Assessment of UHF Frequency Range for Failure Classification in Power Transformers.

Ultrahigh-frequency (UHF) sensing is one of the most promising techniques for assessing the quality of power transformer insulation systems due to its capability to identify failures like partial discharges (PDs) by detecting the emitted UHF signals. However, there are still uncertainties regarding the frequency range that should be evaluated in measurements. For example, most publications have stated that UHF emissions range up to 3 GHz. However, a Cigré brochure revealed that the optimal spectrum is between 100 MHz and 1 GHz, and more recently, a study indicated that the optimal frequency range is between 400 MHz and 900 MHz. Since different faults require different maintenance actions, both science and industry have been developing systems that allow for failure-type identification. Hence, it is important to note that bandwidth reduction may impair classification systems, especially those that are frequency-based. This article combines three operational conditions of a power transformer (healthy state, electric arc failure, and partial discharges on bushing) with three different self-organized maps to carry out failure classification: the chromatic technique (CT), principal component analysis (PCA), and the shape analysis clustering technique (SACT). For each case, the frequency content of UHF signals was selected at three frequency bands: the full spectrum, Cigré brochure range, and between 400 MHz and 900 MHz. Therefore, the contributions of this work are to assess how spectrum band limitation may alter failure classification and to evaluate the effectiveness of signal processing methodologies based on the frequency content of UHF signals. Additionally, an advantage of this work is that it does not rely on training as is the case for some machine learning-based methods. The results indicate that the reduced frequency range was not a limiting factor for classifying the state of the operation condition of the power transformer. Therefore, there is the possibility of using lower frequency ranges, such as from 400 MHz to 900 MHz, contributing to the development of less costly data acquisition systems. Additionally, PCA was found to be the most promising technique despite the reduction in frequency band information.

Identification of Electrical Tree Aging State in Epoxy Resin Using Partial Discharge Waveforms Compared to Traditional Analysis.

Electrical treeing is one of the main degradation mechanisms in high-voltage polymeric insulation. Epoxy resin is used as insulating material in power equipment such as rotating machines, power transformers, gas-insulated switchgears, and insulators, among others. Electrical trees grow under the effect of partial discharges (PDs) that progressively degrade the polymer until the tree crosses the bulk insulation, then causing the failure of power equipment and the outage of the energy supply. This work studies electrical trees in epoxy resin through different PD analysis techniques, evaluating and comparing their ability to identify tree bulk-insulation crossing, the precursor of failure. Two PD measurement systems were used simultaneously-one to capture the sequence of PD pulses and another to acquire PD pulse waveforms-and four PD analysis techniques were deployed. Phase-resolved PD (PRPD) and pulse sequence analysis (PSA) identified tree crossing; however, they were more sensible to the AC excitation voltage amplitude and frequency. Nonlinear time series analysis (NLTSA) characteristics were evaluated through the correlation dimension, showing a reduction from pre- to post-crossing, and thus representing a change to a less complex dynamical system. The PD pulse waveform parameters had the best performance; they could identify tree crossing in epoxy resin material independently of the applied AC voltage amplitude and frequency, making them more robust for a broader range of situations, and thus, they can be exploited as a diagnostic tool for the asset management of high-voltage polymeric insulation.

Insecticide Resistance Status of Aedes albopictus (Diptera: Culicidae) Populations from Cuba.

Aedes albopictus (Skuse, 1894) is one of the major vectors for arboviruses such as dengue, Zika, and chikungunya. Originally from Southeast Asia, this species has spread to Africa, Europe, and the Americas, including Cuba. This spread has been favored by its great adaptability to variable temperatures and to the resistance of its eggs to desiccation. Chemical control of mosquitoes is an essential alternative to stop arbovirus transmission, but insecticide resistance status of the Cuban Ae. albopictus populations is unknown. For this study, Ae. albopictus larvae and adults were collected from two municipalities in Havana, Cuba in 2019. Adult bioassays for deltamethrin, cypermethrin, lambda-cyhalothrin, chlorpyrifos, propoxur, and bendiocarb susceptibility were conducted according to CDC methodology. Larval bioassays for temephos susceptibility were performed following WHO protocols. Resistance profiles for α and ß-esterases, glutathione S-transferase (GST), and multifunction oxidases (MFO) pathways were constructed and analyzed. Resistance to temephos and deltamethrin was detected in Mulgoba and Plaza field populations, but resistance to lambda-cyhalothrin was only found in the Plaza colony. Plaza colony exhibited a higher expression level to all four metabolic enzymes and α-esterases and GTS were over-expressed in Mulgoba. The development of insecticide resistance in Cuban Ae. albopictus populations makes it imperative that we develop integrated control strategies to minimize the development of resistance and provide effective vector control that prevents the onset of arbovirus epidemics.

Characterization of Insecticide Resistance in Aedes aegypti from the Zoological Garden of Havana, Cuba.

Chemical control of Aedes aegypti continues to be an indispensable alternative to preventing dengue, Zika, and chikungunya outbreaks. The Havana Zoological Garden requires constant vigilance because its special characteristics help in the spread of the causal agents of diseases transmitted by mosquitoes, which put the health of visitors at risk. The goals of this study were to determine the level of susceptibility and insecticide resistance mechanisms in the Ae. aegypti population. Temephos susceptibility in larvae was evaluated with bioassays using the World Health Organization's methodology, and susceptibility of adult mosquitoes was determined by the impregnated bottle bioassay, recommended by the Centers for Disease Control and Prevention. Resistance mechanisms were determined with biochemical assays. Mosquito larvae from the Havana Zoo were found resistant to temephos, which was associated with the activity of the enzymes α- and ß-esterases and mixed function oxidases but not glutathione-S-transferase. Adult mosquitoes were susceptible to pyrethroid (lambda-cyhalothrin, deltamethrin, and cypermethrin), organophosphate (chlorpyrifos), and carbamate (bendiocarb). Temephos resistance detected in the mosquito population from the Havana Zoo is an alert for the Vector Control Program, which must take measures to manage their resistance, relying on the surveillance carried out by Cuba's medical entomology laboratories.

A Comparative Analysis Applied to the Partial Discharges Identification in Dry-Type Transformers by Hall and Acoustic Emission Sensors.

Dry-type insulated transformers stand out for their higher applicability in substations, high-voltage instrumentation systems, and electrical installations. In this machine, the insulation system is constituted of dielectric materials such as epoxy resin and Nomex paper. Some critical issues in the operation of this equipment, such as overload, moisture, or heat, can induce a slow degradation of the physical-chemical properties of the dielectric materials, which can culminate in the total failure of the transformer. However, before the transformer's shutdown, it is common to detect discharge activity in the insulation system. Based on this issue, this work proposes an experimental and comparative analysis between acoustic emission and Hall-effect sensors, aiming at differentiating discharges in epoxy resin and Nomex paper, materials that constitute the insulation of the dry-type insulated transformers. Two signal processing techniques were studied: traditional frequency analysis and discrete wavelet transform. The objective is to develop signal processing techniques to differentiate each type of discharge since different discharges require different maintenance actions. The results obtained indicate that acoustic emission sensors and Hall sensors are promising in differentiating discharge in epoxy resin and Nomex paper. Furthermore, the pattern recognition tools presented by this work, which associated the wavelet levels energies and the energy of the full signals with the average band and the equivalent bandwidth, were effective to perform feature extraction of power transformer condition.

First Record of Natural Transovarial Transmission of Dengue Virus in Aedes albopictus from Cuba.

Transovarial transmission (TOT) of dengue virus (DENV) in Aedes spp. is an important mechanism for DENV maintenance in nature and may be important in initiating outbreaks. The objective of this study was to explore the occurrence of TOT in wild Aedes albopictus populations in Cuba. Mosquito larvae were collected in Cotorro municipality, Havana, Cuba, and identified to species. Fifteen pools of Ae. albopictus each containing 30 larvae were processed for DENV detection by using conventional reverse transcription polymerase chain reaction (RT-PCR) and nested PCR. Four out of 15 pools processed were positive for DENV-3, but no other DENV serotype was detected. This is the first time TOT of DENV detected in Cuban field populations of Ae. albopictus, and this suggests that this species may be an important vector of DENV in Cuba.

A New Acoustic-Based Approach for Assessing Induced Adulteration in Bovine Milk.

Milk is an important dietary requirement for many populations due to its high nutritional value. However, increased demand has also made it prone to fraudulent activity. In this sense, scientists have sought to develop simple, low-cost, and portable techniques to achieve quality control of milk in industry and farms as well. This work proposes a new instrumentation system based on acoustic propagation and advanced signal processing techniques to identify milk adulteration by industrial contaminants. A pair of transmitter-receiver low-cost piezoelectric transducers, configured in a pitch-catch mode, propagated acoustic waves in the bovine milk samples contaminated with 0.5% of sodium bicarbonate, urea, and hydrogen peroxide. Signal processing approaches such as chromatic technique and statistical indexes like the correlation coefficient, Euclidian norm and cross-correlation square difference were applied to identify the contaminants. According to the presented results, CCSD and RMSD metrics presented more effectiveness to perform the identification of milk contaminants. However, CCSD was 2.28 × 105 more sensitivity to distinguish adulteration in relation to RMSD. For chromatic clustering technique, the major selectivity was observed between the contamination performed by sodium bicarbonate and urea. Therefore, results indicate that the proposed approach can be an effective and quick alternative to assess the milk condition and classify its contaminants.

Leukocyte telomere length is associated with iron overload in male adults with hereditary hemochromatosis.

BACKGROUND: Hereditary hemochromatosis (HH) is a primary iron overload (IO) condition. Absolute telomere length (ATL) is a marker of cellular aging and DNA damage associated with chronic diseases and mortality. AIM: To evaluate the relationship between ATL and IO in patients with HH. METHODS: Cross-sectional study including 25 patients with HH: 8 with IO and 17 without IO (ferritin < 300 ng/ml) and 25 healthy controls. Inclusion criteria were: age > 18 years, male sex and HH diagnosis. Patients with diabetes or other endocrine and autoimmune diseases were excluded. ATL was measured by real-time PCR. RESULTS: HH patients with IO were older (P<0.001) and showed higher ferritin concentration (P<0.001). Patients with HH, disregarding the iron status, showed higher glucose and body mass index (BMI) than controls (both P<0.01). ATL was shorter in patients with IO than controls [with IO: 8 (6-14), without IO: 13 (9-20), and controls: 19 (15-25) kilobase pairs, P<0.01]; with a linear trend within groups (P for trend <0.01). Differences in ATL remained statistically significant after adjusting by age, BMI and glucose (P<0.05). DISCUSSION: Patients with IO featured shorter ATL while patients without IO showed only mild alterations vs. controls. Screening for IO is encouraged to prevent iron-associated cellular damage and early telomere attrition.

Behavior of an Inductive Loop Sensor in the Measurement of Partial Discharge Pulses with Variations in Its Separation from the Primary Conductor.

Ideally, an insulation system must be capable of electrically insulating the active components of a machine or device subjected to high voltages. However, due to the presence of polluting agents or imperfections inside or on the surface of the insulation, small current pulses called partial discharges (PDs) are common, which partially short-circuit the insulation and cause it to lose its insulating properties, and thus its insulation capacity, over time. In some cases, measurements of this phenomenon are limited by the type of sensor used; if it is not adequate, it can distort the obtained results, which can lead to a misdiagnosis of the state of the device. The inductive loop sensor has experimentally been demonstrated to be capable of properly measuring different types of PDs. However, because of its current design, there are several practical limitations on its use in real devices or environments. An example is the presence of a primary conductor located at a fixed distance from the sensor, through which PD pulses must flow for the sensor to capture them. In this article, the sensor's behavior is studied at different separation distances from the line through which the PD pulses flow. In addition, the measuring capacity of the sensor is tested by removing the presence of the primary conductor and placing the sensor directly over the line through which the PD pulses of a real device flow.

- 174 G>C IL-6 polymorphism and primary iron overload in male patients.

Primary iron overload (IO) is commonly associated with mutations in the hereditary hemochromatosis gene (HFE). Nonetheless, other genetic variants may influence the development of IO beyond HFE mutations. There is a single nucleotide polymorphism (SNP) at - 174 G>C of the interleukin (IL)-6 gene which might be associated with primary IO. Our aim was to study the association between the SNP - 174 G>C gene promoter of IL-6 and primary IO in middle-aged male patients. We studied 37 men with primary IO diagnosed by liver histology. Controls were age-matched male volunteers (n = 37). HFE mutations and the SNP - 174 G>C gene promoter of IL-6 were evaluated by PCR-RFLP. Logistic regression was used to evaluate the association between primary IO and SNP - 174 G>C gene promoter of IL-6. Patients and control subjects were in Hardy-Weinberg equilibrium for the SNP - 174 G>C gene promoter of IL-6 (p = 0.17). Significantly different genotype frequencies were observed between patients (43% CC, 43% CG, and 14% GG) and control subjects (10% CC, 41% CG, and 49% GG) (OR = 4.09, 95% CI = 2.06-8.13; p < 0.0001). The multiple logistic regression analysis showed that IO was significantly associated with CC homozygosis in the SNP - 174 G>C gene promoter of IL-6 (OR = 6.3, 95% CI = 1.9-21.4; p < 0.005) in a model adjusted by age and body mass index. In conclusion, CC homozygosis in the SNP - 174 G>C gene promoter of IL-6 can be proposed as one of the gene variants influencing iron accumulation in male adults with HFE mutations. Studies in larger cohorts are warranted.

A Comparison of Inductive Sensors in the Characterization of Partial Discharges and Electrical Noise Using the Chromatic Technique.

Partial discharges (PDs) are one of the most important classes of ageing processes that occur within electrical insulation. PD detection is a standardized technique to qualify the state of the insulation in electric assets such as machines and power cables. Generally, the classical phase-resolved partial discharge (PRPD) patterns are used to perform the identification of the type of PD source when they are related to a specific degradation process and when the electrical noise level is low compared to the magnitudes of the PD signals. However, in practical applications such as measurements carried out in the field or in industrial environments, several PD sources and large noise signals are usually present simultaneously. In this study, three different inductive sensors have been used to evaluate and compare their performance in the detection and separation of multiple PD sources by applying the chromatic technique to each of the measured signals.

[Iron intake and HFE gen in male adults from Buenos Aires]. / Ingesta de hierro y gen HFE en varones adultos de Buenos Aires.

Excess iron (Fe) intake in subjects carrying certain mutations in the HFE gene may result in Fe overload. To estimate risk of Fe overload, 166 male blood donors (19-65 years) from Buenos Aires city were investigated. Daily Fe intake (FeI), hem Fe intake, and Fe intake from SO4Fe enriched flours were estimated (SARA Computer Program and Food Composition Table, USDA). Serum ferritin and transferrin saturation were determined; criteria for Fe overload was serum ferritin > 300 ng/ml and transferrin saturation = 50%. HFE genotypes C282Y, H63D and S65C were analyzed by PCR-RFLP in blood samples. No participant presented FeI lower than the estimated average requirement (6 mg Fe/day) and 3.0% was over the upper level (45 mg Fe/day). Hem Fe and Fe from flour enrichment were 9.4% and 47.7% of daily Fe intake, respectively. A significant association was observed between the increase in serum ferritin (ng/ml) and the increase in FeI (p = 0.0472); 2.3% of the donors presented serum ferritin > 300 ng/ml and transferrin saturation = 50%. Genotypes associated with hereditary hemochromatosis (H63D, S65C and C282Y) were found in 29.3% of the donors. The percentage of transferrin saturation was higher in subjects carrying mutation than in wild type subjects (p = 0.0167). Although penetrance of hereditary hemochromatosis in the studied group was only 1.2%, an excessive Fe intake could enhance adverse effects in individuals unaware of any family history of Fe overload.

Ingesta de hierro y gen HFE en varones adultos de Buenos Aires / Iron intake and HFE gen in male adults from Buenos Aires

El consumo excesivo de hierro (Fe) en portadores de mutaciones en el gen HFE puede resultar en sobrecarga. Para evaluar el riesgo de sobrecarga de Fe fueron investigados 166 varones adultos donantes de sangre de la ciudad de Buenos Aires. Se estimó la ingesta diaria de Fe (IFe), de Fe hemínico y de Fe proveniente de harinas enriquecidas con SO4Fe. Se determinó ferritina sérica y porcentaje de saturación de transferrina (criterio de sobrecarga de Fe: ferritina sérica > 300 ng/ml y saturación de transferrina ≥ 50%). Las mutaciones C282Y, H63D y S65C fueron investigadas en sangre mediante PCR-RFLP. Todos los participantes cubrieron ampliamente el requerimiento estimado promedio de Fe (6 mg Fe/día) y 3.0% superó el máximo tolerable (45 mg Fe/día). El Fe hemínico correspondió al 9.4% de la IFe y el de harinas enriquecidas al 47.7%. Se observó una asociación entre el aumento de IFe y el de ferritina sérica (p = 0.0472), y el 2.3% de los donantes presentaron ferritina sérica > 300 ng/ml y saturación de transferrina ≥ 50%. El 29.3% de los donantes eran portadores de los genotipos H63D, S65C o C282Y, asociados a hemocromatosis hereditaria, y tenían valores de saturación de transferrina significativamente mayores a los de los donantes wild type (p = 0.0167). Si bien la incidencia clínica de hemocromatosis hereditaria fue baja en el grupo estudiado (1.2%), el consumo excesivo de Fe plantea un riesgo potencial para la salud de individuos que ignoran sus antecedentes familiares de sobrecarga de Fe.

Excess iron (Fe) intake in subjects carrying certain mutations in the HFE gene may result in Fe overload. To estimate risk of Fe overload, 166 male blood donors (19-65 years) from Buenos Aires city were investigated. Daily Fe intake (FeI), hem Fe intake, and Fe intake from SO4Fe enriched flours were estimated (SARA Computer Program and Food Composition Table, USDA). Serum ferritin and transferrin saturation were determined; criteria for Fe overload was serum ferritin > 300 ng/ml and transferrin saturation ≥ 50%. HFE genotypes C282Y, H63D and S65C were analyzed by PCR-RFLP in blood samples. No participant presented FeI lower than the estimated average requirement (6 mg Fe/day) and 3.0% was over the upper level (45 mg Fe/day). Hem Fe and Fe from flour enrichment were 9.4% and 47.7% of daily Fe intake, respectively. A significant association was observed between the increase in serum ferritin (ng/ml) and the increase in FeI (p = 0.0472); 2.3% of the donors presented serum ferritin > 300 ng/ml and transferrin saturation ≥ 50%. Genotypes associated with hereditary hemochromatosis (H63D, S65C and C282Y) were found in 29.3% of the donors. The percentage of transferrin saturation was higher in subjects carrying mutation than in wild type subjects (p = 0.0167). Although penetrance of hereditary hemochromatosis in the studied group was only 1.2%, an excessive Fe intake could enhance adverse effects in individuals unaware of any family history of Fe overload.

Diagnostic Doses of Insecticides for Adult Aedes aegypti to Assess Insecticide Resistance in Cuba.

The objective of this study was to determine diagnostic doses (DDs) of 5 insecticides for the Rockefeller susceptible strain of Aedes aegypti , using the Centers for Disease Control and Prevention (CDC) bottle bioassay as a tool for monitoring insecticide resistance in the Cuban vector control program. The 30-min DD values determined in this study were 13.5 µg/ml, 6.5 µg/ml, 6 µg/ml, 90.0 µg/ml, and 15.0 µg/ml for cypermethrin, deltamethrin, lambda-cyhalothrin, chlorpyrifos, and propoxur, respectively. To compare the reliability of CDC bottle bioassay with the World Health Organization susceptible test, 3 insecticide-resistant strains were evaluated for deltamethrin and lambda-cyhalothrin. Results showed that the bottles can be used effectively from 21 to 25 days after treatment and reused up to 4 times, depending on the storage time. The CDC bottle bioassay is an effective tool to assess insecticide resistance in field populations of Ae. aegypti in Cuba and can be incorporated into vector management programs using the diagnostic doses determined in this study.

Crioglobulina con propiedad crioaglutinina en un paciente con linfoma esplénico de zona marginal / Cryoglobulin with cold agglutinin properties in a patient with splenic marginal zone lymphoma / Crioglobulina com propriedade crioaglutinina em um paciente com linfoma esplênico de zona marginal

El objetivo del trabajo fue describir un caso de linfoma esplénico de zona marginal (LEZM) con un componente monoclonal que posee propiedades de crioglobulina y crioaglutinina, un hallazgo de muy baja frecuencia. Una paciente con LEZM padeció una anemia hemolítica autoinmune 5 años después del diagnóstico, con hematocrito de 0,15 L/L, hemoglobina 49 g/L, lactato deshidrogenasa 16,82 μkat/L, prueba de Coombs directa positiva con anti- IgG/C3d, bilirrubina total 90,6 μmol/L e indirecta de 58,1 μmol/L. No presentó evidencia clínica ni serológica de infección por VIH, hepatitis B ni C. El proteinograma sérico presentó un pico monoclonal de 14 g/L, con crioglobulinemia positiva a las 24 h, y un criocrito de 30%. La crioglobulina purificada fue de tipo I con un componente monoclonal IgM-lambda, coincidente al observado en suero. El suero, el eluato a 37 °C y la crioglobulina purificada de la paciente presentaron actividad de crioaglutinina con especificidad anti-I, fenómeno producido por la misma inmunoglobulina. El hallazgo de una crioglobulina con propiedades de crioaglutinina en pacientes con LEZM no ha sido descrito previamente en la bibliografía.

The aim of this paper is to describe a case of splenic marginal zone lymphoma (SMZL) with monoclonal component having properties of cryoglobulin and cold agglutinin, a finding of very low frequency. A patient with SMZL suffered autoimmune hemolytic anemia five years after diagnosis, with hematocrit 0.15 L/L, hemoglobin 49 g/L, lactate dehydrogenase 16.82 μkat/L, direct Coombs test with anti-IgG/C3d positive, total bilirubin 90.6 μmol/L and indirect 58.1 μmol/L. She presented no clinical or serological evidence of HIV, hepatitis B or C infection. Serum protein electrophoresis showed a monoclonal peak of 14 g/L, with positive cryoglobulinemia at 24 hours, and 30% cryocrit. Purified cryoglobulin was type I with a monoclonal IgM-lambda component coincident with that observed in serum. The patient serum, eluate at 37 °C and purified cryoglobulin showed cold agglutinin activity with anti-I specificity, phenomenon produced by the same immunoglobulin. The finding of a cryoglobulin with cold agglutinin properties in patients with SMZL has not been previously described in the literature.

O objetivo do trabalho foi descrever um caso de linfoma esplênico de zona marginal (LEZM) com um componente monoclonal com propriedades do crioglobulina e crioaglutinina, um achado de muito baixa frequência. Um doente com LEZM sofreu uma anemia hemolítica autoimune cinco anos após o diagnóstico, com hematócrito de 0,15 L/L, hemoglobina 49 g/L, lactato desidrogenase de 16,82 μkat/L, teste de Coombs direto positivo com anti-IgG/C3d, bilirrubina total 90,6 μmol/L e indireta 58,1 μmol/L. Não apresentou evidência clínica ou sorológica de infecção por HIV, hepatite B ou C. O proteinograma sérico mostrou um pico monoclonal de 14 g/L, com crioglobulinemia positiva 24 horas, e um criocrito de 30%. Crioglobulina purificada foi tipo I com o componente monoclonal IgM-lambda, coincidente com a observada no soro. O soro, o eluato a 37 ° C e a crioglobulina purificada do paciente mostraram atividade de crioaglutinina com especificidade anti-I, fenômeno produzido pela mesma imunoglobulina. O achado de uma crioglobulina com propriedades de crioaglutinina em pacientes com LEZM não foi previamente descrito na literatura.

[Ecology of Aedes aegypti and Aedes albopictus in the Americas and disease transmission]. / Ecología de Aedes aegypti y Aedes albopictus en América y transmisión enfermedades.

The recent range expansion of the mosquito Aedes albopictus has been associated in some areas by declines in abundance or local elimination of Aedes aegypti, but the two species still coexist in large regions of the Americas. We offer a summary of the possible mechanisms responsible for the abundance and displacement pattern observed and of their significance in terms of disease transmission. Among these mechanisms we may mention the competition for limiting resources, the differences in the ability to withstand starvation, the apparent competition through differential effects of the parasite Ascogregarina taiwanensis, and the inhibition of Ae. aegypti egg development by Ae. albopictus larvae. Habitat segregation has been proposed as a mechanism promoting the coexistence of the two species through avoidance of direct competition. Aedes aegypti predominates in urban areas, Ae. albopictus in rural ones, and both species coexist in the suburbs. There is also evidence that in certain areas, habitat segregation in terms of distance from the coast can influence the distribution of both species. Another possible cause of the rapid disappearance of Ae. aegypti is reproductive interference between the species. According to this hypothesis, asymmetric effects of interspecific mating favor Ae. albopictus. This type of reproductive interference can result in the elimination of sympatric populations of the affected species and can be one of the major causes for the swiftness with which Ae. aegypti disappeared from some places in the Americas following invasions by Ae. albopictus.

A validation of the spectral power clustering technique (SPCT) by using a Rogowski coil in partial discharge measurements.

Both in industrial as in controlled environments, such as high-voltage laboratories, pulses from multiple sources, including partial discharges (PD) and electrical noise can be superimposed. These circumstances can modify and alter the results of PD measurements and, what is more, they can lead to misinterpretation. The spectral power clustering technique (SPCT) allows separating PD sources and electrical noise through the two-dimensional representation (power ratio map or PR map) of the relative spectral power in two intervals, high and low frequency, calculated for each pulse captured with broadband sensors. This method allows to clearly distinguishing each of the effects of noise and PD, making it easy discrimination of all sources. In this paper, the separation ability of the SPCT clustering technique when using a Rogowski coil for PD measurements is evaluated. Different parameters were studied in order to establish which of them could help for improving the manual selection of the separation intervals, thus enabling a better separation of clusters. The signal processing can be performed during the measurements or in a further analysis.

MDR1/ABCB1 gene polymorphisms in patients with chronic myeloid leukemia.

BACKGROUND: Tyrosine kinase inhibitors (TKIs) are the recommended treatment for patients with chronic myeloid leukemia (CML). The MDR1/ABCB1 gene plays a role in resistance to a wide spectrum of drugs, including TKIs. However, the association of MDR1/ABCB1 gene polymorphisms (SNPs) such as C1236T, G2677T/A, and C3435T with the clinical therapeutic evolution of CML has been poorly studied. We investigated these gene polymorphisms in CML-patients treated with imatinib, nilotinib and/or dasatinib. METHODS: ABCB1-SNPs were studied in 22 CML-patients in the chronic phase (CP) and 2 CML-patients in blast crisis (BC), all of whom were treated with TKIs, and compared with 25 healthy controls using nested-PCR and sequencing techniques. RESULTS: Seventeen different haplotypes were identified: 7 only in controls, 6 only in CML-patients, and the remaining 4 in both groups. The distribution ratios of homozygous TT-variants present on each exon between controls and CML-patients were 2.9 for exon 12, and 0.32 for the other 2 exons. Heterozygous T-variants were observed in all controls (100%) and 75% of CML-patients. Wt-haplotype (CC-GG-CC) was observed in 6 CML-patients (25%). In this wt-group, two were treated with nilotinib and reached a major molecular response. The remaining 4 cases had either a minimal or null molecular response, or developed bone marrow aplasia. CONCLUSION: Our results suggest that SNPs of the MDR1/ABCB1 gene could help to characterize the prognosis and the clinical-therapeutic evolution of CML-patients treated with TKIs. Wt-haplotype could be associated with a higher risk of developing CML, and a worse clinical-therapeutic evolution.

Ecología de Aedes aegypti y Aedes albopictus en América y transmisión enfermedades / Ecology of Aedes aegypti and Aedes albopictus in the Americas and disease transmission

La reciente expansión geográfica del mosquito Aedes albopictus ha estado acompañada en algunos sitios por la disminución en la abundancia o por la eliminación local de Aedes aegypti, pero las dos especies aún coexisten en extensas regiones de América. En este trabajo se ofrece un resumen de los posibles mecanismos responsables de sus patrones de abundancia y desplazamiento, así como de su significado en cuanto a la transmisión de enfermedades. Entre los mecanismos observados, se encuentran la competencia por recursos, las diferencias en la capacidad para soportar la inanición, la competencia aparente a través de efectos diferenciales del parásito Ascogregarina taiwanensis, y la inhibición causada por larvas de Ae. albopictus en el desarrollo de los huevos de Ae. aegypti. Un mecanismo propuesto como promotor de la coexistencia de estas especies es la segregación en diferentes hábitats, lo que evita la competencia directa. Aedes aegypti predomina en áreas urbanas, Ae. albopictus en áreas rurales, y las dos especies coexisten en áreas periurbanas. Existen pruebas de que la distribución de Ae. aegypti y Ae. albopictus también puede verse afectada en ciertas áreas, por la distancia desde la costa. Otra posible causa de la rápida desaparición de Ae. aegypti es la interferencia reproductiva entre las dos especies. De acuerdo con esta hipótesis, los efectos asimétricos de los apareamientos entre especies favorecen a Ae. albopictus. Este tipo de interferencia reproductiva podría ser la causante de la eliminación de poblaciones simpátricas de las especies involucradas y de la rapidez con que Ae. aegypti ha desaparecido de muchos lugares en América luego de la invasión de Ae. albopictus.

The recent range expansion of the mosquito Aedes albopictus has been associated in some areas by declines in abundance or local elimination of Aedes aegypti, but the two species still coexist in large regions of the Americas. We offer a summary of the possible mechanisms responsible for the abundance and displacement pattern observed and of their significance in terms of disease transmission. Among these mechanisms we may mention the competition for limiting resources, the differences in the ability to withstand starvation, the apparent competition through differential effects of the parasite Ascogregarina taiwanensis, and the inhibition of Ae. aegypti egg development by Ae. albopictus larvae. Habitat segregation has been proposed as a mechanism promoting the coexistence of the two species through avoidance of direct competition. Aedes aegypti predominates in urban areas, Ae. albopictus in rural ones, and both species coexist in the suburbs. There is also evidence that in certain areas, habitat segregation in terms of distance from the coast can influence the distribution of both species. Another possible cause of the rapid disappearance of Ae. aegypti is reproductive interference between the species. According to this hypothesis, asymmetric effects of interspecific mating favor Ae. albopictus. This type of reproductive interference can result in the elimination of sympatric populations of the affected species and can be one of the major causes for the swiftness with which Ae. aegypti disappeared from some places in the Americas following invasions by Ae. albopictus.