274 research outputs found
Unraveling mysteries associated with cat-scratch disease, bacillary angiomatosis, and related syndromes.
The search for the infectious agents responsible for cat-scratch disease, bacillary angiomatosis, and related syndromes has a long and often circuitous history. Recognition of the etiologic agents and a new understanding of the fundamental features of the epidemiology and natural history of modern day Bartonella (formerly Rochalimaea)-associated diseases culminate a multipartite story that combines clinical medicine, traditional microbiology, and novel technological approaches to solve a long-standing enigma
High Pressure Structural Stability of Multiferroic Hexagonal REMnO3
Structural changes in REMnO3 (RE= Y, Ho, Lu) under high pressure were
examined by synchrotron x-ray diffraction methods at room temperature.
Compression occurs more readily in the ab plane than along the c-axis. Under
hydrostatic pressure (~11 GPa), the atoms hold their approximate ambient
fractional positions in the unit cell and the spontaneous polarization shows no
significant change. With increased pressure, a pressure-induced hexagonal to
orthorhombic phase transition was observed starting at ~ 22GPa for Lu(Y)MnO3. A
small volume fraction of Lu(Y)MnO3 is converted to the orthorhombic phase when
the pressure is increased to 35 GPa and the orthorhombic phase is maintained on
pressure release. High pressure IR absorption spectroscopy and Mn K-edge near
edge x-ray absorption spectroscopy confirm that the hexagonal P63cm structure
is stable below ~20 GPa and the environment around Mn ion is not changed.
Shifts in the unoccupied p-band density of states with pressure are observed in
the Mn K-Edge spectra. A schematic pressure-temperature phase diagram is given
for the small ion REMnO3 system
Protective effi cacy of prolonged co-trimoxazole prophylaxis in HIV-exposed children up to age 4 years for the prevention of malaria in Uganda: a randomised controlled open-label trial
Background WHO recommends daily co-trimoxazole for children born to HIV-infected mothers from 6 weeks of age
until breastfeeding cessation and exclusion of HIV infection. We have previously reported on the eff ectiveness of
continuation of co-trimoxazole prophylaxis up to age 2 years in these children. We assessed the protective effi cacy and
safety of prolonging co-trimoxazole prophylaxis until age 4 years in HIV-exposed children.
Methods We undertook an open-label randomised controlled trial alongside two observational cohorts in eastern
Uganda, an area with high HIV prevalence, malaria transmission intensity, and antifolate resistance. We enrolled HIVexposed
infants between 6 weeks and 9 months of age and prescribed them daily co-trimoxazole until breastfeeding
cessation and HIV-status confi rmation. At the end of breastfeeding, children who remained HIV-uninfected were
randomly assigned (1:1) to discontinue co-trimoxazole or to continue taking it up to age 2 years. At age 2 years, children
who continued co-trimoxazole prophylaxis were randomly assigned (1:1) to discontinue or continue prophylaxis from
age 2 years to age 4 years. The primary outcome was incidence of malaria (defi ned as the number of treatments for new
episodes of malaria diagnosed with positive thick smear) at age 4 years. For additional comparisons, we observed
48 HIV-infected children who took continuous co-trimoxazole prophylaxis and 100 HIV-unexposed uninfected children
who never received prophylaxis. We measured grade 3 and 4 serious adverse events and hospital admissions. All
children were followed up to age 5 years and all analyses were by intention to treat. This study is registered with
ClinicalTrials.gov, number NCT00527800.
Findings 203 HIV-exposed infants were enrolled between Aug 10, 2007, and March 28, 2008. After breastfeeding ended,
185 children were not infected with HIV and were randomly assigned to stop (n=87) or continue (n=98) co-trimoxazole
up to age 2 years. At age 2 years, 91 HIV-exposed children who had remained on co-trimoxazole prophylaxis were
randomly assigned to discontinue (n=46) or continue (n=45) co-trimoxazole from age 2 years to age 4 years. We
recorded 243 malaria episodes (2·91 per person-years) in the 45 HIV-exposed children assigned to continue cotrimoxazole
until age 4 years compared with 503 episodes (5·60 per person-years) in the 46 children assigned to stop
co-trimoxazole at age 2 years (incidence rate ratio 0·53, 95% CI 0·39–0·71; p<0·0001). There was no evidence of
malaria incidence rebound in the year after discontinuation of co-trimoxazole in the HIV-exposed children who stopped
co-trimoxazole at age 2 years, but incidence increased signifi cantly in HIV-exposed children who stopped co-trimoxazole
at age 4 years (odds ratio 1·78, 95% CI 1·19–2·66; p=0·005). Incidence of grade 3 or 4 serious adverse events, hospital
admissions, or deaths did not signifi cantly diff er between HIV-exposed, HIV-unexposed, and HIV-infected children.
Interpretation Continuation of co-trimoxazole prophylaxis up to 4 years of age seems safe and effi cacious to protect
HIV-exposed children living in malaria-endemic areas
Safety and tolerability of artemether-lumefantrine versus dihydroartemisinin-piperaquine for malaria in young HIV-infected and uninfected children
BACKGROUND: Artemisinin combination therapy has become the standard of care for uncomplicated malaria in most of Africa. However, there is limited data on the safety and tolerability of these drugs, especially in young children and patients co-infected with HIV. METHODS: A longitudinal, randomized controlled trial was conducted in a cohort of HIV-infected and uninfected children aged 4-22 months in Tororo, Uganda. Participants were randomized to treatment with artemether-lumefantrine (AL) or dihydroartemisinin-piperaquine (DP) upon diagnosis of their first episode of uncomplicated malaria and received the same regimen for all subsequent episodes. Participants were actively monitored for adverse events for 28 days and then passively for up to 63 days after treatment. This study was registered in ClinicalTrials.gov (registration # NCT00527800). RESULTS: A total of 122 children were randomized to AL and 124 to DP, resulting in 412 and 425 treatments, respectively. Most adverse events were rare, with only cough, diarrhoea, vomiting, and anaemia occurring in more than 1% of treatments. There were no differences in the risk of these events between treatment groups. Younger age was associated with an increased risk of diarrhoea in both the AL and DP treatment arms. Retreatment for malaria within 17-28 days was associated with an increased risk of vomiting in the DP treatment arm (HR = 6.47, 95% CI 2.31-18.1, p < 0.001). There was no increase in the risk of diarrhoea or vomiting for children who were HIV-infected or on concomitant therapy with antiretrovirals or trimethoprim-sulphamethoxazole prophylaxis. CONCLUSION: Both AL and DP were safe and well tolerated for the treatment of uncomplicated malaria in young HIV-infected and uninfected children. TRIAL REGISTRATION: ClinicalTrials.gov: NCT00527800; http://clinicaltrials.gov/ct2/show/NCT00527800
A coded aperture microscope for X-ray fluorescence full-field imaging
The design and construction of an instrument for full-field imaging of the X-ray fluorescence emitted by a fully illuminated sample are presented. The aim is to produce an X-ray microscope with a few micrometers spatial resolution, which does not need to scan the sample. Since the fluorescence from a spatially inhomogeneous sample may contain many fluorescence lines, the optic which will provide the magnification of the emissions must be achromatic, i.e. its optical properties must be energy-independent. The only optics which fulfill this requirement in the X-ray regime are mirrors and pinholes. The throughput of a simple pinhole is very low, so the concept of coded apertures is an attractive extension which improves the throughput by having many pinholes, and retains the achromatic property. Modified uniformly redundant arrays (MURAs) with 10 mu m openings and 50% open area have been fabricated using gold in a lithographic technique, fabricated on a 1 mu m-thick silicon nitride membrane. The gold is 25 mu m thick, offering good contrast up to 20keV. The silicon nitride is transparent down into the soft X-ray region. MURAs with various orders, from 19 up to 73, as well as their respective negative (a mask where open and closed positions are inversed compared with the original mask), have been made. Having both signs of mask will reduce near-field artifacts and make it possible to correct for any lack of contrast
Protective efficacy of co-trimoxazole prophylaxis against malaria in HIV exposed children in rural Uganda: a randomised clinical trial
Objective To evaluate the protective efficacy of co-trimoxazole prophylaxis against malaria in HIV exposed children (uninfected children born to HIV infected mothers) in Africa
Improvement of CdMnTe Detector Performance by MnTe Purification
Residual impurities in manganese (Mn) are a big obstacle to obtaining high-performance CdMnTe (CMT) X-ray and gamma-ray detectors. Generally, the zone-refining method is an effective way to improve the material's purity. In this work, we purified the MnTe compounds combining the zone-refining method with molten Te, which has a very high solubility for most impurities. We confirmed the improved purity of the material by glow-discharge mass spectrometry (GDMS). We also found that CMT crystals from a multiply-refined MnTe source, grown by the vertical Bridgman method, yielded better performing detectors
Are Urologists Ready for Interpretation of Multiparametric MRI Findings? A Prospective Multicentric Evaluation
Aim: To assess urologists’ proficiency in the interpretation of multiparametric magnetic resonance imaging (mpMRI). Materials and Methods: Twelve mpMRIs were shown to 73 urologists from seven Italian institutions. Responders were asked to identify the site of the suspicious nodule (SN) but not to assign a PIRADS score. We set an a priori cut-off of 75% correct identification of SN as a threshold for proficiency in mpMRI reading. Data were analyzed according to urologists’ hierarchy (UH; resident vs. consultant) and previous experience in fusion prostate biopsies (E-fPB, defined as <125 vs. ≥125). Additionally, we tested for differences between non-proficient vs. proficient mpMRI readers. Multivariable logistic regression analyses (MVLRA) tested potential predictors of proficiency in mpMRI reading. Results: The median (IQR) number of correct identifications was 8 (6–8). Anterior nodules (number 3, 4 and 6) represented the most likely prone to misinterpretation. Overall, 34 (47%) participants achieved the 75% cut-off. When comparing consultants vs. residents, we found no differences in terms of E-fPB (p = 0.9) or in correct identification rates (p = 0.6). We recorded higher identification rates in urologists with E-fBP vs. their no E-fBP counterparts (75% vs. 67%, p = 0.004). At MVLRA, only E- fPB reached the status of independent predictor of proficiency in mpMRI reading (OR: 3.4, 95% CI 1.2–9.9, p = 0.02) after adjusting for UH and type of institution. Conclusions: Despite urologists becoming more familiar with interpretation of mpMRI, their results are still far from proficient. E-fPB enhances the proficiency in mpMRI interpretation
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