Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
Más filtros











Base de datos
Intervalo de año de publicación
1.
Metrologia ; 59(2)2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36578474

RESUMEN

Improvements in a lamp-monochromator-based facility at the National Institute of Standards and Technology (NIST), the Visible near-infrared Spectral Comparator Facility (VisSCF) which is used to calibrate optical detectors for spectral radiant power responsivity from 300 nm to 1100 nm, are described. These changes include extending the VisSCF operational range down to 300 nm from 350 nm, thereby fully covering the ultraviolet-A (UVA) spectral region and partially covering the UVB range. These improvements have lowered the magnitudes of most of the components in the uncertainty budget and have led to combined 0.005 % transfer (k=1) uncertainties in the spectral power responsivity calibrations over most of the spectral range. Redevelopment of the uncertainty budget results in total expanded uncertainties of spectral responsivities of less than 0.1 % (k=2) over the spectral range from 380 nm to 980 nm, with the greatest uncertainty term coming from the calibrations of the transfer standards.

2.
Oxid Med Cell Longev ; 2019: 1523140, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31214275

RESUMEN

Recently, metabolic syndrome (MS) has gained attention in human and animal metabolic medicine. Insulin resistance, inflammation, hyperleptinemia, and hyperinsulinemia are critical to its definition. MS is a complex cluster of metabolic risk factors that together exert a wide range of effects on multiple organs, tissues, and cells in the body. Adipose stem cells (ASCs) are multipotent stem cell population residing within the adipose tissue that is inflamed during MS. Studies have indicated that these cells lose their stemness and multipotency during MS, which strongly reduces their therapeutic potential. They suffer from oxidative stress, apoptosis, and mitochondrial deterioration. Thus, the aim of this study was to rejuvenate these cells in vitro in order to improve their chondrogenic differentiation effectiveness. Pharmacotherapy of ASCs was based on resveratrol and 5-azacytidine pretreatment. We evaluated whether those substances are able to reverse aged phenotype of metabolic syndrome-derived ASCs and improve their chondrogenic differentiation at its early stage using immunofluorescence, transmission and scanning electron microscopy, real-time PCR, and flow cytometry. Obtained results indicated that 5-azacytidine and resveratrol modulated mitochondrial dynamics, autophagy, and ER stress, leading to the enhancement of chondrogenesis in metabolically impaired ASCs. Therefore, pretreatment of these cells with 5-azacytidine and resveratrol may become a necessary intervention before clinical application of these cells in order to strengthen their multipotency and therapeutic potential.


Asunto(s)
Autofagia/efectos de los fármacos , Azacitidina/farmacología , Trasplante de Células Madre Mesenquimatosas , Células Madre Mesenquimatosas/patología , Síndrome Metabólico/fisiopatología , Mitocondrias/metabolismo , Resveratrol/farmacología , Tejido Adiposo/citología , Animales , Diferenciación Celular , Autorrenovación de las Células , Células Cultivadas , Condrogénesis , Femenino , Citometría de Flujo , Enfermedades de los Caballos , Caballos , Humanos , Masculino , Síndrome Metabólico/terapia , Microscopía Electrónica , Nicho de Células Madre
3.
Pol J Vet Sci ; 21(2): 307-316, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-30450870

RESUMEN

One of the most common reasons for horse lameness is subchondral bone cysts (SBCs), which are especially evident in young horse athletes. It is believed that SBC development is strongly associated with an individual's bone growth and/or bone microstructure impairment. Current methods of SBC treatment include pharmacological treatment or surgical procedures which may allow the bone within the cyst to rebuild and be restored to properly developed bone tissue. Thus, we propose filling the SBCs with a 3D complex of alginate hydrogel and autologous adipose derived mesenchymal stem cells (ASCs). We have observed at the in vitro level, that this hydrogel complex induces osteogenic and chondrogenic differentiation potential through the upregulation of bone morphogenetic protein, osteopontin, collagen type I and aggrecan mRNA levels. Moreover, we detected the creation of a 3D extracellular matrix (EM). To investigate the complex in vivo, we chose 8 horses of varying age suffering from SBC, which resulted in lameness, to undergo experimental surgery. We documented the horses' clinical appearance, lameness and radiographic appearance, to determine that there was clinical improvement in 87.75% of the patients (n=7, out of 8 horses) 6 months postoperatively and 100% (n=8, out of 8 horses) a year after surgery. These results are promising for the potential of this procedure to become the standard in SBC treatment.


Asunto(s)
Alginatos , Quistes Óseos , Enfermedades de los Caballos , Trasplante de Células Madre , Animales , Quistes Óseos/terapia , Enfermedades de los Caballos/terapia , Caballos , Hidrogeles , Trasplante de Células Madre/veterinaria , Células Madre
4.
J Res Natl Inst Stand Technol ; 106(4): 641-7, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-27500040

RESUMEN

Two cryogenic radiometers from NIST, one from the Optical Technology Division and the other from the Optoelectronics Division, were compared at three visible laser wavelengths. For this comparison, each radiometer calibrated two photodiode trap detectors for spectral responsivity. The calibration values for the two trap detectors agreed within the expanded (k = 2) uncertainties. This paper describes the measurement and results of this comparison.

5.
Psychol Rep ; 86(3 Pt 2): 1219-25, 2000 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-10932584

RESUMEN

This experiment examined the competitive behavior in a seven-choice Prisoner's Dilemma game of 108 adult students (68 women, 40 men) classified as high, average, or low in competitiveness based on their scores on the Competitiveness Index. Participants were then presented one of three preprogrammed response conditions representing (1) Competitive, (2) De-escalating, or (3) Noncompetitive conflict behavior from a simulated opponent. Participants high in competitiveness engaged in more competitive behavior and reported higher satisfaction with the task than those low in competitiveness. As expected, the Competitive conditions elicited more competitive behavior than Noncompetitive conditions. The results suggest competitive individuals may be particularly susceptible to social cues that trigger competitive behavior.


Asunto(s)
Conducta Competitiva , Conflicto Psicológico , Teoría del Juego , Adulto , Conducta Cooperativa , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudiantes/psicología
6.
Appl Opt ; 36(16): 3614-21, 1997 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-18253383

RESUMEN

The National Institute of Standards and Technology (NIST) is establishing an infrared detector calibration facility to improve radiometric standards at infrared wavelengths. The absolute response of the cryogenic bolometer that serves as the transfer standard for this facility is being linked to the NIST high- accuracy cryogenic radiometer (HACR) at a few laser wavelengths. At the 10.6-microm CO(2) laser line, this link is being established through a pyroelectric detector that has been calibrated against the HACR. We describe the apparatus, methods, and uncertainties for the calibration of this pyroelectric detector.

7.
Appl Opt ; 35(7): 1056-68, 1996 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-21085215

RESUMEN

A high-accuracy cryogenic radiometer has been developed at the National Institute of Standards and Technology to serve as a primary standard for optical power measurements. This instrument is an electrical-substitution radiometer that can be operated at cryogenic temperatures to achieve a relative standard uncertainty of 0.021% at an optical power level of 0.8 mW. The construction and operation of the high-accuracy cryogenic radiometer and the uncertainties in optical power measurements are detailed.

8.
Appl Opt ; 35(22): 4392-403, 1996 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-21102852

RESUMEN

Using the National Institute of Standards and Technology high-accuracy cryogenic radiometer (HACR), we have realized a scale of absolute spectral response between 406 and 920 nm. The HACR, an electrical-substitution radiometer operating at cryogenic temperatures, achieves a combined relative standard uncertainty of 0.021%. Silicon photodiode light-trapping detectors were calibrated against the HACR with a typical relative standard uncertainty of 0.03% at nine laser wavelengths between 406 and 920 nm. Modeling of the quantum efficiency of these detectors yields their responsivity throughout this range with comparable accuracy.

9.
Paraplegia ; 31(11): 715-21, 1993 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-8295781

RESUMEN

Although there are numerous approaches to the treatment of spasticity, many patients are still unable to find a satisfactory method of managing their spasms with acceptable side effects. In the course of our fertility studies using rectal probe electrostimulation (RPES) in SCI men to produce ejaculation, we observed that a majority of the men experienced significant relief of their spasticity for many hours. This report describes a prospective, single-blinded study of this phenomenon in six SCI men and three SCI women who underwent RPES a total of 71 times. The mean age of the subjects was 28.2 years (21-41), the mean time from injury was 6.0 years (0.5-15); there were three paraplegic and six quadriplegic persons: four were Frankel class A and five were class B. Although all subjects had moderate to severe spasticity, only four took antispasm medications; one had undergone surgery for implantation of an epidural stimulator. The effectiveness of RPES on spasticity was evaluated by each subject for frequency of spasms and interference of daily activities and by independent, blinded assessors for tone, frequency of spasms and DTRs; four patients underwent quantitative videotape analysis of the pendulum test and two underwent somatosensory evoked potentials (SSEPs) to evaluate electrical activity in the central nervous system. Treatment variables included varying probe sizes and number of stimulations. All subjects experienced good to excellent decrease in tone, frequency of spasms and interference with ADL from 3 to 24 hours depending on treatment variables used. Mean duration of relief was 8.2 hours.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Terapia por Estimulación Eléctrica/métodos , Espasmo/terapia , Traumatismos de la Médula Espinal/complicaciones , Adulto , Terapia por Estimulación Eléctrica/instrumentación , Equipos y Suministros , Femenino , Humanos , Rodilla/fisiopatología , Masculino , Movimiento (Física) , Nifedipino/uso terapéutico , Paraplejía/etiología , Estudios Prospectivos , Cuadriplejía/etiología , Recto , Espasmo/tratamiento farmacológico , Espasmo/etiología
11.
Paraplegia ; 25(1): 23-6, 1987 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-3562053

RESUMEN

Ischaemic myelopathy is an infrequent but well-known cause of spinal cord injury. While the overall incidence of neurological injury following thoraco-abdominal aortic surgery is low (1-14%), procedures requiring surgical cross-clamping of the aorta have been reported as the major cause of ischaemic cord injury (31%). Little has been reported regarding the clinical and functional outcomes of these injuries. Three patients with a non-penetrating aortic injury who showed evidence of ischaemic cord injury within 72 hours of surgical cross-clamping of the aorta are presented. Data includes functional assessments, muscle strength testing and electromyographic findings. All three patients showed lower thoracic incomplete motor and sensory spinal cord injuries. These findings suggest that, after a period of neurological improvement, a plateau phase is reached at approximately 3 months post injury after which no significant gain in muscle strength is made. All patients were functionally independent and able to ambulate using a straight cane.


Asunto(s)
Isquemia/etiología , Complicaciones Posoperatorias , Médula Espinal/irrigación sanguínea , Adulto , Aorta/cirugía , Electromiografía , Humanos , Plexo Lumbosacro/irrigación sanguínea , Masculino , Conducción Nerviosa
12.
Paraplegia ; 22(4): 244-8, 1984 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-6483466

RESUMEN

The Commonwealth of Virginia has established a comprehensive programme for the management of the spinal cord injury (SCI) patients from the moment of injury through all aspects of rehabilitation into long-term follow-up. An average of 200 new patients are registered per year. A major emphasis of our programme has been the education of the patients and their relations and friends by means of group education of the patients and family follow-up contact, 'Family Days,' group lectures on selected topics, individual discussions, and discharge conferences. Audio-visual aids augment the programme. Patients are provided with printed literature on SCI for their own review and this is subsequently discussed with them. We have worked with the Emergency Rescue Team on early management; and education on prophylaxis has been carried out in the school systems statewide. Public awareness of the problems of the physically handicapped has been encouraged. Through our follow-up clinic we are attempting to reach the community facilities and community physicians, making them aware of the problem of SCI and discussing with them facilities that are available to assist in their management. While much has been accomplished we still have a long way to go.


Asunto(s)
Familia , Educación del Paciente como Asunto , Traumatismos de la Médula Espinal/rehabilitación , Educación en Salud , Humanos , Virginia
13.
Mol Cell Biol ; 4(8): 1561-71, 1984 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-6208477

RESUMEN

The construction of a small library of mouse repetitive DNA has been previously reported (Pietras et al., Nucleic Acids Res. 11:6965-6983, 1983). Here we report that the 35 plasmids in this library corresponding to highly repeated (greater than 30,000 copies per genome) dispersed DNA sequences can be grouped into no more than 5 distinct families. These families together comprise 8 to 10% of the mouse genome. They include the previously described small elements B1, B2, and R and the large MIF-1 element. Twelve of the 35 clones contain evolutionarily conserved (EC) sequences. One EC clone in our library mostly consists of alternating dCdT residues; another consists of tandem repeats of the sequence CCTCT. The majority of B1s and B2s in the genome appear to be homogeneous, whereas R sequences, ECs, and MIF-1s are heterogeneous. Two earlier reports showed highly repeated mammalian DNA sequences in the herpesvirus genome (Peden et al., Cell 31:71-80, 1982; Puga et al., Cell 31:81-87, 1982). We show that sequences homologous to our EC clones are present in the herpesvirus genome, although these polypyrimidine stretches are not detected in poxvirus, adenovirus, and simian virus 40 genomes. We detect transcripts containing homology to all of these sequences in a nuclear transcription assay. Also, we show that small, polyadenylated RNA molecules homologous to B2 sequences are expressed in undifferentiated embryonal carcinoma cells but not in their differentiated derivatives. The significance of these findings is discussed.


Asunto(s)
Clonación Molecular , Genes , Plásmidos , Animales , Núcleo Celular/metabolismo , ADN Recombinante/análisis , Hígado/metabolismo , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Hibridación de Ácido Nucleico , ARN/aislamiento & purificación , Secuencias Repetitivas de Ácidos Nucleicos , Transcripción Genética
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA