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1.
Theor Appl Genet ; 137(9): 214, 2024 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-39223330

RESUMO

KEY MESSAGE: A GWAS in an elite diversity panel, evaluated across 10 environments, identified genomic regions regulating six fiber quality traits, facilitating genomics-assisted breeding and gene discovery in upland cotton. In this study, an elite diversity panel of 348 upland cotton accessions was evaluated in 10 environments across the US Cotton Belt and genotyped with the cottonSNP63K array, for a genome-wide association study of six fiber quality traits. All fiber quality traits, upper half mean length (UHML: mm), fiber strength (FS: g tex-1), fiber uniformity (FU: %), fiber elongation (FE: %), micronaire (MIC) and short fiber content (SFC: %), showed high broad-sense heritability (> 60%). All traits except FE showed high genomic heritability. UHML, FS and FU were all positively correlated with each other and negatively correlated with FE, MIC and SFC. GWAS of these six traits identified 380 significant marker-trait associations (MTAs) including 143 MTAs on 30 genomic regions. These 30 genomic regions included MTAs identified in at least three environments, and 23 of them were novel associations. Phenotypic variation explained for the MTAs in these 30 genomic regions ranged from 6.68 to 11.42%. Most of the fiber quality-associated genomic regions were mapped in the D-subgenome. Further, this study confirmed the pleiotropic region on chromosome D11 (UHML, FS and FU) and identified novel co-localized regions on D04 (FU, SFC), D05 (UHML, FU, and D06 UHML, FU). Marker haplotype analysis identified superior combinations of fiber quality-associated genomic regions with high trait values (UHML = 32.34 mm; FS = 32.73 g tex-1; FE = 6.75%). Genomic analyses of traits, haplotype combinations and candidate gene information described in the current study could help leverage genetic diversity for targeted genetic improvement and gene discovery for fiber quality traits in cotton.


Assuntos
Fibra de Algodão , Genótipo , Gossypium , Fenótipo , Locos de Características Quantitativas , Gossypium/genética , Gossypium/crescimento & desenvolvimento , Fibra de Algodão/análise , Polimorfismo de Nucleotídeo Único , Estudo de Associação Genômica Ampla , Estudos de Associação Genética , Desequilíbrio de Ligação , Mapeamento Cromossômico/métodos , Genoma de Planta , Melhoramento Vegetal
2.
AAPS PharmSciTech ; 22(3): 76, 2021 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-33595780

RESUMO

Collagen and chitosan have haemostatic, tissue fix and wound healing properties but the poor mechanical property limits their application. Therefore, various concentrations of collagen (1-6%) and chitosan (1-2%) were used to develop biopolymer-coated gauzes, with and without glycerol as plasticiser. Glycerol-treated gauzes showed desired mechanical and adhesive property in comparison to polymer-coated gauzes alone. Developed gauzes were characterized using differential scanning calorimetry, thermal gravimetric analysis and Fourier transform infrared spectrophotometry to confirm the biopolymer coating and stability. Scanning electron microscopy showed multilayer coating of the biopolymer and faster clotting in chitosan gauzes in comparison to collagen. Surface plasmon resonance assay confirmed that chitosan exhibited more binding affinity of 65 RU in comparison to collagen, which showed 55 RU with erythrocytes. Decrease in the value of plateletcrit and mean platelet volume confirmed platelet adhesion and aggregation over the surface of polymer-coated dressings. Gamma scintigraphy studies showed 85 ± 2% formulation retention up to 12 h at the wound site in comparison to 40 ± 3% retention of the radiopharmaceutical alone. Collagen and chitosan-coated gauze showed 226 ± 15 s and 179 ± 12 s haemostasis time, respectively, which was significantly less from 506 ± 15 s in standard gauze. Chitosan gauze showed faster wound healing in comparison to the collagen-coated gauze. Chitosan and collagen-coated gauzes showed 55 ± 4% wound contraction on day seven in comparison to 25 ± 2% in the control group, while chitosan gauzes showed complete wound contraction on day fourteenth, while the collagen-coated gauze showed 90 ± 3% on the same day.


Assuntos
Bandagens , Quitosana/farmacologia , Colágeno/farmacologia , Hemostáticos/farmacologia , Cicatrização/efeitos dos fármacos , Adulto , Animais , Biopolímeros/farmacologia , Humanos , Masculino , Ratos , Ratos Sprague-Dawley
3.
AAPS PharmSciTech ; 22(4): 138, 2021 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-33880661

RESUMO

Fabrication of 3D composite scaffolds was carried out by lyophilization of variable concentrations of collagen and chitosan gel solutions. Fibrinogen and thrombin aerosol were deposited over the surface of scaffolds to enhance hemostasis and wound healing. Composite scaffolds were characterized using differential scanning calorimetry, thermogravimetric analysis, and Fourier-transform infrared spectrophotometer to ascertain the aerosol deposition and stability. Scanning electron microscope showed multilayered porosity with pore size of ~30 µm and mushroom-like fibril growth of aerosol. A detailed investigation by surface plasmon resonance confirmed higher binding affinity of collagen toward the human blood platelets and erythrocytes in comparison to chitosan and was found to increase with the increase in blood cell concentration from 480.8 to 886.4 RU for erythrocytes. Scaffolds showed higher binding response for platelets than erythrocytes, while fibrinogen and thrombin showed no or limited interaction. Highest blood sorption of 83 ± 4% was observed in case of aerosol deposited scaffolds. Aerosol deposited scaffolds showed minimum clotting time of 20 ± 3 s and bleeding time of 38 ± 4 s, which was significantly lower compared to the scaffolds without aerosol treatment. Aerosol deposited composite scaffolds with 2:1 concentration of chitosan/collagen showed complete wound contraction by day 14, while 50% was observed in case of the control group. In vivo studies revealed that chitosan had a crucial role in the inflammatory phase, while collagen played an important role in the proliferation and maturation phase. The present study suggests that the fabricated 3D composite scaffolds with bioactive moieties may be a potential candidate for enhanced hemostasis and wound healing applications.


Assuntos
Hemostasia , Alicerces Teciduais/química , Cicatrização , Animais , Varredura Diferencial de Calorimetria , Quitosana/química , Colágeno/química , Liofilização , Humanos , Porosidade , Engenharia Tecidual/métodos
4.
New Phytol ; 225(1): 326-339, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31465541

RESUMO

Awns are stiff, hair-like structures which grow from the lemmas of wheat (Triticum aestivum) and other grasses that contribute to photosynthesis and play a role in seed dispersal. Variation in awn length in domesticated wheat is controlled primarily by three major genes, most commonly the dominant awn suppressor Tipped1 (B1). This study identifies a transcription repressor responsible for awn inhibition at the B1 locus. Association mapping was combined with analysis in biparental populations to delimit B1 to a distal region of 5AL colocalized with QTL for number of spikelets per spike, kernel weight, kernel length, and test weight. Fine-mapping located B1 to a region containing only two predicted genes, including C2H2 zinc finger transcriptional repressor TraesCS5A02G542800 upregulated in developing spikes of awnless individuals. Deletions encompassing this candidate gene were present in awned mutants of an awnless wheat. Sequence polymorphisms in the B1 coding region were not observed in diverse wheat germplasm whereas a nearby polymorphism was highly predictive of awn suppression. Transcriptional repression by B1 is the major determinant of awn suppression in global wheat germplasm. It is associated with increased number of spikelets per spike and decreased kernel size.


Assuntos
Mapeamento Cromossômico , Loci Gênicos , Proteínas Repressoras/metabolismo , Supressão Genética , Transcrição Gênica , Triticum/anatomia & histologia , Triticum/genética , Sequência de Aminoácidos , Sequência de Bases , Segregação de Cromossomos/genética , Deleção de Genes , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Estudos de Associação Genética , Marcadores Genéticos , Estudo de Associação Genômica Ampla , Haplótipos/genética , Endogamia , Tamanho do Órgão , Proteínas de Plantas/química , Proteínas de Plantas/genética , Locos de Características Quantitativas/genética , Recombinação Genética/genética , Regulação para Cima/genética
5.
Funct Integr Genomics ; 19(1): 91-107, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30151724

RESUMO

Two hundred one hexaploid wheat accessions, representing 200 years of selection and breeding history, were sampled from the National Small Grains Collection in Aberdeen, ID, and evaluated for five root traits at the seedling stage. A paper roll-supported hydroponic system was used for seedling growth. Replicated roots samples were analyzed by WinRHIZO. We observed accessions with nearly no branching and accessions with up to 132 cm of branching. Total seminal root length ranged from 70 to 248 cm, a 3.5-fold difference. Next-generation sequencing was used to produce single-nucleotide polymorphism (SNP) markers and genomic libraries that were aligned to the wheat reference genome IWGSCv1 and were called single-nucleotide polymorphism (SNP) markers. After filtering and imputation, a total of 20,881 polymorphic sites were used to perform association mapping in TASSEL. Gene annotations were conducted for identified marker-trait associations (MTAs) with - log10P > 3.5 (p value < 0.003). In total, we identified 63 MTAs with seven for seminal axis root length (SAR), 24 for branching (BR), four for total seminal root length (TSR), eight for root dry matter (RDM), and 20 for root diameter (RD). Putative proteins of interest that we identified include chalcone synthase, aquaporin, and chymotrypsin inhibitor for SAR, MYB transcription factor and peroxidase for BR, zinc fingers and amino acid transporters for RDM, and cinnamoyl-CoA reductase for RD. We evaluated the effects of height-reducing Rht alleles and the 1B/1R translocation event on root traits and found presence of the Rht-B1b allele decreased RDM, while presence of the Rht-D1b allele increased TSR and decreased RD.


Assuntos
Regulação da Expressão Gênica de Plantas , Genoma de Planta , Proteínas de Plantas/genética , Raízes de Plantas/genética , Característica Quantitativa Herdável , Plântula/genética , Triticum/genética , Regulação da Expressão Gênica no Desenvolvimento , Ontologia Genética , Genes de Plantas , Estudo de Associação Genômica Ampla , Sequenciamento de Nucleotídeos em Larga Escala , Hidroponia , Anotação de Sequência Molecular , Proteínas de Plantas/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Polimorfismo de Nucleotídeo Único , Poliploidia , Locos de Características Quantitativas , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Triticum/crescimento & desenvolvimento , Triticum/metabolismo
6.
Theor Appl Genet ; 132(4): 1247-1261, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30680419

RESUMO

KEY MESSAGE: The optimization of training populations and the use of diagnostic markers as fixed effects increase the predictive ability of genomic prediction models in a cooperative wheat breeding panel. Plant breeding programs often have access to a large amount of historical data that is highly unbalanced, particularly across years. This study examined approaches to utilize these data sets as training populations to integrate genomic selection into existing pipelines. We used cross-validation to evaluate predictive ability in an unbalanced data set of 467 winter wheat (Triticum aestivum L.) genotypes evaluated in the Gulf Atlantic Wheat Nursery from 2008 to 2016. We evaluated the impact of different training population sizes and training population selection methods (Random, Clustering, PEVmean and PEVmean1) on predictive ability. We also evaluated inclusion of markers associated with major genes as fixed effects in prediction models for heading date, plant height, and resistance to powdery mildew (caused by Blumeria graminis f. sp. tritici). Increases in predictive ability as the size of the training population increased were more evident for Random and Clustering training population selection methods than for PEVmean and PEVmean1. The selection methods based on minimization of the prediction error variance (PEV) outperformed the Random and Clustering methods across all the population sizes. Major genes added as fixed effects always improved model predictive ability, with the greatest gains coming from combinations of multiple genes. Maximum predictabilities among all prediction methods were 0.64 for grain yield, 0.56 for test weight, 0.71 for heading date, 0.73 for plant height, and 0.60 for powdery mildew resistance. Our results demonstrate the utility of combining unbalanced phenotypic records with genome-wide SNP marker data for predicting the performance of untested genotypes.


Assuntos
Genômica , Estações do Ano , Seleção Genética , Triticum/genética , Alelos , Marcadores Genéticos , Genética Populacional , Genótipo , Fenótipo , Melhoramento Vegetal , Polimorfismo de Nucleotídeo Único/genética , Análise de Componente Principal
7.
Theor Appl Genet ; 131(10): 2245-2266, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30109391

RESUMO

Key message Major stem rust resistance QTLs proposed to be Rpg2 from Hietpas-5 and Rpg3 from GAW-79 were identified in chromosomes 2H and 5H, respectively, and will enhance the diversity of stem rust resistance in barley improvement programs. Stem rust is a devastating disease of cereal crops worldwide. In barley (Hordeum vulgare ssp. vulgare), the disease is caused by two pathogens: Puccinia graminis f. sp. secalis (Pgs) and Puccinia graminis f. sp. tritici (Pgt). In North America, the stem rust resistance gene Rpg1 has protected barley from serious losses for more than 60 years; however, widely virulent Pgt races from Africa in the Ug99 group threaten the crop. The accessions Hietpas-5 (CIho 7124) and GAW-79 (PI 382313) both possess moderate-to-high levels of adult plant resistance to stem rust and are the sources of the resistance genes Rpg2 and Rpg3, respectively. To identify quantitative trait loci (QTL) for stem rust resistance in Hietpas-5 and GAW-79, two biparental populations were developed with Hiproly (PI 60693), a stem rust-susceptible accession. Both populations were phenotyped to the North American Pgt races of MCCFC, QCCJB, and HKHJC in St. Paul, Minnesota, and to African Pgt races (predominately TTKSK in the Ug99 group) in Njoro, Kenya. In the Hietpas-5/Hiproly population, a major effect QTL was identified in chromosome 2H, which is proposed as the location for Rpg2. In the GAW-79/Hiproly population, a major effect QTL was identified in chromosome 5H and is the proposed location for Rpg3. These QTLs will enhance the diversity of stem rust resistance in barley improvement programs.


Assuntos
Resistência à Doença/genética , Hordeum/genética , Doenças das Plantas/genética , Locos de Características Quantitativas , Basidiomycota , Cromossomos de Plantas , Genes de Plantas , Ligação Genética , Genótipo , Hordeum/microbiologia , Fenótipo , Melhoramento Vegetal , Doenças das Plantas/microbiologia
8.
Theor Appl Genet ; 131(10): 2267, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30173395

RESUMO

Unfortunately, one co-author name was incorrectly published in the original publication. The complete correct name should read as follows.

9.
Nanomedicine ; 14(4): 1301-1313, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29641982

RESUMO

Paclitaxel (PTX) is a microtubule inhibitor administered as an albumin-bound nanoformulation for the treatment of breast cancer. However, the effectiveness of PTX is limited by resistance mechanisms mediated in part by upregulation of the anti-apoptotic BCL-2 and P-glycoprotein (P-gp). Present investigation was designed to study the synergistic potential of NuBCP-9 and PTX loaded polymeric nanoparticles to minimize the dose and improve the efficacy and safety. PTX and NuBCP-9 loaded polylactic acid-polyethylene glycol-polypropylene glycol-polyethylene glycol [PLA-(PEG-PPG-PEG)] nanoparticles were prepared by double emulsion solvent evaporation method. PTX and NuBCP-9 loaded NPs displayed an average size of 90 nm with spherical morphology. PTX and NuBCP-9 dual loaded NPs reducedIC50 by ~40-fold and acted synergistically. Treatment of the syngeneic EAT mice with PTX-NuBCP-9/NPs resulted in improved efficacy than that alone treated mice. Overall, the concomitant delivery PTX and NuBCP-9 loaded NPs showed superior activity than that of PTX and NuBCP-9 alone treated mice.


Assuntos
Nanopartículas/química , Oligopeptídeos/química , Paclitaxel/química , Polímeros/química , Albuminas/química , Sobrevivência Celular/efeitos dos fármacos , Sistemas de Liberação de Medicamentos/métodos , Sinergismo Farmacológico , Feminino , Humanos , Células MCF-7
10.
AAPS PharmSciTech ; 18(1): 156-165, 2017 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-26912356

RESUMO

Deferoxamine iron chelator has a limited therapeutic index due to rapid clearance from blood and possesses dose-limiting toxicity. Therefore, an intravenous deferoxamine delivery system based on dialdehyde cellulose (DAC) polymer was developed and its efficacy and toxicity were tested in iron-overloaded animals. The amino groups of deferoxamine were conjugated to free aldehyde moieties of dialdehyde cellulose via Schiff base reaction to form dialdehyde cellulose-deferoxamine (DAC-DFO) conjugate and characterized by Fourier transform infrared spectrophotometer, scanning electron microscope, and X-ray diffraction. The toxicity of prepared formulation was analyzed by XTT cell viability assay and LD50 study in mice. The change in serum iron levels, after intravenous administration of formulation, was observed in iron-overloaded rats. The DAC-DFO conjugate was tagged with Tc-99m to study the blood kinetics and observe change in blood circulation time. DAC-DFO conjugate was dispersible in water at concentration ∼75 mg/ml. In vitro cytotoxicity assay and LD50 study in mice indicated significantly enhanced safety of covalently bound deferoxamine (at >1000 mg/kg body weight compared to free drug at ∼270 mg/kg dose). A preliminary scintigraphy imaging and blood clearance study, with technetium-99m, indicated prolonged circulation of conjugated DFO in rabbit blood. A single dose of formulation injected into iron overloaded animals was found to maintain the normal serum iron levels until 10 days. The polymeric conjugate was effective in maintaining normal serum iron levels until 10 days at a dose of 100 mg/kg body weight.


Assuntos
Celulose/análogos & derivados , Desferroxamina/administração & dosagem , Desferroxamina/química , Portadores de Fármacos/química , Ferro/metabolismo , Animais , Celulose/administração & dosagem , Celulose/química , Química Farmacêutica/métodos , Portadores de Fármacos/administração & dosagem , Ferro/sangue , Sobrecarga de Ferro/sangue , Sobrecarga de Ferro/tratamento farmacológico , Cinética , Masculino , Camundongos , Coelhos , Ratos , Ratos Sprague-Dawley , Difração de Raios X/métodos
12.
J Chem Phys ; 142(5): 054707, 2015 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-25662660

RESUMO

In this work, we have studied the fluorescence quenching and solid state diffusion of 2, 3, 5, 6-tetrafluoro-7, 7', 8, 8'-tetracyano quinodimethane (F4-TCNQ) using photoluminescence (PL) spectroscopy. Quenching studies were performed with tris (8-hydroxyquinolinato) aluminum (Alq3) in solid state samples. Thickness of F4-TCNQ was varied in order to realize different concentrations and study the effect of concentration. PL intensity has reduced with the increase in F4-TCNQ thicknesses. Stern-Volmer and bimolecular quenching constants were evaluated to be 13.8 M(-1) and 8.7 × 10(8) M(-1) s(-1), respectively. The quenching mechanism was found to be of static type, which was inferred by the independent nature of excited state life time from the F4-TCNQ thickness. Further, solid state diffusion of F4-TCNQ was studied by placing a spacing layer of α-NPD between F4-TCNQ and Alq3, and its thickness was varied to probe the diffusion length. PL intensity was found to increase with the increase in this thickness. Quenching efficiency was evaluated as a function of distance between F4-TCNQ and Alq3. These studies were performed for the samples having 1, 2.5, and 5.5 nm thicknesses of F4-TCNQ to study the thickness dependence of diffusion length. Diffusion lengths were evaluated to be 12.5, 15, and 20 nm for 1, 2.5, and 5.5 nm thicknesses of F4-TCNQ. These diffusion lengths were found to be very close to that of determined by secondary ion mass spectroscopy technique.

13.
Theor Appl Genet ; 127(2): 283-95, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24170350

RESUMO

KEY MESSAGE: Genetic diversity and population structure in the US Upland cotton was established and core sets of allelic richness were identified for developing association mapping populations in cotton. Elite plant breeding programs could likely benefit from the unexploited standing genetic variation of obsolete cultivars without the yield drag typically associated with wild accessions. A set of 381 accessions comprising 378 Upland (Gossypium hirsutum L.) and 3 G. barbadense L. accessions of the United States cotton belt were genotyped using 120 genome-wide SSR markers to establish the genetic diversity and population structure in tetraploid cotton. These accessions represent more than 100 years of Upland cotton breeding in the United States. Genetic diversity analysis identified a total of 546 alleles across 141 marker loci. Twenty-two percent of the alleles in Upland accessions were unique, specific to a single accession. Population structure analysis revealed extensive admixture and identified five subgroups corresponding to Southeastern, Midsouth, Southwest, and Western zones of cotton growing areas in the United States, with the three accessions of G. barbadense forming a separate cluster. Phylogenetic analysis supported the subgroups identified by STRUCTURE. Average genetic distance between G. hirsutum accessions was 0.195 indicating low levels of genetic diversity in Upland cotton germplasm pool. The results from both population structure and phylogenetic analysis were in agreement with pedigree information, although there were a few exceptions. Further, core sets of different sizes representing different levels of allelic richness in Upland cotton were identified. Establishment of genetic diversity, population structure, and identification of core sets from this study could be useful for genetic and genomic analysis and systematic utilization of the standing genetic variation in Upland cotton.


Assuntos
Variação Genética , Gossypium/genética , Alelos , Marcadores Genéticos , Gossypium/classificação , Filogenia , Estados Unidos
14.
Artigo em Inglês | MEDLINE | ID: mdl-39473111

RESUMO

The adverse outcome that patients experience as a result of anti-cancer therapy failure is primarily caused by metastasis. Making cancer a chronic disease with regular but controlled relapses is the real issue in increasing cancer patient lifespans. This can only be achieved by developing efficient therapeutic techniques that target critical targets in the metastatic process. New targeted therapy medications continue to emerge, and research into the molecular targeted therapy of tumors is flourishing. The ineffectiveness of conventional chemotherapy in targeting metastatic cells is primarily due to its ability to promote the selection of chemo-resistant cell populations that engage in epithelial-to-mesenchymal transition (EMT), which in turn encourages the colonization of distant sites and maintains the initial metastatic process. In considering this circumstance, research into a broad range of small molecules and biologics has been initiated to develop anti-metastatic medications that target particular targets implicated in the different stages of metastasis. With their ability to concentrate on cancer cells while avoiding normal cells, tar-geted medications offer a promising alternative to conventional chemotherapy that is both highly effective and relatively safe. Many obstacles, including an inadequate response rate and drug resistance, persist for small-molecule targeted anti-cancer medications, despite significant ad-vancements in this area. We encouraged small-molecule-focused anti-cancer therapy develop-ment by extensively assessing them by target classification. We reviewed current challenges, listed licenced drugs and key drug candidates in clinical trials for each target, and made sugges-tions for improving anti-cancer drug research and development. This review aims to discuss pre-sent and future small molecule inhibitor research and development for cancer treatment.

15.
J Colloid Interface Sci ; 679(Pt A): 465-475, 2024 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-39368166

RESUMO

HYPOTHESIS: Building competitive color conversion pixels for microdisplays made of semiconductor nanocrystals requires reaching a deposition thickness high enough to absorb all the blue light from the backlight unit. In the case of dielectrophoretic directed assembly of such nanocrystals, modeling and simulations may help understand what the intrinsic limitations of the process are, and may be used to propose new assembly routes. EXPERIMENTS: A theoretical model of dielectrophoretic interactions between polarizable nano-spheres and an electrostatically patterned substrate has been developed. Monte Carlo simulations have been run using this model to rationalize the effects of parameters driving the dielectrophoretic directed assembly and to find optimal deposition conditions for reaching a maximal thickness of nanocrystal pixels. Experiments with CdSe quantum plates and with alumina spheres embedding quantum plates (micro-pearls) have been carried out and compared to the model. FINDINGS: Modeling and simulations reveal that the directed assembly of semiconductor nanocrystals is limited essentially by the small object size, which sets the maximum dielectrophoretic force they can undergo. They indicate that using larger objects should allow reaching unprecedented assembly heights, but will induce lateral extension of the assembly. This trade-off has been illustrated with diagrams in the parameter space and confirmed experimentally with micro-pearls.

16.
Adv Mater ; 36(33): e2401611, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38848668

RESUMO

Integrating tunneling magnetoresistance (TMR) effect in memristors is a long-term aspiration because it allows to realize multifunctional devices, such as multi-state memory and tunable plasticity for synaptic function. However, the reported TMR in different multiferroic tunnel junctions is limited to 100%. This work demonstrates a giant TMR of -266% in La0.6Sr0.4MnO3(LSMO)/poly(vinylidene fluoride)(PVDF)/Co memristor with thin organic barrier. Different from the ferroelectricity-based memristors, this work discovers that the voltage-driven florine (F) motion in the junction generates a huge reversible resistivity change up to 106% with nanosecond (ns) timescale. Removing F from PVDF layer suppresses the dipole field in the tunneling barrier, thereby significantly enhances the TMR. Furthermore, the TMR can be tuned by different polarizing voltage due to the strong modification of spin-polarization at the LSMO/PVDF interface upon F doping. Combining of high TMR in the organic memristor paves the way to develop high-performance multifunctional devices for storage and neuromorphic applications.

17.
Opt Lett ; 38(19): 3854-7, 2013 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-24081070

RESUMO

In this Letter, the effect of F(4)-TCNQ insertion at the anode/hole transport layer (HTL) interface was studied on joule heating and the lifetime of organic light-emitting diodes (OLEDs). Joule heating was found to reduce significantly (pixel temperature decrease by about 10 K at a current density of 40 mA/cm(2)) by this insertion. However, the lifetime was found to reduce significantly with a 1 nm thick F(4)-TCNQ layer, and it improved by increasing the thickness of this layer. Thermal diffusion of F(4)-TCNQ into HTL leads to F(4)-TCNQ ionization by charge transfer, and drift of these molecules into the emissive layer caused faster degradation of the OLEDs. This drift was found to reduce with an increase in the thickness of F(4)-TCNQ.

19.
Heliyon ; 8(11): e11442, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36387457

RESUMO

The objective of present work is to fabricate porous three-dimensional biocomposite scaffolds with interconnected pore networks and mechanical strength for wound healing. Variable concentrations of chitosan and methylcellulose hydrogels were blended in the presence of calcium cations to prepare scaffolds by freeze-drying method. Curcumin-aerosol was deposited over the scaffold surface to improve antimicrobial efficacy. Scaffold stability and curcumin interaction were evaluated by Differential Scanning Calorimeter, Thermal Gravimetric Analyzer and Fourier Transform Infrared Spectrophotometer. Scanning Electron Microscopy indicate multi-layered porosity, mesh-like structure and pore-size ranging from 50 to 500 µm. Erythrocyte interaction with chitosan and methylcellulose using Surface Plasmon Resonance assay in the presence of curcumin depicted high binding affinity of chitosan alone than curcumin. The antibacterial activity of SCF-4C against Escherichia coli and Staphylococcus aureus and the instant haemostasis in erythrocyte-agglutination assay by SCF-7 indicate good material properties for wound treatment. Bleeding time and wound healing efficacy conducted on Sprague Dawley rats depict minimum clotting time of SCF-4 (∼32 ± 2 s) compared to SCF-4C (∼45 ± 2 s), while highest ∼85 ± 5 s was observed in curcumin alone. SCF-4C exhibit complete wound healing on day14 in diabetic animals. In-vivo studies confirmed that high concentration of chitosan in presence of curcumin enhances diabetic wound healing process.

20.
Front Microbiol ; 12: 638003, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33796089

RESUMO

Micro-organisms colonized the world before the multi-cellular organisms evolved. With the advent of microscopy, their existence became evident to the mankind and also the vast processes they regulate, that are in direct interest of the human beings. One such process that intrigued the researchers is the ability to grow in presence of toxic metals. The process seemed to be simple with the metal ions being sequestrated into the inclusion bodies or cell surfaces enabling the conversion into nontoxic nanostructures. However, the discovery of genome sequencing techniques highlighted the genetic makeup of these microbes as a quintessential aspect of these phenomena. The findings of metal resistance genes (MRG) in these microbes showed a rather complex regulation of these processes. Since most of these MRGs are plasmid encoded they can be transferred horizontally. With the discovery of nanoparticles and their many applications from polymer chemistry to drug delivery, the demand for innovative techniques of nanoparticle synthesis increased dramatically. It is now established that microbial synthesis of nanoparticles provides numerous advantages over the existing chemical methods. However, it is the explicit use of biotechnology, molecular biology, metabolic engineering, synthetic biology, and genetic engineering tools that revolutionized the world of microbial nanotechnology. Detailed study of the micro and even nanolevel assembly of microbial life also intrigued biologists and engineers to generate molecular motors that mimic bacterial flagellar motor. In this review, we highlight the importance and tremendous hidden potential of bio-engineering tools in exploiting the area of microbial nanoparticle synthesis. We also highlight the application oriented specific modulations that can be done in the stages involved in the synthesis of these nanoparticles. Finally, the role of these nanoparticles in the natural ecosystem is also addressed.

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