Sulfur-enhanced thermoluminescence of γ-radiated zirconia

Sulfur-modified zirconia with various S contents have been characterized and analyzed for potential applications in dosimetry. The thermoluminescent signal induced by gamma radiation in pure zirconia and sulfated zirconia in the tetragonal phase has been considered. Experimental results show that the thermoluminescent glow peak depends on both the crystalline structure and sulfate concentration and that the response is linear for an ample range of irradiation.Зразки модифікованої сірого двоокису цирконію з різним вмістом сірки охарактеризовано і проаналізовано з точки зору потенційного застосування в дозиметрії. Розглянуто термолюмінісцентний сигнал, викликаний гамма-випромінюванням в чистому і сульфатованому двоокису цирконію в тетрагональної фазі. Експериментальні результати показують, що пік термолюмінісцентного світіння залежить як від кристалічної структури, так і від концентрації сульфату. Ця характеристика лінійна для великого діапазону опромінення.Образцы модифицированной серой двуокиси циркония с различным содержанием серы охарактеризованы и проанализированы с точки зрения потенциального применения в дозиметрии. Рассмотрен термолюминисцентный сигнал, вызванный гамма-излучением в чистой и сульфатированной двуокиси циркония в тетрагональной фазе. Экспериментальные результаты показывают, что пик термолюминисцентного свечения зависит как от кристаллической структуры, так и от концентрации сульфата. Эта характеристика линейна для большого диапазона облучения

Soil and water pollution in a banana production region in tropical Mexico

The effects of abundant Mancozeb (Mn, Zn— bisdithiocarbamate) applications (2.5 kg ha-1week-1 for 10 years) on soil and surface-, subsurface- and groundwater pollution were monitored in a banana production region of tropical Mexico. In soils, severe manganese accumulation was observed, wheras the main metabolite ethylenethiourea was near the detection limit. Surface and subsurface water was highly polluted with ethylenethiourea, the main metabolite of Mancozeb (22.5 and 4.3 lg L-1, respectively), but not with manganese. In deep ground water, no ethylenethiourea was detected. The level of pollution in the region presents a worrisome risk for aquatic life and for human health

Fotometría de estrellas infrarrojas en cinco micrones

New observations in 5 μ have been obtained for the infrared stars NML-Tau, TX Cam, BN Mon and T Lyr. The results of this photometry, plus additional measurements in U, B, V, R, T, J, K, L, are given in Tables 1 and 2. The effective temperatures and bolometric corrections for the four objects under study are found in Table 4. We confirm the flat-typed maximum for Carbon Stars. Johnson suggests that it is caused by some absorption within the J-filter. We may conclude that the objects TX Cam and NML-Tau are not Carbon Stars (see Figure 1), most likely, they are M or S long-period variables, because of the light variations and the strong (U-B) - typical of Mira Stars. This is in agreement with our previous results and the spectrophotometric results of Wing, Spinrad and Kuhi.Asociación Argentina de Astronomí

Fotometría de estrellas infrarrojas en cinco micrones

New observations in 5 μ have been obtained for the infrared stars NML-Tau, TX Cam, BN Mon and T Lyr. The results of this photometry, plus additional measurements in U, B, V, R, T, J, K, L, are given in Tables 1 and 2. The effective temperatures and bolometric corrections for the four objects under study are found in Table 4. We confirm the flat-typed maximum for Carbon Stars. Johnson suggests that it is caused by some absorption within the J-filter. We may conclude that the objects TX Cam and NML-Tau are not Carbon Stars (see Figure 1), most likely, they are M or S long-period variables, because of the light variations and the strong (U-B) - typical of Mira Stars. This is in agreement with our previous results and the spectrophotometric results of Wing, Spinrad and Kuhi.Asociación Argentina de Astronomí

Clusters in the Luminous Giant HII Regions in M101

(Abridged) We have obtained HST WFPC2 observations of three very luminous but morphologically different giant HII regions (GHRs) in M101, NGC5461, NGC5462, and NGC5471, in order to study cluster formation in GHRs. The measured (M_F547M - M_F675W) colors and M_F547M magnitudes are used to determine the ages and masses of the cluster candidates with M_F547M <= -9.0. NGC5461 is dominated by a very luminous core, and has been suggested to host a super-star cluster (SSC). Our observations show that it contains three R136-class clusters superposed on a bright stellar background in a small region. This tight group of clusters may dynamically evolve into an SSC in the future, and may appear unresolved and be identified as an SSC at large distances, but at present NGC5461 has no SSCs. NGC5462 has loosely distributed HII regions and clusters without a prominent core. It has the largest number of cluster candidates among the three GHRs, but most of them are faint and older than 10 Myr. NGC5471 has multiple bright HII regions, and contains a large number of faint clusters younger than 5 Myr. Two of the clusters in NGC5471 are older than R136, but just as luminous; they may be the most massive clusters in the three GHRs. The fraction of stars formed in massive clusters is estimated from the clusters' contribution to the total stellar continuum emission and a comparison of the ionizing power of the clusters to the ionizing requirement of the associated HII regions. Both estimates show that <~ 50% of massive stars are formed in massive clusters. The cluster luminosity functions (CLFs) of the three GHRs show different slopes. NGC5462 has the steepest CLF and the most loosely distributed interstellar gas, qualitatively consistent with the hypothesis that massive clusters are formed in high-pressure interstellar environments.Comment: 36 pages (figures not included), 16 figures (3 of them are color figures). Figures are in JPEG or GIF format with a lower resolution due to the size limit of the file. For a higher resolution version of the paper, please download from http://www.astro.uiuc.edu/~c-chen/clusters.pdf. accepted for ApJ (scheduled for the ApJ 2005 February issue

Fotometría de estrellas infrarrojas en cinco micrones

New observations in 5 μ have been obtained for the infrared stars NML-Tau, TX Cam, BN Mon and T Lyr. The results of this photometry, plus additional measurements in U, B, V, R, T, J, K, L, are given in Tables 1 and 2. The effective temperatures and bolometric corrections for the four objects under study are found in Table 4. We confirm the flat-typed maximum for Carbon Stars. Johnson suggests that it is caused by some absorption within the J-filter. We may conclude that the objects TX Cam and NML-Tau are not Carbon Stars (see Figure 1), most likely, they are M or S long-period variables, because of the light variations and the strong (U-B) - typical of Mira Stars. This is in agreement with our previous results and the spectrophotometric results of Wing, Spinrad and Kuhi.Asociación Argentina de Astronomí

Rapid on-Chip Assembly of Niosomes: Batch versus Continuous Flow Reactors

The large-scale continuous production of niosomes remains challenging. The inherent drawbacks of batch processes such as large particle polydispersity and reduced batch-to-batch reproducibility are here overcome by using commercially available microfluidic reactors. Compared to the traditional batch-based film hydration method, herein, we demonstrate that it is possible to carry out the homogeneous, large-scale (up to 120 mg/min) production of niosomes using two different synthesis techniques (the thin film hydration method and the emulsification technique). Niosomes particle size can be controlled depending on the need by varying the synthesis temperature. The high cytocompatibility of the resulting niosomes was also demonstrated in this work on three different somatic cell lines. For the first time, the structure of the niosome multilamellar shell was also elucidated using high-resolution transmission electron microscopy (HR-STEM) as well as their colloidal stability over time (6 weeks) under different storage conditions. The morphology of cryo-protected or as-made niosomes was also evaluated by HR-STEM after freeze-drying. Finally, the dual ability of those synthetic, nonionic, surfactant-based vesicles to carry both hydrophilic and hydrophobic molecules was also here demonstrated by using laser scanning confocal microscopy

Tuberculosis in children treated with second-line drugs under programmatic conditions in Lima, Peru.

OBJECTIVE: To characterise childhood tuberculosis (TB) treated with second-line drugs (SLDs) in Lima, Peru. DESIGN: Results for the age groups <5 and 5-14 years were compared and treatment outcomes were assessed in cases reported between 2011 and 2015 from six districts of Lima. RESULTS: Of 96 reported cases, 82 were evaluated. Among these, 59% were boys; the median age was 8 years and 32% were aged <5 years. Contact with a TB case was reported in 82% of cases; 90% were treatment-naïve, 98% had pulmonary localisation and 50% underwent the tuberculin skin test (purified protein derivative), with induration 10 mm in 88%. A positive smear was found in 40%, all in the 5-14 years age group, and 46% were culture-positive. Only 26% had confirmed multidrug-resistant TB, 90% of whom were in the 5-14 years age group. SLDs for confirmed or probable drug-resistant TB (DR-TB) were administered to all cases, with a high proportion of success (over 83%), no failures or deaths and a high proportion of loss to follow-up. CONCLUSION: The main indication for SLDs in childhood TB was the empirical treatment of DR-TB due to contact with one or more identified DR-TB patients. Bacteriological confirmation was limited; however, treatment success was adequate