The Time-resolved and Extreme-conditions XAS (TEXAS) facility at the European Synchrotron Radiation Facility: the energy-dispersive X-ray absorption spectroscopy beamline ID24.

The European Synchrotron Radiation Facility has recently made available to the user community a facility totally dedicated to Time-resolved and Extreme-conditions X-ray Absorption Spectroscopy--TEXAS. Based on an upgrade of the former energy-dispersive XAS beamline ID24, it provides a unique experimental tool combining unprecedented brilliance (up to 10(14) photons s(-1) on a 4 µm × 4 µm FWHM spot) and detection speed for a full EXAFS spectrum (100 ps per spectrum). The science mission includes studies of processes down to the nanosecond timescale, and investigations of matter at extreme pressure (500 GPa), temperature (10000 K) and magnetic field (30 T). The core activities of the beamline are centered on new experiments dedicated to the investigation of extreme states of matter that can be maintained only for very short periods of time. Here the infrastructure, optical scheme, detection systems and sample environments used to enable the mission-critical performance are described, and examples of first results on the investigation of the electronic and local structure in melts at pressure and temperature conditions relevant to the Earth's interior and in laser-shocked matter are given.

The time-resolved and extreme conditions XAS (TEXAS) facility at the European Synchrotron Radiation Facility: the general-purpose EXAFS bending-magnet beamline BM23.

BM23 is the general-purpose EXAFS bending-magnet beamline at the ESRF, replacing the former BM29 beamline in the framework of the ESRF upgrade. Its mission is to serve the whole XAS user community by providing access to a basic service in addition to the many specialized instruments available at the ESRF. BM23 offers high signal-to-noise ratio EXAFS in a large energy range (5-75 keV), continuous energy scanning for quick-EXAFS on the second timescale and a micro-XAS station delivering a spot size of 4 µm × 4 µm FWHM. It is a user-friendly facility featuring a high degree of automation, online EXAFS data reduction and a flexible sample environment.

Synchrotron radiation Mössbauer spectra of a rotating absorber with implications for testing velocity and acceleration time dilation.

Many Mössbauer spectroscopy (MS) experiments have used a rotating absorber in order to measure the second-order transverse Doppler (TD) shift, and to test the validity of the Einstein time dilation theory. From these experiments, one may also test the clock hypothesis (CH) and the time dilation caused by acceleration. In such experiments the absorption curves must be obtained, since it cannot be assumed that there is no broadening of the curve during the rotation. For technical reasons, it is very complicated to keep the balance of a fast rotating disk if there are moving parts on it. Thus, the Mössbauer source on a transducer should be outside the disk. Friedman and Nowik have already predicted that the X-ray beam finite size dramatically affects the MS absorption line and causes its broadening. We provide here explicit formulas to evaluate this broadening for a synchrotron Mössbauer source (SMS) beam. The broadening is linearly proportional to the rotation frequency and to the SMS beam width at the rotation axis. In addition, it is shown that the TD shift and the MS line broadening are affected by an additional factor assigned as the alignment shift which is proportional to the frequency of rotation and to the distance between the X-ray beam center and the rotation axis. This new shift helps to align the disk's axis of rotation to the X-ray beam's center. To minimize the broadening, one must focus the X-ray on the axis of the rotating disk and/or to add a slit positioned at the center, to block the rays distant from the rotation axis of the disk. Our experiment, using the (57)Fe SMS, currently available at the Nuclear Resonance beamline (ID18) at the ESRF, with a rotating stainless steel foil, confirmed our predictions. With a slit installed at the rotation axis (reducing the effective beam width from 15.6 µm to 5.4 µm), one can measure a statistically meaningful absorption spectrum up to 300 Hz, while, without a slit, such spectra could be obtained up to 100 Hz only. Thus, both the broadening and the alignment shift are very significant and must be taken into consideration in any rotating absorber experiment. Here a method is offered to measure accurately the TD shift and to test the CH.

Body-centered cubic iron-nickel alloy in Earth's core.

Cosmochemical, geochemical, and geophysical studies provide evidence that Earth's core contains iron with substantial (5 to 15%) amounts of nickel. The iron-nickel alloy Fe(0.9)Ni(0.1) has been studied in situ by means of angle-dispersive x-ray diffraction in internally heated diamond anvil cells (DACs), and its resistance has been measured as a function of pressure and temperature. At pressures above 225 gigapascals and temperatures over 3400 kelvin, Fe(0.9)Ni(0.1) adopts a body-centered cubic structure. Our experimental and theoretical results not only support the interpretation of shockwave data on pure iron as showing a solid-solid phase transition above about 200 gigapascals, but also suggest that iron alloys with geochemically reasonable compositions (that is, with substantial nickel, sulfur, or silicon content) adopt the bcc structure in Earth's inner core.

Beating the miscibility barrier between iron group elements and magnesium by high-pressure alloying.

Iron and magnesium are almost immiscible at ambient pressure. The low solubility of Mg in Fe is due to a very large size mismatch between the alloy components. However, the compressibility of Mg is much higher than that of Fe, and therefore the difference in atomic sizes between elements decreases dramatically with pressure. Based on the predictions of ab initio calculations, we demonstrate in a series of experiments in a multianvil apparatus and in electrically and laser-heated diamond anvil cells that high pressure promotes solubility of magnesium in iron. At the megabar pressure range, more than 10 at. % of Mg can dissolve in Fe and then the alloy can be quenched to ambient conditions. A generality of the concept of high-pressure alloying between immiscible elements is demonstrated by its application to two other Fe group elements, Co and Ni.

p53 mutations in basal cell carcinomas arising in routine users of sunscreens.

Sun exposure histories were obtained from a series of patients age 35 or younger following diagnosis and removal of a basal cell carcinoma (BCC). The DNA was extracted from tumor biopsy samples derived from BCC of 10 patients who reported that they did not use sunscreens during youth (age 18 or younger) and 10 patients who routinely employed sunscreens during this age period. Exons 5-9 of the p53 gene were then amplified in three fragments from these samples using a nested polymerase chain reaction (PCR) approach and screened for mutations using an RNA heteroduplex assay. All PCR products displaying evidence of a mutation were sequenced. It was found that 6 of the 10 patients who were not routine sunscreen users displayed mutations in these p53 exons. All of the mutations were located at dipyrimidine sites, five of the six were C-->T transitions and one mutation was a tandem double mutation, consistent with a role for solar UVB in BCC formation. In contrast, only one p53 mutation was detected in the group of 10 patients who routinely employed sunscreens during childhood and adolescence. Hence, a significantly (P = 0.029) lower level of p53 mutations was detected in the BCC obtained from sunscreen users compared with tumors derived from nonusers. These findings suggest that the mechanisms involved in the etiology of skin carcinogenesis differ in sunscreen users compared with people who did not routinely employ sunscreens. These data are also indicative of a protective effect associated with sunscreen use against the formation of p53 mutations. It is possible that the patients who were diagnosed with BCC despite their use of sunscreens possessed a genetic susceptibility for skin cancer formation and developed BCC through a p53-independent pathway. Alternatively, solar UVA wavelengths, that were generally not blocked by the suncare products employed by the sunscreen users, may have played a significant role in BCC development through induction of a mutation(s) in an oncogene and/or a tumor suppressor gene, other than p53, for these patients.

[Non-Hodgkin's lymphoma: diagnostic problems]. / Chloniak z limfocytów t obwodowych--problemy diagnostyczne.

The aim of this article was to describe rarely occurred non-Hodgkin's lymphomas from peripheral lymphocyte T. Epidemiology, course of the disease and difficulties of diagnostic was described with the special regards of early diagnostic.

[Microsurgery of larynx in own material at the Otolaryngological Clinic of the Central Clinical Hospital at the Military School of Medicine]. / Mikrochirurgia krtani w materiale Kliniki Otolaryngologicznej Centralnego Szpitala Klinicznego WAM.

In paper authors presented own material of performed in the years 1991-1996 in Clinic of Otolaryngology Central Clinical Hospital Military School of Medicine microsurgical operations of larynx (classic and laser). The authors postulate that indications for clinical diagnostic and therapeutic procedures should be considerably extended in diseases of larynx. This operating technique considerably shorten hospitalization period of patients and significantly contribute to an increase of percentage of early diagnoses of cancer of the larynx.

[Endoscopic surgery of the sinus: own experiences]. / Chirurgia endoskopowa nosa i zatok przynosowych--doswiadczenia wlasne.

In the Clinic of Otolaryngology Central Clinical Hospital Military School of Medicine in Warsaw in years 1992-1996 there were performed 187 endoscopic operations of nose and paranasal sinuses. Authors analised own material paying particular attention to indications, benefits and failures of these operations. Authors postulate that indications for clinical diagnostic and therapeutic procedures of this technique should be considerably extended in diseases of nose and paranasal sinuses. The application of endoscopic sinus surgery in our Clinic decreased the number of more extended operations of paranasal sinuses.

[Humoral response to mycobacteria in patients with Crohn disease]. / Respuesta humoral a micobacterias en pacientes con enfermedad de Crohn.

The recent recovery of Mycobacterium paratuberculosis from tissues of patients with Crohn's disease has highlighted the possible etiologic role of this microorganism in the disease. However, the immunological evidence generated by various groups supporting this hypothesis is as yet inconclusive. A specific antibody response might be masked in these patients by the wide antigenic homologies prevailing within the genus Mycobacterium. The present study was undertaken with the purpose of exploring the humoral response to M. paratuberculosis in patients with Crohn's disease, by means of a cross-absorption procedure recently proposed for unveiling the presence of specific antibodies in bovine paratuberculosis. Antibodies IgG to M. paratuberculosis were investigated by enzyme-linked immunosorbent assay in 90 serum samples from 17 patients with Crohn's disease, 23 patients with ulcerative colitis an 14 with other bowel diseases. Samples from 86 subjects without bowel disease (healthy individuals and patients with tuberculosis, mycobacterioses and fungal diseases) were also included as controls. The specificity of these antibodies was explored by the absorption of sera with an ubiquitous Mycobacterium (M. phlei). The results were compared to those obtained by similar ELISA tests employing M. avium or M. tuberculosis as antigens. A faint humoral response to M. paratuberculosis and M. tuberculosis was detected in patients with Crohn's disease. Cross-absorption with M. phlei did not disclose a specific response nor was an increase in antibody levels detected in patients studied periodically. Sera from patients with ulcerative colitis and other bowel diseases also showed a slight reaction to mycobacteria.(ABSTRACT TRUNCATED AT 250 WORDS)

Preliminary evaluation of a simple method for detection of bovine tuberculosis: the glutaraldehyde test.

The glutaraldehyde test (GT) is performed by mixing whole blood with a 1.25% glutaraldehyde solution. Gelification time is shorter in tuberculous cattle. This test was performed in blood samples obtained from: (a) 48 cattle with bacteriologically confirmed tuberculous lesions; (b) 61 animals with no evidence of tuberculosis at the time of slaughterhouse inspection, 14 of which had hydatid cysts; (c) 260 tuberculin-negative apparently healthy animals, and (d) 21 cattle, also tuberculin-negative but serologically positive for brucellosis. Sensitivity for detecting tuberculosis was 85.4% (41 of 48 animals). The test was negative in 298 out of 307 healthy animals (97.1% specificity). This specificity decreased when the test was applied in animals with evidence of diseases other than tuberculosis. This simple, rapid and inexpensive method could play a complementary role to the tuberculin test for detecting tuberculous cattle, especially in endemic areas with scarce resources and facilities.

The administration of foot and mouth disease vaccine with oil adjuvant and its influence on the diagnosis of bovine tuberculosis.

The possible influence of vaccination with oil adjuvanted foot and mouth disease vaccines on the tuberculin response was investigated in 32 normal guinea pigs and 190 non-tuberculous bovines. Circulating anti-Mycobacterium bovis IgG antibodies were analysed by an enzyme-linked immunosorbent assay (ELISA), in order to determine the effect of the vaccination on the humoral response against mycobacteria in cattle. Control animals were either nonvaccinated or injected with aluminium hydroxide adjuvanted vaccine. Administration of foot and mouth disease vaccine had no apparent influence on the tuberculin responses of either guinea pigs or cattle, nor did it influence the level of anti-M. bovis antibodies in cattle.

[Usefulness of the enzyme immunoassay in the diagnosis of tuberculosis]. / Utilidad del enzimoinmunoensayo en el diagnóstico de la tuberculosis.

To assess the usefulness of enzyme immunoassay as a rapid method of diagnosing tuberculosis, a study was conducted of 687 serum samples from 271 children and 416 adults. With 55 sera from nontuberculous children as controls, the specificity was 0.98, and with 137 controls from the adult population, 0.93. Prior vaccination with BCG did not influence the level of detectable anti-PPD antibody. The results were similar in healthy PPD-positive and negative adults. The test differentiated mycoses and nontuberculous mycobacterioses from tuberculosis. The sensitivity rates in 49 children and 200 adults diagnosed with bacteriologically confirmed pulmonary and extrapulmonary tuberculosis were calculated at 0.51 and 0.69, respectively. In those tuberculosis cases not bacteriologically confirmed or at other sites, the test was positive in 28.1% of 114 children and in 48.6% of 35 adults. The cost, speed, and availability of reagents for this test were comparable to those for direct microscopic examination. Both methods were positive for 49% of the tuberculosis cases confirmed by culture, and a total of 84% of those cases were found positive using one method or the other. It is concluded that enzyme immunoassay can be especially useful in the rapid diagnosis of nonbacilliferous pulmonary, extrapulmonary, and childhood tuberculosis.

Evaluación de cuatro antígenos para la detección de anticuerpos anti-Mycobacterium bovis por enzimoinmunoensayo / Evaluation of four antigens for the detection of anti-mycobacterium bovis antibodies by enzime-linked immunosonhet assay

Cuatro tuberculinas PPD bovinas fueron evaluadas como antígenos en un enzimoinmunoensayo (EIE) para el diagnóstico de tuberculosis bovina, anteriormente desarrollado por nosotros. Tres de estos PPD estaban preparados con M. bovis cepa AN 5: (a) CEPANZO (CPZ), (b): Estándar de la Comunidad Económica Europea (CEE) y (c) un PPD producido a partir de cultivos no autoclavados, inactivados por fenol (F). El cuarto PPD fue preparado con M. bovis BCG en el Instituto Pasteur, Paris (IP). Estos 4 antígenos se probaron en EIE frente a sueros de 22 bovinos sanos de área de tuberculosis y a otros 22 con tuberculosis bacteriológicamente confirmada. Los resultados expresados en valores medio de densidad óptica (DO) frente a sueros de animales sanos fueron: (a) con CPZ como antígeno: 45 ñ 22, (b) con CEE: 24 ñ 10, (c) con F: 103 ñ 56 y (d) con IP, 56 ñ 20; y frente a sueros de animales tuberculosos: (a) 588 ñ 158, (b): 510 ñ 234, (c): 782 ñ 138, y (d) 441 ñ 189. Los resultados obtenidos con CEE y con F guardan estrecha correlación con los de CPZ (r: 0,97 y 0,94 respectivamente), mientras que IP demostró una menor especificidad, por lo que también fue menor su correlación con los resultados obtenindos con CPZ (r` 0.87). Se concluye que empleando como antígeno tnto CPZ, CEE como F, el EIE alcanza especificidad y sensibilidad similares mientras que IP resulta inadecuado para esta prueba

Micobacteriosis: un caso en un piscicultor / Mycobacteriosis: a case in a psiciculturist

Se presenta un caso de micobacteriosis detectado en el Laboratorio Central de Salud Pública de la Provincia del Chaco (República Argentina), a partir de muestras de úlcera en el dedo de un piscicultor y muestras de agua de las distintas peceras de este paciente, cuyas cepas correspondieron al Mycobacterium scrofulaceum. M. fortuitum y M. chelonei

Especificidad de algunas sensitinas micobacterianas. / Standardization of some mycobacterial sensitins

El objeto de este proyecto fue obtener una provision de sensitinas micobacterianas puras y estandarizadas, que podrian emplearse en el futuro en la Republica Argentina en estudios experimentales o epidemiologicos. Se prepararan 17 lotes de sensitinas (derivados proteinicos purificados) a partir de 17 cepas de referencia de las siguientes especies o grupos micobacterianos: (a) Complejo M-avium-intracellulare-scrofulaceum (MAIS) serotipos 1, 4 6, 7, 10, 11, 15, 16, 17, 20, 41 y M avium cepa D4; (b) Especies de crecimiento rapido M. fortuitum y M. chelonei; (c) Especies fotocromogenas M. kansasii y M. marinum. La especificidad de estos preparados se determino por pruebas intradermicas comparativas hechas a grupos de cobayos previamente sensibilizados con las cepas originales. Seis de los 10 antigenos preparados del complejo MAIS, y las 3 sensitinas de M. fortuitum, M. chelonei y M.kansasii mostraron un grado aceptable de especificidad. Por lo tanto, estos preparados podrian resultar de utilidad en estudios sobre la sensibilizacion natural por esas especies de micobacterias en poblaciones humanas y en ganado bovino de la Republica Argentina

Enfermedad producida por micobacterias no tuberculosas en Buenos Aires, Argentina / Diseases caused by nontuberculous mycobacteria in Buenos Aires, Argentina

Se presentan los resultados de un estudio sobre la prevalencia de micobacterias no tuberculosas realizado en 4 894 pacientes de los cuales se extrajeron 8 006 cultivos estudiados durante cuatro anos (19771980)