Fluoride doped γ-Fe2O3 nanoparticles with increased MRI relaxivity.

Iron oxide nanoparticles (IONs) are being actively researched and experimented with as contrast agents for Magnetic Resonance Imaging (MRI), as well as image-directed delivery of therapeutics. The efficiency of an MRI contrast agent can be described by its longitudinal and transverse relaxivities, r1 and r2. γ-Fe2O3 nanoparticles - doped with fluoride in a controlled manner and functionalised with citric acid - showed a 3-fold increase in r1 and a 17-fold increase in r2 in a magnetic field of 3 T and almost 6-fold increase in r1 and a 14-fold increase in r2 at 11 T. Following fluorination, PXRD shows that the crystal structure of γ-Fe2O3 is maintained, Mössbauer spectroscopy shows that the oxidation state of the Fe cation is unchanged and HREM shows that the particle size does not vary. However, magnetisation curves show a large increase in the coercive field, pointing towards a large increase in the magnetic anisotropy for the fluorinated nanoparticles compared to the un-doped γ-Fe2O3 nanoparticles. Therefore, a chemically induced increase in magnetic anisotropy appears to be the most relevant parameter responsible for the large increase in relaxivity for γ-Fe2O3 nanoparticles.

Evaluation of current approaches to stream classification and a heuristic guide to developing classifications of integrated aquatic networks.

Conservation and management of fresh flowing waters involves evaluating and managing effects of cumulative impacts on the aquatic environment from disturbances such as: land use change, point and nonpoint source pollution, the creation of dams and reservoirs, mining, and fishing. To assess effects of these changes on associated biotic communities it is necessary to monitor and report on the status of lotic ecosystems. A variety of stream classification methods are available to assist with these tasks, and such methods attempt to provide a systematic approach to modeling and understanding complex aquatic systems at various spatial and temporal scales. Of the vast number of approaches that exist, it is useful to group them into three main types. The first involves modeling longitudinal species turnover patterns within large drainage basins and relating these patterns to environmental predictors collected at reach and upstream catchment scales; the second uses regionalized hierarchical classification to create multi-scale, spatially homogenous aquatic ecoregions by grouping adjacent catchments together based on environmental similarities; and the third approach groups sites together on the basis of similarities in their environmental conditions both within and between catchments, independent of their geographic location. We review the literature with a focus on more recent classifications to examine the strengths and weaknesses of the different approaches. We identify gaps or problems with the current approaches, and we propose an eight-step heuristic process that may assist with development of more flexible and integrated aquatic classifications based on the current understanding, network thinking, and theoretical underpinnings.

Separation of visibly-excited fluorescent components in fingerprint residue by thin-layer chromatography.

The use of lasers for the detection of fingermarks is widespread in the forensic field. Despite this, and the fact that many studies have been conducted into the composition of fingermark residue, the components responsible for the inherent visible fluorescence remain unidentified. Traditionally compositional studies have been performed on sweat, sebum, or skin surface washes, none of which are truly representative of the situation when a fingerprint is deposited on a surface. In this paper thin-layer chromatography (TLC) has been performed on sebum-rich fingermarks laid directly onto TLC plates and an argon ion laser used to visualize the separated components. It has been found to be a robust and reproducible method for studying the fluorescent components in fingermark residue and is considered to be more realistic than other methods of sample preparation as it eliminates the chances of extraneous matter being extracted from the skin surface. Investigations into the nature of the separated compounds have also been made and the results are reported.

A new visibly-excited fluorescent component in latent fingerprint residue induced by gaseous electrical discharge.

A technique that exposes fingerprint residue to a gaseous electrical discharge in nitrogen followed by treatment with ammonium hydrogen carbonate vapors to produce fluorescence is investigated. Particular attention is made to fluorescence observed via laser illumination at 514 nm. Insight into the nature of the fluorescent components is achieved through the use of thin-layer chromatography (TLC) of fingerprint residue. Results reported indicate the fluorescence observed is from previously non-fluorescent fractions of the fingerprint residue, and TLC results point towards lipid derivatives as a possible source of the fluorescence.

Isolated large third-trimester intracranial cyst on fetal ultrasound: fact or fiction?

OBJECTIVE: To distinguish the fact from artifact of an isolated, large, intracranial cyst on prenatal sonography (PSG). BACKGROUND: The use of PSG is rapidly increasing with most obstetric ultrasounds occurring in general community settings like small hospitals and clinics with personnel who have variable training, experience, and interest levels. In contrast, most PSG articles and books are produced in large subspecialty centers with concentrated referral bases plus both highly-trained and experienced personnel. DESIGN/METHODS: We report a series of 2 normal newborn patients who had a large prenatal unilateral intracranial cyst diagnosed by PSG in the 10 years between July of 1989 and 1999 at a rural community hospital. The newborns had imaging studies at birth and their neurodevelopmental progress was followed for several years. Textbook, bibliography and computerized Medline (1966-present) searches including prenatal ultrasound, observer variation, diagnostic errors, reproducibility of results, sensitivity and specificity, accuracy, central nervous system, false-positive, prenatal diagnosis, and brain were examined starting in August 1996 for reports. RESULTS: There were 4079 obstetric ultrasounds performed in 3.5 years, January 1996 through July 1999 at this rural community facility. This rate extrapolates to a total of 11 654 obstetric ultrasounds over the 10-year study period in which the 2 cases of intracranial cyst artifact occurred. Thus, the incidence of 2 intracranial cyst artifacts was estimated as 2/11 654 PSG, a .0002% false-positive rate. CONCLUSIONS: This is the first report of the occurrence of PSG artifacts in a community facility. Artifact is a real problem and needs to be specified in differential diagnoses. There are ways to decrease sonographic artifact-or at least to recognize it-so our estimates at a community hospital for its occurrence are presented with the relevant technical and ethical issues. None of these issues have been previously reported in the pediatric literature. Our false-positive rate for large intracranial cyst compares favorably with other reports. Our estimate may inflate our denominator by reporting scans rather than the number of fetuses scanned, and our numerator may miss cases that moved from the community. Confusion differentiating PSG artifact from reality often occurs when interpreting static or frozen real-time images. The signs that sonogram images may be artifacts include defects that: extend outside the fetal body; change shape, size and echogenecity with different scan planes; are not seen on all examinations; and are isolated in an otherwise normal fetus. Failure to offer quality PSG in clinical settings where it is available restricts access of pregnant women to the diagnosis of fetal anomalies, and therefore restricts access to the options of pregnancy termination, fetal therapy like fetal surgery, and delivery options of timing, setting, and mode. We suggest a multidisciplinary approach to prenatal abnormalities like isolated third trimester unilateral intracranial cyst in both primary and tertiary care settings aids interpretation followed by expectant conservative management without elaborate, risky, or terminal interventions.

Migrating atelectasis in Werdnig-Hoffmann disease: pulmonary manifestations in two cases of spinal muscular atrophy type 1.

Spinal muscular atrophy (SMA) or Werdnig-Hoffmann disease is the second most common neuromuscular disease, with 25% of cases presenting in infancy. Deletions in the survival motor neuron gene are believed responsible for autosomal-recessive SMA. SMA affects about 1 in 10,000 births. Symptomatic newborns have severe hypotonia, may have respiratory distress, may be unable to feed, and rapidly progress to death early in infancy. This paper describes another early pulmonary manifestation of SMA, i.e., migrating or rotating atelectasis, in 2 patients with infantile SMA. Migrating or rotating atelectasis may suggest the diagnosis of SMA.

Reherniation and pseudoreherniation of a congenital diaphragmatic hernia.

The differential in growth is apparent between lobes within the lung as well as between the two lungs. Any catch-up has clearly not corrected the hypoplasia present at birth. In addition, the small size and distorted shape as well as the abnormal proportions between the trachea and between the two main bronchi point to further functional irregularities based on structural distortion.

Prevention of childhood injuries. Part II: Recreational injuries.

This is the second of two articles on the prevention of childhood injuries. Here, interventions to reduce death and disability among children from recreational injuries are identified. The major categories of recreational injury are listed, the magnitude of the problem defined, the risk factors described, and selected interventions of the National Committee for Injury Prevention and Control summarized. Recommendations for practice are discussed.

Injury prevention: a survey of clinical practice.

The purpose of this study was to determine what education and training pediatric nurse practitioners receive about injury prevention and control and what kinds of clinical activities PNPs perform with regard to injury prevention and control. Sixty-four members of the Greater New York Chapter of the National Association of Pediatric Nurse Associates and Practitioners were questioned. Data on demographic, professional, and practice characteristics and on education and training and clinical activities in injury prevention and control were collected. Results indicated that advice about child car restraints and automobile seat belts was routinely given by less than 30% of practitioners, information about smoke detectors was given by about 15%, and advice about firearms in the home was given by 7% or less. Implications for counseling to prevent injuries are discussed.

Prevention of childhood injuries. Part I: Motor vehicle injuries.

Unintentional (accidental) injuries are the leading cause of death in childhood and adolescence. In this article, interventions to reduce death and disability among children from motor vehicle injuries are identified. The major categories of injury are listed, the magnitude of the problem is defined, the risk factors are described, and selected interventions of the National Committee for Injury Prevention and Control are summarized. Recommendations for practice are discussed.

Childhood injuries: an epidemiologic approach.

Injuries are the leading cause of childhood death and disability in the United States today. However, injuries can be studied, their magnitude described, and risk factors identified. Furthermore, many injuries can be prevented and controlled with available knowledge and technology.

The effect of legal drinking age on fatal injuries of adolescents and young adults.

This study examined the effect of legal drinking age (LDA) on fatal injuries in persons aged 15 to 24 years in the United States between 1979 and 1984. Effects on pre-LDA teens, adolescents targeted by LDA, initiation at LDA, and post-LDA drinking experience were assessed. A higher LDA was also associated with reduced death rates for motor vehicle drivers, pedestrians, unintentional injuries excluding motor vehicle injuries, and suicide. An initiation effect on homicides was identified. Reductions in injury deaths related to drinking experience were not found. In general, a higher LDA reduced deaths among adolescents and young adults for various categories of violent death.

Training in injury prevention for health professionals.

BACKGROUND: The shortage of health professionals with training in injury epidemiology and control is an obstacle to injury prevention. METHODS: Two two-hour workshops in childhood injury epidemiology and control were provided to nurses and physicians in the New York City Department of Health. RESULTS: 101 nurses and 76 physicians received the training. Workshop I test scores rose from 60% to 75%. Workshop II test scores rose from 67% to 88%. DISCUSSION: Training in injury prevention increases knowledge. Future studies will examine the effect of training on practice.

Left atrial dimension on the frontal thoracic radiograph: a method for assessing left atrial enlargement.

Left atrium size on the frontal radiograph was assessed by measuring the distance from the middle of the "double density" to the left main bronchus in 148 normal patients and 48 consecutive patients with echocardiographic evidence of left atrial enlargement. The measurement was less than 7.0 cm in 96% of normal patients and greater than 7.0 cm in 90% of patients with left atrial enlargement. This measurement is more easily obtainable than measurements and signs requiring a cardiac series, and is usually readily available for sequential evaluations of left atrial size. It is a less reliable gauge of left atrial size in children.