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1.
Br J Pharmacol ; 2023 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-37658519

RESUMO

Red blood cells (RBCs) have traditionally been seen as simple carriers of gases and nutrients in the body. One important non-canonical function of RBCs in the cardiovascular system is the regulation of nitric oxide (NO) metabolism. It has been shown that RBCs can scavenge NO, transport NO metabolites and produce NO in hypoxic conditions, thereby inducing hypoxic vasodilation. RBCs also express endothelial nitric oxide synthase (eNOS). However, the physiological significance of RBC eNOS has been controversial for many years. This review article provides a comprehensive overview of the experimental research on RBC eNOS signalling in vivo. The data show that RBC eNOS signalling modulates intracellular NO production and NO-haem levels, as well as participating in extracellular paracrine NO metabolite signalling, which contributes to regulating peripheral vascular resistance, blood pressure and cardioprotection. Additionally, this article explores the molecular mechanisms of sytemic regulation mediated by RBC eNOS and the implications of RBC eNOS in cardiovascular health and disease.

2.
Sci Total Environ ; 904: 166355, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37595920

RESUMO

Ambient peroxy radical (RO2⁎ = HO2 + RO2) concentrations were measured at a suburban site in a major prefecture-level city (Huaibei) in the boundary of Jiangsu-Anhui-Shandong-Henan region, which is the connecting belt of air pollution in the Beijing-Tianjin-Hebei region and the Yangtze River Delta. Measurements were carried out during the period of September to October 2021 to elucidate the formation mechanism of O3 pollution. The observed maximum concentration of peroxy radicals was 73.8 pptv. A zero-dimensional box model (Framework for 0-Dimensional Atmospheric Modeling, F0AM) based on Master Chemical Mechanism (MCM3.3.1) was used to predict radical concentrations for comparison with observations. The model reproduced the daily variation of peroxy radicals well, but discrepancies still appear in the morning hours. As in previous field campaigns, systematic discrepancies between modelled and measured RO2⁎ concentrations are observed in the morning for NO mixing ratios higher than 1 ppbv. Between 6:00 and 9:00 am, the model significantly underpredicts RO2⁎ by a mean factor of 7.2. This underprediction can be explained by a missing RO2⁎ source of 1.2 ppbv h-1 which originated from the photochemical conversion of an alkene-like chemical species. From the model results it shows that the main sources of ROx (= OH + HO2 + RO2) are the photolysis of oxygenated volatile organic compounds (OVOCs, 33 %), O3 and HONO (25 %), and HCHO (24 %). And the major sinks of ROx transitioned from a predominant reaction of radicals with NOx in the morning to a predominant peroxy self- and cross-reaction in the late afternoon. The introduction of an alkene-like species increased RO2 radical concentration and resulted in 14 % increase in net daily integrated ozone production, indicating the possible significance of the mechanism of alkene-like species oxidation to peroxy radicals. This study provides important information for subsequent ozone pollution control policies in Jiangsu-Anhui-Shandong-Henan region.

3.
Sports (Basel) ; 10(9)2022 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-36136384

RESUMO

This is a cross-sectional study that examined the association between fitness trainers' educational qualifications and experience, and the risk of their trainees' musculoskeletal pain. The study included 1177 trainees (aged 15−60 years) from 74 fitness centers in Bangladesh. Data were collected by using the Nordic musculoskeletal questionnaire, including potential confounders such as demographic factors (e.g., age, occupation), and training-related factors (e.g., workout knowledge, overweight lifting). Multiple logistic regression was performed for a binary outcome (pain­yes or no), and a generalized linear model was fitted for the ordinal outcome (pain­sites of the body). The trainers' lower experience (no or ≤1 year) was associated with higher odds of their trainees' musculoskeletal pain (OR: 2.53, 95% CI: 1.18−5.44) compared to trainers with >5 years of experience; however, no association was found between the trainers' education and the risk of their trainees' musculoskeletal pain, after controlling for potential confounders. Similarly, the trainees trained by trainers with lower experience had more than two-time the risk of having pain in different sites (IRR: 2.04, 95% CI: 1.50−2.79). The trainers' experience may play a pivotal role in the trainees' musculoskeletal pain. Further study is warranted in this regard.

4.
Mil Med ; 186(Suppl 1): 288-294, 2021 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-33499518

RESUMO

INTRODUCTION: Short response time is critical for future military medical operations in austere settings or remote areas. Such effective patient care at the point of injury can greatly benefit from the integration of semi-autonomous robotic systems. To achieve autonomy, robots would require massive libraries of maneuvers collected with the goal of training machine learning algorithms. Although this is attainable in controlled settings, obtaining surgical data in austere settings can be difficult. Hence, in this article, we present the Dexterous Surgical Skill (DESK) database for knowledge transfer between robots. The peg transfer task was selected as it is one of the six main tasks of laparoscopic training. In addition, we provide a machine learning framework to evaluate novel transfer learning methodologies on this database. METHODS: A set of surgical gestures was collected for a peg transfer task, composed of seven atomic maneuvers referred to as surgemes. The collected Dexterous Surgical Skill dataset comprises a set of surgical robotic skills using the four robotic platforms: Taurus II, simulated Taurus II, YuMi, and the da Vinci Research Kit. Then, we explored two different learning scenarios: no-transfer and domain-transfer. In the no-transfer scenario, the training and testing data were obtained from the same domain; whereas in the domain-transfer scenario, the training data are a blend of simulated and real robot data, which are tested on a real robot. RESULTS: Using simulation data to train the learning algorithms enhances the performance on the real robot where limited or no real data are available. The transfer model showed an accuracy of 81% for the YuMi robot when the ratio of real-tosimulated data were 22% to 78%. For the Taurus II and the da Vinci, the model showed an accuracy of 97.5% and 93%, respectively, training only with simulation data. CONCLUSIONS: The results indicate that simulation can be used to augment training data to enhance the performance of learned models in real scenarios. This shows potential for the future use of surgical data from the operating room in deployable surgical robots in remote areas.


Assuntos
Robótica , Competência Clínica , Simulação por Computador , Humanos , Laparoscopia , Aprendizado de Máquina
5.
Front Physiol ; 11: 566871, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33240096

RESUMO

The kidney is extensively innervated by sympathetic nerves playing an important role in the regulation of blood pressure homeostasis. Sympathetic nerve activity is ultimately controlled by the central nervous system (CNS). Norepinephrine, the main sympathetic neurotransmitter, is released at prejunctional neuroeffector junctions in the kidney and modulates renin release, renal vascular resistance, sodium and water handling, and immune cell response. Under physiological conditions, renal sympathetic nerve activity (RSNA) is modulated by peripheral mechanisms such as the renorenal reflex, a complex interaction between efferent sympathetic nerves, central mechanism, and afferent sensory nerves. RSNA is increased in hypertension and, therefore, critical for the perpetuation of hypertension and the development of hypertensive kidney disease. Renal sympathetic neurotransmission is not only regulated by RSNA but also by prejunctional α2-adrenoceptors. Prejunctional α2-adrenoceptors serve as autoreceptors which, when activated by norepinephrine, inhibit the subsequent release of norepinephrine induced by a sympathetic nerve impulse. Deletion of α2-adrenoceptors aggravates hypertension ultimately by modulating renal pressor response and sodium handling. α2-adrenoceptors are also expressed in the vasculature, renal tubules, and immune cells and exert thereby effects related to vascular tone, sodium excretion, and inflammation. In the present review, we highlight the role of α2-adrenoceptors on renal sympathetic neurotransmission and its impact on hypertension. Moreover, we focus on physiological and pathophysiological functions mediated by non-adrenergic α2-adrenoceptors. In detail, we discuss the effects of sympathetic norepinephrine release and α2-adrenoceptor activation on renal sodium transporters, on renal vascular tone, and on immune cells in the context of hypertension and kidney disease.

6.
J Family Med Prim Care ; 9(8): 4415-4417, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33110872

RESUMO

Mitral stenosis (MS) is the most common valvular heart disease in developing countries where rheumatic fever is common. It is also more common in women. The normal mitral orifice is 4-5 square cm in area and the symptoms do not occur until the orifice area falls to below 2.0 square cm and usually below 1.5 square cm. The orifice area decreases by 0.1-0.3 square cm per year. Rarely, the dilatation of the left atrium may cause the symptoms of dysphagia from esophageal compression. Although cardiovascular dysphagia is rare, it should be considered in the case of mitral stenosis. The etiologies of mitral stenosis can be congenital, acquired, or iatrogenic. This case report presents a patient having dysphagia due to an enlarged left atrium.

7.
Circ Res ; 127(5): 593-606, 2020 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-32418507

RESUMO

RATIONALE: Kidney homeostasis is critically determined by the coordinated activity of the renin-angiotensin system (RAS), including the balanced synthesis of its main effector peptides Ang (angiotensin) II and Ang (1-7). The condition of enzymatic overproduction of Ang II relative to Ang (1-7) is termed RAS dysregulation and leads to cellular signals, which promote hypertension and organ damage, and ultimately progressive kidney failure. ACE2 (angiotensin-converting enzyme 2) and NEP (neprilysin) induce the alternative, and potentially reno-protective axis by enhancing Ang (1-7) production. However, their individual contribution to baseline RAS balance and whether their activities change in chronic kidney disease (CKD) has not yet been elucidated. OBJECTIVE: To examine whether NEP-mediated Ang (1-7) generation exceeds Ang II formation in the healthy kidney compared with diseased kidney. METHODS AND RESULTS: In this exploratory study, we used liquid chromatography-tandem mass spectrometry to measure Ang II and Ang (1-7) synthesis rates of ACE, chymase and NEP, ACE2, PEP (prolyl-endopeptidase), PCP (prolyl-carboxypeptidase) in kidney biopsy homogenates in 11 healthy living kidney donors, and 12 patients with CKD. The spatial expression of RAS enzymes was determined by immunohistochemistry. Healthy kidneys showed higher NEP-mediated Ang (1-7) synthesis than Ang II formation, thus displaying a strong preference towards the reno-protective alternative RAS axis. In contrast, in CKD kidneys higher levels of Ang II were recorded, which originated from mast cell chymase activity. CONCLUSIONS: Ang (1-7) is the dominant RAS peptide in healthy human kidneys with NEP rather than ACE2 being essential for its generation. Severe RAS dysregulation is present in CKD dictated by high chymase-mediated Ang II formation. Kidney RAS enzyme analysis might lead to novel therapeutic approaches for CKD.


Assuntos
Angiotensina II/metabolismo , Angiotensina I/metabolismo , Rim/enzimologia , Neprilisina/metabolismo , Fragmentos de Peptídeos/metabolismo , Insuficiência Renal Crônica/enzimologia , Sistema Renina-Angiotensina , Idoso , Enzima de Conversão de Angiotensina 2/antagonistas & inibidores , Enzima de Conversão de Angiotensina 2/metabolismo , Animais , Estudos de Casos e Controles , Quimases/metabolismo , Inibidores Enzimáticos/farmacologia , Feminino , Humanos , Rim/efeitos dos fármacos , Masculino , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Neprilisina/antagonistas & inibidores
8.
J Am Soc Nephrol ; 31(4): 783-798, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32086277

RESUMO

BACKGROUND: Increased nerve activity causes hypertension and kidney disease. Recent studies suggest that renal denervation reduces BP in patients with hypertension. Renal NE release is regulated by prejunctional α2A-adrenoceptors on sympathetic nerves, and α2A-adrenoceptors act as autoreceptors by binding endogenous NE to inhibit its own release. However, the role of α2A-adrenoceptors in the pathogenesis of hypertensive kidney disease is unknown. METHODS: We investigated effects of α2A-adrenoceptor-regulated renal NE release on the development of angiotensin II-dependent hypertension and kidney disease. In uninephrectomized wild-type and α2A-adrenoceptor-knockout mice, we induced hypertensive kidney disease by infusing AngII for 28 days. RESULTS: Urinary NE excretion and BP did not differ between normotensive α2A-adrenoceptor-knockout mice and wild-type mice at baseline. However, NE excretion increased during AngII treatment, with the knockout mice displaying NE levels that were significantly higher than those of wild-type mice. Accordingly, the α2A-adrenoceptor-knockout mice exhibited a systolic BP increase, which was about 40 mm Hg higher than that found in wild-type mice, and more extensive kidney damage. In isolated kidneys, AngII-enhanced renal nerve stimulation induced NE release and pressor responses to a greater extent in kidneys from α2A-adrenoceptor-knockout mice. Activation of specific sodium transporters accompanied the exaggerated hypertensive BP response in α2A-adrenoceptor-deficient kidneys. These effects depend on renal nerves, as demonstrated by reduced severity of AngII-mediated hypertension and improved kidney function observed in α2A-adrenoceptor-knockout mice after renal denervation. CONCLUSIONS: Our findings reveal a protective role of prejunctional inhibitory α2A-adrenoceptors in pathophysiologic conditions with an activated renin-angiotensin system, such as hypertensive kidney disease, and support the concept of sympatholytic therapy as a treatment.


Assuntos
Hipertensão Renal/etiologia , Hipertensão Renal/prevenção & controle , Nefrite/etiologia , Nefrite/prevenção & controle , Receptores Adrenérgicos alfa 2/fisiologia , Sistema Nervoso Simpático/fisiopatologia , Transmissão Sináptica/fisiologia , Angiotensina II , Animais , Modelos Animais de Doenças , Hipertensão Renal/fisiopatologia , Camundongos , Camundongos Knockout , Nefrite/fisiopatologia , Simpatectomia
9.
Am J Gastroenterol ; 113(9): 1363-1375, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30171215

RESUMO

BACKGROUND: Postinfection irritable bowel syndrome (PI-IBS) and functional dyspepsia (PI-FD), though reported from the temperate countries, have not been studied in the tropics; PI-malabsorption syndrome (MAS), which mimics PI-IBS, is reported from the tropics. No report till date on PI-IBS excluded PI-MAS. We studied: (i) the frequency of continuing bowel dysfunction after acute gastroenteritis (AG), (ii) its predictors, and (iii) PI-MAS among patients with PI-IBS. METHODS: 345 consecutive subjects each, with AG and age- and gender-matched healthy controls were followed up 3-monthly for 12 months using a translated-validated questionnaire and functional gastrointestinal disorders (FGIDs) were diagnosed by Rome III criteria. Symptom duration >3 months but <6 months was diagnosed as chronic bowel dysfunction (CBD) and dyspeptic symptoms, respectively. MAS was diagnosed if 2/3 tests (D-xylose H2 breath test, Sudan III-stained stool microscopy, and duodenal histology) were abnormal. Fecal microbiological studies were performed in 245/345 (71%) patients. RESULTS: AG patients more often developed PI-IBS and PI-FD than controls (16.5 vs. 2.6% and 7.4 vs. 0.6%, respectively; p<0.001). Presence of FD was a risk factor for PI-IBS and IBS for PI-FD. On multivariate analysis, dyspeptic symptoms, CBD, and weight loss were the risk factors for PI-FGIDs. The frequency of PI-IBS following Vibrio cholera and other bacterial infection was comparable. Malabsorption was present among 2/23 (9%) patients with PI-IBS. CONCLUSION: FGIDs are common after AG; dyspeptic symptoms, CBD, and weight loss were risk factors for PI-FGIDs. Vibrio cholerae infection caused PI-FGID, which was never reported. About 9 % patients fulfilling the criteria for PI-IBS had PI-MAS.


Assuntos
Infecções Bacterianas/complicações , Diarreia/complicações , Dispepsia/epidemiologia , Gastroenterite/complicações , Síndrome do Intestino Irritável/epidemiologia , Adulto , Bactérias/isolamento & purificação , Infecções Bacterianas/diagnóstico , Infecções Bacterianas/microbiologia , Bangladesh/epidemiologia , Estudos de Casos e Controles , Doença Crônica/epidemiologia , Diarreia/diagnóstico , Diarreia/microbiologia , Dispepsia/diagnóstico , Dispepsia/etiologia , Feminino , Seguimentos , Gastroenterite/diagnóstico , Gastroenterite/microbiologia , Humanos , Incidência , Síndrome do Intestino Irritável/diagnóstico , Síndrome do Intestino Irritável/etiologia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Risco , Índice de Gravidade de Doença , Inquéritos e Questionários/estatística & dados numéricos , Redução de Peso , Adulto Jovem
10.
Langmuir ; 34(49): 15014-15020, 2018 12 11.
Artigo em Inglês | MEDLINE | ID: mdl-30110549

RESUMO

Mica is the current substrate of choice for DNA nanostructure imaging, mainly due to its atomically flat surface. However, these mica substrates are often not optically clear. In this work, sapphire has been evaluated as an alternative substrate, with potential to enable parallel optical and AFM studies. Well known for its thermal and chemical properties, sapphire is a hard ionic material with excellent optical properties. Because sapphire lacks the excellent basal cleavage properties of the sheet silicate mica, a process to anneal it at high temperature in water vapor was developed to achieve near atomically smooth (average roughness = 0.141 nm) terraces. AFM imaging was used to determine the dimensions of these terraces and to characterize the morphology of the DNA nanostructures, revealing that their structures were preserved, indicating that annealed c-plane cut (0001) sapphire is a promising substitute for mica as a flat and transparent substrate for DNA nanostructure studies.


Assuntos
Óxido de Alumínio/química , DNA/química , Nanoestruturas/química , Microscopia de Força Atômica/métodos , Microscopia de Fluorescência/métodos , Conformação de Ácido Nucleico , Propriedades de Superfície
11.
Langmuir ; 33(30): 7389-7392, 2017 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-28679055

RESUMO

DNA nanostructures (DN) are powerful platforms for the programmable assembly of nanomaterials. As applications for DN both as a structural material and as a support for functional biomolecular sensing systems develop, methods enabling the determination of reaction kinetics in real time become increasingly important. In this report, we present a study of the kinetics of streptavidin binding onto biotinylated DN constructs enabled by these planar structures. High-speed AFM was employed at a 2.5 frame/s rate to evaluate the kinetics and indicates that the binding fully saturates in less than 60 s. When the the data was fitted with an adsorption-limited kinetic model, a forward rate constant of 5.03 × 105 s-1 was found.

12.
Nanomaterials (Basel) ; 6(11)2016 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-28335324

RESUMO

Although there is a long history of the study of the interaction of DNA with carbon surfaces, limited information exists regarding the interaction of complex DNA-based nanostructures with the important material graphite, which is closely related to graphene. In view of the capacity of DNA to direct the assembly of proteins and optical and electronic nanoparticles, the potential for combining DNA-based materials with graphite, which is an ultra-flat, conductive carbon substrate, requires evaluation. A series of imaging studies utilizing Atomic Force Microscopy has been applied in order to provide a unified picture of this important interaction of structured DNA and graphite. For the test structure examined, we observe a rapid destabilization of the complex DNA origami structure, consistent with a strong interaction of single-stranded DNA with the carbon surface. This destabilizing interaction can be obscured by an intentional or unintentional primary intervening layer of single-stranded DNA. Because the interaction of origami with graphite is not completely dissociative, and because the frustrated, expanded structure is relatively stable over time in solution, it is demonstrated that organized structures of pairs of the model protein streptavidin can be produced on carbon surfaces using DNA origami as the directing material.

13.
J Water Health ; 13(4): 1113-22, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26608772

RESUMO

Scarcity of drinking water in the coastal area of Bangladesh compels the inhabitants to be highly dependent on alternative water supply options like rainwater harvesting system (RWHS), pond sand filter (PSF), and rain-feed ponds. Susceptibility of these alternative water supply options to microbial contamination demands a low-cost water treatment technology. This study evaluates the effectiveness of solar disinfection (SODIS) to treat drinking water from available sources in the southwest coastal area of Bangladesh. A total of 50 households from Dacope upazila in Khulna district were selected to investigate the performance of SODIS. Data were collected in two rounds to examine fecal coliform (FC) and Escherichia coli (E. coli) contamination of drinking water at the household water storage containers and SODIS bottles, and thereby determined the effectiveness of SODIS in reducing fecal contamination. All water samples were analyzed for pH, electrical conductivity, turbidity and salinity. SODIS significantly reduced FC and E. coli contamination under household conditions. The median health risk reduction by SODIS was more than 96 and 90% for pond and RWHS, respectively. Besides, turbidity of the treated water was found to be less than 5 NTU, except pond water. Only 34% of the participating households routinely adopted SODIS during the study.


Assuntos
Desinfecção/métodos , Água Potável/análise , Enterobacteriaceae/efeitos da radiação , Luz Solar , Purificação da Água/métodos , Bangladesh , Escherichia coli/efeitos da radiação , Fezes/microbiologia
14.
Vet Res ; 46: 96, 2015 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-26380970

RESUMO

Poultry is the most frequent reservoir of non-typhoid Salmonella enterica for humans. Understanding the interactions between chickens and S. enterica is therefore important for vaccine design and subsequent decrease in the incidence of human salmonellosis. In this study we therefore characterized the interactions between chickens and phoP, aroA, SPI1 and SPI2 mutants of S. Enteritidis. First we tested the response of HD11 chicken macrophage-like cell line to S. Enteritidis infection monitoring the transcription of 36 genes related to immune response. All the mutants and the wild type strain induced inflammatory signaling in the HD11 cell line though the response to SPI1 mutant infection was different from the rest of the mutants. When newly hatched chickens were inoculated, the phoP as well as the SPI1 mutant did not induce an expression of any of the tested genes in the cecum. Despite this, such chickens were protected against challenge with wild-type S. Enteritidis. On the other hand, inoculation of chickens with the aroA or SPI2 mutant induced expression of 27 and 18 genes, respectively, including genes encoding immunoglobulins. Challenge of chickens inoculated with these two mutants resulted in repeated induction of 11 and 13 tested genes, respectively, including the genes encoding immunoglobulins. In conclusion, SPI1 and phoP mutants induced protective immunity without inducing an inflammatory response and antibody production. Inoculation of chickens with the SPI2 and aroA mutants also led to protective immunity but was associated with inflammation and antibody production. The differences in interaction between the mutants and chicken host can be used for a more detailed understanding of the chicken immune system.


Assuntos
Doenças das Aves Domésticas/imunologia , Doenças das Aves Domésticas/microbiologia , Salmonelose Animal/imunologia , Salmonelose Animal/microbiologia , Vacinas contra Salmonella/imunologia , Salmonella enteritidis , Animais , Ceco/imunologia , Ceco/microbiologia , Linhagem Celular , Galinhas , Macrófagos/imunologia , Masculino , Mutação , Salmonella enteritidis/genética , Salmonella enteritidis/imunologia , Vacinas Atenuadas/imunologia
15.
Acc Chem Res ; 47(6): 1750-8, 2014 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-24803094

RESUMO

CONSPECTUS: DNA based nanotechnology provides a basis for high-resolution fabrication of objects almost without physical size limitations. However, the pathway to large-scale production of large objects is currently unclear. Operationally, one method forward is to use high information content, large building blocks, which can be generated with high yield and reproducibility. Although flat DNA origami naturally invites comparison to pixels in zero, one, and two dimensions and voxels in three dimensions and has provided an excellent mechanism for generating blocks of significant size and complexity and a multitude of shapes, the field is young enough that a single "brick" has not become the standard platform used by the majority of researchers in the field. In this Account, we highlight factors we considered that led to our adoption of a cross-shaped, non-space-filling origami species, designed by Dr. Liu of the Seeman laboratory, as the building block ideal for use in the fabrication of finite one-dimensional arrays. Three approaches that can be employed for uniquely coding origami-origami linkages are presented. Such coding not only provides the energetics for tethering the species but also uniquely designates the relative orientation of the origami building blocks. The strength of the coding approach implemented in our laboratory is demonstrated using examples of oligomers ranging from finite multimers composed of four, six, and eight origami structures to semi-infinite polymers (100mers). Two approaches to finite array design and the series of assembly steps that each requires are discussed. The process of AFM observation for array characterization is presented as a critical case study. For these soft species, the array images do not simply present the solution phase geometry projected onto a two-dimensional surface. There are additional perturbations associated with fluidic forces associated with sample preparation. At this time, reconstruction of the "true" or average solution structures for blocks is more readily achieved using computer models than using direct imaging methods. The development of scalable 1D-origami arrays composed of uniquely addressable components is a logical, if not necessary, step in the evolution of higher order fully addressable structures. Our research into the fabrication of arrays has led us to generate a listing of several important areas of future endeavor. Of high importance is the re-enforcement of the mechanical properties of the building blocks and the organization of multiple arrays on a surface of technological importance. While addressing this short list of barriers to progress will prove challenging, coherent development along each of these lines of inquiry will accelerate the appearance of commercial scale molecular manufacturing.


Assuntos
DNA/química , Nanoestruturas/química , Nanotecnologia/métodos , Microscopia de Força Atômica , Conformação de Ácido Nucleico
16.
Chem Commun (Camb) ; 50(26): 3413-6, 2014 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-24513858

RESUMO

We have developed an approach, which routinely generates ~10 micron long one dimensional (1D) arrays of DNA origami. Coupled with a sequential assembly method with a very short (~1 min) reaction time, this extended platform enables the production, in high yield, of 1D arrays of biomolecules or conjugates.


Assuntos
DNA/química , Pontos Quânticos , Propriedades de Superfície
17.
Beilstein J Nanotechnol ; 5: 501-506, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-33708460

RESUMO

Maintaining the structural fidelity of DNA origami structures on substrates is a prerequisite for the successful fabrication of hybrid DNA origami/semiconductor-based biomedical sensor devices. Molybdenum disulfide (MoS2) is an ideal substrate for such future sensors due to its exceptional electrical, mechanical and structural properties. In this work, we performed the first investigations into the interaction of DNA origami with the MoS2 surface. In contrast to the structure-preserving interaction of DNA origami with mica, another atomically flat surface, it was observed that DNA origami structures rapidly lose their structural integrity upon interaction with MoS2. In a further series of studies, pyrene and 1-pyrenemethylamine, were evaluated as surface modifications which might mitigate this effect. While both species were found to form adsorption layers on MoS2 via physisorption, 1-pyrenemethylamine serves as a better protective agent and preserves the structures for significantly longer times. These findings will be beneficial for the fabrication of future DNA origami/MoS2 hybrid electronic structures.

18.
J Am Chem Soc ; 135(7): 2451-4, 2013 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-23384162

RESUMO

Development of a simple and efficient methodology to control the placement, spacing, and alignment of single-walled carbon nanotubes (SWCNTs) is essential for nanotechnology device application. Building on the growing understanding that the strong π-π interaction between the bases of single-stranded DNA (ssDNA) and CNTs is sufficient not only to drive CNT solubility in water but also to stabilize individual nanotubes against clustering in aqueous solution, a new motif for functionalizing DNA origami (DO) with CNTs is demonstrated. CNTs solubilized via wrapping with ssDNA react with DO constructs displaying linear arrays of ssDNA, leading to immobilization of the CNTs onto the DO scaffold. This study demonstrates the immobilization of ssDNA-wrapped CNTs at specific positions on single DO constructs. Furthermore, multiple DO constructs assembled into extended one-dimensional arrays have been used to successfully align pairs of CNTs exceeding 500 nm in length in a parallel orientation. This result provides a simplified, alternative approach to immobilization of CNTs with programmed spacing and orientation.


Assuntos
DNA/química , Ácidos Nucleicos Imobilizados/química , Nanotecnologia/métodos , Nanotubos de Carbono/química , Microscopia de Força Atômica , Solubilidade
19.
Comp Immunol Microbiol Infect Dis ; 34(4): 335-45, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21543119

RESUMO

Oral administration of attenuated Salmonella vaccine may provide valuable advantages such as low cost, easy preparation, and safety. Attenuated Salmonella vaccines also serve as carriers of foreign antigens and immunomodulatory cytokines. Presently, an attenuated Salmonella enterica serovar Typhimurium strain was used as a carrier for open reading frame 7 (ORF7) protein of porcine reproductive and respiratory syndrome virus (PRRSV), a swine pathogen of significant global economic importance. Initially, an attenuated S. enterica serovar Typhimurium expressing ORF7 gene derived from PRRSV Korean isolate was constructed. Following oral administration of a single dose of the attenuated Salmonella vaccine expressing PRRSV ORF7, humoral and cell-mediated immune responses specific for ORF7 were induced at both systemic and mucosal sites including spleen, mesenteric lymph node, Peyer's patch, and laminar propria, as evaluated by determining serum ORF7-specific IgG and mucosal IgA responses, as well as Th1- and Th2-type cytokine production from antigen-stimulated T cells. The induced humoral responses were sustained for at least 12weeks post-immunization. In particular, the immunized mice displayed immune responses to both the foreign ORF7 antigen and Salmonella itself. The results indicate the value of attenuated S. enterica serovar Typhimurium as an oral carrier of PRRSV antigenic proteins to induce effective systemic and mucosal immunity.


Assuntos
Imunidade nas Mucosas , Linfonodos/imunologia , Linfócitos/imunologia , Nódulos Linfáticos Agregados/imunologia , Vírus da Síndrome Respiratória e Reprodutiva Suína/genética , Salmonelose Animal/prevenção & controle , Baço/imunologia , Vacinação , Vacinas Atenuadas/administração & dosagem , Administração Oral , Animais , Antígenos de Bactérias , Antígenos Virais/imunologia , Sequência de Bases , Células Cultivadas , Feminino , Imunoglobulina A/análise , Imunoglobulina A/biossíntese , Imunoglobulina G/análise , Imunoglobulina G/biossíntese , Linfonodos/citologia , Linfonodos/microbiologia , Ativação Linfocitária , Linfócitos/microbiologia , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Fases de Leitura Aberta/genética , Fases de Leitura Aberta/imunologia , Nódulos Linfáticos Agregados/citologia , Nódulos Linfáticos Agregados/microbiologia , Vírus da Síndrome Respiratória e Reprodutiva Suína/química , Vírus da Síndrome Respiratória e Reprodutiva Suína/imunologia , Salmonelose Animal/imunologia , Salmonelose Animal/metabolismo , Salmonella typhimurium/crescimento & desenvolvimento , Salmonella typhimurium/imunologia , Baço/citologia , Baço/microbiologia , Suínos , Equilíbrio Th1-Th2
20.
Kobe J Med Sci ; 54(5): E260-3, 2009 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-19628966

RESUMO

This is a case report of compound elevated skull fracture. This is a very rare variant of skull fractures. A CT angiogram demonstrated occlusion in the mid 1/3rd of superior sagittal sinus. Only few cases have been reported before. This patient was managed by the Neurosurgery department of Square Hospitals Ltd. Dhaka who had a history of assault and diagnosed as compound elevated fracture. He was managed surgically and was discharged without any intracranial complication. Etiology, clinical findings and operatives findings had a similarity with other published cases.


Assuntos
Fraturas Expostas/patologia , Osso Parietal/lesões , Fraturas Cranianas/patologia , Seio Sagital Superior/patologia , Adulto , Fraturas Expostas/cirurgia , Humanos , Masculino , Osso Parietal/patologia , Fraturas Cranianas/cirurgia
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