanoceramic composite demonstrating superplasticity at a surprisingly lower temperature and higher strain rate. The next part will show that an alumina-carbon nanotube-niobium nanocomposite produced fracture toughness values that are three times higher than that of pure nanocrystalline alumina. It was possible to take advantage of both fiber-toughening and ductile-metal toughening in this investigation. In the fourth section, discussed will be a silicon-nitride/silicon-carbide nanocomposite, produced by pyrolysis of liquid polymer precursors, demonstrating one of the lowest creep rates reported so far in ceramics at the comparable temperature of 1400℃ This was first achieved by avoiding the oxynitride glass phase at the intergrain boundaries. One important factor in the processing of these nanocomposites was the use of the electrical field assisted sintering method. This allowed the sintering to be completed at significantly lower temperatures and during much shorter times. These improvements in mechanical properties will be discussed in the context of the results from the microstructural investigations. The processing and characterization of ceramic nanocomposites, which produce bulk nanostructures with attractive mechanical properties, have been emphasized and introduced at Prof. Mukherjee’s Lab at UC Davis. The following subjects will be introduced in detail in Part ⅡI, Ⅲ, and Ⅳ. In Part Ⅱ, the paper will describe a three-phase alumina-based nanoceramic composite demonstrating superplasticity at a surprisingly lower temperature and higher strain rate. The next part will show that an alumina-carbon nanotube-niobium nanocomposite produced fracture toughness values that are three times higher than that of pure nanocrystalline alumina. It was possible to take advantage of both fiber-toughening and ductile-metal toughening in this investigation. In the fourth section, discussed will be a silicon-nitride/silicon-carbide nanocomposite, produced by pyrolysis of liquid polymer precursors, demonstrating one of the lowest creep rates reported so far in ceramics at the comparable temperature of 1400℃ This was first achieved by avoiding the oxynitride glass phase at the intergrain boundaries. One important factor in the processing of these nanocomposites was the use of the electrical field assisted sintering method. This allowed the sintering to be completed at significantly lower temperatures and during much shorter times. These improvements in mechanical properties will be discussed in the context of the results from the microstructural investigations.

Targeted inhibition of galectin 1 by thiodigalactoside dramatically reduces body weight gain in diet-induced obese rats

Mukherjee, R,Kim, S W,Park, T,Choi, M S,Yun, J W Nature Publishing Group 2015 International Journal of Obesity Vol.39 No.9

Background:Galectin 1 (GAL1), an animal lectin is well characterized in the context of cancer, tumor environment, but its physiological roles in obesity remain to be demonstrated. In this study, we investigated whether targeted inhibition of GAL1 prevents obesity based on the previous observations that GAL1 is highly expressed in adipose tissues of high-fat diet (HFD)-induced obese rats.Methods:Lipogenic capacity of Lgals1 knocked down adipocytes was evaluated by determining the expression levels of major lipogenic markers using real-time PCR and immunoblot analysis. GAL1 partner proteins were identified using co-immunoprecipitation followed by protein mass fingerprinting. Finally, inhibitory effect of GAL1 by thiodigalactoside (TDG) was assessed in adipocytes and HFD-induced obese rats.Results:Knockdown of GAL1-encoding gene (Lgals1) attenuated adipogenesis and lipogenesis in both 3T3-L1 and HIB1B adipocytes. Further, direct treatment with TDG, a potent inhibitor of GAL1, to cultured adipocytes in vitro significantly reduced fat accumulation. Our animal experiment revealed that intraperitoneal injection of TDG (5 mg kg<SUP>−1</SUP>) once per week for 5 weeks in Sprague-Dawley (SD) rats resulted in dramatic inhibition of HFD-induced body weight gain (27.3% reduction compared with HFD-fed controls) by inhibiting adipogenesis and lipogensis as well as by increasing expression of the proteins associated with thermogenesis and energy expenditure.Conclusion:GAL1 has an essential role in HFD-induced obesity development. From a clinical viewpoint, pharmaceutical targeting of GAL1 using TDG and other inhibitor compounds would be a novel therapeutic approach for the treatment of obesity.

Gender-dependent Protein Expression in White Adipose Tissues of Lean and Obese Rats Fed a High Fat Diet

Mukherjee, Rajib,Choi, Jung-Won,Choi, Duk Kwon,Oh, Tae Seok,Liu, Hao,Yun, Jong Won S. Karger AG 2012 CELLULAR PHYSIOLOGY AND BIOCHEMISTRY Vol.29 No.3

<P>Proper understanding of molecular mechanisms underlying gender dimorphism in obesity for better nutritional recommendation is still in early stages. As white adipose tissues (WAT) is most important tissue in obesity metabolism, comparative proteomic analysis of all three WAT deposits at the same time to yield immensely important protein markers was the primary goal of this study.</P>

Organic phototransistors based on solution grown, ordered single crystalline arrays of a π-conjugated molecule

Mukherjee, Biswanath,Sim, Kyoseung,Shin, Tae Joo,Lee, Junghyun,Mukherjee, Moumita,Ree, Moonhor,Pyo, Seungmoon The Royal Society of Chemistry 2012 Journal of materials chemistry Vol.22 No.7

<P>High quality, single crystalline, ordered arrays of a π-conjugated organic molecule, <I>N,N′</I>-dioctyl-3,4,9,10-perylene tetracarboxylic diimide (PTCDI-C<SUB>8</SUB>), were grown by solution processing and used to fabricate a low-cost, high-performance organic phototransistor (OPT). The single crystalline nature of the microstructure was investigated using 2D-GIXD measurement. The organic field-effect transistor fabricated using periodic arrays of elongated crystals exhibited a photoresponsivity (<I>P</I>) of <I>ca.</I> 1 A W<SUP>−1</SUP> and a photo to dark current ratio (<I>I</I><SUB>on</SUB>/<I>I</I><SUB>off</SUB>) of 2.5 × 10<SUP>3</SUP> at <I>V</I><SUB>G</SUB> = 12 V and a maximum <I>P</I> of <I>ca.</I> 7 A W<SUP>−1</SUP> at the high gate bias regime (<I>V</I><SUB>G</SUB> = 50 V) with an optical power of <I>ca.</I> 7.5 mW cm<SUP>−2</SUP>. With polymeric gate dielectric, the OPT exhibited very stable n-type characteristics both in the dark and under light illumination and showed reproducible photo-switching behavior. The dependence of the photocurrent on the gate/drain voltage and on illumination intensity provided an effective way to control the number of photo-carriers generated in the active material, enabling the precise tuning of the device's performance. Performance comparison between OPTs with ordered crystal arrays and thin films of PTCDI-C<SUB>8</SUB> confirmed that the material's intrinsic properties were better realized in the crystalline device, presumably because of higher charge carrier mobility and better charge transport capability. This one-step, solution-based, self-assembly fabrication of multifunctional (photodetection, photoswitching, signal amplification) optoelectronic devices has potential to aid the development of organic semiconductors with high-quality micro/nanostructures for large-scale application and low-cost optoelectronic devices.</P> <P>Graphic Abstract</P><P>An organic phototransistor (OPT) was fabricated using solution grown, periodic arrays of PTCDI-C<SUB>8</SUB> single crystals. The OPT exhibited high photosensitivity (7 A W<SUP>−1</SUP>), high on/off current ratio (2.5 × 10<SUP>3</SUP>) and reproducible photo-switching at low optical power. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2jm14179e'> </P>

Magnon bistability in a hybrid cavity–magnon system

Mukherjee Kousik,Jana Paresh Chandra 한국물리학회 2023 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.82 No.4

We have explored the magnon bistability in cavity–magnon system. The stationary solution of the Heisenberg–Langevin equation is obtained numerically and magnon profle is studied as function of diferent experimentally feasible system parameters. The magnon profle shows an anticlockwise hysteresis loop and the loop area increases with input power. The mean magnon number shows bistable nature. The Kittel mode can transit from one stable state to another stable state near two transition points. The threshold powers of transition and bistable region strongly depend on magnon dissipation rate, photon-magnon coupling strength, and Kerr nonlinear strength. This study confrms that bistable quantum states may supply a platform to describe bistability at macroscopic regime in nonlinear systems. This study may also be used in potential applications in magnetic spintronics.

Novel mesoporous microspheres of Al and Ni doped LMO spinels and their performance as cathodes in secondary lithium ion batteries

Mukherjee, Santanu,Schuppert, Nicholas,Bates, Alex,Lee, Sang C.,Park, Sam Taylor and Francis 2017 INTERNATIONAL JOURNAL OF GREEN ENERGY Vol.14 No.7

Quercetin Down-regulates IL-6/STAT-3 Signals to Induce Mitochondrial-mediated Apoptosis in a Non-small-cell Lung-cancer Cell Line, A549

Mukherjee, Avinaba,Khuda-Bukhsh, Anisur Rahman KOREAN PHARMACOPUNCTURE INSTITUTE 2015 Journal of pharmacopuncture Vol.18 No.1

Objectives: Quercetin, a flavonoid compound, has been reported to induce apoptosis in cancer cells, but its anti-inflammatory effects, which are also closely linked with apoptosis, if any, on non-small-cell lung cancer (NSCLC) have not so far been critically examined. In this study, we tried to determine if quercetin had any demonstrable anti-inflammatory potential, which also could significantly contribute to inducing apoptosis in a NSCLC cell line, A549. Methods: In this context, several assays, including cytotoxicity, flow cytometry and fluorimetry, were done. Gene expression was analyzed by using a western blot analysis. Results: Results revealed that quercetin could induce apoptosis in A549 cells through mitochondrial depolarization by causing an imbalance in B-cell lymphoma 2/Bcl2 Antagonist X (Bcl2/Bax) ratio and by down-regulating the interleukine-6/signal transducer and activator of transcription 3 (IL-6/STAT3) signaling pathway. An analysis of the data revealed that quercetin could block nuclear factor kappa-light-chain-enhancer of activated B cells (NF-${\kappa}B$) activity at early hours, which might cause a down-regulation of the IL-6 titer, and the IL-6 expression, in turn, could inhibit p-STAT3 expression. Down-regulation of both the STAT3 and the NF-${\kappa}B$ expressions might, therefore, cause down-regulation of Bcl2 activity because both are major upstream effectors of Bcl2. Alteration in Bcl2 responses might result in an imbalance in the Bcl2/Bax ratio, which could ultimately bring about mitochondria mediated apoptosis in A549 cells. Conclusion: Overall, the finding of this study indicates that a quercetin induced anti-inflammatory pathway in A549 cells appeared to make a significant contribution towards induction of apoptosis in NSCLC and, thus, may have a therapeutic use such as a strong apoptosis inducer in cancer cells.

Freshness Assessment of Indian Gooseberry (Phyllanthus emblica) Using Probabilistic Neural Network

Mukherjee Alok,Sarkar Tanmay,Chatterjee Kingshuk 한국농업기계학회 2021 바이오시스템공학 Vol.46 No.4

Purpose In this paper, a probabilistic neural network (PNN)-based simple model for the detection of freshness in Indian gooseberry or amla (Phyllanthus emblica) samples has been developed. Methods The amla images have been analyzed using two features: hue histogram, which is a kind of color representative of the image, and entropy analysis, which corresponds to texture analysis of the sample images. Three freshness classes have been assigned depending on the freshness of the samples and governed by the Hedonic scale. Results The proposed PNN model is also tested with five different activation functions; out of which, radial and triangular basis functions are found to yield the most accurate results. Moreover, the hue-PNN model is found to possess marginal superiority over the entropy-PNN model, thus signifying the higher effectiveness of the former in the proposed work. The proposed work is computationally lighter as it contains PNN as the single analysis tool, aided by the image histograms. Moreover, the experiments have been conducted with the images captured using smartphones only, which establishes the portability of capturing images. Conclusions High freshness classification accuracy of 97.5%, ease of implementation, and use of smartphone captured images widen its practical applicability of developing into a smartphone application-based module.

The Indian Ocean: Historians Writing History

Mukherjee, Rila The Asian Association of World Historians 2013 The Asian review of world histories Vol.1 No.2