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1.
Adv Mind Body Med ; 37(4): 20-25, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38466050

RESUMO

Heartfulness meditation (HM) trains the practitioner's attention as they progress towards reaching a super-conscious state. The process is supported by guided "Heartfulness cleaning," which helps clear the mind. This study aimed to examine the short-term effects of HM on affect and cognition and determine whether performing Heartfulness cleaning beforehand influenced the meditation outcome. Forty-eight experienced meditators (age range: 19-71 years and a male-to-female ratio: 27:21) were randomly assigned to 3 sessions: (i) HM, (ii) Heartfulness meditation preceded by cleaning, and (iii) quiet rest as a control. Mood state and emotional well-being were assessed before and after each intervention using established scales such as the Brief Mood Introspection Scale, Global Vigor and Affect Scale, Spielberger's State-Trait Anxiety Inventory, and the Digit Letter Substitution Test. After engaging in both HM and Heartfulness cleaning meditation (HCM) practices, there was a noticeable increase in feelings of pleasantness (7.3%, 7.0%, respectively) and positivity (7.5%, 7.8%, respectively), accompanied by a decrease in negative affect (14.4%, 16.5%, respectively). Additionally, HM and HCM increased in the net and total scores on a substitution test designed to measure associative learning. In contrast, there were no changes observed after 30 minutes of non-meditation. In summary, the findings of this study provide support for the positive impact of Heartfulness meditation and Heartfulness cleaning meditation on emotions, as well as their ability to enhance performance in tasks involving complex attention and associative learning. It should be noted that preceding Heartfulness meditation with 5 minutes of Heartfulness cleaning did not significantly alter the overall outcome of the meditation practice.


Assuntos
Meditação , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Afeto , Cognição , Condicionamento Clássico , Emoções
2.
Anal Chem ; 86(8): 3856-62, 2014 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-24479881

RESUMO

Digital microfluidics (DMF) is a powerful technique for simple and precise manipulation of microscale droplets of fluid. This technique enables processing and analysis of a wide variety of samples and reagents and has proven useful in a broad range of chemical, biological, and medical applications. Handling of "real-world" samples has been a challenge, however, because typically their volumes are greater than those easily accommodated by DMF devices and contain analytes of interest at low concentration. To address this challenge, we have developed a novel "world-to-DMF" interface in which an integrated companion module drives the large-volume sample through a 10 µL droplet region on the DMF device, enabling magnet-mediated recovery of bead-bound analytes onto the device as they pass through the region. To demonstrate its utility, we use this system for extraction of RNA from human whole blood lysates (110-380 µL) and further purification in microscale volumes (5-15 µL) on the DMF device itself. Processing by the system was >2-fold faster and consumed 12-fold less reagents, yet produced RNA yields and quality fully comparable to conventional preparations and supporting qRT-PCR and RNA-Seq analyses. The world-to-DMF system is designed for flexibility in accommodating different sample types and volumes, as well as for facile integration of additional modules to enable execution of more complex protocols for sample processing and analysis. As the first technology of its kind, this innovation represents an important step forward for DMF, further enhancing its utility for a wide range of applications.


Assuntos
Técnicas Analíticas Microfluídicas/métodos , Microfluídica/métodos , RNA/sangue , Desenho de Equipamento , Humanos , Indicadores e Reagentes , RNA/isolamento & purificação , Reprodutibilidade dos Testes
3.
Front Psychol ; 15: 1283980, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38577121

RESUMO

Consciousness has intrigued philosophers and scholars for millennia and has been the topic of considerable scientific investigation in recent decades. Despite its importance, there is no unifying definition of the term, nor are there widely accepted measures of consciousness. Indeed, it is likely that consciousness-by its very nature-eludes measurement. It is, however, possible to measure how consciousness manifests as a lived experience. Yet here, too, holistic measures are lacking. This investigation describes the development and validation of the Awareness Atlas, a measure of the manifestation of consciousness. The scale was informed by heart-based contemplative practices and the resulting lived experience with a focus on the impacts of manifestation of consciousness on daily life. Four hundred forty-nine individuals from the USA, Canada, India, and Europe participated in psychometric testing of the scale. Exploratory and confirmatory factor analyses were used for validation, demonstrating excellent validity in measuring manifestation of consciousness. The final model fit exceeded all required thresholds, indicating an excellent fitted model with a single dimensionality to measure the manifestation of consciousness comprised of four subscales: Relationship to Others; Listening to the Heart; Connection with Higher Self; and Acceptance and Letting Go. Number of years meditating and practicing Heartfulness meditation were positively related to the total and subscale scores. Test-retest reliability was excellent for the total scale, and good to excellent for the four subscales. Findings demonstrate that the Awareness Atlas is a well-constructed tool that will be useful in examining changes in manifestation of consciousness with various experiences (e.g., meditation, life-altering conditions).

4.
Anal Biochem ; 438(1): 90-6, 2013 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-23535274

RESUMO

To fully understand the interactions of a pathogen with its host, it is necessary to analyze the RNA transcripts of both the host and pathogen throughout the course of an infection. Although this can be accomplished relatively easily on the host side, the analysis of pathogen transcripts is complicated by the overwhelming amount of host RNA isolated from an infected sample. Even with the read depth provided by second-generation sequencing, it is extremely difficult to get enough pathogen reads for an effective gene-level analysis. In this study, we describe a novel capture-based technique and device that considerably enriches for pathogen transcripts from infected samples. This versatile method can, in principle, enrich for any pathogen in any infected sample. To test the technique's efficacy, we performed time course tissue culture infections using Rift Valley fever virus and Francisella tularensis. At each time point, RNA sequencing (RNA-Seq) was performed and the results of the treated samples were compared with untreated controls. The capture of pathogen transcripts, in all cases, led to more than an order of magnitude enrichment of pathogen reads, greatly increasing the number of genes hit, the coverage of those genes, and the depth at which each transcript was sequenced.


Assuntos
Francisella tularensis/genética , Francisella tularensis/fisiologia , Interações Hospedeiro-Patógeno , Vírus da Febre do Vale do Rift/genética , Vírus da Febre do Vale do Rift/fisiologia , Análise de Sequência de RNA/métodos , Linhagem Celular , Perfilação da Expressão Gênica , Humanos , Macrófagos/microbiologia , Macrófagos/virologia , Hibridização de Ácido Nucleico , RNA Bacteriano/genética , RNA Mensageiro/genética , RNA Viral/genética
5.
J Ayurveda Integr Med ; 14(6): 100793, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37797350

RESUMO

BACKGROUND: In Indian context, infertility is often a silent struggle. Despite the high prevalence of infertility in the country, the majority of couples do not share their struggles with family or friends due to social stigma, thus increasing their psychological vulnerability. Heartfulness meditation has shown to decrease stress, anxiety, loneliness and improve sleep along with quality of life. OBJECTIVES: The current retrospective series evaluated the effectiveness of Heartfulness-based integrative therapy on infertility outcomes. METHODS: The program consisted of a 5- day onsite lifestyle modification workshop and online follow up meditation sessions. RESULTS: 54 couples with infertility participated in the program with a mean age of 30.74 years (SD 5.04) for females and 34.03 years (SD 4.54) for males. 15 couples presented with male infertility, 16 couples presented with female infertility and in 5 couples both partners had infertility problems. Further, 18 couples had unexplained infertility. 24 couples conceived with 18 natural conceptions, five via assisted reproductive technology and one spontaneous abortion. CONCLUSION: The program was beneficial in the cohort who utilized it as prescribed resulting in conception of 24 out of 54 couples. Future research investigating the causal relationship of Heartfulness meditation on fertility outcomes in a randomized control study could solidify this treatment method to be used independently or as an adjuvant therapy with assisted reproductive technologies.

6.
Electrophoresis ; 33(23): 3506-13, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23135807

RESUMO

We have developed an automated quality control (QC) platform for next-generation sequencing (NGS) library characterization by integrating a droplet-based digital microfluidic (DMF) system with a capillary-based reagent delivery unit and a quantitative CE module. Using an in-plane capillary-DMF interface, a prepared sample droplet was actuated into position between the ground electrode and the inlet of the separation capillary to complete the circuit for an electrokinetic injection. Using a DNA ladder as an internal standard, the CE module with a compact LIF detector was capable of detecting dsDNA in the range of 5-100 pg/µL, suitable for the amount of DNA required by the Illumina Genome Analyzer sequencing platform. This DMF-CE platform consumes tenfold less sample volume than the current Agilent BioAnalyzer QC technique, preserving precious sample while providing necessary sensitivity and accuracy for optimal sequencing performance. The ability of this microfluidic system to validate NGS library preparation was demonstrated by examining the effects of limited-cycle PCR amplification on the size distribution and the yield of Illumina-compatible libraries, demonstrating that as few as ten cycles of PCR bias the size distribution of the library toward undesirable larger fragments.


Assuntos
Eletroforese em Microchip/instrumentação , Biblioteca Gênica , Análise de Sequência de DNA/instrumentação , DNA/análise , DNA/química , Eletroforese em Microchip/métodos , Desenho de Equipamento , Humanos , Leucócitos Mononucleares/química , Limite de Detecção , Reprodutibilidade dos Testes , Análise de Sequência de DNA/métodos , Análise de Sequência de DNA/normas
7.
Front Psychol ; 13: 806131, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35619781

RESUMO

Today, as research into the contemplative sciences is being widely referenced, the research community would benefit from an understanding of the Heartfulness method of meditation. Heartfulness offers an in-depth experiential practice focused on the evolution of human consciousness using the ancient technique of Pranahuti (yogic Transmission) during Meditation, in combination with the more active mental practice of "Cleaning." Both are enabled by initiation into the Heartfulness practices. These unique features distinguish Heartfulness from other paths that have been described in the scientific literature thus far. In this introductory paper, we present the Heartfulness practices, the philosophy upon which the practices are based, and we reflect on the putative mechanisms through which Heartfulness could exert its effects on the human body and mind in the light of scientific research that has been done in other meditation systems. We conclude with suggestions for future research on the Heartfulness way of meditation.

8.
Electrophoresis ; 31(16): 2804-12, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20737447

RESUMO

Rapid and specific characterization of bacterial endospores is dependent on the ability to rupture the cell wall to enable analysis of the intracellular components. In particular, bacterial spores from the bacillus genus are inherently robust and very difficult to lyze or solubilize. Standard protocols for spore inactivation include chemical treatment, sonication, pressure, and thermal lysis. Although these protocols are effective for the inactivation of these agents, they are less well suited for sample preparation for analysis using proteomic and genomic approaches. To overcome this difficulty, we have designed a simple capillary device to perform thermal lysis of bacterial spores. Using this device, we were able to super heat (195 degrees C) an ethylene glycol lysis buffer to perform rapid flow-through rupture and solubilization of bacterial endospores. We demonstrated that the lysates from this preparation method are compatible with CGE as well as DNA amplification analysis. We further demonstrated the flow-through lysing device could be directly coupled to a miniaturized electrophoresis instrument for integrated sample preparation and analysis. In this arrangement, we were enabled to perform sample lysis, fluorescent dye labeling, and protein electrophoresis analysis of bacterial spores in less than 10 min. The described sample preparation device is rapid, simple, inexpensive, and easily integratable with various microfluidic devices.


Assuntos
Bacteriólise/fisiologia , Esporos Bacterianos/fisiologia , Bacillus/genética , Bacillus/crescimento & desenvolvimento , Bacillus/isolamento & purificação , Bacillus/fisiologia , Bacillus anthracis/genética , Bacillus anthracis/fisiologia , Bacillus cereus/genética , Bacillus cereus/fisiologia , Bacillus subtilis/genética , Bacillus subtilis/fisiologia , Ação Capilar , Divisão Celular , Primers do DNA , DNA Bacteriano/genética , Corantes Fluorescentes , Técnicas de Amplificação de Ácido Nucleico/métodos , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase , Solubilidade , Esporos Bacterianos/genética , Esporos Bacterianos/isolamento & purificação , Termodinâmica
9.
Lab Chip ; 9(20): 2933-40, 2009 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-19789746

RESUMO

There is significant interest in developing on-chip DNA hybridization assays to leverage the advantages of lab-on-a-chip systems, which include smaller sample and reagent volumes, faster processing speeds, and greater opportunities for large-scale integration. While much research has explored ways to integrate DNA microarrays on-chip, little work has been done to incorporate hybridization with existing microscale separation platforms. We present the first separation of single-stranded and double-stranded oligonucleotides in a nanofluidic device. We couple this separation with free-solution hybridization to develop a simple, electrokinetic technique that detects DNA hybridization without sample labeling. The technique is used both to detect target DNA sequences and to quantitatively measure hybridization kinetics. To demonstrate the method, we measured the second order reaction coefficient of complementary 20-mer oligonucleotides as a function of sodium ion concentration, which ranged from 0.0048 mol(-1).sec(-1) at 5 mM sodium to 0.42 mol(-1).sec(-1) at 50 mM. We also distinguished between a pair of complementary oligonucleotides and a pair with a single nucleotide mismatch, observing a two-fold difference in hybridization rate. Additionally, we observed a relative change in the mobility of single-stranded and double-stranded DNA with increasing sodium concentration, suggesting that our device may provide a useful platform for studying biomolecule transport in nanochannels.


Assuntos
DNA de Cadeia Simples/isolamento & purificação , DNA/isolamento & purificação , Dispositivos Lab-On-A-Chip , Hibridização de Ácido Nucleico/métodos , Oligonucleotídeos/isolamento & purificação , Pareamento Incorreto de Bases , DNA/genética , DNA de Cadeia Simples/genética , Desenho de Equipamento , Cinética , Oligonucleotídeos/genética
10.
Lab Chip ; 9(4): 507-15, 2009 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-19190785

RESUMO

To enable several on-chip cell handling operations in a fused-silica substrate, small shallow micropores are radially embedded in larger deeper microchannels using an adaptation of single-level isotropic wet etching. By varying the distance between features on the photolithographic mask (mask distance), we can precisely control the overlap between two etch fronts and create a zero-thickness semi-elliptical micropore (e.g. 20 microm wide, 6 microm deep). Geometrical models derived from a hemispherical etch front show that micropore width and depth can be expressed as a function of mask distance and etch depth. These models are experimentally validated at different etch depths (25.03 and 29.78 microm) and for different configurations (point-to-point and point-to-edge). Good reproducibility confirms the validity of this approach to fabricate micropores with a desired size. To illustrate the wide range of cell handling operations enabled by micropores, we present three on-chip functionalities: continuous-flow particle concentration, immobilization of single cells, and picoliter droplet generation. (1) Using pressure differentials, particles are concentrated by removing the carrier fluid successively through a series of 44 shunts terminated by 31 microm wide, 5 microm deep micropores. Theoretical values for the concentration factor determined by a flow circuit model in conjunction with finite volume modeling are experimentally validated. (2) Flowing macrophages are individually trapped in 20 microm wide, 6 microm deep micropores by hydrodynamic confinement. The translocation of transcription factor NF-kappaB into the nucleus upon lipopolysaccharide stimulation is imaged by fluorescence microscopy. (3) Picoliter-sized droplets are generated at a 20 microm wide, 7 microm deep micropore T-junction in an oil stream for the encapsulation of individual E. coli bacteria cells.


Assuntos
Técnicas Citológicas , Técnicas Analíticas Microfluídicas/métodos , Animais , Linhagem Celular , Desenho de Equipamento , Escherichia coli/citologia , Macrófagos/citologia , Camundongos , Técnicas Analíticas Microfluídicas/instrumentação , Porosidade , Reprodutibilidade dos Testes
11.
J Am Chem Soc ; 131(39): 14066-74, 2009 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-19746908

RESUMO

Biologically functional cationic phospholipid-gold nanoplasmonic carriers have been designed to simultaneously exhibit carrier capabilities, demonstrate improved colloidal stability, and show no cytotoxicity under physiological conditions. Cargo, such as RNA, DNA, proteins, or drugs, can be adsorbed onto or incorporated into the cationic phospholipid bilayer membrane. These carriers are able to retain their unique nanoscale optical properties under physiological conditions, making them particularly useful in a wide range of imaging, therapeutic, and gene delivery applications that utilize selective nanoplasmonic properties.


Assuntos
Portadores de Fármacos/síntese química , Ouro/química , Bicamadas Lipídicas/química , RNA/metabolismo , Cátions , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Estabilidade de Medicamentos , Técnicas de Transferência de Genes , Humanos , Luz , Nanopartículas Metálicas , Fosfolipídeos/química , RNA/farmacologia , Espalhamento de Radiação , Tensoativos/química
12.
Sci Rep ; 9(1): 11475, 2019 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-31391493

RESUMO

The Oxford MinION, the first commercial nanopore sequencer, is also the first to implement molecule-by-molecule real-time selective sequencing or "Read Until". As DNA transits a MinION nanopore, real-time pore current data can be accessed and analyzed to provide active feedback to that pore. Fragments of interest are sequenced by default, while DNA deemed non-informative is rejected by reversing the pore bias to eject the strand, providing a novel means of background depletion and/or target enrichment. In contrast to the previously published pattern-matching Read Until approach, our RUBRIC method is the first example of real-time selective sequencing where on-line basecalling enables alignment against conventional nucleic acid references to provide the basis for sequence/reject decisions. We evaluate RUBRIC performance across a range of optimizable parameters, apply it to mixed human/bacteria and CRISPR/Cas9-cut samples, and present a generalized model for estimating real-time selection performance as a function of sample composition and computing configuration.


Assuntos
Sequenciamento de Nucleotídeos em Larga Escala/métodos , Modelos Genéticos , Análise de Sequência de DNA/métodos , Bacteriófago lambda/genética , Sistemas CRISPR-Cas/genética , DNA Bacteriano/genética , DNA Viral/genética , Escherichia coli/genética , Células HeLa , Sequenciamento de Nucleotídeos em Larga Escala/instrumentação , Humanos , Nanoporos , Estudo de Prova de Conceito , Análise de Sequência de DNA/instrumentação
13.
Sci Rep ; 9(1): 17504, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31745197

RESUMO

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

14.
Anal Chem ; 80(16): 6365-72, 2008 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-18510341

RESUMO

We have extended the principle of optical tweezers as a noninvasive technique to actively sort hydrodynamically focused cells based on their fluorescence signal in a microfluidic device. This micro fluorescence-activated cell sorter (microFACS) uses an infrared laser to laterally deflect cells into a collection channel. Green-labeled macrophages were sorted from a 40/60 ratio mixture at a throughput of 22 cells/s over 30 min achieving a 93% sorting purity and a 60% recovery yield. To rule out potential photoinduced cell damage during optical deflection, we investigated the response of mouse macrophage to brief exposures (<4 ms) of focused 1064-nm laser light (9.6 W at the sample). We found no significant difference in viability, cell proliferation, activation state, and functionality between infrared-exposed and unexposed cells. Activation state was measured by the phosphorylation of ERK and nuclear translocation of NF-kappaB, while functionality was assessed in a similar manner, but after a lipopolysaccharide challenge. To demonstrate the selective nature of optical sorting, we isolated a subpopulation of macrophages highly infected with the fluorescently labeled pathogen Francisella tularensis subsp. novicida. A total of 10,738 infected cells were sorted at a throughput of 11 cells/s with 93% purity and 39% recovery.


Assuntos
Separação Celular/métodos , Diagnóstico por Imagem , Francisella tularensis/efeitos da radiação , Macrófagos/efeitos da radiação , Microfluídica/métodos , Pinças Ópticas , Animais , Núcleo Celular/metabolismo , Proliferação de Células , Sobrevivência Celular , Células Cultivadas , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Citometria de Fluxo , Fluorescência , Corantes Fluorescentes , Francisella tularensis/imunologia , Francisella tularensis/metabolismo , Proteínas de Fluorescência Verde , Lipopolissacarídeos/farmacologia , Ativação de Macrófagos/efeitos da radiação , Macrófagos/imunologia , Macrófagos/microbiologia , Camundongos , NF-kappa B/metabolismo , Fosforilação/efeitos da radiação , Transporte Proteico , Transdução de Sinais , Tularemia/imunologia
15.
Sci Rep ; 8(1): 3159, 2018 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-29453452

RESUMO

Emerging sequencing technologies are allowing us to characterize environmental, clinical and laboratory samples with increasing speed and detail, including real-time analysis and interpretation of data. One example of this is being able to rapidly and accurately detect a wide range of pathogenic organisms, both in the clinic and the field. Genomes can have radically different GC content however, such that accurate sequence analysis can be challenging depending upon the technology used. Here, we have characterized the performance of the Oxford MinION nanopore sequencer for detection and evaluation of organisms with a range of genomic nucleotide bias. We have diagnosed the quality of base-calling across individual reads and discovered that the position within the read affects base-calling and quality scores. Finally, we have evaluated the performance of the current state-of-the-art neural network-based MinION basecaller, characterizing its behavior with respect to systemic errors as well as context- and sequence-specific errors. Overall, we present a detailed characterization the capabilities of the MinION in terms of generating high-accuracy sequence data from genomes with a wide range of nucleotide content. This study provides a framework for designing the appropriate experiments that are the likely to lead to accurate and rapid field-forward diagnostics.


Assuntos
Nanoporos , Nucleotídeos/genética , Análise de Sequência de DNA/métodos , Algoritmos , Genômica , Processos Estocásticos
16.
Lab Chip ; 7(12): 1825-31, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18030407

RESUMO

We demonstrate a new method for joining thermoplastic surfaces to produce microfluidic devices. The method takes advantage of the sharply defined permeation boundary of case-II diffusion to generate dimensionally controlled, activated bonding layers at the surfaces being joined. The technique is capable of producing bonds that exhibit cohesive failure, while preserving the fidelity of fine features in the bonding interface. This approach is uniquely suited to production of layered microfluidic structures, as it allows the bond-forming interface between plastic parts to be precisely manipulated at micrometre length scales. Distortions in microfluidic device channels are limited to the size scale of the permeant-swollen layer; 6 microm deep channels are routinely produced with no detectable cross-sectional distortions. Conventional thermal diffusion bonding of identical parts yields less strongly bonded microfluidic structures with increasingly severe dimensional compressions as bonding temperatures approach the thermoplastic glass-transition temperature: a preliminary rheological analysis is consistent with the observed compressions. The bond-enhancing procedure is easily integrated in standard process flows, uses inexpensive reagents, and requires no specialized equipment.

17.
PLoS One ; 10(3): e0118182, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25826708

RESUMO

Advances in molecular biology, microfluidics, and laboratory automation continue to expand the accessibility and applicability of these methods beyond the confines of conventional, centralized laboratory facilities and into point of use roles in clinical, military, forensic, and field-deployed applications. As a result, there is a growing need to adapt the unit operations of molecular biology (e.g., aliquoting, centrifuging, mixing, and thermal cycling) to compact, portable, low-power, and automation-ready formats. Here we present one such adaptation, the rotary zone thermal cycler (RZTC), a novel wheel-based device capable of cycling up to four different fixed-temperature blocks into contact with a stationary 4-microliter capillary-bound sample to realize 1-3 second transitions with steady state heater power of less than 10 W. We demonstrate the utility of the RZTC for DNA amplification as part of a highly integrated rotary zone PCR (rzPCR) system that uses low-volume valves and syringe-based fluid handling to automate sample loading and unloading, thermal cycling, and between-run cleaning functionalities in a compact, modular form factor. In addition to characterizing the performance of the RZTC and the efficacy of different online cleaning protocols, we present preliminary results for rapid single-plex PCR, multiplex short tandem repeat (STR) amplification, and second strand cDNA synthesis.


Assuntos
Automação Laboratorial , Reação em Cadeia da Polimerase/métodos , Humanos , Reação em Cadeia da Polimerase/normas , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
18.
J Org Chem ; 62(9): 2738-2741, 1997 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-11671633

RESUMO

Increasing electron demand in the reactions of G-NMBH anions with substituted phenyldimethylsulfonium ions decreases the alpha-effect for the methyl transfers toward 1.0 (zero effect). An extrapolation shows the possibility of an inverse effect (<1.0). The reactivity of G-NMBH anions correlates with SET parameters and with the known propensity of phenyldimethylsulfonium ions to accept a single electron into a sigma C-S orbital concomitant with expulsion of a CH(3) group. These correlations indicate inclusion of some SET character into the wavefunction of the S(N)2 transition state for these reactions, in agreement with the Shaik and Pross SCD model of the S(N)2 reaction.

19.
J Vis Exp ; (78)2013 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-23962881

RESUMO

Study of cells in culture (in vitro analysis) has provided important insight into complex biological systems. Conventional methods and equipment for in vitro analysis are well suited to study of large numbers of cells (≥ 10(5)) in milliliter-scale volumes (≥ 0.1 ml). However, there are many instances in which it is necessary or desirable to scale down culture size to reduce consumption of the cells of interest and/or reagents required for their culture, stimulation, or processing. Unfortunately, conventional approaches do not support precise and reproducible manipulation of micro-scale cultures, and the microfluidics-based automated systems currently available are too complex and specialized for routine use by most laboratories. To address this problem, we have developed a simple and versatile technology platform for automated culture, stimulation, and recovery of small populations of cells (100-2,000 cells) in micro-scale volumes (1-20 µl). The platform consists of a set of fibronectin-coated microcapillaries ("cell perfusion chambers"), within which micro-scale cultures are established, maintained, and stimulated; a digital microfluidics (DMF) device outfitted with "transfer" microcapillaries ("central hub"), which routes cells and reagents to and from the perfusion chambers; a high-precision syringe pump, which powers transport of materials between the perfusion chambers and the central hub; and an electronic interface that provides control over transport of materials, which is coordinated and automated via pre-determined scripts. As an example, we used the platform to facilitate study of transcriptional responses elicited in immune cells upon challenge with bacteria. Use of the platform enabled us to reduce consumption of cells and reagents, minimize experiment-to-experiment variability, and re-direct hands-on labor. Given the advantages that it confers, as well as its accessibility and versatility, our platform should find use in a wide variety of laboratories and applications, and prove especially useful in facilitating analysis of cells and stimuli that are available in only limited quantities.


Assuntos
Técnicas Citológicas/instrumentação , Técnicas Citológicas/métodos , Animais , Automação/instrumentação , Automação/métodos , Escherichia coli/citologia , Escherichia coli/imunologia , Macrófagos/citologia , Macrófagos/imunologia , Macrófagos/microbiologia , Camundongos , Técnicas Analíticas Microfluídicas/instrumentação , Técnicas Analíticas Microfluídicas/métodos
20.
PLoS One ; 8(7): e68988, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23894387

RESUMO

Next-generation sequencing (NGS) is emerging as a powerful tool for elucidating genetic information for a wide range of applications. Unfortunately, the surging popularity of NGS has not yet been accompanied by an improvement in automated techniques for preparing formatted sequencing libraries. To address this challenge, we have developed a prototype microfluidic system for preparing sequencer-ready DNA libraries for analysis by Illumina sequencing. Our system combines droplet-based digital microfluidic (DMF) sample handling with peripheral modules to create a fully-integrated, sample-in library-out platform. In this report, we use our automated system to prepare NGS libraries from samples of human and bacterial genomic DNA. E. coli libraries prepared on-device from 5 ng of total DNA yielded excellent sequence coverage over the entire bacterial genome, with >99% alignment to the reference genome, even genome coverage, and good quality scores. Furthermore, we produced a de novo assembly on a previously unsequenced multi-drug resistant Klebsiella pneumoniae strain BAA-2146 (KpnNDM). The new method described here is fast, robust, scalable, and automated. Our device for library preparation will assist in the integration of NGS technology into a wide variety of laboratories, including small research laboratories and clinical laboratories.


Assuntos
Biblioteca Gênica , Sequenciamento de Nucleotídeos em Larga Escala/instrumentação , Técnicas Analíticas Microfluídicas/instrumentação , Análise de Sequência de DNA/instrumentação , DNA Bacteriano/genética , Genoma Bacteriano/genética , Genoma Humano/genética , Humanos , Integração de Sistemas
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