41 research outputs found
Prenatal diagnosis of mosaic ring chromosome 16 - a rare event with uncertain prognosis
Ring chromosomes are rare cytogenetic findings (prenatal frequency ~ 0.0075%) often associated with an abnormal phenotype, depending of the chromosomal origin, genetic content and the presence of a mosaic. Supernumerary ring chromosome 16 [r(16)] is rarely observed and mosaicism makes the genotype/phenotype correlation difficult.
We report a de novo mosaic r(16) detected after prenatal diagnosis in a woman referred for advanced maternal age. Multiplex ligation-dependent probe amplification (MLPA) for aneuploidy testing of chromosomes 13, 18, 21 and X was normal. Karyotype was 47,XX,+r[10]/46,XX[15]. Chromosomal microarray analysis (CMA) on DNA obtained from long-term cultured amniocytes did not detect any alterations. MLPA with a pericentromeric probe kit on an uncultured sample showed a chromosome 16 gain, encompassing 16p11.2 and 16q11.2 regions, including TGFB1I1, AHSP, VPS35 and ORC6 genes, leading to partial characterization of the r(16). Although no phenotype has been correlated with overexpression of these genes, the 16p11.2 region is associated with neurodevelopmental disorders. Nevertheless individuals with microduplication of 16p11.2 and normal development have been described. The lack of a precise definition of genetic content of the r(16) and its mosaic form leads to uncertain prognosis of clinical outcome.N/
Emission factors from residential combustion appliances burning Portuguese biomass fuels
Smoke from residential wood burning has been identified as a major contributor to air pollution,
motivating detailed emission measurements under controlled conditions. A series of experiments were
performed to compare the emission levels from two types of wood-stoves to those of fireplaces. Eight
types of biomass were burned in the laboratory: wood from seven species of trees grown in the
Portuguese forest (Pinus pinaster, Eucalyptus globulus, Quercus suber, Acacia longifolia, Quercus
faginea, Olea europaea and Quercus ilex rotundifolia) and briquettes produced from forest biomass
waste. Average emission factors were in the ranges 27.5–99.2 g CO kg 1, 552–1660 g CO2 kg 1, 0.66–
1.34 g NO kg 1, and 0.82–4.94 g hydrocarbons kg 1 of biomass burned (dry basis). Average particle
emission factors varied between 1.12 and 20.06 g kg 1 biomass burned (dry basis), with higher burn
rates producing significantly less particle mass per kg wood burned than the low burn rates. Particle
mass emission factors from wood-stoves were lower than those from the fireplace. The average emission
factors for organic and elemental carbon were in the intervals 0.24–10.1 and 0.18–0.68 g kg 1 biomass
burned (dry basis), respectively. The elemental carbon content of particles emitted from the energyefficient
‘‘chimney type’’ logwood stove was substantially higher than in the conventional cast iron
stove and fireplace, whereas the opposite was observed for the organic carbon fraction. Pinus pinaster,
the only softwood species among all, was the biofuel with the lowest emissions of particles, CO, NO and
hydrocarbons
Ash agglomeration and deposition during combustion of poultry litter in a bubbling fluidized-bed combustor
peer-reviewedn this study, we have characterized the ash resulting from fluidized bed combustion of poultry litter as being dominated by a coarse fraction of crystalline ash composed of alkali-Ca-phosphates and a fine fraction of particulate K2SO4 and KCl. Bed agglomeration was found to be coating-induced with two distinct layers present. The inner layer (0.05–0.09 mm thick) was formed due to the reaction of gaseous potassium with the sand (SiO2) surface forming K-silicates with low melting points. Further chemical reaction on the surface of the bed material strengthened the coating forming a molten glassy phase. The outer layer was composed of loosely bound, fine particulate ash originating from the char. Thermodynamic equilibrium calculations showed slag formation in the combustion zone is highly temperature-dependent, with slag formation predicted to increase from 1.8 kg at 600 °C to 7.35 kg at 1000 °C per hour of operation (5.21 kg of ash). Of this slag phase, SiO2 and K2O were the dominant phases, accounting for almost 95%, highlighting the role of K-silicates in initiating bed agglomeration. The remaining 5% was predicted to consist mainly of Al2O3, K2SO4, and Na2O. Deposition downstream in the low-temperature regions was found to occur mostly through the vaporization–condensation mechanism, with equilibrium decreasing significantly with decreasing temperatures. The dominant alkali chloride-containing gas predicted to form in the combustion zone was KCl, which corresponds with the high KCl content in the fine baghouse ash
Axial Concentration Profiles and NO Flue Gas in a Pilot-Scale Bubbling Fluidized Bed Coal Combustor
Atmospheric bubbling fluidized bed coal combustion of a bituminous coal and anthracite with
particle diameters in the range 500-4000 ím was investigated in a pilot-plant facility. The
experiments were conducted at steady-state conditions using three excess air levels (10, 25, and
50%) and bed temperatures in the 750-900 °C range. Combustion air was staged, with primary
air accounting for 100, 80, and 60% of total combustion air. For both types of coal, high NO
concentrations were found inside the bed. In general, the NO concentration decreased monotonically
along the freeboard and toward the exit flue; however, during combustion with high air
staging and low to moderate excess air, a significant additional NO formation occurred near the
secondary air injection point. The results show that the bed temperature increase does not affect
the NO flue gas concentration significantly. There is a positive correlation between excess air
and the NO flue gas concentration. The air staging operation is very effective in lowering the
NO flue gas, but there is a limit for the first stage stoichiometry below which the NO flue gas
starts rising again. This effect could be related with the coal rank
Classification of the dup 15q13.3 CNV: A National data collection
Introduction: The proximal region 15q11q14 is one of the most unstable regions in
the human genome, with six recognizable break points (BP1-BP6). In 15q13.3 there is
a recurrent small CNV (BP4-BP5) consisting of a 350-680 Kb duplication,
encompassing the CHRNA7 gene, which encodes the alpha 7 subunit of the neuronal
nicotinic acetylcholine receptor.
Although microdeletions of CHRNA7 are known to cause intellectual disability and
neuropsychiatric phenotypes with high penetrance, the patogenicity of CHRNA7
duplications remains unclear. Microduplication 15q13.3 seems to be associated with a
phenotypic spectrum of cognitive impairment and neuropsychiatric/neurobehavioral
disorders. However, the penetrance of this CNV is considered incomplete since it is
present in clinically unaffected individuals in the general population and it is frequently
inherited from apparently clinically normal parents. Nonetheless, some pedigree
studies have found a history of neuropsychiatric problems among carrier family
members.
This study aimed at re-evaluating the dup 15q13.3 CNV in national laboratories.
Materials and Methods: Our study collected data on 15q13.3 microduplications in
eight Portuguese genetics laboratories, among subjects referred for microarray.
Results: Here we present a total of seventeen cases with dup 15q13.3. The subjects
had somewhat variable phenotypes, with a bias towards developmental delay and
autism spectrum disorders. Inheritance was established for eight of the subjects, and
the majority originated from the father. We had no access to clinical data on carrier
parents. No de novo CNV was found. All laboratories involved classified this variant as
of uncertain significance.
Discussion/Conclusion: To better determine whether this CNV is benign or
pathogenic, careful characterization of patient and control cohorts must be performed,
including detailed patient phenotyping, inheritance, clinical evaluation of carrier
parents, prevalence in controls, as well as genetic functional studies.
We strongly support the creation of a national database for uncertain CNVs in order to
clarify the relevance of these recurrent findings, allowing a definitive classification in
either pathogenic or benign
Solid state synthesis of Ca2Fe2O5 by reactive firing of calcite and siderite
The brownmillerite phase Ca2Fe2O5 was processed by the reactive firing of calcite and a natural siderite for prospective catalytic applications. Thermogravimetry and X-ray diffraction (XRD) was used to monitor the decomposition of precursors and its dependence on heating rate and atmosphere. Taguchi planning was used to assess the impact of firing temperature, time, and rate of heating on the conversion of precursors reflected by I(121)sp : I(121)b peak intensity ratio of main XRD reflections of secondary spinel phase CaFe2O4 and brownmillerite. The onset of additional minor phases (Ca2Al2SiO7 and Ca2SiO4) was ascribed to the reaction of a fraction of calcia with gangue components of the siderite precursor. Thermodynamic modelling was used as a guideline for synthesis in non-oxidising conditions to hinder the onset of CaFe2O4. These guidelines allowed one to obtain high conversion to Ca2Fe2O5 with enhanced crystallinity at 700 ºC, in an inert Ar atmosphere. Faster reactivity at T ≥ 800ºC in this oxygen lean atmosphere, leads to highly crystalline Ca2Fe2O5 coexisting with the onset of wustite and/or metallic Fe, which account for the oxygen balance, and calcium silicates, by reaction of calcia with silica.publishe