Determining the Aethalometer multiple scattering enhancement factor C from the filter loading parameter.

Light-absorbing aerosols heat the atmosphere; an accurate quantification of their absorption coefficient is mandatory. However, standard reference instruments (CAPS, MAAP, PAX, PTAAM) are not always available at each measuring site around the world. By integrating all previous published studies concerning the Aethalometers, the AE33 filter loading parameter, provided by the dual-spot algorithm, were used to determine the multiple scattering enhancement factor from the Aethalometer itself (hereinafter CAE) on an yearly and a monthly basis. The method was developed in Milan, where Aethalometer measurements were compared with MAAP data; the comparison showed a good agreement in terms of equivalent black carbon (R2 = 0.93; slope = 1.02 and a negligible intercept = 0.12 µg m-3) leading to a yearly experimental multiple scattering enhancement factor of 2.51 ± 0.04 (hereinafter CMAAP). On a yearly time base the CAE values obtained using the new approach was 2.52 ± 0.01, corresponding to the experimental one (CMAAP). Considering the seasonal behavior, higher experimental CMAAP and computed CAE values were found in summer (2.83 ± 0.12) whereas, the lower ones in winter/early-spring (2.37 ± 0.03), in agreement with the single scattering albedo behavior in the Po Valley. Overall, the agreement between the experimental CMAAP and CAE showed a root mean squared error (RMSE) of just 0.038 on the CMAAP prediction, characterized by a slope close to 1 (1.001 ± 0.178), a negligible intercept (-0.002 ± 0.455) and a high degree of correlation (R2 = 0.955). From an environmental point of view, the application of a dynamic (space/time) determination of CAE increases the accuracy of the aerosol heating rate (compared to applying a fixed C value) up to 16 % solely in Milan, and to 114 % when applied in the Arctic at 80°N.

Consistent determination of the heating rate of light-absorbing aerosol using wavelength- and time-dependent Aethalometer multiple-scattering correction.

Accurate and temporally consistent measurements of light absorbing aerosol (LAA) heating rate (HR) and of its source apportionment (fossil-fuel, FF; biomass-burning, BB) and speciation (black and brown Carbon; BC, BrC) are needed to evaluate LAA short-term climate forcing. For this purpose, wavelength- and time-dependent accurate LAA absorption coefficients are required. HR was experimentally determined and apportioned (sources/species) in the EMEP/ACTRIS/COLOSSAL-2018 winter campaign in Milan (urban-background site). Two Aethalometers (AE31/AE33) were installed together with a MAAP, CPC, OPC, a low volume sampler (PM2.5) and radiation instruments. AE31/AE33 multiple-scattering correction factors (C) were determined using two reference systems for the absorption coefficient: 1) 5-wavelength PP_UniMI with low time resolution (12 h, applied to PM2.5 samples); 2) timely-resolved MAAP data at a single wavelength. Using wavelength- and time-independent C values for the AE31 and AE33 obtained with the same reference device, the total HR showed a consistency (i.e. reproducibility) with average values comparable at 95% probability. However, if different reference devices/approaches are used, i.e. MAAP is chosen as reference instead of a PP_UniMI, the HR can be overestimated by 23-30% factor (by both AE31/AE33). This became more evident focusing on HR apportionment: AE33 data (corrected by a wavelength- and time-independent C) showed higher HRFF (+24 ± 1%) and higher HRBC (+10 ± 1%) than that of AE31. Conversely, HRBB and HRBrC were -28 ± 1% and -29 ± 1% lower for AE33 compared to AE31. These inconsistencies were overcome by introducing a wavelength-dependent Cλ for both AE31 and AE33, or using multi-wavelength apportionment methods, highlighting the need for further studies on the influence of wavelength corrections for HR determination. Finally, the temporally-resolved determination of C resulted in a diurnal cycle of the HR not statistically different whatever the source- speciation- apportionment used.

Radon levels and doses in dwellings in two villages in Kosovo, affected by depleted uranium.

The radon ((222)Rn) activity concentration in 15 dwellings in the Planej village and 10 dwellings in the Gorozhup village has been measured with the aim to complement the national radon survey and to compare the results of two different measurement techniques. The radon concentration has been measured in winter and spring using alpha scintillation cells and in winter, spring and summer by exposing solid-state nuclear track detectors. Both methods gave similar results. Radon concentrations in both villages were similar, ranging from 82 to 432 Bq m(-3); the value of 400 Bq m(-3) was exceeded only in two dwellings. The resulting annual effective doses ranged from 1.78 to 6.40 mSv, with the average values of 3.28 mSv in the Planej village and 3.87 mSv in the Gorozhup village.

Diurnal and seasonal variations of concentration and size distribution of nano aerosols (10-1100 nm) enclosing radon decay products in the Postojna Cave, Slovenia.

At the lowest point along the tourist route in the Postojna Cave, the activity concentration of radon ((222)Rn) short-lived decay products and number concentration and size distribution of background aerosol particles in the size range of 10-1100 nm were measured. In the warm yearly season, aerosol concentration was low (52 cm(-3)) with 21 % particles smaller than 50 nm, while in the cold season, it was higher (1238 cm(-3)) with 8 % of <50 nm particles. Radon activity concentrations were 4489 and 1108 Bq m(-3), and fractions of unattached radon decay products were 0.62 and 0.13, respectively.

Exposure to radon in dwellings in the Sharri community, Kosovo.

Indoor air radon concentration was measured by exposing etched track detectors in the sleeping and living rooms of 18 houses in 6 villages of the Sharri community in Kosovo. Values ranged from 24 to 209 Bq m(-3), with only one exceeding 200 Bq m(-3), with a geometric mean and geometric standard deviation of 95.4 Bq m(-3) and 1.6, respectively. On the basis of the assumption that the spring radon concentrations obtained in this survey represent the yearly average, annual effective doses of residents were calculated; they range from 0.89 to 4.7 mSv y(-1), with the geometric mean and geometric standard deviation of 1.5 mSv y(-1) and 2.2, respectively. No mitigation measures are planned to be undertaken.

Exposure to radon in the Gadime Cave, Kosovo.

Air radon concentration was measured in summer and winter at 11 points along the tourist guided route in the Gadime Cave in Kosovo using alpha scintillation cells and etched track detectors. At two points in summer, values higher than 1700Bqm(-3) were observed; they otherwise were in the range 400-1000Bqm(-3). Values were lower in winter. The effective dose received by a person during a 90min visit is 3.7microSv in summer and 2.5microSv in winter. For a tourist guide the annual effective dose is less than 3.5mSv.

Sixteen novel mutations identified in COL4A3, COL4A4, and COL4A5 genes in Slovenian families with Alport syndrome and benign familial hematuria.

Alport syndrome (ATS) and benign familial hematuria (BFH) are type IV collagen inherited disorders. Mutations in COL4A5 are generally believed to cause X-linked ATS, whereas mutations in COL4A3 and COL4A4 genes can be associated with the autosomal-recessive and -dominant type of ATS or BFH. In view of the wide spectrum of phenotypes, an exact diagnosis is sometimes difficult to achieve. This study involved screening each exon with boundary intronic sequences of COL4A3, COL4A4, and COL4A5 genes by optimized polymerase chain reaction-single-stranded conformational polymorphism analysis in 17 families with ATS and in 40 families diagnosed as having BFH. Twelve different mutations were found in the COL4A5 gene in ATS patients, comprising nine missense mutations, a splice site mutation, a mutation causing frameshift, and a nonsense mutation. One of the missense mutations (p.G624D) was present not only in one family with ATS but also in five families with suspected BFH. Three heterozygous mutations in the COL4A3 gene (two missense and one frameshift) and four heterozygous mutations in COL4A4 (two splice site, one in-frame deletion, and one missense) were identified in patients with BFH. Sixteen mutations are to the best of our knowledge new and private.

Carotid artery intima-media thickness and angiotensin-converting enzyme gene polymorphism in the offspring of parents with premature stroke.

AIM: To determine some common cardiovascular risk factors, alterations in the measurements of intima-media thickness (IMT) and the distribution of the angiotensin-converting enzyme (ACE) polymorphism in children of parents with premature stroke, and to investigate the cardiovascular risk of these children and the potential need for some preventive measures. METHODS: A family history of cardiovascular disease represents a cardiovascular risk factor in the offspring. This association has not yet been clearly determined for cerebrovascular accidents. New technology allows us to investigate the risk for cardiovascular disease at an early presymptomatic stage. We applied the measurement of IMT of carotid arteries by ultrasound imaging and the determination of the ACE insertion/deletion (I/D) polymorphism in blood to evaluate the predisposition for cerebrovascular disease in the offspring of patients with previous stroke. We investigated 58 subjects whose parents had experienced a cerebrovascular accident before the age of 45 y and compared them with a matched control group whose parents had not suffered a stroke. RESULTS: The results of IMT at various sites of the carotid arteries and the genotype distribution of the ACE gene were not significantly different between the study group and the control group. In addition, no differences were found in the serum levels of lipid fractions or other biochemical variables. CONCLUSION: We conclude that determination of the carotid IMT and of the ACE I/D polymorphism do not permit discrimination of the cardiovascular risk in children of parents with or without premature stroke.

Early renal insufficiency in a neonate with de novo partial trisomy of chromosome 10q.

Partial trisomy of the long arm of chromosome 10 is a well-defined but rare syndrome. Clinical features of this chromosomopathy are a distinctive dysmorphic appearance, developmental delay, growth retardation, and in some cases, abnormalities of the extremities and renal, cardiac and ocular anomalies. This report describes a neonate with symmetric growth retardation and multiple dysmorphic features, in whom chromosomal analysis revealed a partial trisomy of chromosome 10q with a monosomy of the 13q34 region. The phenotype shares many common features with previously published cases. In addition to the typical features, our case also shows renal hypoplasia with early renal insufficiency and some genital anomalies.

Familial hypomagnesemia--hypercalciuria and pseudotumor cerebri.

Approximately 30 patients with familial hypomagnesemia-hypercalciuria have been reported. We describe an 8-year-old girl with cardinal findings of familial hypomagnesemia-hypercalciuria (hypomagnesemia, hypermagnesiuria, hypercalciuria, renal insufficiency, hyperuricemia, elevated serum parathormone, hyposthenuria and nephrocalcinosis), who received combination therapy consisting of magnesium salts, thiazide diuretic and potassium supplementation. At the 4-year follow-up investigation under this treatment, the patient was found to have cerebral pseudotumor (increased intracranial pressure with normal or small ventricles on neuroimaging, no evidence of an intracranial mass and normal cerebrospinal fluid composition) with papilledema and visual field defects. Thiazide therapy was terminated and the cerebral pseudotumor disappeared. The authors hypothesize that cerebral pseudotumor in this patient was related to severe hypocalcemia, as a consequence of profound hypomagnesemia induced by protracted thiazide treatment. To our knowledge, this is the first report of a child with familial hypomagnesemia-hypercalciuria who developed pseudotumor cerebri after thiazide therapy.

Angiotensin-converting enzyme gene polymorphism as a cardiovascular risk factor in children.

A family history of cardiovascular disease predicts cardiovascular risk in the next generation, which is either the result of inherited traits or certain living habits in some families. The aim of our study was to evaluate both variables and particularly the role of one of the possible genetic risk factors--angiotensin-converting enzyme (ACE) gene polymorphism. History and anthropometric and biochemical parameters, ACE gene polymorphism and carotid wall thickness--intima media thickness (IMT) were studied in two groups of children: in children whose parents had a stroke before the age of 45 years and in children without a positive family history. The preliminary results of the present study failed to confirm our hypothesis that ACE gene polymorphism is a cardiovascular risk factor in children of parents with premature stroke.

Possible influence of genes located on chromosome 6 within or near to the major histocompatibility complex on development of essential hypertension.

Studies both in spontaneously hypertensive rats and in humans have suggested that genes within or near to the HLA complex on chromosome 6p may be associated and linked to the regulation of blood pressure. The aim of this study was to determine whether HLA alleles and their combinations contribute to increased blood pressure, as well as to identify chromosome region that may contain genes involved in the pathogenesis of essential hypertension. Our results suggest that presence of HLA-DRB1*0101/2 DQB1*0501/2 DQA1*0102 allelic combination represents risk factor for development of essential hypertension in Slovenians, while the risk is decreased in individuals possessing HLA-DRB1*1601/2 DQB1*0502 DQA1*0102 or DRB3*. The linkage study indicates a possibility that at least one of the genes responsible for increased blood pressure is located near or within the HLA complex. A possible candidate is human endotelin-1 gene encoding a highly potent vasoactive peptide.

A case of insertional translocation resulting in partial trisomy 16p.

This report concerns the case of a boy with partial trisomy 16p resulting from the insertional translocation of the short arm of chromosome 16 into the long arm of chromosome 1 in his father. He was referred for genetic testing because of mental retardation, short stature, microcephaly, seizures and multiple dysmorphic features. Chromosome analysis performed in the child demonstrated the presence of additional material in the long arm of chromosome 1. Paternal high resolution chromosome analysis and fluorescence in situ hybridisation revealed the following karyotype: 46,XY,ins(1;16)(q42;p13.1p13.3), while the karyotype of the boy is 46,XY,der(1),ins(1;16)(q42;p13.1p13.3)pat. This is the first reported case of partial trisomy 16p due to paternal insertional translocation.

Possible influence of genes located on chromosome 6 within or near to the major histocompatibility complex on development of essential hypertension.

Studies both in spontaneously hypertensive rats and in humans have suggested that genes within or near to the HLA complex on chromosome 6p may be associated and linked to the regulation of blood pressure. The aim of this study was to determine whether HLA alleles and their combinations contribute to increased blood pressure, as well as to identify chromosome region that may contain genes involved in the pathogenesis of essential hypertension. Our results suggest that presence of HLA-DRB1*0101/2 DQB1*0501/2 DQA1*0102 allelic combination represents risk factor for development of essential hypertension in Slovenians, while the risk is decreased in individuals possessing HLA-DRB1*1601/2 DQB1*0502 DQA1*0102 or DRB3*. The linkage study indicates a possibility that at least one of the genes responsible for increased blood pressure is located near or within the HLA complex. A possible candidate is human endotelin-1 gene encoding a highly potent vasoactive peptide.