K-edge imaging with the XPAD3 hybrid pixel detector, direct comparison of CdTe and Si sensors.

We investigate the improvement from the use of high-Z CdTe sensors for pre-clinical K-edge imaging with the hybrid pixel detectors XPAD3. We compare XPAD3 chips bump bonded to Si or CdTe sensors in identical experimental conditions. Image performance for narrow energy bin acquisitions and contrast-to-noise ratios of K-edge images are presented and compared. CdTe sensors achieve signal-to-noise ratios at least three times higher than Si sensors within narrow energy bins, thanks to their much higher detection efficiency. Nevertheless Si sensors provide better contrast-to-noise ratios in K-edge imaging when working at equivalent counting statistics, due to their better estimation of the attenuation coefficient of the contrast agent. Results are compared to simulated data in the case of the XPAD3/Si detector. Good agreement is observed when including charge sharing between pixels, which have a strong impact on contrast-to-noise ratios in K-edge images.

Uranium removal from water using cellulose triacetate membranes added with activated carbon.

Ultrafiltration removal of uranium from water, with composite activated carbon cellulose triacetate membranes (AC-CTA), was investigated. The filtrate was provided by uraninite dissolution with pH=6-8. Removal efficiencies were calculated measuring solutions' radioactivities. Membranes were mainly characterized by microscopy analysis, revealing iron after permeation. Uranyl removal was 35±7%. Chemical speciation indicates the presence of (UO(2))(2)CO(3)(OH)(3)(-), UO(2)CO(3), UO(2)(CO(3))(2)(2-) and Fe(2)O(3)(s) as main compounds in the dissolution, suggesting co-adsorption of uranium and iron by the AC during filtration, as the leading rejection path.

In situ study of the metal-insulator transition in VO2 by EELS and ab initio calculations.

Changes in the dielectric properties during the thermochromic transition of commercial VO(2) powders were determined in situ, by analyzing the low-loss region of the electron energy-loss spectroscopy (EELS) spectra in a transmission electron microscope at room temperature (insulator phase) and 100 degrees C (metallic phase). A comparison of experimental EELS spectra and ab initio density-functional theory calculations (WIEN2k code) within the generalized gradient approximation (GGA) is presented. A characteristic peak around 5.6 eV appears in the energy-loss function in metallic phase, which is absent in insulator phase. The origin of the characteristic peak is analyzed by means of energy-band structure calculations.

Navigation system for visual impaired persons based on satellital location.

A system designed to assist visual impaired persons to travel in a city without external help using GPS navigation system has been developed. With the use of a BIuetooth hands-free, the user only has to give spoken commands to receive spoken directions to get to his/her destination. The directions received from the system will help him/her to walk parallel to the tangent of the walk-side and to walk through the most convenient route. This means that the route calculated to arrive to the destination point not only will be the shortest, but also the least risky one. The system can also be personalized by the user, entering his/her own waypoints.

Galphimia glauca organic fraction antagonizes LTD(4)-induced contraction in guinea pig airways.

Galphimia glauca is used for the treatment of asthma and allergies in Latin American traditional medicine. The ethylacetate fraction from its aerial parts was assayed for bronchoconstriction induced by antigen and several agonists in guinea pig tracheae. The organic fraction significantly inhibited the contractile response to ovalbumin in tracheae from sensitized guinea pigs, and significantly and selectively inhibited the bronchoconstriction induced by leukotriene D(4) (LTD(4)). The relative potency of the ethylacetate fraction of G. glauca to produce a concentration-dependent rightward shift of LTD(4) concentration-response curve was similar to that reported for SK&F 104353, a well-known competitive LTD(4)-antagonist.

Xanthorrhizol induces endothelium-independent relaxation of rat thoracic aorta.

Xanthorrhizol, a bisabolene isolated from the medicinal plant Iostephane heterophylla, was assayed on rat thoracic aorta rings to elucidate its effect and likely mechanism of action, by measuring changes of isometric tension. Xanthorrhizol (1, 3, 10, 30 and 100 microg/mL) significantly inhibited precontractions induced by KCI-; (60mM), noradrenaline (10(-6) M) or CaCl2 (1.0 mM). Increasing concentrations of external calcium antagonized the inhibitory effect on KCl-induced contractions. The vasorelaxing effect of xanthorrhizol was not affected by indomethacin (10 microM) or L-NAME (100 microM) in intact rat thoracic aorta rings precontracted by noradrenaline, which suggested that the effect was not mediated through either endothelium-derived prostacyclin (PGI2) or nitric oxide release from endothelial cells. Endothelium removal did not affect the relaxation induced by xanthorrhizol on rat thoracic aorta rings, discarding the participation of any substance released by the endothelium. Xanthorrhizol inhibitory effect was greater on KCI- and CaCl2-induced contractions than on those induced by noradrenaline. Xanthorrhizol inhibitory effect in rat thoracic aorta is likely explained for interference with calcium availability by inhibiting calcium influx through both voltage- and receptor-operated channels.

Seizures induced by penicillin microinjections in the mesencephalic tegmentum.

The location and extension of a convulsive area in the brain stem in cats was determined through penicillin microinjections (0.5-1.0 microl) of a concentrated sodium penicillin solution (500 IU/microl), stereotactically oriented to multiple structures, in fully awake animals, partially restrained through a rod fixation system that avoided pain, allowed the observation of clinical seizures and simultaneous recording of EEG, EMG and multiple unit activity (MUA) from the injected site and the motor cortex (Cx). Clinical and EEG seizure patterns in relation to the injected sites and penicillin doses were studied in another group of animals using doses from 12.5 IU/0.1 microl to 125 IU/1.0 microl. The time relationship between muscular clonus, EEG spikes and MUA at the injected site and Cx were analyzed. The only area in which penicillin induced seizures was the mesencephalic tegmentum (MT). The amount of penicillin but not the stereotactic coordinates determined the seizure type. MT EEG and MUA paroxysms anticipated clinical seizure and Cx EEG spikes. When Cx EEG appeared, they were accompanied by an increase in MUA beginning in the Cx and EMG, followed by significant increase in MT MUA. The sequence of events suggest that MT seizure activity propagates via alternative pathways not involving direct reticulospinal or pyramidal tract pathways.

Evaluación in vitro de la actividad antibacteriana de plantas medicinales utilizadas por la etnia tacana / Evaluation in vitro of the activity antibacteriana of medicinal plants utilized by ethnical group Tacana

En el presente estudio se trabajó con muestras de plantas medicinales pertenecientes a la Etnia Tacana, Provincia Abel Iturralde del Departamento de La Paz. Los extractos crudos de estas plantas fueron evaluadas por su Actividad antibacteriana "in vitro", contra bacterias causales de infecciones como: Staphylococcus aureus y Shigella flexneri. El resultado de los tamizajes preliminares de la prueba antibacteriana por el método de difusión, indica que del total de 147 plantas probadas a 1 mg, fueron positivos 78.2 por ciento de los extractos orgánicos crudos, y el 14.9 por ciento de los extractos acuosos. Las plantas que tuvieron actividad en el primer tamizaje contra Staphylococcus aureus y Shigella flexneri, se evaluaron en una segunda prueba, se escogieron 5 extractos orgánicos para la separación química por exclusión molecular, de los cuales se eligió el extracto de Tapirira guianensis (Anacardiaceae). Mediante un seguimiento biodirigido se aisló y purificó el principio activo de la Tapirira guianensis, determinándose la concentración Mínima Inhibitoria y Concentración Mínima Bactericida que fue 625 ug/ml contra Staphylococcus aureus y se realizaron estudios espectroscopicos de RMN

A blood micro-culture system for the diagnosis of bacteremia in pediatric patients.

The aim of this study was to evaluate the utility of a volume-modified blood culture system to diagnose bacteremia in newborns and infants. A total of 793 paired blood cultures, obtained from 464 patients (173 newborns and 291 infants), were analyzed. Vacutainer tubes containing 18 ml supplemented peptone broth sodium-polyanethol-sulfonate were used as the gold standard, in comparison with a blood micro-culture system containing 1.8 ml of the broth. Prior to antibiotic treatment, 2.2 ml of blood was obtained from each patient; 0.2 ml was inoculated in a blood micro-culture tube and 2 ml in a routine tube. Sensitivity, specificity and predictive values were calculated. Microorganisms were isolated in 153 standard blood culture tubes and 151 blood micro-culture tubes. The sensitivity of the blood micro-culture system was 95%, specificity 99% and positive and negative predictive values 96% and 99% respectively. The sensitivity and specificity of blood micro-culture in neonates and infants is high. We recommend that this system be used for the diagnosis of bacteremia in newborns and infants in laboratories where manual systems are still in use.

The benefits of psychiatric hospitalization for older nursing home residents.

OBJECTIVE: To examine the demographic characteristics and treatment outcomes of nursing home residents admitted to a geropsychiatric inpatient unit. DESIGN: A retrospective cohort design based on an ongoing data base effort. SETTING: The geropsychiatric inpatient unit of the Houston Veterans Affairs Medical Center Hospital. PARTICIPANTS: All admissions to the unit from nursing homes during an 18-month period. MEASUREMENTS: Mini-Mental State Examination, Brief Psychiatric Rating Scale, Hamilton Rating Scale for Depression, Cohen-Mansfield Agitation Inventory, Rating Scale for Side Effects, and Global Assessment of Functioning were administered on admission and discharge. RESULTS: Paired t tests comparing change scores revealed significant decreases in general psychiatric symptoms (P < .001), depression (P < .001), and agitation (P < .001); significant improvement in global functioning (P < .001); with no significant changes in cognitive status (P = .485) or side effects (P = .120). When the patients were subgrouped according to reasons for admission, paired t tests revealed decreases in violence (CMAI Factor 1; P = .000), psychosis (BPRS thought disorder scale; P = .000 and hostility subscale; P < .008), and depression (HAM-D; P = .002). Four patients were discharged to less restrictive environments, all with chronic mental illnesses. CONCLUSION: Inpatient psychiatric hospitalization significantly benefits nursing home residents with and without dementia who are admitted for severe behavior problems.

Comparison of five methods for the detection of measles specific immunoglobulin G antibody.

In this work we compare the sensitivity, specificity and predictive values of hemagglutination inhibition (HI), immunofluorescent assay (IFA), biotin-streptavidin immunofluorescent assay (B/SA-IFA), enzyme-linked immunosorbent assay (EIA) and plaque neutralization test (PN). This study includes serum samples from children taken before and after vaccination, children with clinically diagnosed measles and household contacts. EIA were the most specific and better serological diagnostic test. HI and IFA had high sensitivity but low specificity. An alternative to EIA is B/SAIFA, which is cheaper than EIA and can be used in the study of small outbreaks or in isolated cases.

[Amikacin in single daily doses in children with fever]. / Amikacina en dosis única diaria en ninõs con fiebre.

A randomized clinical trial was performed in children with cancer, fever and neutropenia, to evaluate the efficacy of amikacin once daily versus thrice daily dosing plus carbenicillin in both groups. Fifty patients were included, 25 patients in group A who received amikacin once daily and 25 in group B who received amikacin thrice daily. No intergroup differences were observed, i.e., fever diminished in a median of 6 days (2-8 days) vs. 7 days (3-12 days) in groups A and B respectively (p = 0.37);clinical improvement was observed in a median of 6 days (3-10 days) vs 7 days (2-14 days) (p = 0.68). One patient in group A and two in B died. The peak levels of amikacin on the 7th day of treatment were 10-60 and 7-25 micrograms/mL in groups A and B respectively, and the serum creatinine levels were 0.3 - 0.7 for group A and 0.2 - 0.8 mg/dL for group B; none of the patients presented a creatinine above 40% of the basal value. Three patients of group A had amikacin levels higher than 40 micrograms/mL without increasing the creatinine levels; our observations do not suggest that toxicity is higher. We conclude that the administration of aminoglycoside once daily seems to be as effective as the traditional dosing.

Vasorelaxant effect of the analgesic clonixin on rat aorta.

1. A novel vasorelaxant effect of clonixinate of L-lysine (Clx), analgesic and anti-inflammatory, was studied in rat aortic rings. 2. Clx completely relaxed aortic rings contracted by KCl 70 mM and together with its analog flunixin exhibited lesser potency but equal efficacy than verapamil. In comparison, indomethacin, which is a more potent cyclo-oxygenase inhibitor relaxed only about 40% of the maximal contraction of aortic rings. 3. Furthermore, Clx antagonized Ca2+ dependent aortic contraction and BAY K-8644 induced aortic contraction suggesting its calcium antagonist character. 4. From these results it can be concluded that the hypotensive effect seen in rats in vivo after Clx i.v. injection arises because of vasodilatory effect of Clx and gives further support to the proposal that the pharmacological mechanism of action of Clx should be calcium antagonism.

Indirect immunofluorescent assay (IFA) in buffy coat as a rapid diagnostic test for invasive candidiasis.

In order to have a diagnostic test for invasive candidiasis, an immunofluorescent assay (IFA) in buffy coat was developed and evaluated. This test was compared to buffy coat culture and blood culture. The study was divided into two parts: evaluation of the diagnostic test in a rabbit model, and for diagnosis in patients at high risk for invasive candidiasis. Part I: Rabbits were experimentally infected. Of 13 rabbits with disseminated candidiasis blood was drawn from central venous catheter and from peripheral veins. From catheters, Candida was detected in 13/13, 10/13 and 8/13, by buffy coat culture, IFA, and blood culture, respectively. From peripheral veins, Candida was detected in 10/10 by buffy coat cultures, in 6/10 by IFA and in 3/10 by blood cultures. The gold standard was histopathological diagnosis; sensitivity for IFA was 60% with peripheral blood and 76% with catheter blood samples. Part II: IFA and blood cultures were compared in clinical samples from hospitalized children. Forty patients were included. Candida was isolated from blood cultures in four patients whereas IFA detected Candida in 22 patients. Differences were statistically significant (p < 0.05). We conclude that IFA in buffy coat smears is a reliable test to detect candidemia, and would be a useful tool to help physicians with treatment decisions with amphotericin B.