2,041 research outputs found
Whole-exome sequencing to disentangle the complex genetics of hippocampal sclerosis-temporal lobe epilepsy
Colloidal Magnetic Heterostructured Nanocrystals with Asymmetric Topologies: Seeded-Growth Synthetic Routes and Formation Mechanisms
Colloidal inorganic nanocrystals, free-standing crystalline nanostructures generated and processed in solution phase, represent an important class of advanced nanoscale materials owing to the flexibility with which their physical–chemical properties can be controlled through synthetic tailoring of their compositional, structural and geometric features and the versatility with which they can be integrated in technological fields as diverse as optoelectronics, energy storage/ conversion/production, catalysis and biomedicine. In recent years, building upon mechanistic knowledge acquired on the thermodynamic and kinetic processes that underlie nanocrystal evolution in liquid media, synthetic nanochemistry research has made impressive advances, opening new possibilities for the design, creation and mastering of increasingly complex “colloidal molecules”, in which nanocrystal modules of different materials are clustered together via solid-state bonding interfaces into free-standing, easily processable multifunctional nanocomposite systems. This Review will provide a glimpse into this fast-growing research field by illustrating progress achieved in the wet-chemical development of last-generation breeds of all-inorganic heterostructured nanocrystals (HNCs) in asymmetric non-onionlike geometries, inorganic analogues of polyfunctional organic molecules, in which distinct nanoscale crystalline modules are interconnected in hetero-dimer, hetero-oligomer and anisotropic multidomain architectures via epitaxial heterointerfaces of limited extension. The focus will be on modular HNCs entailing at least one magnetic material component combined with semiconductors and/or metals, which hold potential for generating enhanced or unconventional magnetic properties, while offering diversified or even new chemical-physical properties and functional capabilities. The available toolkit of synthetic strategies, all based on the manipulation of seeded-growth techniques, will be described, revisited and critically interpreted within the framework of the currently understood mechanisms of colloidal heteroepitaxy
Healthcare personnel and hand decontamination in intensive care units: Knowledge, attitudes, and behaviour in Italy
The purpose of this study was to evaluate knowledge, attitudes, and behaviour regarding hand decontamination in personnel of intensive care units (ICUs) in Italy. All ICU physicians and nurses in 19 and five randomly selected hospitals in Campania and Calabria (Italy) were mailed a questionnaire focusing on demographics and practice characteristics; knowledge about prevention of hospital acquired infection; attitudes and behaviour with respect to hand decontamination; and use of gloves. A total of 413 questionnaires were returned giving a response rate of 66.6%. Overall, 53.2% agreed with the correct responses on knowledge related to infection control, and this knowledge was significantly higher in neonatal and medicine-surgery wards and in larger ICUs. A positive attitude was reported by the large majority who agreed that hand decontamination reduces the risk of infection in patients (96.8%) and personnel (86.2%), and the positive attitude was significantly higher among older and female personnel and in those with a higher level of knowledge. Only 60% always decontaminate hands at the start of a shift, and 72.5% before and after a patient contact. Higher compliance is reported for invasive manoeuvres, such as urinary catheters (96.5%) and intravenous lines (77.1%). Routine hand decontamination between each patient was significantly higher in females, and in neonatal and medicine-surgery ICUs. Our results suggest that interventions should not only be focused on predisposing factors (knowledge), but also on enabling (facilitating) and reinforcing (gratifying) factors
The Economically Important Nitrogen Pathways of Southwest Florida
The global phenomenon of burgeoning coastal population growth has led to
coastal watershed landscape transformation and ecosystem degradation, prompting
policy-makers to set limits on freshwater withdrawals and labile nutrient loads. Important
components of Florida’s economies lie in the state’s expansive coastal zone; the
organisms driving the billion-dollar recreational fishing industry are rooted in coastal
habitats, while the agriculture and real-estate industries sprawl throughout numerous
coastal watersheds. This study aimed to identify the connections between anthropogenic
land use and essential juvenile fish nursery habitats within the coastal zone, which is the
first critical step for sustaining the ecology and related economies of the region.
The need for this study arises from the fact that these economies are
interconnected through nitrogen, and therefore nitrogen management can influence their
prosperity or collapse. Juvenile fish nursery habitats are located in waters that receive
nitrogen from adjacent landscapes. Runoff delivers nitrogen derived from human
nitrogen use and processing within the watersheds to the juvenile fish nursery habitats.
Ecosystem managers must understand that although copious amounts of nitrogen
applied to land may ultimately support nursery habitat foodwebs, overwhelming nitrogen
loads may also create algal blooms that decay and cause lethal hypoxic events leading
to ecosystem degradation. This study aims to pinpoint the specific nitrogen sources that
support primary production and ultimately fish production in watersheds dominated by
agricultural landscapes and residential neighborhoods.
Stable isotopes are versatile tools used to identify these connections. The
nitrogen and carbon compounds that make up the moieties of an ecosystem inherently
carry information on major nitrogen sources, trophic structure as well as the crucial
information concerning dominant nitrogen removal and transformative processes that
occur within sediments. Specifically in this study, the stable isotopes of carbon and
nitrogen of dissolved inorganic nitrogen, primary producers, and fish were used to
identify 1) the connections between urban and agricultural landscapes and the nutrients
that percolate through the foodweb, 2) the primary producers that support fish biomass,
3) the origins of sedimentary organic matter that can provide new nitrogen via recycling,
and 4) the heterogeneous function of fish nursery habitats in polluted systems. This
study was conducted during the region’s wet and dry seasons and in over thirty
watersheds that differ from each other in terms of size and anthropogenic influence.
In agricultural watersheds, nitrogen derived from row crops and tree crops
ultimately supported fish production during the wet season. Convective afternoon
thunderstorms coupled with runoff delivered nitrogen from the landscape to receiving
waters. These nutrients supported phytoplankton which deposited into the sediments
and supported benthic foodwebs. During the dry season, nitrogen derived from row
crops and nitrogen transformation in the sediments ultimately supported fish production.
In this case, irrigation water used for agriculture delivered nitrogen from lands covered
with row crops to the nursery habitats in receiving waters.
The dry season was characterized by the nitrogen transformation process known
as dissimilatory nitrogen reduction to ammonium (DNRA), where biologically available
nitrate is converted to biologically available ammonium. Phytoplankton deposits, most
likely delivered during the wet season, were recycled through the slow burning DNRA
processes, which provided nitrogen for the benthic microalgae that dominated in the dry
season. These organisms in turn supported benthic communities which ultimately
supported dry season fish production.
In small urban watersheds, nitrogen derived from septic tanks, lawn irrigation,
leaky sewage pipes, and atmospheric deposition ultimately supported fish production via
phytoplankton, but unlike the nitrogen sources in agricultural watersheds, these sources
(with the exception of atmospheric deposition) were seasonally consistent because a
mechanisms to deliver nitrogen derived from septic tanks, lawn fertilizer, and leaky
sewage pipes were, at least to some extent, available during both seasons.
In polluted, tidal, fish-nursery habitats, the specific mechanism that
allowed nursery habitats to decrease the ratio of mortality over growth rates of
juvenile fish was not consistent among systems. These mechanisms were likely
dependent on physical-chemical parameters and stream geomorphology. If the
geomorphology or physical-chemical characteristics of nursery habitats are not
adequate to set up an efficient nitrogen transfer process to fish, these habitats
become more of a haven from predators rather than a source of food for fish.
This study has several implications for management. Managers must first
recognize that microalgae are dominant supporters of tidal nursery foodwebs. Managers
must define the relationship between nitrogen loads and fish abundance. If this
relationship is unknown, the results of increasing nitrogen loads on fish production will
remain uncertain; foodwebs in nursery habitats may collapse due to eutrophication, or
fish abundance may increase due to increases in food supply. Connectivity factors
derived from stable isotope mechanistic mass-balance models can be used as
measurable targets for groups of watersheds. The use of wetlands as nitrogen
remediation tools may not be effective at removing nitrogen; nitrogen transformation
processes such as DNRA likely outweigh removal processes in wetland soils
IDIOPATHIC PARTIAL EPILEPSY WITH AUDITORY FEATURES (IPEAF): A CLINICAL AND GENETIC STUDY OF 53 SPORADIC CASES
The purpose of our study was to describe the clinical characteristics of sporadic
(S) cases of partial epilepsy with auditory features (PEAF) and pinpoint
clinical, prognostic and genetic differences with respect to previously reported
familial (F) cases of autosomal dominant partial epilepsy with auditory features
(ADPEAF). We analysed 53 patients (24 females and 29 males) with PEAF diagnosed
according to the following criteria: partial epilepsy with auditory symptoms,
negative family history for epilepsy and absence of cerebral lesions on NMR
study. All patients underwent a full clinical, neuroradiological and
neurophysiological examination. Forty patients were screened for mutations in
LGI1/epitempin, which is involved in ADPEAF. Age at onset ranged from 6 to 39
years (average 19 years). Secondarily generalized seizures were the most common
type of seizures at onset (79%). Auditory auras occurred either in isolation
(53%) or associated with visual, psychic or aphasic symptoms. Low seizure
frequency at onset and good drug responsiveness were common, with 51% of patients
seizure-free. Seizures tended to recur after drug withdrawal. Clinically, no
major differences were found between S and F patients with respect to age at
onset, seizure frequency and response to therapy. Analysis of LGI1/epitempin
exons failed to disclose mutations. Our data support the existence of a peculiar
form of non-lesional temporal lobe epilepsy closely related to ADPEAF but without
a positive family history. This syndrome, here named IPEAF, has a benign course
in the majority of patients and could be diagnosed by the presence of auditory
aura. Although LGI1 mutations have been excluded, genetic factors may play an
aetiopathogenetic role in at least some of these S cases
X-ray microtomography to study the microstructure of cream cheese-type products.
In this work, the imaging x-ray microtomography technique, new to the field of food science, was used for the analysis of fat microstructure and quantification of the fat present in cream cheese-type products. Five different types of commercially produced cheeses, chosen for their variability of texture, were used for this experiment: sample A, sample B, sample C, sample D, and sample E. Appropriate quantitative 3-dimensional parameters describing the fat structure were calculated (e.g., the geometric parameter percentage of fat volume was calculated for each image as a representation of the percentage of total fat content within the sample). The dynamic-mechanical properties of these samples were also studied using a controlled-strain rotational rheometer. Storage modulus and loss modulus were determined in a frequency range of 0.01 to 10 Hz. The strain value was obtained by preliminary strain sweep oscillatory trials to determine the linear viscoelastic region of the cream cheese-type products. Statistical correlation analysis was performed on the results to help identify any microstructural-mechanical structure relationships. The results from this study show that microtomography is a suitable technique for the microstructural analysis of fat in cream cheese-type products, as it does not only provide an accurate percentage of the volume of the fat present but can also determine its spatial distribution
Large Loops of Magnetic Current and Confinement in Four Dimensional Lattice Gauge Theory
We calculate the heavy quark potential from the magnetic current due to
monopoles in four dimensional lattice gauge theory. The magnetic current
is found from link angle configurations using the DeGrand-Toussaint
identification method. The link angle configurations are generated in a cosine
action simulation on a lattice. The magnetic current is resolved into
large loops which wrap around the lattice and simple loops which do not.
Wrapping loops are found only in the confined phase. It is shown that the long
range part of the heavy quark potential, in particular the string tension, can
be calculated solely from the large, wrapping loops of magnetic current.Comment: 15 pages (Latex file plus 3 postscript files appended), Univeristy of
Illinois Preprint ILL-(TH)-93-\#1
Avoiding spurious feedback loops in the reconstruction of gene regulatory networks with dynamic bayesian networks
Feedback loops and recurrent structures are essential to the regulation and stable control of complex biological systems. The application of dynamic as opposed to static Bayesian networks is promising in that, in principle, these feedback loops can be learned. However, we show that the widely applied BGe score is susceptible to learning spurious feedback loops, which are a consequence of non-linear regulation and autocorrelation in the data. We propose a non-linear generalisation of the BGe model, based on a mixture model, and demonstrate that this approach successfully represses spurious feedback loops
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