OBJECT Intraventicular hemorrhage (IVH) is a common complication of preterm birth, and the prognosis of IVH is incompletely characterized. The objective of this study was to describe the outcomes of ...IVH in a population-based cohort with minimal selection bias. METHODS All very preterm (≥ 30 completed weeks) patients born in the province of Nova Scotia were included in a comprehensive database. This database was screened for infants born to residents of Nova Scotia from January 1, 1993, to December 31, 2010. Among very preterm infants successfully resuscitated at birth, the numbers of infants who died, were disabled, developed cerebral palsy, developed hydrocephalus, were blind, were deaf, or had cognitive/language scores assessed were analyzed by IVH grade. The relative risk of each outcome was calculated (relative to the risk for infants without IVH). RESULTS Grades 2, 3, and 4 IVH were significantly associated with an increased overall mortality, primarily in the neonatal period, and the risk increased with increasing grade of IVH. Grade 4 IVH was significantly associated with an increased risk of disability (RR 2.00, p < 0.001), and the disability appeared to be primarily due to cerebral palsy (RR 6.07, p < 0.001) and cognitive impairment (difference in mean MDI scores between Grade 4 IVH and no IVH: -19.7, p < 0.001). No infants with Grade 1 or 2 IVH developed hydrocephalus, and hydrocephalus and CSF shunting were not associated with poorer outcomes when controlling for IVH grade. CONCLUSIONS Grades 1 and 2 IVH have much better outcomes than Grades 3 or 4, including a 0% risk of hydrocephalus in the Grade 1 and 2 IVH cohort. Given the low risk of selection bias, the results of this study may be helpful in discussing prognosis with families of very preterm infants diagnosed with IVH.
This work presents iron isotope data in the western equatorial Pacific. Marine aerosols and top core margin sediments display a slightly heavy Fe isotopic composition (δ56Fe) of 0.33 ± 0.11‰ (2SD) ...and 0.14 ± 0.07‰, respectively. Samples reflecting the influence of Papua New Guinea runoff (Sepik River and Rabaul volcano water) are characterized by crustal values. In seawater, Fe is mainly supplied in the particulate form and is found with a δ56Fe between −0.49 and 0.34 ± 0.07‰. The particulate Fe seems to be brought mainly by runoff and transported across continental shelves and slopes. Aerosols are suspected to enrich the surface Vitiaz Strait waters, while hydrothermal activity likely enriched New Ireland waters. Dissolved Fe isotopic ratios are found between −0.03 and 0.53 ± 0.07‰. They are almost systematically heavier than the corresponding particulate Fe, and the difference between the signature of both phases is similar for most samples with Δ56FeDFe – PFe = +0.27 ± 0.25‰ (2SD). This is interpreted as an equilibrium isotopic fractionation revealing exchange fluxes between both phases. The dissolved phase being heavier than the particles suggests that the exchanges result in a net nonreductive release of dissolved Fe. This process seems to be locally significantly more intense than Fe reductive dissolution documented along reducing margins. It may therefore constitute a very significant iron source to the ocean, thereby influencing the actual estimation of the iron residence time and sinks. The underlying processes could also apply to other elements.
Key Points
Isotopic composition of dissolved and particulate Fe in seawaterIsotopic composition of Fe in marine aerosol, Sepik, and margin sedimentsNonreductive release would be an important source of dissolved Fe
Abstract
Developing the next generation of scanning helium microscopes requires the fabrication of optical elements with complex internal geometries. We show that resin stereolithography (SLA) 3D ...printing produces low-cost components with the requisite convoluted structures whilst achieving the required vacuum properties, even without
in situ
baking. As a case study, a redesigned pinhole plate optical element of an existing scanning helium microscope was fabricated using SLA 3D printing. In comparison to the original machined component, the new optical element minimised the key sources of background signal, in particular multiple scattering and the secondary effusive beam.
This work demonstrates for the first time the feasibility of the measurement of the isotopic composition of dissolved iron in seawater for a typical open ocean Fe concentration range (0.1–1 nM). It ...also presents the first data of this kind. Iron is preconcentrated using a Nitriloacetic Acid Superflow resin and purified using an AG1x4 anion exchange resin. The isotopic ratios are measured with a MC‐ICPMS Neptune, coupled with a desolvator (Aridus II), using a 57Fe‐58Fe double spike mass bias correction. Measurement precision (0.13‰, 2SD) allows resolving small iron isotopic composition variations within the water column, in the Atlantic sector of the Southern Ocean (from δ57Fe = −0.19 to +0.32‰). Isotopically light iron found in the Upper Circumpolar Deep Water is hypothesized to result from organic matter remineralization. Shallow samples suggest that, if occurring, an iron isotopic fractionation during iron uptake by phytoplankton is characterized by a fractionation factor, such as: ∣Δ57Fe(plankton‐seawater)∣ < 0.48‰.
Chronic motor cortex stimulation (MCS) has been used to treat medically refractory neuropathic pain over the past 20 years. We investigated this procedure using a prospective multicentre randomized ...blinded crossover trial.
Twelve subjects with three different neuropathic pain syndromes had placement of MCS systems after which they were randomized to receive low ("subtherapeutic") or high ("therapeutic") stimulation for 12 weeks, followed by a crossover to the other treatment group for 12 weeks. The primary outcome measure was the pain visual analogue scale (VAS). Secondary outcome measures included McGill Pain Questionnaire (MPQ), Beck Depression Inventory-II, medication log, work status, global impression of change, and SF-36 quality of life scale.
The trial was halted early due to lack of efficacy. One subject withdrew early due to protocol violation and five subjects withdrew early due to transient adverse events. Six subjects with upper extremity pain completed the study. There was no significant change in VAS with low or high stimulation and no significant improvement in any of the outcome measures from low to high stimulation. SF-36 role physical and mental health scores were worse with high compared to low stimulation (p=0.024, p=0.005).
We failed to show that MCS is an effective treatment for refractory upper extremity neuropathic pain and suggest that previous studies may have been skewed by placebo effects, or ours by nocebo. We suggest that a healthy degree of skepticism is warranted when considering this invasive therapy for upper extremity pain syndromes.
Multi-layered functionally gradient metal materials are formed by metal material deposing with Laser Engineered Net Shaping (LENS) technology. LENS is an additive manufacturing technique that employs ...a high-power laser as the power source to fuse powdered metals into fully dense three-dimensional structures layer by layer. Layer thickness is an important factor in machining and processing of such advanced materials, as well as in the production, as a feedback to LENS machine operator. Knowing the thickness of the manufactured layer of multi-layered metal material is fundamental for understanding the LENS process and optimizing the machining operations. In this article, software for visual multi-layered functionally graded material layer thickness measurement is presented. The layer thickness is automatically determined by the software that is programmed in Matlab/Simulink, high-level programming language. The software is using cross-section metallographic images of cladded layers for thickness measuring. Graphic User Interface is also created and presented. The results of measurement are presented to demonstrate the efficiency of the developed measurement software.
Open neural tube defects or myelomeningoceles are a common congenital condition caused by failure of closure of the neural tube early in gestation, leading to a number of neurologic sequelae ...including paralysis, hindbrain herniation, hydrocephalus and neurogenic bowel and bladder dysfunction. Traditionally, the condition was treated by closure of the defect postnatally but a recently completed randomized controlled trial of prenatal versus postnatal closure demonstrated improved neurologic outcomes in the prenatal closure group. Fetal surgery, or more precisely maternal-fetal surgery, raises a number of ethical issues that we address including who the patient is, informed consent, surgical innovation and equipoise as well maternal assumption of risk. As the procedure becomes more widely adopted into practice, we suggest close monitoring of new fetal surgery centers, in order to ensure that the positive results of the trial are maintained without increased risk to both the mother and fetus.
In understanding the nature of contrast in the emerging field of neutral helium microscopy, it is important to identify if there is an atom-surface scattering distribution that can be expected to ...apply broadly across a range of sample surfaces. Here we present results acquired in a scanning helium microscope (SHeM) under typical operating conditions, from a range of surfaces in their native state,
i.e.
without any specialist sample preparation. We observe diffuse scattering, with an approximately cosine distribution centred about the surface normal. The 'cosine-like' distribution is markedly different from those distributions observed from the well-prepared, atomically pristine, surfaces typically studied in helium atom scattering experiments. Knowledge of the typical scattering distribution in SHeM experiments provides a starting basis for interpretation of topographic contrast in images, as well as a reference against which more exotic contrast mechanisms can be compared.
By studying well defined geometries (microspheres) in scanning helium microscopy (SHeM) the default scattering distribution for technological surfaces in SHeM is found to be diffuse and approximately cosine.
Purpose
Myelomeningocele is typically a disabling condition that results in neurologic, orthopedic, and urologic morbidity. The aim of this study was to examine the trends over time in both incidence ...and outcomes of myelomeningocele (MMC) in British Columbia (BC).
Methods
A retrospective chart review was performed of all children with MMC followed in the British Columbia Children’s Hospital (BCCH) Spinal Cord Clinic between 1971 and 2016. The incidence of new MMC cases and the long-term outcomes of MMC were compared between two 10-year cohorts. The first cohort comprised children born with MMC between 1971 and 1981, and the second cohort comprised children born with MMC between 1996 and 2006.
Results
A total of 309 children with MMC were followed in the BCCH Spinal Cord Clinic between 1971 and 2016. There were 101 and 46 children with MMC in the two-time cohorts, respectively. Between the earlier and later cohorts, there was a significant difference in the following: MMC incidence 2.5/10,000 births vs 1.1/10,000 births, respectively (
p
= 0.0002), mortality 18 vs 0% (
p
= 0.0009), and the proportion of cases repaired in under 48 h 56 vs 98% (
p
< 0.0001). For surviving children, the proportion of children attending special classes was significantly different between the earlier and later cohorts 16 vs 46%, respectively (
p
= 0.0002), whereas all other outcome measures, including the proportion with hydrocephalus, kyphoscoliosis, Chiari II surgery, bowel and bladder continence, recreation participation, obesity, and ambulation, were not significantly different.
Conclusions
In BC, the incidence of new cases of MMC has decreased between 1971 and 2016, while the probability of survival for these patients has increased. Despite earlier and more universal post-natal repair, long-term outcomes have not improved significantly over time. Future research should focus on developing ways of reducing disability and improving quality of life for MMC patients and their families.
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