1,198 research outputs found

    Analysis of S-band solid-state transmitters for the solar power satellite

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    The possibility of replacing the Reference System antenna in which thermionic devices are used for the dc-to-microwave conversion, with solid-state elements was explored. System, device, and antenna module tradeoff investigations strongly point toward the desirability of changing the transmitter concept to a distributed array of relatively low power elements, deriving their dc power directly from the solar cell array and whose microwave power outputs are combined in space. The approach eliminates the thermal, weight, and dc-voltage distribution problems of a system in which high power tubes are simply replaced with clusters of solid state amplifiers. The proposed approach retains the important advantages of a solid state system: greatly enhanced reliability and graceful degradation of the system

    Specific immunoassays confirm association of <i>Mycobacterium avium</i> subsp. <i>paratuberculosis</i> with type-1 but not type-2 diabetes mellitus

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    Background Mycobacterium avium subspecies paratuberculosis (MAP) is a versatile pathogen with a broad host range. Its association with type-1 diabetes mellitus (T1DM) has been recently proposed. Rapid identification of infectious agents such as MAP in diabetic patients at the level of clinics might be helpful in deciphering the role of chronic bacterial infection in the development of autoimmune diseases such as T1DM. Methodology/Principal Findings We describe use of an ELISA method to identify live circulating MAP through the detection of a cell envelope protein, MptD by a specific M13 phage – fMptD. We also used another ELISA format to detect immune response to MptD peptide. Both the methods were tested with blood plasma obtained from T1DM, type-2 diabetes (T2DM) patients and non-diabetic controls. Our results demonstrate MptD and fMptD ELISA assays to be accurate and sensitive to detect MAP bacilli in a large fraction (47.3%) of T1DM patients as compared to non-diabetic controls (12.6%) and those with confirmed T2DM (7.7%). Comparative analysis of ELISA assays performed here with 3 other MAP antigen preparations, namely HbHA, Gsd and whole cell MAP lysates confirmed comparable sensitivity of the MptD peptide and the fMptD based ELISA assays. Moreover, we were successful in demonstrating positive bacterial culture in two of the clinical specimen derived from T1DM patients. Conclusions and Significance The MptD peptide/fMptD based ELISA or similar tests could be suggested as rapid and specific field level diagnostic tests for the identification of MAP in diabetic patients and for finding the explanations towards the occurrence of type-1 or type-2 diabetes in the light of an active infectious trigger

    <i>Gut Pathogens</i>: enteric health at the interface of changing microbiology

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    The International Society for Genomic and Evolutionary Microbiology (ISOGEM) in collaboration with BioMed Central Ltd. has launched Gut Pathogens with the aim of providing a high-quality forum for research on enteric infections of humans and animals. The journal led by three Editors-in-Chief and supported by a highly qualified and organized international Editorial Board publishes open access research articles of repute in areas of biology and the pathogenesis of bacterial, parasitic and viral infections of the gut including their diagnosis, epidemiology and clinical management

    Drug intake and actinic keratosis: A case-control study

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    Background: Actinic keratosis (AK) is a form of premalignant keratinocyte dysplasia. Recently, the ABSTRACT role of photosensitizing drugs in the development of AK has been postulated. Objective: This study evaluated a possible association between the use of photosensitizing drugs and the development of AK. A secondary aim was to identify a possible association between any medication other than those primarily examined and AK. Methods: A single-center, case-control study assessed the cumulative drug exposure of 90 patients with AK and 90 controls visiting a dermatology service for other skin ailments. Before the visit, patients were interviewed to collect data on daily therapy and the lag-time of discontinued drugs within the last 2 years, and to record the drug's active ingredient, dosage, and duration of therapy. In addition, sociodemographic characteristics including age, sex, educational level, skin phototype, and cumulative sun exposure habits were gathered. Results: By logistic regression, exposures to angiotensin II receptor blockers (ARBs) and antiplatelet agents were identified as independent risk factors for the development of AK. ARB intake was associated with AK only at high exposure (OR = 13.6; 95% CI, 2.0-93.8). The use of antiplatelet drugs was borderline, yet not significant, at low exposure (OR = 3.31; 95% CI, 0.86-12.7), but increased in a dose-dependent manner. The strongest correlation was found at the highest cumulative dose (>1100 dose unit-years (OR = 4.38; 95% CI, 1.16-16.6). Conclusions: High exposure to ARBs and antiplatelet agents may promote AK carcinogenesis in at-risk patients

    First-Time Mothers’ and Fathers’ Developmental Changes in the Perception of Their Daughters’ and Sons’ Temperament: Its Association With Parents’ Mental Health

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    Objective: Most studies investigating the role of parenting behaviors on a child’s development are directed to mothers. However, recent analyses show that mothers and fathers have a different influence on a child’s functioning, specifically her/his temperament. The present study explored the developmental change of parents’ perception of their daughters’ and sons’ temperament and its association with parental mental health problems. Methods: The sample included 188 parents (94 couples) and their at-term 94 babies (55.3% boys, 44.7% girls). Assessments by self-reports were conducted at 3 (Time 1) and 12 (Time 2) months after the children’s birth; at Time 1, mothers and fathers independently answered: the State–Trait Anxiety Inventory (STAI), the Edinburgh Postnatal Depression Scale (EPDS), and the Infant Behavior Questionnaire (IBQ-R). At Time 2, EPDS, STAI, and IBQ-R were again administered to mothers and fathers. Results: In general, mothers and fathers would give similar descriptions of their child’s temperament throughout the first year of life; however, infant temperament showed developmental changes as well as gender differences. Mother and father anxiety and depression symptoms are associated with the infants’ negative affectivity. Also, mothers with high anxiety and depression levels perceive their infants with a minor tendency to approach novelty, to seek environmental stimulation, and to express/experience positive emotions. Conclusion: The results highlight the need to screen for infants’ temperament vulnerabilities in the context of maternal and paternal depression in order to protect the child from behavioral, cognitive, and emotional difficulties and to create specific programs aimed at preventing dysfunctional parent–infant relationships

    Specific Immunoassays Confirm Association of Mycobacterium avium Subsp. paratuberculosis with Type-1 but Not Type-2 Diabetes Mellitus

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    Mycobacterium avium subspecies paratuberculosis (MAP) is a versatile pathogen with a broad host range. Its association with type-1 diabetes mellitus (T1DM) has been recently proposed. Rapid identification of infectious agents such as MAP in diabetic patients at the level of clinics might be helpful in deciphering the role of chronic bacterial infection in the development of autoimmune diseases such as T1DM.We describe use of an ELISA method to identify live circulating MAP through the detection of a cell envelope protein, MptD by a specific M13 phage--fMptD. We also used another ELISA format to detect immune response to MptD peptide. Both the methods were tested with blood plasma obtained from T1DM, type-2 diabetes (T2DM) patients and non-diabetic controls. Our results demonstrate MptD and fMptD ELISA assays to be accurate and sensitive to detect MAP bacilli in a large fraction (47.3%) of T1DM patients as compared to non-diabetic controls (12.6%) and those with confirmed T2DM (7.7%). Comparative analysis of ELISA assays performed here with 3 other MAP antigen preparations, namely HbHA, Gsd and whole cell MAP lysates confirmed comparable sensitivity of the MptD peptide and the fMptD based ELISA assays. Moreover, we were successful in demonstrating positive bacterial culture in two of the clinical specimen derived from T1DM patients.The MptD peptide/fMptD based ELISA or similar tests could be suggested as rapid and specific field level diagnostic tests for the identification of MAP in diabetic patients and for finding the explanations towards the occurrence of type-1 or type-2 diabetes in the light of an active infectious trigger

    Rapid identification of Mycobacterium tuberculosis Beijing genotypes on the basis of the Mycobacterial interspersed repetitive unit locus 26 signature

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    Mycobacterium tuberculosis Beijing strains are prevalent in many parts of the world and often give rise to large institutional outbreaks. Such highly transmissible strains, often associated with multidrug resistance, are likely underrepresented in outbreaks reported from developing countries, mainly due to nonavailability of fast detection methods suitable in epidemiological surveillance studies. We evaluated a PCR assay based on amplification of mycobacterial interspersed repetitive unit locus 26 as a stand-alone method for unambiguous identification of Beijing strains. The method was used on blinded samples from 10 standard strains whose Beijing status was already confirmed by spoligotyping. All 10 strains were accurately identified, and their profiles were corroborated successfully with spoligotypes. The method was also applied to 70 different non-Beijing clinical isolates from different countries to allow discrimination of isolates. Owing to its accuracy, simplicity, and rapidity, the assay can be employed in laboratory-level testing of isolates linked to certain outbreaks. The test can also be adopted for direct application on clinical samples to save time on culturing bacilli for genotyping

    Epilithic diatom assemblages and environmental quality of the Su Gologone karst spring (centraleastern Sardinia, Italy)

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    Karst springs are considered among the most vulnerable groundwater-dependent ecosystems. Despite their ecological value and importance as strategic water sources, Mediterranean karst springs are still poorly investigated. The aim of this study was to analyse the epilithic diatom assemblages and to test their usefulness as indicators of environmental quality on the Su Gologone spring (central-eastern Sardinia, Italy), a biotope of great natural value and a precious source of drinking water. A total of 89 diatom taxa were found with 25 new records for Sardinian running waters. Species richness, Shannon-Wiener and Pielou indices showed good biotic integrity. The dominant taxa were alkaliphilous, halophobous-oligohalobous exigent, xeno-oligosaprobic and characteristic of oligotrophic waters. The eutrophication/pollution index − diatom based (EPI-D) and the Navicula Nitzschia Surirella indices indicated respectively an excellent/good biological water quality and a low physical disturbance. However, the biological and chemical oxygen demand, and the microbiological variables (E. coli, fecal and total coliforms) revealed an organic contamination of the water, although moderate. The judgment provided by the EPI-D should be verified after updating of the index. In fact, 10 taxa found in this study are not currently considered by the EPI-D method

    Executive function impairment in early - treated PKU subjects with normal mental development

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    Executive functions were studied in 14 early and continuously treated PKU subjects (age 10.8 years, range 8-13) in comparison with controls matched for IQ, sex, age and socioeconomic status. Brain MRI examination was normal in all PKU patients. Neuropsychological evaluation included Wisconsin Card Sorting Test, Rey-Osterreith Complex Figure Test, Elithorn's Perceptual Maze Test, Weigl's Sorting Test, Tower of London, Visual Search and Motor Motor Learning Test. Whatever the IQ, PKU subjects performed worse than controls in tests exploring executive functions. Subgrouping the PKU subjects according to the quality of dietary control for the entire follow-up period (using 400 micromol/L as cut-off value for blood phenylalanine (Phe) concentration) showed that patients with worse dietary control performed more poorly than both the PKU group with the best dietary control and the control group. However, a mild impairment of executive functions was still found in PKU patients with a good dietary control (Phe 400 micromol/L) compared to controls. Concerning the PKU group as a whole, no linear correlation was found between neuropsychological performance and historical and concurrent biochemical parameters. We conclude that (a) PKU patients, even when treated early, rigorously and continuously, show an impairment of frontal lobe functions; (b) a protracted exposure to moderately high levels of Phe can affect frontal lobe functions independently of the possible effect of the same exposure on IQ; (c) in order to reduce the risk of frontal lobe dysfunction, the target of dietary therapy should be to maintain blood Phe concentration below 400 micromol/L
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