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Glass disk fusion method for the X-ray fluorescence analysis of rocks and silicates
(Wiley Analytical Science, 1990-08)A study of the physical and practical aspects needed for a successful solid solution method for XRF analysis is presented in the light of the theory and practice of the glass-making industry. An inexpensive manual glass ... -
Estimating impacts on developing countries of the decrease in U.S. training opportunities for foreign medical graduates.
(Academic Medicine, 1991)Between 1973 and 1983, the number of foreign nationals from developing nations who entered the United States for graduate medical education decreased by approximately 90%. Many of those who would have studied in the United ... -
Mineralogical analysis with the firing temperature of limestone and clay mixture from Dominican Republic using Mössbauer spectroscopy and X-ray powder diffractometry
(Springer Link, 1991)The study of a limestone and clay mixture using Mössbauer spectroscopy, and X-ray powder spectrometry (XRD) for different firing temperatures are presented. This type of mixture is used in raw minerals in order to obtain ... -
Determination of trace elements in organic specimens by energy-dispersive x-ray fluorescence using a fundamental parameters method
(Wiley Analytical Science, 1991)A rapid method for the simultaneous determination of trace elements in milk powder by energy-dispersive x-ray fluorescence has been developed. The measurement system consists of an Si(Li) detector, an x-ray tube coupled ... -
Performance of the parallel plate avalanche counter (PPAC) for improving the depth profile of conversion electron Mössbauer spectroscopy (CEMS)
(Journal of Radioanalytical and Nuclear Chemistry, 1991)The parallel plate avalanche counter (PPAC) built in our laboratory was used to measure the CEM spectra of iron electrodeposited over a steel substrate. The electron counter was operated with ketone gas inside the ionization ... -
Cognitive abilities in androgen-insensitive subjects: comparison with control males and females from the same kindred
(PUBLMed, 1991-05)To determine the effect of androgen insensitivity on cognitive abilities, subjects with the syndrome of complete androgen insensitivity (AI) were compared to control males and females from the same kindred on the Spanish ... -
A compton peak method for incident angle determination in XRF with annular excitation
(X-Ray Spectrometry, 1992)Established methods for measuring the incident angle related to XRF when radioisotope annular sources are involved are briefly discussed. As an alternative technique, a direct measurement of the incident angle from the ... -
Prevalence of HTLV infection in the Dominican Republic: association with neurological disease
(PulbMed, 1992-02)The presence of the human T-cell leukemia virus (HTLV) in Dominican blood donors and patients with tropical spastic paraparesis (TSP) was first detected in 1987. To define further the seroprevalence in the country, nearly ... -
X-ray fluorescence characterization of ming-dynasty porcelain rescued from a spanish shipwreck
(wiley, 1992-02)A radioisotope induced X-ray fluorescence method was used to measure trace elements in Ming porcelain. Thirty pieces of blue-and-white Chinese porcelain, belonging to the Ch'eng Hua reign (AD 1465-87) and rescued from a ... -
Prostate visualization studies in males homozygous and heterozygous for 5 alpha-reductase deficiency
(The Journal of Clinical Endocrinology & Metabolism, 1992-10-01)Male pseudohermaphrodites with 5 alpha-reductase deficiency have ambiguous genitalia and nonpalpable prostates on rectal examination, suggesting the dihydrotestosterone dependency of these structures. To clearly delineate ... -
Luteinizing hormone pulsatility in subjects with 5-alpha-reductase deficiency and decreased dihydrotestosterone production
(PulbMed, 1994-04)The pattern of LH pulsatility in male pseudohermaphrodites with inherited 5 alpha-reductase-2 deficiency (5 alpha RD) and decreased levels of plasma dihydrotestosterone was compared to that in normal males. Analysis of ... -
Mössbauer and X-ray fluorescence study of sediments from Samana Bay, Dominican Republic
(Journal of Radioanalytical and Nuclear Chemistry, 1995-08)The chemical state of iron in sediments collected from Samana Bay has been determined by Mössbauer spectroscopy. The Mössbauer spectra were composed of two paramagnetic doulets, which correspond to high=spin ferric and ... -
Acanthamoeba keratitis. Contact lens and noncontact lens characteristics
(Ophthalmology ., 1995-09)To identify potential differences in time to diagnosis and final visual outcome between contact lens and noncontact lens users with Acanthamoeba keratitis. Prior studies have shown early diagnosis and therapy to be related ... -
The biochemical and phenotypic characterization of females homozygous for 5 alpha-reductase-2 deficiency
(The Journal of Clinical Endocrinology & Metabolism,, 1995-11)The biochemical and physiologic manifestations of decreased 5 alpha-dihydrotestosterone (DHT) in females are characterized. Three females from the large Dominican kindred with 5 alpha-reductase-2 deficiency were identified ... -
5α-Reductase-2 gene mutations in the Dominican Republic .
(Journal of Clinical Endocrinology and Metabolism, 1996)Male pseudohermaphroditism due to 5α-reductase deficiency was clinically and biochemically described in a large Dominican kindred of 23 families with 38 affected subjects in 1974. Recently, the 5α-reductase-2 gene defect ... -
4-Hydroxyphenylpropan-7,8-diols and derivatives from Narvalina domingensis
(Phytochemistry, 1996)Investigation of a Haitian medicinal plant, Narvalina domingensis, afforded, erythro- and threo-4-hydroxyphenylpropan-7,8-diol and their 7-O- methyl ether, 7-O-ethyl ethers and 4-O-isovaleric acid esters. The structures ... -
Adaptive digital access protocol: a MAC protocol for multiservice broadband access networks
(IEEE Communications Magazine, 1996-03)The authors describe a protocol that can adapt to the changing demands of a mix of synchronous transfer mode (STM) and asynchronous transfer mode (ATM) applications and efficiently allocate bandwidth to a variety of bursty ... -
Trace element determination of mercury by total-reflection X-ray fluorescence
(Spectrochimica Acta Part B: Atomic Spectroscopy, 1997-07-01)A rapid and simple method is presented for the determination of trace amounts of ionic mercury in solutions by total-reflection X-ray fluorescence. The method relies on the formation of a mercury amalgam on a 50 nm thick ... -
A novel mutation of the human luteinizing hormone receptor in 46XY and 46XX sisters.
(Journal of Clinical Endocrinology and Metabolism, 1998)We repor t a novel homozygous mutation of the LH receptor (LHR) gene in three siblings: two 46XY and one 46XX. The 46XY siblings presented with female external genitalia, primary amenorrhea, and lack of breast development. ... -
Levels of chlorinated hydrocarbons and trace metals in bivalves and nearshore sediments from the Dominican Republic
(Marine Pollution Bulletin, 1998-12)Bivalves (Crassostrea rizhophorae, Isognomon alatus, Codakia orbicularis Linné, and Tellina fausta) and sediment samples collected from 12 locations along the Dominican Republic coastline were used to assess the degree of ...