Uranium speciation in weathered granitic waste rock piles: an XAFS investigation

Investigation of uranium migration in the waste piles of granite rock in the Limousin region of France is vital for developing strategies which address related environmental issues. Despite the fact that the concentration of uranium is far below the lower end of the cut off level in these piles, the large volume of rocks – which measure in the hundreds of metric tons – and their conditions of repository make this type of waste a source of concern for the international community. In this work, X-ray absorption spectroscopy techniques (XAFS) were employed in order to identify the speciation of uranium in the different categories of samples collected from various regions of the rock piles which had undergone 50 years of weathering. The samples, such as weathered granite, arena and technosoils, were studied in order to probe the transformation of the U bearing complex. XANES indicates U(vi) valence with uranyl species in all samples. Using a linear combination analysis and shell fitting approach, distinct speciation of uranium was observed in the different categories of samples. In the weathered rock and arena samples with relics of magmatic U minerals, uranyl phosphates comparable to autunite are shown to be dominantly linked with monodentate PO₄³⁻. However, the samples collected from technosoils are found to have a mixture of U-phosphate and U-clay minerals (phyllosilicates and silicates). Irrespective of the collection location, all the samples were found to contain U(vi)-oxo species The equatorial O ligands occur as two shells with an average separation of 0.14–0.21 Å. Moreover, all the samples have an Al/Si/P shell around 3.1 Å. A detailed EXAFS curve fit analysis shows that disorder afflicts the entire range of samples which can be attributed to either inhomogeneous binding sites on the disordered clay minerals or to the presence of a mixture of uranium-bearing minerals. XAFS investigations highlight the uranyl overriding forms of U (as U sorbed on clay minerals and secondary uranyl phosphates or silicates) contribute to the retention of U, even in oxidizing conditions known to enhance the mobility of U.

Uranium speciation determined by XAFS reveals its retention in weathered waste rock piles by the formation of stable secondary uranium complexes.     

UK national re-audit of sexual history-taking

A focused repeat national audit of sexual history-taking was conducted in genitourinary (GU) medicine clinics in the UK in 2010, addressing several areas of practice under-performance identified in the baseline 2008 national audit. The case-notes of 4285 patients were audited. An increase in documentation was observed for all measures, except legibility which was unchanged. Despite the overall improvement, several measures (chaperone offer, condom usage and four of five aspects of HIV risk assessment) remained below target.     

Occult hepatitis B virus infection in chronic liver disease: full-length genome and analysis of mutant surface promoter

BACKGROUND AND AIMS: Genome sequence of hepatitis B virus (HBV) from occult chronic infection is scarce. Fifty-six (9.4%) of 591 patients seronegative for hepatitis B surface antigen (HBsAg) with chronic liver disease were positive for HBV DNA. The complete HBV genome from 9 of these patients (S1-S9) and 5 controls positive for HBsAg (SWT.1-SWT.5) were analyzed. METHODS: Overlapping genome fragment amplification, cloning, and sequencing was performed on these cases. Functional analysis of surface promoter was conducted using fusion construct. RESULTS: All patients with occult infection except one (S8) had a low viral titer. Eight patients had infection with genotype A (S1-S5, SWT.1-2, SWT.5) and 6 had infection with genotype D (S6-S9, SWT.3-4). S4 and S5.1 of genotype A had the characteristic nucleotide deletions in core and pre-S1 region seen in genotype D. The major observations in patients with occult HBV infection were as follows: frequent quasispecies variation, deletions in pre-S2/S region affecting the surface promoters (nt 3025-54) and pre-S protein (S3, S5, S6, S8), truncated precore (S6, S8, S7.1) and core (S9) owing to stop signal, alternate start codon for the Polymerase gene (S3, S9), and YMDD mutation (S1, S4, S9) in patients not on antiviral therapy. HBsAg and core proteins could be shown immunohistochemically in 3 of 5 liver biopsy specimens available. The mutant surface promoters (pre-S2 and S) on functional analysis showed alterations in HBsAg expression. CONCLUSIONS: These changes in the regulatory region with possible alterations in the ratio of large and small surface proteins along with other mutations in the genome may decrease the circulating HBsAg level synergistically, making the immunodetection in serum negative.     

Incidental radiation to axilla in early breast cancer treated with intensity modulated tangents and comparison with conventional and 3D conformal tangents

PurposeTo analyze incidental radiation doses to minimally dissected axilla with Intensity modulated radiotherapy (IMRT), 3D conformal radiotherapy (3DCRT) and standard tangents (ST).Methods & materialsWe prospectively evaluated incidental radiation to axilla in fifty cases of early breast cancer treated with breast conservation surgery with sentinel node biopsy alone followed by whole breast irradiation with IMRT. Three plans were devised for each CT dataset, comprising ST, 3DCRT and IMRT tangents. Doses to axillary nodal levels I, II and III were evaluated for mean dose, V95, V90, V80 and V50. Comparisons were made using ANOVA.ResultsThe mean doses delivered to axilla by the three techniques (IMRT, 3DCRT, ST) were: 78% (range 67–90, SD ± 5.2%), 80% (63–95, ±7.5%) and 87% (73–98, ±4.8%) for level I (IMRT vs ST; p = 0.037); 70% (46–89, ±12.4%), 72% (34–93, ±15.5%) and 65% (29–87, ±11.8%) for level II; and 51% (28–76, ±11.1%), 53% (19–86, ±13.7%) and 41% (6–72, ±10.6%) for level III, respectively. V90 values (volume receiving 90% of dose) for the three techniques were 49% (43–53, ±2.7%), 57% (51–65, ±3.1%) and 73% (65–80, ±3.4%) for level I (IMRT vs ST; p = 0.029); 35% (26–42, ±4.7%), 41% (33–50, ±4.2%) and 25% (17–36, ±4.5%) for level II (IMRT vs ST; p = 0.068); and 15% (9–22, ±3.4%), 16% (10–24, ±3.7%) and 8 (5–12, ±3.1%) for level III (IMRT vs ST; p = 0.039), respectively.ConclusionAxillary levels I and II (lower axilla) receive substantial amount of incidental radiation doses with all the three techniques; however, conformal techniques (IMRT, 3DCRT) deliver significantly lesser incidental radiation to lower axilla than ST technique.     

An in-vitro evaluation of a novel design of miniplate for fixation of fracture segments in the transition zone of parasymphysis-body region of mandible using finite element analysis

The mandibular parasymphysis and body regions are highly dynamic areas. They are constantly subjected to both occlusal and muscular forces. Fractures at this transition zone of the parasymphysis and body region thus represent a special pattern that creates a dilemma for the surgeons — whether to use one miniplate fixation or two miniplates as per Champy's guidelines. Mental nerve paresthesia is a very common complication due to dissection and stretching of the mental nerve in this region. Hence, an in-vitro research study of a novel twin fork design of miniplate is performed, which evaluates the biomechanical behavior using computerized finite element analysis. A comparison is carried out with the conventional design. The results show that the twin fork miniplate produces the lowest stresses — 23.821 MPa — and the least total structural deformation after applying the maximum occlusal bite force. This study concludes that the newly designed miniplate is superior in terms of stability because it shows the least structural deformation, and produces the lowest equivalent stresses on application of maximal occlusal forces. An additional advantage is the preservation of the mental nerve during the plating procedure because the broad end of the Y shape allows atraumatic positioning of the miniplate and hence the fixation of fractured segments.     

Adverse drug reactions to antiretroviral therapy in AIDS patients at a tertiary care hospital in India: A prospective observational study

Objectives: To identify the adverse drug reactions (ADRs) to antiretroviral therapy (ART) and to assess their impact on treatment compliance in patients with HIV/AIDS. Materials and Methods: Two hundred and thirty-five (235) AIDS patients who received ART were monitored for ADRs over a period of 6 months. The incidence and nature of ADRs occurring with different ART regimens were recorded. We also assessed the severity, causality as well as the impact of ADRs on the patients' compliance. Results: Of 235 patients receiving ART, 90.6% patients experienced ADRs. A total of 618 ADRs involving various systems were observed. A majority were related to gastrointestinal (42.39%) and central nervous (25.57%) system. 23.1% ADRs were severe in intensity. Severe ADRs occurred in 41 out of 235 (17.4%) patients necessitating drug withdrawal. A majority of the patients (87.8%) who complained of severe ADRs received combination of stavudine, lamivudine and nevirapine. Causality assessment revealed 6.63% ADRs were probable and 93.3% ADRs were possible. Non-compliance due to ADRs was observed in 28.9% patients. Conclusions: Myriad ADRs are associated with ART which leads to poor patient compliance. With the increasing access to ART in India, it is prudent that antiretroviral drugs are used judicially with regular monitoring of ADRs.