RESUMEN
This study presents a new method for measuring the Seebeck coefficient under high pressure in a multi-anvil apparatus. The application of a dual-heating system enables precise control of the temperature difference between both ends of the sample in a high-pressure environment. Two pairs of W-Re thermocouples were employed at both ends of the sample to monitor and control the temperature difference, and independent probes were arranged to monitor the electromotive force (emf) produced by temperature oscillation at a given target temperature. The temperature difference was controlled within 1 K during the resistivity measurements to eliminate the influence of the emf owing to a sample temperature gradient. The Seebeck measurement was successfully measured from room temperature to 1400 K and was obtained by averaging the two measured values with opposite thermal gradient directions (â¼20 K). Thermoelectric properties were measured on disk-shaped p-type Si wafers with two different carrier concentrations as a reference for high Seebeck coefficients. This method is effective to determine the thermoelectric power of materials under pressure.
RESUMEN
Tardigrades can cope with adverse environmental conditions by turning into anhydrobiotes with a characteristic tun shape. Tun formation is an essential morphological adaptation for tardigrade entry into the anhydrobiotic state. The tun cell structure and ultrastructure have rarely been explored in tardigrades in general and never in Hypsibius exemplaris. We used transmission electron microscopy to compare cellular organization and ultrastructures between hydrated and anhydrobiotic H. exemplaris. Despite a globally similar cell organelle structure and a number of cells not significantly different between hydrated and desiccated tardigrades, reductions in the sizes of both cells and mitochondria were detected in dehydrated animals. Moreover, in anhydrobiotes, secretory active cells with a dense endoplasmic reticulum network were observed. Interestingly, these anhydrobiote-specific cells are in a close relationship with a specific extracellular structure surrounding each cell. It is possible that this rampart-like extracellular structure resulted from the accumulation of anhydrobiotic-specific material to protect the cells. Interestingly, after five hours of rehydration, the number of secretory cells decreased, and the specific extracellular structure began to disappear. Twenty-four hours after the beginning of rehydration, the cellular structure and ultrastructure were comparable to those observed in hydrated tardigrades.
Asunto(s)
Adaptación Fisiológica , Núcleo Celular/fisiología , Desecación/métodos , Microscopía Electrónica de Transmisión/métodos , Mitocondrias/fisiología , Tardigrada/fisiología , Animales , Núcleo Celular/ultraestructura , Mitocondrias/ultraestructura , Tardigrada/ultraestructuraRESUMEN
BACKGROUND: Medial elbow injuries are common in baseball pitchers. This study investigated the reliability of medial elbow elastography measurement and the characteristics of the medial elbow stabilizers. METHODS: Medial elbow joint space gapping and the strain ratios of the ulnar collateral ligament (UCL) and the forearm flexor-pronator muscle (FPM) were measured at rest and during gripping in 29 healthy college students. The intraclass correlation coefficients of elastography were calculated. The data were compared between tissues and between rest and gripping. RESULTS: The intraclass correlation coefficients (ICC1,3) of the elastography measurements were 0.91 and 0.83 for the UCL and 0.80 and 0.85 for the FPM for each examiner. Medial elbow joint space gapping during gripping (3.1 ± 0.6 mm) was significantly less than that at rest (3.8 ± 0.8 mm, P < .001). The strain ratios for both the UCL and FPM during gripping were significantly greater than those at rest (17.64 ± 10.97 during gripping vs. 3.94 ± 1.92 at rest for UCL, P < .001; 1.72 ± 0.99 during gripping vs. 0.35 ± 1.92 at rest for FPM, P < .001). The strain ratio for the UCL was significantly greater than that for the FPM both at rest (P < .001) and during gripping (P < .001). CONCLUSIONS: Elastography measurements of the UCL and FPM have almost perfect reliability. Gripping reduces medial elbow joint space gapping compared with rest. For both tissues, gripping reduces their elasticity compared with rest. The elasticity of the UCL is less than that of the FPM both at rest and during gripping.
Asunto(s)
Ligamento Colateral Cubital/diagnóstico por imagen , Diagnóstico por Imagen de Elasticidad , Elasticidad/fisiología , Articulación del Codo/diagnóstico por imagen , Fuerza de la Mano/fisiología , Músculo Esquelético/diagnóstico por imagen , Ligamento Colateral Cubital/fisiología , Articulación del Codo/fisiología , Antebrazo , Humanos , Masculino , Músculo Esquelético/fisiología , Reproducibilidad de los Resultados , Adulto JovenRESUMEN
BACKGROUND: Repetitive pitching induces an increase in medial elbow joint space gapping and may consequently lead to local tissue stress and injury. Use of an elbow brace may prevent this from occurring by preventing an increase of medial elbow joint space gapping. However, an elbow brace adds weight to the limb and may increase the burden on the throwing arm. OBJECTIVE: To investigate whether use of an elbow brace during repetitive pitching reduces shoulder and arm range of motion and grip strength. DESIGN: Prospective crossover study. SETTING: University campus. PARTICIPANTS: Twenty-five healthy high school baseball players. METHODS: Each participant pitched 100 times under two conditions: without an elbow brace (control) and wearing an elbow brace. MAIN OUTCOME MEASUREMENTS: Shoulder and elbow range of motion (ROM) before pitching and after every block of 20 pitches. Grip strength before pitching and after 100 pitches. RESULTS: There was no significant main effect and interaction for ROM between the two conditions and between pitching sets. In both conditions, grip strength after 100 pitches was significantly lower than that before pitching (P < .05). When the two conditions were compared, there was no significant difference before pitching or after 100 pitches. CONCLUSIONS: Use of elbow brace does not alter shoulder and elbow ROM or decrease grip strength after repetitive pitching up to 100 times compared with a no brace condition. An elbow brace can be used during repetitive pitching without causing an increased mechanical burden on the throwing arm. LEVEL OF EVIDENCE: II.
Asunto(s)
Béisbol/fisiología , Tirantes , Articulación del Codo/fisiología , Adolescente , Estudios Cruzados , Fuerza de la Mano/fisiología , Humanos , Masculino , Estudios Prospectivos , Rango del Movimiento Articular/fisiología , Articulación del Hombro/fisiologíaRESUMEN
BACKGROUND: To prevent elbow injury in baseball players, various methods have been used to measure medial elbow joint stability with valgus stress. However, no studies have investigated higher levels of elbow valgus stress. This study investigated medial elbow joint space gapping measured ultrasonically resulting from a 30 N valgus stress vs. gravitational valgus stress after a repetitive throwing task. METHODS: The study included 25 high school baseball players. Each subject pitched 100 times. The ulnohumeral joint space was measured ultrasonographically, before pitching and after each successive block of 20 pitches, with gravity stress or 30 N valgus stress. Two-way repeated measures analysis of variance and Pearson correlation coefficient analysis were used. RESULTS: The 30 N valgus stress produced significantly greater ulnohumeral joint space gapping than gravity stress before pitching and at each successive 20-pitch block (P < .01). For the 2 stress methods, ulnohumeral joint space gapping increased significantly from baseline after 60 pitches (P < .01). Strong significant correlations were found between the 2 methods for measurement of medial elbow joint space gapping (r = 0.727-0.859, P < .01). CONCLUSIONS: Gravity stress and 30 N valgus stress may produce different effects with respect to medial elbow joint space gapping before pitching; however, 30 N valgus stress appears to induce greater mechanical stress, which may be preferable when assessing joint instability but also has the potential to be more aggressive. The present results may indicate that constraining factors to medial elbow joint valgus stress matched typical viscoelastic properties of cyclic creep.
Asunto(s)
Béisbol , Articulación del Codo/fisiología , Inestabilidad de la Articulación/fisiopatología , Adolescente , Béisbol/lesiones , Fenómenos Biomecánicos , Elasticidad , Articulación del Codo/diagnóstico por imagen , Gravitación , Humanos , Inestabilidad de la Articulación/diagnóstico por imagen , Masculino , Instituciones Académicas , Estrés Mecánico , UltrasonografíaRESUMEN
Post-conflict affiliation between former opponents or between one of the former opponents and bystanders might have the function of conflict management, which reduces the costs associated with aggressions. One of the suggested functions of post-conflict affiliation is decreased renewed aggressions directed from aggressors to victims. However, the effect of post-conflict affiliation on renewed aggressions by victims has not been investigated. We examined whether post-conflict affiliations decreased the number of renewed aggressions initiated by winners or losers in captive bottlenose dolphins. Both winners and losers initiated renewed aggressions. However, these aggressions decreased after post-conflict affiliation between former opponents, initiated by bystanders to winners, initiated by losers to bystanders, and initiated by bystanders to losers. Post-conflict affiliation between former opponents is suggested to function as reconciliation. Post-conflict affiliation initiated by losers to bystanders is suggested to function as the protection of losers. Post-conflict affiliations initiated by bystanders to one of former opponents are suggested to function as both appeasement and protection of the opponent who affiliates with bystanders.
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Conducta Animal , Delfín Mular , Conflicto Psicológico , Conducta Social , Agresión , AnimalesRESUMEN
BACKGROUND: Heart-type fatty acid-binding protein (H-FABP) is proposed as an early biomarker for acute myocardial infarction (AMI), but its prognostic value is unclear in acute coronary syndrome (ACS). We evaluated the prognostic value of the H-FABP concentration relative to cardiac troponin T (cTnT) in the early hours of ACS. METHODS: Serum concentrations of H-FABP and cTnT were measured on admission in 328 consecutive patients hospitalized for ACS within 6 h after the onset of chest pain [AMI, 241 (73.5%) patients; ST-segment elevation myocardial infarction, 154 (47.0%) patients; and emergent coronary angiography within 24 h after admission, 287 (87.5%) patients]. Cardiac events, which were defined as cardiac death or subsequent nonfatal AMI, were monitored for 6 months after admission. RESULTS: During the 6-month follow-up period, there were 25 cardiac events, including 15 cardiac deaths and 10 subsequent nonfatal AMIs. Stepwise multivariate analyses including clinical, electrocardiographic, and biochemical variables revealed that increased H-FABP (above the median of 9.8 microg/L), but not increased cTnT (above the median of 0.02 microg/L), was independently associated with cardiac events in all patients [relative risk (RR) = 8.96; P = 0.0004], the subgroup of patients with ST-segment elevation myocardial infarction (RR = 11.3; P = 0.02), and the subgroup of patients with unstable angina and non-ST-segment elevation myocardial infarction (RR = 8.31; P = 0.007). The area under the ROC curve was higher for H-FABP than for cTnT (0.711 vs 0.578; P = 0.08), suggesting that H-FABP concentrations have a greater predictive capacity for cardiac events than cTnT. CONCLUSION: Serum H-FABP is a potential independent predictor of cardiac events within 6 months of patient admission and may provide prognostic information superior to cTnT in the early hours of ACS.
Asunto(s)
Proteínas Portadoras/sangre , Cardiopatías/diagnóstico , Miocardio/metabolismo , Troponina T/sangre , Enfermedad Aguda , Biomarcadores/sangre , Dolor en el Pecho/diagnóstico , Muerte , Proteínas de Unión a Ácidos Grasos , Estudios de Seguimiento , Cardiopatías/epidemiología , Hospitalización , Humanos , Persona de Mediana Edad , Análisis Multivariante , Infarto del Miocardio/diagnóstico , Infarto del Miocardio/epidemiología , Valor Predictivo de las Pruebas , Estudios Prospectivos , Riesgo , Factores de TiempoRESUMEN
Supporting roles of stromal cells in preferential colonization of myeloma cells in bone marrow and development of associated osteoclastic osteolysis through cell-cell interactions have been indicated. Here we examined the effects of a monoclonal antibody to alpha4 integrin (anti-alpha4 Ab) that disrupts myeloma cell-stromal cell interactions mediated via alpha4beta1 integrin and vascular cell adhesion molecule-1 (VCAM-1) on myeloma cell growth in bone marrow and accompanying osteolysis. The anti-alpha4 Ab decreased VCAM-1-stimulated 5TGM1/luc cell growth in culture. The 5TGM1 murine myeloma cells stably transfected with the firefly luciferase (5TGM1/luc) were inoculated from tail vein in bg/xid/nd mice. Preventative administration of the anti-alpha4 Ab suppressed the elevation of serum IgG2b levels, decreased 5TGM1/luc tumor burden with increased apoptosis in bone and spleen, reduced bone destruction with diminished number of osteoclasts, and prolonged survival of 5TGM1/luc-bearing mice. In contrast, therapeutic administration of the antibody failed to show these effects. However, therapeutic administration of the antibody combined with melphalan significantly suppressed serum IgG2b levels and tumor burden in bone. Our results suggest that the interactions with stromal cells via alpha4beta1/VCAM-1 are critical to the development of myeloma and associated osteolysis and that disruption of these interactions using anti-alpha4 Ab is a potential therapeutic approach for myeloma.
Asunto(s)
Anticuerpos/metabolismo , Integrina alfa4/inmunología , Mieloma Múltiple/inmunología , Osteoclastos/inmunología , Molécula 1 de Adhesión Celular Vascular/metabolismo , Animales , Anticuerpos/química , Anticuerpos Monoclonales/química , Apoptosis , Células de la Médula Ósea/metabolismo , Huesos/patología , Comunicación Celular , División Celular , Línea Celular Tumoral , Supervivencia Celular , Inmunoglobulina G/sangre , Inmunoglobulina G/química , Integrina alfa4/química , Integrina alfa4beta1/metabolismo , Luciferasas/metabolismo , Melfalán/farmacología , Ratones , Osteoclastos/metabolismo , Osteólisis , Proteínas Recombinantes/química , Bazo/metabolismo , Bazo/patología , Factores de TiempoRESUMEN
BACKGROUND: Recent studies have suggested that cardiac troponin T (cTnT) and troponin I may detect ongoing myocardial damage involved in the progression of chronic heart failure (CHF). This study was prospectively designed to examine whether the combination of cTnT, a marker for ongoing myocardial damage, and B-type natriuretic peptide (BNP), a marker for left ventricular overload, would effectively stratify patients with CHF after initiation of treatment. METHODS: We measured serum cTnT, plasma BNP, and left ventricular ejection fraction (LVEF) on admission for worsening CHF [New York Heart Association (NYHA) functional class III to IV] and 2 months after initiation of treatment to stabilize CHF (n = 100; mean age, 68 years). RESULTS: Mean (SD) concentrations of cTnT [0.023 (0.066) vs 0.063 (0.20) micro g/L] and BNP [249 (276) vs 753 (598) ng/L], percentage increased cTnT (>0.01 micro g/L; 35% vs 60%), NYHA functional class [2.5 (0.6) vs 3.5 (5)], and LVEF [43 (13)% vs 36 (12)%] were significantly (P <0.01) improved 2 months after treatment compared with admission. During a mean follow-up of 391 days, there were 44 cardiac events, including 12 cardiac deaths and 32 readmissions for worsening CHF. On a stepwise Cox regression analysis, increased cTnT and BNP were independent predictors of cardiac events (P <0.001). cTnT >0.01 micro g/L and/or BNP >160 ng/L 2 months after initiation of treatment were associated with increased cardiac mortality and morbidity rates. CONCLUSION: The combination of cTnT and BNP measurements after initiation of treatment may be highly effective for risk stratification in patients with CHF.
Asunto(s)
Insuficiencia Cardíaca/diagnóstico , Péptido Natriurético Encefálico/sangre , Troponina T/sangre , Anciano , Biomarcadores/sangre , Enfermedad Crónica , Femenino , Insuficiencia Cardíaca/tratamiento farmacológico , Insuficiencia Cardíaca/mortalidad , Humanos , Masculino , Readmisión del Paciente/estadística & datos numéricos , Valor Predictivo de las Pruebas , Estudios Prospectivos , Medición de Riesgo , Función Ventricular IzquierdaRESUMEN
We prospectively evaluated whether the combination of admission measurements of a marker for myocardial cell injury and a marker for left ventricular overload would effectively risk stratify patients with acutely decompensated heart failure. We measured serum concentrations of cardiac troponin T (cTnT) using a second-generation assay, as well as serum cardiac troponin I (cTnI) and plasma atrial and brain natriuretic peptide (BNP) concentrations on admission in 98 consecutive patients hospitalized for worsening chronic heart failure (mean age 69 years; 5 patients were in New York Heart Association functional class II, 35 were in class III, and 58 patients were in class IV). During a mean follow-up period of 451 days, there were 37 cardiac events, including 21 cardiac deaths (14 in-hospital deaths) and 16 readmissions for worsening heart failure. In a stepwise Cox regression analysis, including these biochemical markers, age, sex, functional class, and left ventricular ejection fraction, cTnT, and BNP were found to be significantly independent predictors of both cardiac death (p <0.05) and cardiac events (p <0.01). A cTnT >0.033 microg/L and/or a BNP >440 pg/ml on admission was correlated with an incremental increase in in-hospital cardiac mortality, overall cardiac mortality, and cardiac event rate. Kaplan-Meier analysis revealed that this combination could reliably stratify the patients into low-, intermediate-, and high-risk groups for cardiac events. Measuring the combination of admission concentrations of cTnT and BNP may be a highly effective means of risk stratification of patients hospitalized for worsening chronic heart failure.