Thermal conductivity and electrical resistivity : standard reference materials--tungsten SRM's 730 and 799, from 4 to 3000K /

Includes bibliographical references.

Catalog of standard reference materials issued by the National Bureau of Standards

Mode of access: Internet.

The American business and accounting encyclopaedia : a standard reference work for business men and accountants, profusely illustrated with many special forms, tables, and diagrams never before published /

Paged continuously.

Standard reference materials: Preparation of NBS white cast iron spectrochemical standards

Mode of access: Internet.

Tumor microenvironmental genomic alterations in juvenile nasopharyngeal angiofibroma

Background To better characterize the pathophysiology of juvenile nasopharyngeal angiofibroma (JNA), endothelial and stromal cells were evaluated by genomic imbalances in association with transcript expression levels of genes mapped on these altered regions. Methods. High-resolution comparative genomic hybridization (HR-CGH) was used in laser-captured endothelial and stromal cells from 9 JNAs. Ten genes were evaluated by quantitative real-timereverse transcription polymerase chain reaction (qRT-PCR) in 15 cases. Results. Although gains were more frequently detected in endothelial cells, 57% of chromosomal alterations were common by both components. Gene expression analyses revealed a positive correlation between endothelial and stromal components for ASPM, CDH1, CTNNB1, FGF18, and SUPT16H. A significant difference was found for FGF18 and AURKB overexpression in stromal cells and AR down-expression in endothelial cells. Conclusions. A similar pattern of gene expression and chromosomal imbalances in both exponents would suggest a common mechanism of functional regulation. AURKB, FGF18, and SUPT16H were identified as potential molecular markers in JNA. (C) 2011 Wiley Periodicals, Inc. Head Neck 34: 485-492, 2012

Columnar cell lesions of the breast: The missing link in breast cancer progression? A morphological and molecular analysis

Columnar cell lesions (CCLs) of the breast are a spectrum of lesions that have posed difficulties to pathologists for many years, prompting discussion concerning their biologic and clinical significance. We present a study of CCL in context with hyperplasia of usual type (HUT) and the more advanced lesions ductal carcinoma in situ (DCIS) and invasive ductal carcinoma. A total of 81 lesions from 18 patients were subjected to a comprehensive morphologic review based upon a modified version of Schnitt's classification system for CCL, immunophenotypic analysis (estrogen receptor [ER], progesterone receptor [PgR], Her2/neu, cytokeratin 5/6 [CK5/6], cytokeratin 14 [CK14], E-cadherin, p53) and for the first time, a whole genome molecular analysis by comparative genomic hybridization. Multiple CCLs from 3 patients were studied in particular detail, with topographic information and/or showing a morphologic spectrum of CCL within individual terminal duct lobular units. CCLs were ER an PgR positive, CK5/6 and CK14 negative, exhibit low numbers of genetic alterations and recurrent 16q loss, features that are similar to those of low grade in situ and invasive carcinoma. The molecular genetic profiles closely reflect the degree of proliferation and atypia in CCL, indicating some of these lesions represent both a morphologic and molecular continuum. In addition, overlapping chromosomal alterations between CCL and more advanced lesions within individual terminal duct lobular units suggest a commonality in molecular evolution. These data further support the hypothesis that CCLs are a nonobligate, intermediary step in the development of some forms of low grade in situ and invasive carcinoma. Copyright: © 2005 Lippincott Williams & Wilkins, Inc.

The molecular genetics of breast cancer: The contribution of comparative genomic hybridization

Comparative genomic hybridization (CGH) has been the technique of choice over the last 10 years for mapping DNA copy number changes in human tumors. Here we review the literature to demonstrate how CGH has contributed to the comprehension of molecular aspects of breast tumorigenesis. At least two distinct molecular pathways of breast cancer have been characterized that show a strong correlation with histological grade. It seems that grade I invasive ductal carcinomas (IDCs) arise from well-differentiated ductal carcinoma in situ (DCIS), whereas grade III IDCs come from poorly differentiated DCIS. In addition, dedifferentiation from a low- to a high-grade breast cancer has proven an unlikely phenomenon. CGH has been instrumental in dissecting distinct molecular pathways toward breast malignancy and in establishing a direct relationship between genotype and clinical pathological features. (C) 2005 Elsevier GrnbH. All rights reserved.

Reference distribution of the bioelectrical impedance vector in healthy term newborns

Bioelectrical impedance vector analysis (BIVA) is a new method that is used for the routine monitoring of the variation in body fluids and nutritional status with assumptions regarding body composition values. The aim of the present study was to determine bivariate tolerance intervals of the whole-body impedance vector and to describe phase angle (PA) values for healthy term newborns aged 7-28 d. This descriptive cross-sectional study was conducted on healthy term neonates born at a low-risk public maternity. General and anthropometric neonatal data and bioelectrical impedance data (800 mu A-50 kHz) were obtained. Bivariate vector analysis was conducted with the resistance-reactance (RXc) graph method. The BIVA software was used to construct the graphs. The study was conducted on 109 neonates (52.3% females) who were born at term, adequate for gestational age, exclusively breast-fed and aged 13 (SD 3.6) d. We constructed one standard, reference, RXc-score graph and RXc-tolerance ellipses (50, 75 and 95 %) that can be used with any analyser. Mean PA was 3.14 (SD 0.43)degrees (3.12 (SD 0.39)degrees for males and 3.17 (SD 0.48)degrees for females). Considering the overlapping of ellipses of males and females with the general distribution, a graph for newborns aged 7-28 d with the same reference tolerance ellipse was defined for boys and girls. The results differ from those reported in the literature probably, in part, due to the ethnic differences in body composition. BIVA and PA permit an assessment without the need to know body weight and the prediction error of conventional impedance formulas.

Normative reference of standing long jump for Colombian schoolchildren aged 9-17.9 years: The FUPRECOL study

El propósito del presente estudio era generar los valores normativos de salto largo para niños de 9-17.9 años, e investigar las diferencias de sexo y grupo de edad

Use of new biochemical plasmatic markers, plasma free and total metanephrines, for the diagnosis and follow-up of neuroblastoma in children with clinical correlation

Background: Neuroblastoma is a paediatrictumour derived from the neural crest. Biochemical diagnosis and follow up rely on quantitation of urinary catecholamines (dopamine and noradrenaline) and their metabolites vanillylmandelic acid (VMA) and homovanillic acid (HVA) (gold-standard). When combined, these analyses have a sensitivity of 95%. However, they are clearly limited by inaccuracy of urine collection in young children and normalisation of catecholamine concentrations by creatininuria. Recent development in biochemical diagnosis of pheochromocytoma, another neural crest tumour found in adults, shows that plasmatic measurement of methoxylated catecholamines called metanephrines are more sensitive and specific than other biomarkers. Moreover, a study to determine the reference intervals for metanephrines in a pediatric population has recently been completed. The aim of this work is to describe the role of metanephrines monitoring in the follow up of neuroblastoma. Method: This retrospective study included patients with neuroblastoma in whom the following parameters were determined: plasma free and total metanephrines, plasma catecholamines, 24h urinary catecholamines and metanephrines in absolute value and corrected by creatinine, VMA and HVA at the diagnosis and during treatment at the University Hospital of Lausanne (Switzerland). Eleven patients aged between the first day of life and 7 years old were followed between 2005 and 2012. Clinical outcome and biochemical concentrations of the analytes were correlated. Results: At diagnosis, plasma free and total normetanephrines and methoxytyramine have a sensitivity of 100% compared to 85% for the actual gold standard. Metanephrine remain below the upper reference limit as expected since these tumours do not produce adrenaline. The relationship between biochemical markers and clinical outcome is illustrated graphically. Plasma or urinary normetanephrine and methoxytyramine correlate better with the history of the patient than VMA and HVA, as evaluated by ordinal logistic regression. Concentrations of analytes in urine show a better correlation with clinical events when the results are corrected by creatininuria. Conclusion: Normetanephrine and methoxytyramine reflect disease history in neuroblastoma patients and could play a significant role in the follow up of this type of tumour. Formal studies in a sufficient number of patients are needed to confirm this preliminary observation.

Percentiles de grasa corporal por bioimpedancia eléctrica en niños y adolescentes de Bogotá, Colombia: Estudio FUPRECOL

Objetivo: Recientemente, se han propuesto varios dispositivos de impedancia bioeléctrica (BIA) para la estimación rápida de la grasa corporal. Sin embargo, no han sido publicadas referencias de grasa corporal para niños y adolescentes en población Colombiana. El objetivo de este estudio fue establecer percentiles de grasa corporal por BIA en niños y adolescentes de Bogotá, Colombia de entre 9 y 17.9 años, pertenecientes al estudio FUPRECOL. Métodos: Estudio descriptivo y transversal, realizado en 2.526 niños y 3.324 adolescentes de entre 9 y 17.9 años de edad, pertenecientes a instituciones educativas oficiales de Bogotá, Colombia. El porcentaje de grasa corporal fue medido con Tanita® Analizador de Composición Corporal (Modelo BF-689), según edad y sexo. Se tomaron medidas de peso, talla, circunferencia de cintura, circunferencia de cadera y estado de maduración sexual por auto-reporte. Se calcularon los percentiles (P3, P10, P25, P50, P75, P90 y P97) y curvas centiles por el método LMS según sexo y edad y se realizó una comparación entre los valores de la CC observados con estándares internacionales. Resultados: Se presentan valores de porcentaje de grasa corporal y las curvas de percentiles. En la mayoría de los grupos etáreos la grasa corporal de las chicas fue mayor a la de los chicos. Sujetos cuyo porcentaje de grasa corporal estaba por encima del percentil 90 de la distribución estándar normal se consideró que tenían un elevado riesgo cardiovascular (chicos desde 23,4-28,3 y chicas desde 31,0-34,1). En general, nuestros porcentajes de grasa corporal fueron inferiores a los valores de Turquía, Alemania, Grecia, España y Reino Unido. Conclusiones: Se presentan percentiles del porcentaje de grasa por BIA según edad y sexo que podrán ser usados de referencia en la evaluación del estado nutricional y en la predicción del riesgo cardiovascular desde edades tempranas.

Fast sequential multi-element determination of Ca, Mg, K, Cu, Fe, Mn and Zn for foliar diagnosis using high-resolution continuum source flame atomic absorption spectrometry: Feasibility of secondary lines, side pixel registration and least-squares background correction

The fast sequential multi-element determination of Ca, Mg, K, Cu, Fe, Mn and Zn in plant tissues by high-resolution continuum source flame atomic absorption spectrometry is proposed. For this, the main lines for Cu (324.754 nm), Fe (248.327 nm), Mn (279.482 nm) and Zn (213.857 nm) were selected, and the secondary lines for Ca (239.856 nm), Mg (202.582 nm) and K (404.414 nm) were evaluated. The side pixel registration approach was studied to reduce sensitivity and extend the linear working range for Mg by measuring at wings (202.576 nm; 202.577 nm; 202.578 nm; 202.580 nm: 202.585 nm; 202.586 nm: 202.587 nm; 202.588 nm) of the secondary line. The interference caused by NO bands on Zn at 213.857 nm was removed using the least-squares background correction. Using the main lines for Cu, Fe, Mn and Zn, secondary lines for Ca and K, and line wing at 202.588 nm for Mg, and 5 mL min(-1) sample flow-rate, calibration curves in the 0.1-0.5 mg L-1 Cu, 0.5-4.0 mg L-1 Fe, 0.5-4.0 mg L-1 Mn, 0.2-1.0 mg L-1 Zn, 10.0-100.0 mg L-1 Ca, 5.0-40.0 mg L-1 Mg and 50.0-250.0 mg L-1 K ranges were consistently obtained. Accuracy and precision were evaluated after analysis of five plant standard reference materials. Results were in agreement at a 95% confidence level (paired t-test) with certified values. The proposed method was applied to digests of sugar-cane leaves and results were close to those obtained by line-source flame atomic absorption spectrometry. Recoveries of Ca, Mg, K, Cu, Fe, Mn and Zn in the 89-103%, 84-107%, 87-103%, 85-105%, 92-106%, 91-114%, 96-114% intervals, respectively, were obtained. The limits of detection were 0.6 mg L-1 Ca, 0.4 mg L-1 Mg, 0.4 mg L-1 K, 7.7 mu g L-1 Cu, 7.7 mu g L-1 Fe, 1.5 mu g L-1 Mn and 5.9 mu g L-1 Zn. (C) 2009 Elsevier B.V. All rights reserved.

Determination of selenium in nutritionally relevant foods by graphite furnace atomic absorption spectrometry using arsenic as internal standard

A method has been developed for the direct determination of Se in nutritionally relevant foods by graphite furnace atomic absorption spectrometry. Tungsten/rhodium carbide coating on the integrated platform of a transversely heated graphite atomizer or W coating with co-injection of Pd(NO3)(2) were used as a permanent modifiers. Samples and reference solutions were spiked with 500 mu g L-1 As and absorbance variations due to changes in experimental conditions were minimized. For 20 mu L aqueous analytical solutions delivered into the graphite tube, analytical curves in the 5.0-40 mu g L-1 with good linear correlation were established. Pyrolysis and atomization temperatures were evaluated using pyrolysis and atomization curves, respectively. The optimized heating program (temperature, ramp time, hold time) of the graphite tube of the Perkin-Elmer SIMAA 6000 atomic absorption spectrometer was: dry steps (110 degrees C, 5 s, 10 s; 130 degrees C, 15 s, 15 s); air-assisted pyrolysis step (600 degrees C, 20 s, 40 s; 20 degrees C, 1 s, 40 s); pyrolysis step (1300 degrees C, 10 s, 20 s); atomization step (2100 degrees C, 0 s, 4 s); clean step (2550 degrees C, 1 s, 5 s). The method was applied for Se determination in coconut water, coconut milk, soybean milk, cow milk, tomato juice, mango juice, grape juice and drinking water samples and four standard reference materials and results were in agreement at 95% confidence level. The lifetime of the tube was 500 firings and the relative standard deviations of measurements of typical samples containing 25 mu gL(-1) Se were 3.0% and 6.0% (n = 12) with and without internal standardization, respectively. The limits of detection were in the 0.35 mu g L-1-0.7 mu g Se L-1 range. The accuracy of the proposed method was evaluated by an addition-recovery experiment and all recovered values were in the 98-109% range. (c) 2004 Elsevier Ltd. All rights reserved.

Leukocyte and thrombocyte reference values for channel catfish (Ictalurus punctatus Raf), with an assessment of morphologic, cytochemical, and ultrastructural features

Background: Hematology tests are useful to evaluate physiologic disturbances in fish and can provide important information for the diagnosis and prognosis of disease. Objectives: the primary purpose of this study was to define reference intervals for thrombocytes and leukocytes in healthy channel catfish (Ictalurus punctactus). In addition, the morphologic, cytochernical, and ultrastructural features of blood cells were assessed. Methods: Blood samples (0.5 mL were collected into EDTA from 40 clinically healthy catfish on a commercial fish farm in Jaboticabal, Brazil. Thrombocyte, total WBC, and differential WBC counts were determined and reference intervals were calculated as the 25-95th percentiles of data. Thrombocyte and leukocyte morphology was assessed in blood smears stained with May Griinwald-Giemsa-Wright and ultrastructurally by transmission electron microscopy. Cytochemical staining patterns were described using periodic acid-Schiff (PAS), peroxidase, nonspecific esterase, alkaline phosphatase, and toluidine blue. Results: Reference intervals were as follows: thrombocytes 58,802-99,569/mu L; total WBCs 27,460-41,523/mu L; lymphocytes 5380-11,581/mu L; monocytes 2949-7459/mu L; neutrophils 12,529-22,748/mu L, and basophils 736-2003/mu L. Neutrophils were positive for peroxidase and PAS; monocytes were positive for nonspecific esterase; and basophils were positive with toluidine blue. Conclusion: the morphologic and staining features of neutrophils and monocytes of channel catfish are similar to those of mammals, and the presence of basophils in this species was verified. These reference intervals and morphologic findings provide a foundation for future investigations on the functions and alterations of blood cells in channel catfish.