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Background: Biallelic variants in POLR1C are associated with POLR3-related leukodystrophy (POLR3-HLD), or 4H leukodystrophy (Hypomyelination, Hypodontia, Hypogonadotropic Hypogonadism), and Treacher Collins syndrome (TCS). The clinical spectrum of POLR3-HLD caused by variants in this gene has not been described. Methods: A cross-sectional observational study involving 25 centers worldwide was conducted between 2016 and 2018. The clinical, radiologic and molecular features of 23 unreported and previously reported cases of POLR3-HLD caused by POLR1C variants were reviewed. Results: Most participants presented between birth and age 6 years with motor difficulties. Neurological deterioration was seen during childhood, suggesting a more severe phenotype than previously described. The dental, ocular and endocrine features often seen in POLR3-HLD were not invariably present. Five patients (22%) had a combination of hypomyelinating leukodystrophy and abnormal craniofacial development, including one individual with clear TCS features. Several cases did not exhibit all the typical radiologic characteristics of POLR3-HLD. A total of 29 different pathogenic variants in POLR1C were identified, including 13 new disease-causing variants. Conclusions: Based on the largest cohort of patients to date, these results suggest novel characteristics of POLR1C-related disorder, with a spectrum of clinical involvement characterized by hypomyelinating leukodystrophy with or without abnormal craniofacial development reminiscent of TCS.
Background: Genetically-determined leukoencephalopathies comprise a rare group of inherited white matter disorders. The vast majority are associated with a progressive disease course and early death. This study seeks to determine the clinical and demographic correlates of stress in parents of leukodystrophy patients, for future clinical guidance. Methods: A cross-sectional study including 36 families was performed. Children aged 1 month to 12 years with a diagnosed leukodystrophy or genetically-determined leukoencephalopathy were included. 31 mothers and 24 fathers completed the Parental Stress Index, 4th edition (PSI-4). One demographic questionnaire was completed per family. Clinical data was gathered within 6 months of the questionnaires. Statistical analysis was performed with total stress (TS) scores as the primary outcome. Results: Mothers and fathers had comparable TS scores. No clinical or demographic factors predicted the father’s TS score. Greater ambulatory impairment, using the GMFCS scale, correlated to lower TS scores in the mother. Conclusions: The progressive nature of these conditions makes it such that anticipating a child’s inability to walk may cause more stress for mothers than a child’s actual inability to ambulate. The inability of all other variables to predict total stress highlights a need for individualized approaches when addressing stress in these families.
Two studies of OH maser emission in envelopes of late type stars -miras (3) and OH/IR objects- have been performed with the Nancay radio-telescope. Mainly, the OH miras are found with thicker dust envelopes than the non OH ones. A sample of unidentified IRAS point sources selected on their colors has been observed. We have detected 46 new OH sources. The OH detection rate is a function of the galactic longitude and of the IRAS spectral classification.
We sought to comprehensively assess the prevalence and outcomes of complications associated with Staphylococcus aureus bacteremia (SAB) in children. Secondarily, prevalence of methicillin resistance and outcomes of complications from methicillin-resistant S. aureus (MRSA) vs. methicillin-susceptible S. aureus SAB were assessed. This is a single-center cross-sectional study of 376 patients ⩽18 years old with SAB in 1990–2014. Overall, 197 (52%) patients experienced complications, the most common being osteomyelitis (33%), skin and soft tissue infection (31%), and pneumonia (25%). Patients with complications were older (median 3 vs. 0·7 years, P = 0·05) and more had community-associated SAB (66% vs. 34%, P = 0·001). Fewer patients with complications had a SAB-related emergency department or hospital readmission (10% vs. 19%, P = 0·014). Prevalence of methicillin resistance increased from 1990–1999 to 2000–2009, but decreased in 2010–2014. Complicated MRSA bacteremia resulted in more intensive care unit admissions (66% vs. 47%, P = 0·03) and led to increased likelihood of having ⩾2 foci (58% vs. 26%, P < 0·001). From multivariate analysis, community-associated SAB increased risk and concurrent infections decreased risk of complications (odds ratio (OR) 1·82 (1·1–3·02), P = 0·021) and (OR 0·58 (0·34–0·97), P = 0·038), respectively. In conclusion, children with SAB should be carefully evaluated for complications. Methicillin resistance remains associated with poor outcomes but have decreased in overall prevalence.
Background: 4H or POLR3-related leukodystrophy is an autosomal recessive disorder characterized by hypomyelination, hypodontia and hypogonadotropic hypogonadism caused by mutations in POLR3A, POLR3B and POLR1C. The endocrine abnormalities have never been systematically studied. Methods: A cross sectional international multicenter study was performed and the following variables were assessed: weight, height, head circumference, pubertal history, hormone levels and neurological and non-neurological features. Data was analyzed to determine whether there was a correlation between the presence of endocrine abnormalities and mutations in a specific gene and/or the presence of specific symptoms such as other non-neurological symptoms. Results: Data was collected on 156 patients. Endocrine data were available for 144 patients. The most common endocrine abnormalities seen in this cohort were short stature (54/90 patients (60%)) and delayed puberty (53/70 patients (76%)). 13 of the 58 patients tested (22%) had abnormal thyroid function. Patients with POLR3A mutations were more likely to have endocrine abnormalities. Conclusions: Our results confirm that the most common endocrine features in 4H leukodystrophy are short stature and pubertal abnormalities. However, the other potential endocrine abnormalities are typically under-investigated in this patient population. A prospective study is required to investigate the extent and severity of the endocrine abnormalities in 4H leukodystrophy.
Background: Genetic leukoencephalopathies are a group of neurodegenerative diseases imposing a great burden on patients and families. There is no previous systematic study looking at the impacts of these diseases. Methods: HRQOL was assessed using the Pediatric Quality of Life Inventory (PedsQL) model. A total of 24 patients with genetically determined leukoencephalopathies and their family members completed the PedsQL questionnaires. Detailed clinical assessments were performed at the time the questionnaires were filled. HRQOL results were correlated with the severity of the clinical features and the presence vs. absence of a definitive molecular diagnosis. Results: Preliminary results show lower PedsQL total scores for patients without compared to with a molecular diagnosis. Emotional and physical functioning scores were significantly impaired in patients without a molecular diagnosis. Lower total scores were obtained for patients who presented more severe clinical features such as lost ambulatory functions and dysphagia. Conclusions: Overall, our preliminary results indicate that patients without a molecular diagnosis have an impaired HRQOL and that more severely affected patients have a poorer HRQOL. Further analyses and studies on a larger population of patients in a prospective fashion are required to assess the burden of these diseases and identify potential modifiable factors.
Leptospirosis incidence has increased markedly since 1995 in Thailand, with the eastern and northern parts being the most affected regions, particularly during flooding events. Here, we attempt to overview the evolution of human prevalence during the past decade and identify the environmental factors that correlate with the incidence of leptospirosis and the clinical incidence in humans. We used an extensive survey of Leptospira infection in rodents conducted in 2008 and 2009 and the human incidence of the disease from 2003 to 2012 in 168 villages of two districts of Nan province in Northern Thailand. Using an ad-hoc developed land-use cover implemented in a geographical information system we showed that humans and rodents were not infected in the same environment/habitat in the land-use cover. High village prevalence was observed in open habitat near rivers for the whole decade, or in 2008–2009 mostly in rice fields prone to flooding, whereas infected rodents (2008–2009) were observed in patchy habitat with high forest cover, mostly situated on sloping ground areas. We also investigated the potential effects of public health campaigns conducted after the dramatic flood event of 2006. We showed that, before 2006, human incidence in villages was explained by the population size of the village according to the environmental source of infection of this disease, while as a result of the campaigns, human incidence in villages after 2006 appeared independent of their population size. This study confirms the role of the environment and particularly land use, in the transmission of bacteria, emphasized by the effects of the provincial public health campaigns on the epidemiological pattern of incidence, and questions the role of rodents as reservoirs.
Carbon films deposited by filtered cathodic vacuum arc have been used to form high quality Schottky diodes on p-Si. Energetic deposition with an applied substrate bias of -1 kV and with a substrate temperature of 100 °C has produced carbon diodes with rectification ratios of ∼ 3 × 106, saturation currents of ∼0.02 nA and ideality factors close to unity (n = 1.05). Simulations were used to estimate the effective work function and the thickness of an interfacial mixed (C/SiO2) layer from the current/voltage characteristics of the diodes.
The charge - transfer reaction between protons and oxygen atoms is critical to the chemistry of the oxygen family; the corresponding rate was evaluated by Field and Steigman (1971) on the assumption of orbiting collisions and statistical probability distribution among the levels. We re-examine this reaction, including the fine-structure excitation process, basing our analysis on a careful description of the different potential curves arising from the O-H+ and 0+-H systems and on the evaluation of the coupling responsible for the transitions.
In the past year, several organizations have fabricated reliable, high-brightness LEDs from III-Nitride materials that emit in the blue and green. Recently, Nichia in Japan have announced lasing action in GaN-based diodes. Quantum well structures are key to all these results, offering higher brightness, narrower EL linewidths, and a wider spectral range. In order for the III-Nitride technology to develop, the material growth technique must offer high volume at low cost in addition to the requisite device performance. To date, only MOVPE has demonstrated this capability. We have previously reported the growth of GaN, InGaN, and AlGaN layers by MOVPE in a multi-wafer, high-speed rotating disk reactor. Both n- and p-doping and high quality optical properties have been achieved. In this paper we extend this earlier work and present results of the performance of InGaN / (Al)GaN quantum well structures. Intense PL spectra were observed in the violet and blue regions. The thinnest wells show evidence from PL and DCXRD measurments of either discontinuous layers (islands) or a diffuse upper interface, with preliminary TEM results showing the latter to be the most likely. We also report excellent uniformity of these quantum well structures, and show electroluminescence from a SQW diode emitting at 473 nm.
In this contribution, we show that the dominant electroluminescent emission of hydrogenated amorphous silicon (a-Si:H) thin-film solar cells follows a diode law, whose radiative ideality factor nr is larger than one. This is in contrast to crystalline silicon and Cu(In, Ga)Se2 solar cells for which nr equals one. As a consequence, the existing quantitative analysis for the extraction of the local junction voltage Vj(r) from luminescence images fails for a-Si:H solar cells. We expand the existing analysis method, and include the radiative ideality factor nr into the model. With this modification, we are able to determine the local junction voltage Vj(r) for a-Si:H solar cells and modules. We investigated the local junction voltage Vj(r) and the radiative ideality factor nr for both initial and stabilized a-Si:H solar modules. Furthermore, we show that the apparent radiative ideality factor is affected by the spectral sensitivity of the used camera system.
The information stored in animal feed databases is highly variable, in terms of both provenance and quality; therefore, data pre-processing is essential to ensure reliable results. Yet, pre-processing at best tends to be unsystematic; at worst, it may even be wholly ignored. This paper sought to develop a systematic approach to the various stages involved in pre-processing to improve feed database outputs. The database used contained analytical and nutritional data on roughly 20 000 alfalfa samples. A range of techniques were examined for integrating data from different sources, for detecting duplicates and, particularly, for detecting outliers. Special attention was paid to the comparison of univariate and multivariate solutions. Major issues relating to the heterogeneous nature of data contained in this database were explored, the observed outliers were characterized and ad hoc routines were designed for error control. Finally, a heuristic diagram was designed to systematize the various aspects involved in the detection and management of outliers and errors.
Triticale possesses favourable agronomic attributes originating from both its wheat and rye progenitors, including high grain and biomass yields. Triticale, primarily used as animal feed in North America, is an excellent candidate for production of industrial bio-products. Little is known about the coordination of gene expression of rye and wheat genomes in this intergeneric hybrid, but significant DNA losses from the parental genomes have been reported. To clarify the regulation of gene expression in triticale, we carried out 454 sequencing of cDNAs obtained from root, leaf, stem and floral tissues in different lines of triticale and rye exhibiting different phenotypes and assembled reads into contigs. Related to the data assembly were the absence of reference genomes and the paucity of rye sequences in GenBank or other public databases. Consequently, we have sequenced cDNA libraries from roots, seedlings, leaves, floral tissues and immature seeds to facilitate the identification of triticale sequences originating from rye. To further characterize the wheat-derived cDNAs, we also developed a database close to 25,000 non-redundant full-length wheat coding sequence genes, based on existing databases and contigs that were verified against protein sequences from the grass genomes of Brachypodium distachyon, rice, sorghum and maize.
Carbon grading in the buffer layer at the p/i interface increases the open circuit voltage of both p-i-n and n-i-p amorphous silicon solar cells. We propose that carbon grading enlarges the electric field and reduces the electron tunneling at the p/i interface.
We demonstrated the high quality growth of exceedingly thick pseudomorphic layers on free-standing, compliant substrates using InGaAs and GaAs materials. A 1% compressively strained InGaAs layer was grown on a relaxed GaAs platform by MBE. We fabricated the 800 Å-thick compliant platforms before growing a lattice-mismatched layer that exceeds its critical thickness by about twenty times.
X-ray analysis confirms a shift in the InGaAs peaks grown on the compliant substrate. Such shifts are characteristic of strained layers. Atomic Force Microscope analysis verifies that the layers on compliant substrates are much smoother than layers grown on a plain substrate.
Pseudomorphic growth exceeding the critical thickness has important applications in the design of various electronic and photonic devices.
Primary rat bone marrow cells were cultured on bacteriological grade polystyrene dishes which had been treated in selected areas with concentrated sulphuric acid. X-ray photoelectron spectroscopy, angle-resolved and imaging modes, and atomic force microscopy showed that the acid treatment brought about both chemical and topographical changes in the substratum surface. While the bone marrow cells attached to both treated and untreated areas of the surfaces of the dishes, the distribution of early mineralized extracellular matrix in these areas was reproducibily different. Thus, using extracellular matrix deposition as a marker, modification of the polymer surface resulted in the cells adhering to treated and untreated areas exhibiting different phenotypes.
The structure of CeO2 films grown on (1102) sapphire and on YBCO thin films was investigated. The films reported on here were grown by pulsed excimer laser deposition and their surface structure was probed using atomic force microscopy. We found that CeO2 films grown on sapphire were epitaxial with a granular structure which is smooth on an atomic scale. We see evidence of a surface reconstruction on a very smooth CeO2 (100) oriented surface. At higher growth temperatures, three dimensional islands begin to form. When a CeO2 film is grown on top of a YBCO film, the growth mode is two dimensional. The steps in this layer by layer growth are a surprisingly large 2 nm. This is about equal to 4 times the CeO2 lattice constant. This step height appears to be temperature dependent.