RESUMO
The influence of a local thermal treatment on the properties of Ti-Al-N coatings is not understood. In the present work, a Ti0.52Al0.48N coating on a WC-Co substrate was heated with a diode laser up to 900 °C for 30 s and radially symmetric lateral gradients of phases, residual stress and hardness were characterized ex-situ using position-resolved synchrotron X-ray diffraction, Raman spectroscopy, transmission electron microscopy and nanoindentation. The results reveal (i) a residual stress relaxation at the edge of the irradiated area and (ii) a compressive stress increase of few GPa in the irradiated area center due to the Ti-Al-N decomposition, in particular due to the formation of small wurtzite (w) AlN domains. The coating hardness increased from 35 to 47 GPa towards the center of the heated spot. In the underlying heated substrate, a residual stress change from about - 200 to 500 MPa down to a depth of 6 µm is observed. Complementary, in-situ high-temperature X-ray diffraction analysis of stresses in a homogeneously heated Ti0.52Al0.48N coating on a WC-Co substrate was performed in the range of 25-1003 °C. The in-situ experiment revealed the origin of the observed thermally-activated residual stress oscillation across the laser heated spot. Finally, it is demonstrated that the coupling of laser heating to produce lateral thermal gradients and position-resolved experimental techniques opens the possibility to perform fast screening of structure-property relationships in complex materials.
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We are proposing optimal training conditions that can lead to an increase in the number of serial sarcomeres (SSN) and muscle fascicle length (FL) in spastic muscles. Therapeutic interventions for increasing FL in clinical populations with neurological origin, in whom relative shortness of muscle fascicles contributed to the presentation of symptoms such as spasticity, contracture, and limited functional abilities, do not generally meet these conditions, and therefore, result in less than satisfactory outcomes. Based on a review of literature, we argue that protocols of exercise interventions that led to sarcomerogenesis, and increases in SSN and FL in healthy animal and human models satisfied three criteria: 1) all involved eccentric exercise at appropriately high velocity; 2) resulted in positive strain of muscle fascicles; and 3) momentary deactivation in the stretched muscle. Accordingly, to increase FL in spastic muscles, new exercise protocols in which the three presumed criteria are satisfied, must be developed, and long-term muscle architectural and functional adaptations to such trainings must be examined.
Assuntos
Espasticidade Muscular , Músculo Esquelético , Adaptação Fisiológica , Animais , Exercício Físico , Humanos , SarcômerosRESUMO
Rheumatoid arthritis was first described unambiguously in 1800, but its etiology and historical origins are still obscure. Definite rheumatoid arthritis has not been demonstrated in pre-19th century Old World skeletal remains. Six individuals who lived 3000 to 5000 years ago in northwestern Alabama and present erosive polyarthritis characteristic of rheumatoid arthritis are described. The diagnosis raises the possibility that rheumatoid arthritis can be associated with a New World pathogen or allergen.
Assuntos
Artrite Reumatoide/história , Indígenas Norte-Americanos , Alabama , Artrite Reumatoide/diagnóstico por imagem , História Antiga , Humanos , RadiografiaRESUMO
The luciferase gene from the firefly, Photinus pyralis, was used as a reporter of gene expression by light production in transfected plant cells and transgenic plants. A complementary DNA clone of the firefly luciferase gene under the control of a plant virus promoter (cauliflower mosaic virus 35S RNA promoter) was introduced into plant protoplast cells (Daucus carota) by electroporation and into plants (Nicotiana tabacum) by use of the Agrobacterium tumefaciens tumor-inducing plasmid. Extracts from electroporated cells (24 hours after the introduction of DNA) and from transgenic plants produce light when mixed with the substrates luciferin and adenosine triphosphate. Light produced by the action of luciferase was also detected in undisrupted leaves or cells in culture from transgenic plants incubated in luciferin and in whole transgenic plants "watered" with luciferin. Although light was detected in most organs in intact, transgenic plants (leaves, stems, and roots), the pattern of luminescence appeared to reflect both the organ-specific distribution of luciferase and the pathway for uptake of luciferin through the vasculature of the plant.
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In situ Raman spectroscopy shows the simultaneous incorporation of small amounts of Bi3+ and Yb3+ into the lattice of BaTiO3 to break the average symmetry inferred from X-ray powder diffraction analysis and permittivity measurements. In particular, Bi3+ with a stereochemically active lone-pair of electrons induces severe lattice strain and the coexistence of different local crystal symmetries over a wide temperature range, effectively controlling the physical properties, such as the temperature dependence of the permittivity and the Curie temperature. These results show that compositional gradients based in small variations of these two dopants could successfully explain the enhanced thermal stability of the permittivity in core-shell type ceramics, whereas the lower capacitance of the shell can also cap the maximum permittivity at the Curie temperature.
RESUMO
The nucleotide sequence of the luciferase gene from the firefly Photinus pyralis was determined from the analysis of cDNA and genomic clones. The gene contains six introns, all less than 60 bases in length. The 5' end of the luciferase mRNA was determined by both S1 nuclease analysis and primer extension. Although the luciferase cDNA clone lacked the six N-terminal codons of the open reading frame, we were able to reconstruct the equivalent of a full-length cDNA using the genomic clone as a source of the missing 5' sequence. The full-length, intronless luciferase gene was inserted into mammalian expression vectors and introduced into monkey (CV-1) cells in which enzymatically active firefly luciferase was transiently expressed. In addition, cell lines stably expressing firefly luciferase were isolated. Deleting a portion of the 5'-untranslated region of the luciferase gene removed an upstream initiation (AUG) codon and resulted in a twofold increase in the level of luciferase expression. The ability of the full-length luciferase gene to activate cryptic or enhancerless promoters was also greatly reduced or eliminated by this 5' deletion. Assaying the expression of luciferase provides a rapid and inexpensive method for monitoring promoter activity. Depending on the instrumentation employed to detect luciferase activity, we estimate this assay to be from 30- to 1,000-fold more sensitive than assaying chloramphenicol acetyltransferase expression.
Assuntos
Luciferases/genética , Animais , Sequência de Bases , Linhagem Celular , Chlorocebus aethiops , Clonagem Molecular , Besouros/genética , DNA/genética , Luciferina de Vaga-Lumes/metabolismo , Regulação da Expressão Gênica , Genes , Luciferases/metabolismo , Regiões Promotoras Genéticas , RNA Mensageiro/genéticaRESUMO
A DNA segment carrying a cDNA copy of the luciferase gene (luc) of the North American firefly Photinus pyralis, fused to the lambda PR promoter and expressed in Escherichia coli [de Wet et al., Proc. Natl. Acad. Sci. USA 82 (1985) 7870-7873], was inserted into a broad-host-range plasmid vector and established in a variety of Gram-negative bacteria. Luciferase activity, expressed from the lambda PR promoter, was detected in both intact cells and extracts prepared from cells of strains of Rhizobium meliloti, R. phaseoli, R. fredii, Pseudomonas aeruginosa, Agrobacterium tumefaciens, Acinetobacter calcoaceticus and Azotobacter vinelandii. The highest levels of activity, determined by measurements of both intact cells and extracts, were observed for P. aeruginosa and the three species of Rhizobium examined. Expression of luciferase activity also was relatively high in R. meliloti bacteroids of mature alfalfa nodules. This activity was readily detectable in intact nodules using x-ray film or in extracts prepared from purified bacteroids.
Assuntos
Expressão Gênica , Bactérias Gram-Negativas/genética , Luciferases/genética , Medicago sativa/genética , Rhizobium/genética , Animais , Besouros/enzimologia , Conjugação Genética , DNA Bacteriano/biossíntese , DNA Bacteriano/isolamento & purificação , Resistência Microbiana a Medicamentos , Escherichia coli/genética , Luciferases/biossíntese , Plasmídeos , Regiões Promotoras Genéticas , SimbioseRESUMO
In summary the use of immobilized luciferases along with other enzymes offers a method for measuring a wide variety of metabolites or enzymes. The assays are rapid, sensitive, and specific and can be automated. It is anticipated that many more assays for different compounds will be developed in the future.
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Enzimas Imobilizadas/metabolismo , Luciferases/metabolismo , Di-Hidrolipoamida Desidrogenase/metabolismo , Cinética , Medições Luminescentes , Oxirredutases/metabolismo , Espectrofotometria/métodos , Vibrio/enzimologiaRESUMO
The procedures described here have been developed for only a few antigens at present. It seems very likely that they can be extended to any other antigen of choice. For sensitivities in the picomole range, the luciferase-antigen procedure is satisfactory. For increased sensitivity, the glucose-6-phosphate dehydrogenase-antigen is the method of choice. With some minor modifications the sensitivity of this assay can certainly be increased. The lower limits of detection will ultimately be determined by the affinity of the antibody for the antigen, not by the detection system.
Assuntos
Dinitrofenóis/análise , Imunoensaio , Luciferases , Metotrexato/análise , Trinitrotolueno/análise , Complexo Antígeno-Anticorpo , Antígenos/análise , Besouros/enzimologia , Glucosefosfato Desidrogenase , Humanos , Soros Imunes , Indicadores e Reagentes , Medições Luminescentes , MicroquímicaRESUMO
PURPOSE: To study the perceived effectiveness of bioethics consultation as evaluated by both professional staff and patients and their families. PATIENTS AND METHODS: An evaluation questionnaire was forwarded to physicians, nurses and patients or family members who were associated with 20 sequential cases referred for ethics consultation during a 2-year period. Respondents were asked to rate the consult as very helpful, somewhat helpful, or not helpful concerning a variety of issues related to the care of the patients. Responses were reviewed for agreement or disagreement between the three sample groups. RESULTS: Ninety-six percent of physicians and 95% of nurses sampled felt that the consult was helpful, compared with only 65% of the patient/family responses. Lack of communication between patients and staff was cited as a problem in all cases in which the consult was deemed unhelpful by patients and family. CONCLUSIONS: Patients or family members and professional staff have different perceptions regarding the value of bioethics consultation. When asked for comments, patients/family members cite lack of communication with professional staff as their primary reason for responding negatively. Earlier mobilization of consultative staff, rigorous training of consultants in techniques of conflict resolution, and education of primary caregivers regarding recognition of communication problems may serve to narrow this perceptual divergence.
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Atitude do Pessoal de Saúde , Atitude , Ética Médica , Encaminhamento e Consulta , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Comunicação , Conflito Psicológico , Estudos de Avaliação como Assunto , Família , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Enfermeiras e Enfermeiros , Médicos , Relações Profissional-Família , Relações Profissional-Paciente , Estudos Retrospectivos , Inquéritos e QuestionáriosRESUMO
OBJECTIVE: To evaluate the long-term stability of the refractive outcome after metal-blade radial keratotomy procedures. DESIGN: A cohort of 146 patients who underwent 225 consecutive metal-blade radial keratotomy procedures that were performed under a uniform protocol between November 1979 and August 1981 was monitored prospectively, with 64% of the patients followed up for at least 5 years. MAIN OUTCOME MEASURES: Changes in spherical equivalent and changes in average keratometry were evaluated within the following periods: 3 months to 1 year; 1 to 2 years; 2 to between 3 and 4 years (mean, 3.7 years); between 3 and 4 (mean, 3.7 years) to between 5 and 12 years (mean, 8.5 years); and 1 to between 5 and 12 years (mean, 8.5 years). RESULTS: Total mean change in refraction between 1 year and the average of 8.5 years of follow-up was 1.01 diopters (D) (SD, 1.13 D). At 1 year, 31% of the cases were at least 1 D hyperopic, whereas at an average of 8.5 years, 48% were at least 1 D hyperopic. Fifty-four percent of the cases had shifted in the hyperopic direction by 1 D or more. Stepwise regression analysis failed to identify significant predictive factors for the hyperopic shifts. CONCLUSIONS: The trend toward progressive hyperopic shifts within this cohort has continued with time. Other long-term studies have documented similar, although somewhat smaller, hyperopic shifts among both patients treated with metal-blade and patients treated with diamond-blade procedures. Causative factors for the hyperopic shift have not been identified. It remains to be seen if eyes undergoing current, more cautious surgical approaches to radial keratotomy will also experience this phenomenon.
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Ceratotomia Radial , Refração Ocular , Seguimentos , Humanos , Ceratotomia Radial/instrumentação , Estudos Prospectivos , Erros de Refração/epidemiologia , Análise de Regressão , Fatores de Tempo , Resultado do TratamentoAssuntos
Aminoácidos/metabolismo , Enzimas/metabolismo , Ácidos Graxos/metabolismo , Luciferina de Vaga-Lumes/metabolismo , Nucleotídeos de Adenina/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Catálise , Fenômenos Químicos , Físico-Química , Coenzima A/metabolismo , Insetos , Ligases/metabolismo , Luciferases/metabolismo , Luminescência , Oxigênio/metabolismo , RNA de Transferência/metabolismoRESUMO
Our purpose in this study was to determine the importance of the luminance range of the display system for the detection of simulated masses in mammograms. Simulated masses were embedded in selected portions (512 x 512 pixels) of mammograms digitized at 50 micro pixels, 12 bits deep. The masses were embedded in one of four quadrants in the image. An observer experiment was conducted in which the observer's task was to determine in which quadrant the mass is located. The key variables involved in each trial included the position of the mass, the contrast level of the mass, and the luminance of the display. The contrast of the mass with respect to the background was fixed to one of four selected contrast levels. The digital images were printed to film, and displayed on a mammography lightbox. The display luminance was controlled by placing neutral density films between the laser printed films of mammographic backgrounds and the lightbox. The resulting maximum luminances examined in this study ranged from 34 cd/m2 to 2056 cd/m2. Twenty observers viewed 80 different images (20 observations at each of 4 different mass contrast levels) under each of the 5 luminance conditions for a total of 800 independent observations per observer. An analysis of variance yielded no statistically significant correlation between the luminance range of the display and the feature detection rate of the simulated masses in mammograms. However, the performance of the lower luminance display systems (less than 300 cd/m2), may be reduced due to the high levels of ambient light found in many reading environments.
Assuntos
Apresentação de Dados , Mamografia/métodos , Intensificação de Imagem Radiográfica/métodos , Análise de Variância , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/diagnóstico por imagem , Feminino , Humanos , Luz , Modelos Teóricos , Distribuição Normal , Variações Dependentes do Observador , Reprodutibilidade dos TestesRESUMO
A bioluminescence assay for bile acids was developed using a co-immobilized 3 alpha-hydroxysteroid dehydrogenase, diaphorase, and bacterial luciferase. The assay was specific for bile acids containing a free 3 alpha-hydroxyl group, as well as androsterone. Light output was linear over a bile acid concentration range of 1-20 000 pmol. Intra-assay precision was 6.2-8.2% and the recovery of added standards was 92-110%. Comparison of results using the bioluminescence assay with those using gas liquid chromatography revealed an excellent correlation (r = 0.99, n = 31). Since the bioluminescence assay is rapid, sensitive, specific, and uses inexpensive reagents, it appears to be an ideal method for the measurement of total bile acids in serum.
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3-Hidroxiesteroide Desidrogenases , Ácidos e Sais Biliares/sangue , Fenômenos Químicos , Química , Cromatografia Gasosa , Di-Hidrolipoamida Desidrogenase , Enzimas Imobilizadas , Humanos , Luciferases , Medições LuminescentesRESUMO
PURPOSE: A Phase I U.S. FDA clinical study of a plate haptic posterior chamber phakic intraocular lens (STAAR Surgical Implantable Contact Lens) for treatment of hyperopia was conducted at 4 sites in the United States. The purpose of this report is to assess the short-term safety and efficacy. METHODS: Ten patients with hyperopia between +2.50 and +10.875 D were implanted in one eye each with the posterior chamber plate phakic intraocular lens and were examined at baseline and 1 day, 1 week, 1, 3, and 6 months after surgery. Mean baseline hyperopia was +6.63 D. RESULTS: At 6 months postoperatively, 7 of 10 eyes (70%) had an uncorrected visual acuity of 20/20 or better and 10 of 10 (100%) had 20/40 or better. Eight of ten eyes (80%) had a spectacle-corrected visual acuity within 1 line of baseline; the other two eyes (20%) had an improvement of 3 lines. Mean 6-month postoperative spherical equivalent refraction was +0.20 +/- 0.61D (range, -0.50 to +1.50 D), a reduction of 6.025 D from baseline. Eight of 10 eyes (80%) were within +/-0.50 D of emmetropia, 9 eyes (90%) were within +/-1.00 D, and all eyes (100%) were within +/-1.50 D. No operative or postoperative complications or adverse reactions were observed. CONCLUSIONS: Results support the short-term safety, efficacy, and predictability of the STAAR Surgical Implantable Contact Lens (plate haptic posterior chamber phakic intraocular lens) in the treatment of hyperopia.
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Hiperopia/cirurgia , Implante de Lente Intraocular , Cristalino , Lentes Intraoculares , Adulto , Materiais Biocompatíveis , Seguimentos , Humanos , Metacrilatos , Pessoa de Meia-Idade , Refração Ocular , Segurança , Resultado do Tratamento , Acuidade VisualRESUMO
Two hundred patients were enrolled in a randomized, prospective clinical trial comparing the use of 10-0 nylon, 10-0 polypropylene (Prolene), 11-0 polyester (Mersilene), and 10-0 polyethylene (Novafil) suture materials on the amount and decay curves of surgically induced astigmatism following intraocular lens (IOL) surgery. Patients with Mersilene and nylon sutures had the highest amounts of induced with-the-rule (WTR) cylinder (significantly more than Prolene) at one day after surgery. However, the WTR cylinder decayed rapidly for nylon during the first three months but more slowly for Mersilene because of its lack of stretchability. The Prolene group had the lowest level of induced WTR cylinder at one day, but against-the-rule (ATR) drift occurred, leaving cases with ATR astigmatism by a year. The nylon group had the second highest amount of induced WTR cylinder at one day, which had decayed to ATR cylinder by five months. Between one and two years postoperatively, the nylon group experienced a significant ATR shift. The amount of early induced WTR cylinder seemed to be related to the knot-tying technique and tissue gripping characteristics, whereas the shape of the decay curve was related to the material characteristics of the suture.
Assuntos
Astigmatismo/etiologia , Suturas , Adulto , Idoso , Idoso de 80 Anos ou mais , Extração de Catarata/efeitos adversos , Feminino , Seguimentos , Humanos , Lentes Intraoculares/efeitos adversos , Masculino , Pessoa de Meia-Idade , Nylons , Poliésteres , Polietilenotereftalatos , Polipropilenos , Complicações Pós-Operatórias , Estudos Prospectivos , Acuidade VisualRESUMO
A new procedure, hyperopic thermokeratoplasty (HTK), developed in the Soviet Union for the correction of hyperopia, uses controlled thermal burns of the corneal stroma with a retractable probe tip preset to penetrate the cornea at 95% depth. The coagulations are applied in a radial pattern for spherical hyperopia. Only the peripheral cornea is treated and the effect is titrated by varying the optical zone and number of rays. The thermal effect flattens the peripheral cornea and steepens the central cornea. In this report, we prospectively evaluated the refractive results of a group of 61 HTK patients. Mean preoperative spherical equivalent was 3.9 diopters (D). Mean follow-up to date is 5.2 months, with 44% of cases evaluated at six months and 31% at one year. The initial effect of surgery (at one day) was a mean decrease in hyperopia of 6.0 D (standard error of the mean [S.E.] = 0.3 D), resulting in a mean spherical equivalent of -2.1 D (S.E. = 0.2 D). There was a steep regression of effect between one day and two months at which point average refraction was close to emmetropia. After two months, there was a gradual but continuing regression of effect, leveling off after six months. At five to six months, 63% of cases were undercorrected by at least a diopter; at 9 to 12 months, 83% of cases were undercorrected. The overall change in spherical equivalent at each time increased as optical zone size decreased.(ABSTRACT TRUNCATED AT 250 WORDS)
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Substância Própria/cirurgia , Eletrocoagulação , Hiperopia/cirurgia , Adulto , Idoso , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias , Estudos Prospectivos , Erros de Refração/diagnóstico , Resultado do Tratamento , Acuidade VisualRESUMO
One hundred twelve patients scheduled for uncomplicated cataract removal were randomly assigned to receive a STAAR Elastimide three-piece foldable intraocular lens inserted through a 4.0 mm incision or a STAAR poly(methyl methacrylate) (PMMA) lens inserted through a 7.0 mm incision. The same surgeon performed all surgeries using identical techniques, except for incision size and number of sutures. Patients receiving Elastimide lenses had significantly better uncorrected visual acuity postoperatively than patients receiving PMMA lenses and also had significantly less keratometric cylinder, surgically induced cylinder (vector method), and refractive cylinder. The Elastimide foldable lens offers the advantages of small incision surgery for patients who require a three-piece lens.
Assuntos
Extração de Catarata/métodos , Lentes Intraoculares , Elastômeros de Silicone , Técnicas de Sutura , Idoso , Idoso de 80 Anos ou mais , Estudos de Avaliação como Assunto , Feminino , Humanos , Lentes Intraoculares/efeitos adversos , Masculino , Metilmetacrilato , Metilmetacrilatos , Pessoa de Meia-Idade , Complicações Pós-Operatórias , Desenho de Prótese , Acuidade VisualRESUMO
In a unilateral prospective clinical trial, 77 cases were randomized to receive a 3M multifocal IOL or a conventional monofocal implant. Multifocal cases had better uncorrected near vision than monofocal cases at the two to four month visit. Thirty percent of the multifocal cases had near acuity J1, while only 4% of the monofocal cases had that acuity. Eighty-seven percent of multifocal cases and 71% of monofocal cases had near acuities of J1 to J3. With distance correction in place, 54% of multifocal cases had near acuities of J1 to J2, while only 28% of monofocal cases had comparable acuities (P = .04). There have been no serious postoperative complications in either group.
Assuntos
Lentes Intraoculares , Óptica e Fotônica , Erros de Refração/fisiopatologia , Acuidade Visual , Extração de Catarata , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Desenho de Prótese , Resultado do TratamentoRESUMO
A single center, single surgeon, randomized, prospective clinical trial was performed comparing the effectiveness of small (3.5 mm to 4.0 mm) incision intraocular lens surgery and a larger (6.0 mm) incision in improving uncorrected visual acuity and reducing post-operative inflammation and surgically induced astigmatism. One hundred twelve eligible unilateral cases were randomized to receive a 3.5 mm to 4.0 mm incision with implantation of an Allergan Medical Optics three-piece SI-18NB silicone lens (56 cases) or a 6.0 mm incision with implantation of a three-piece biconvex poly(methyl methacrylate) lens (56 cases). At one day after surgery, significantly (P less than .01) more patients with 3.5 mm incisions had 20/40 or better uncorrected visual acuity than patients with 6.0 mm incisions (45% vs 20%). Forty percent of patients with 6.0 mm incisions vs 14% of patients with 3.5 mm incisions had visual acuities of 20/100 or worse. At one day after surgery, the larger incision group had significantly higher (P less than .01) mean keratometric cylinder (2.28 diopters vs 1.28 diopters in the small incision group). The two groups were comparable by three months. Laser flare/cell meter measurements were taken for each group but showed no significant differences in mean flare or cell measurements between the groups.