584 research outputs found
Prescription of the first prosthesis and later use in children with congenital unilateral upper limb deficiency: A systematic review
Background: The prosthetic rejection rates in children with an upper limb transversal reduction deficiency are considerable. It is unclear whether the timing of the first prescription of the prosthesis contributes to the rejection rates. Objective: To reveal whether scientific evidence is available in literature to confirm the hypothesis that the first prosthesis of children with an upper limb deficiency should be prescribed before two years of age. We expect lower rejection rates and better functional outcomes in children fitted at young age. Methods: A computerized search was performed in several databases (Medline, Embase, Cinahl, Amed, Psycinfo, PiCarta and the Cochrane database). A combination of the following keywords and their synonyms was used: "prostheses, upper limb, upper extremity, arm and congenital''. Furthermore, references of conference reports, references of most relevant studies, citations of most relevant studies and related articles were checked for relevancy. Results: The search yielded 285 publications, of which four studies met the selection criteria. The methodological quality of the studies was low. All studies showed a trend of lower rejection rates in children who were provided with their first prosthesis at less than two years of age. The pooled odds ratio of two studies showed a higher rejection rate in children who were fitted over two years of age ( pooled OR 3.6, 95% CI 1.6-8.0). No scientific evidence was found concerning the relation between the age at which a prosthesis was prescribed for the first time and functional outcomes. Conclusion: In literature only little evidence was found for a relationship between the fitting of a first prosthesis in children with a congenital upper limb deficiency and rejection rates or functional outcomes. As such, clinical practice of the introduction of a prosthesis is guided by clinical experience rather than by evidence-based medicine
Age at first prosthetic fitting and later functional outcome in children and young adults with unilateral congenital below-elbow deficiency:A cross-sectional study
The objective of this study was to evaluate whether prosthetic fitting before the age of one year is associated with better outcomes in children with unilateral congenital below-elbow deficiency compared to children fitted after the age of one. Twenty subjects aged 6-21 years were recruited (five prosthetic users and 15 non-users). The Child Amputee Prosthetics Project-Prosthesis Satisfactory Inventory (CAPP-PSI) and the Prosthetic Upper Extremity Functional Index (PUFI) were used to assess patient satisfaction and functional use of the prosthesis. Videotapes were used to assess motor performance. Initial prosthetic fitting before one year of age was related to use of a prosthesis for at least four years. Age at first fitting was not associated with satisfaction with the prosthesis, functional use of the prosthesis or motor skills. Discrepancies between ease of performance with prosthesis and usefulness of the prosthesis as well as between capacity and performance of activities were found. The video assessments showed impaired movement adaptation to some tasks in six subjects. In conclusion, early prosthetic fitting seems to have a limited impact on prosthesis use during later stages of life
Development of postural adjustments during reaching in typically developing infants from 4 to 18 months
Knowledge on the development of postural adjustments during infancy, in particular on the development of postural muscle coordination, is limited. This study aimed at the evaluation of the development of postural control during reaching in a supported sitting condition. Eleven typically developing infants participated in the study and were assessed at the ages of 4, 6, 10 and 18 months. We elicited reaching movements by presenting small toys at an arm’s length distance, whilst activity of multiple arm, neck and trunk muscles was recorded using surface EMG. A model-based computer algorithm was used to detect the onset of phasic muscle activity. The results indicated that postural muscle activity during reaching whilst sitting supported is highly variable. Direction-specific postural activity was inconsistently present from early age onwards and increased between 10 and 18 months without reaching a 100 % consistency. The dominant pattern of activation at all ages was the ‘complete pattern’, in which all direction-specific muscles were recruited. At 4 months, a slight preference for top-down recruitment existed, which was gradually replaced by a preference for bottom-up recruitment. We conclude that postural control during the ecological task of reaching during supported sitting between 4 and 18 months of age is primarily characterized by variation. Already from 4 months onwards, infants are—within the variation—sometimes able to select muscle recruitment strategies that are optimal to the task at hand
The quality of general movements in infants with complex congenital heart disease undergoing surgery in the neonatal period
Background: Advances in diagnostic technologies, surgical management, and perioperative care have increased survival for neonates with complex congenital heart disease (CCHD). The success of these advances exposed a heightened risk of brain injury and developmental disabilities. The General Movements Assessment, a non-invasive method, may detect early neurodevelopmental impairments in high-risk infants. Aims: To examine whether infants with CCHD undergoing neonatal surgery have higher prevalence of atypical general movements (GMs) than a reference group, and whether single ventricle physiology with systemic oxygen saturations <90% increases risk for atypical GMs. Methods: Serial General Movements Assessment (GMA) in a cohort of infants with CCHD (n = 74) at writhing (term-6 weeks) and fidgety (7–17 weeks) GM-age. GMA focused on the presence of definitely abnormal GM-complexity and absent fidgety movements. Single GMAs at 3 months were available from a reference sample of Dutch infants (n = 300). Regression analyses examined relationships between cardiac characteristics and definitely abnormal GM-complexity. Results: Higher prevalence of definitely abnormal GM-complexity in infants with CCHD compared to reference infants (adjusted OR 5.938, 95% CI 2.423–14.355), single ventricle CCHD increased the risk. Occurrence of absent fidgety movements was similar in infants with CCHD and reference infants (adjusted OR 0.475, 95% CI 0.058–3.876). Systemic postoperative oxygen saturations <90% was associated with higher risk of definitely abnormal GM-complexity at fidgety (adjusted OR 16.445 95% CI 1.149–235.281), not at writhing age. Conclusions: Infants with CCHD, especially those with single ventricle CCHD, are at increased risk of definitely abnormal GM-complexity. GMA at fidgety age is recommended
Risk factors in early life for developmental coordination disorder:a scoping review
AIM: To perform a scoping literature review of associations between risk factors in early life and developmental coordination disorder (DCD). METHOD: PubMed, Embase, CINAHL, PsycINFO, and Web of Science (January 1994-March 2019) were searched to identify studies on early risk factors and motor impairment or DCD. The effect of single and multiple risk factors was assessed. Level of evidence was evaluated following the Centre for Evidence-Based Medicine guidelines. Meta-analysis on the effect of preterm birth was performed. RESULTS: Thirty-six studies fulfilled inclusion criteria; 35 had evidence level 3, one had level 4. Highest evidence was available that preterm birth and male sex in term-born children were associated with DCD. The odds ratio of preterm birth was 2.02 (95% confidence interval: 1.43-2.85). Low to moderate evidence was available that parental subfertility, maternal smoking during pregnancy, postnatal corticosteroid treatment in infants born preterm, extra corporeal membrane oxygenation, retinopathy of prematurity, abnormalities on magnetic resonance imaging scans at term age, and accumulating perinatal or neonatal risk factors were associated with motor impairment. INTERPRETATION: Limited information on early risk factors of DCD is available. Only preterm birth and male sex were consistently associated with an increased risk of DCD
Field-Induced Two-Step Phase Transitions in the Singlet Ground State Triangular Antiferromagnet CsFeBr
The ground state of the stacked triangular antiferromagnet CsFeBr is a
spin singlet due to the large single ion anisotropy . The
field-induced magnetic ordering in this compound was investigated by the
magnetic susceptibility, the magnetization process and specific heat
measurements for an external field parallel to the -axis. Unexpectedly, two
phase transitions were observed in the magnetic field higher than 3 T. The
phase diagram for temperature versus magnetic field was obtained. The mechanism
leading to the successive phase transitions is discussed.Comment: 8 pages, 9 figures, 10 eps files, jpsj styl
Analysis of strain and stacking faults in single nanowires using Bragg coherent diffraction imaging
Coherent diffraction imaging (CDI) on Bragg reflections is a promising
technique for the study of three-dimensional (3D) composition and strain fields
in nanostructures, which can be recovered directly from the coherent
diffraction data recorded on single objects. In this article we report results
obtained for single homogeneous and heterogeneous nanowires with a diameter
smaller than 100 nm, for which we used CDI to retrieve information about
deformation and faults existing in these wires. The article also discusses the
influence of stacking faults, which can create artefacts during the
reconstruction of the nanowire shape and deformation.Comment: 18 pages, 6 figures Submitted to New Journal of Physic
Twinning superlattices in indium phosphide nanowires
Here, we show that we control the crystal structure of indium phosphide (InP)
nanowires by impurity dopants. We have found that zinc decreases the activation
barrier for 2D nucleation growth of zinc-blende InP and therefore promotes the
InP nanowires to crystallise in the zinc blende, instead of the commonly found
wurtzite crystal structure. More importantly, we demonstrate that we can, by
controlling the crystal structure, induce twinning superlattices with
long-range order in InP nanowires. We can tune the spacing of the superlattices
by the wire diameter and the zinc concentration and present a model based on
the cross-sectional shape of the zinc-blende InP nanowires to quantitatively
explain the formation of the periodic twinning.Comment: 18 pages, 4 figure
Avalanche amplification of a single exciton in a semiconductor nanowire
Interfacing single photons and electrons is a crucial ingredient for sharing
quantum information between remote solid-state qubits. Semiconductor nanowires
offer the unique possibility to combine optical quantum dots with avalanche
photodiodes, thus enabling the conversion of an incoming single photon into a
macroscopic current for efficient electrical detection. Currently, millions of
excitation events are required to perform electrical read-out of an exciton
qubit state. Here we demonstrate multiplication of carriers from only a single
exciton generated in a quantum dot after tunneling into a nanowire avalanche
photodiode. Due to the large amplification of both electrons and holes (>
10^4), we reduce by four orders of magnitude the number of excitation events
required to electrically detect a single exciton generated in a quantum dot.
This work represents a significant step towards single-shot electrical read-out
and offers a new functionality for on-chip quantum information circuits
Genetic risk factors for ischaemic stroke and its subtypes (the METASTROKE Collaboration): a meta-analysis of genome-wide association studies
<p>Background - Various genome-wide association studies (GWAS) have been done in ischaemic stroke, identifying a few loci associated with the disease, but sample sizes have been 3500 cases or less. We established the METASTROKE collaboration with the aim of validating associations from previous GWAS and identifying novel genetic associations through meta-analysis of GWAS datasets for ischaemic stroke and its subtypes.</p>
<p>Methods - We meta-analysed data from 15 ischaemic stroke cohorts with a total of 12 389 individuals with ischaemic stroke and 62 004 controls, all of European ancestry. For the associations reaching genome-wide significance in METASTROKE, we did a further analysis, conditioning on the lead single nucleotide polymorphism in every associated region. Replication of novel suggestive signals was done in 13 347 cases and 29 083 controls.</p>
<p>Findings - We verified previous associations for cardioembolic stroke near PITX2 (p=2·8×10−16) and ZFHX3 (p=2·28×10−8), and for large-vessel stroke at a 9p21 locus (p=3·32×10−5) and HDAC9 (p=2·03×10−12). Additionally, we verified that all associations were subtype specific. Conditional analysis in the three regions for which the associations reached genome-wide significance (PITX2, ZFHX3, and HDAC9) indicated that all the signal in each region could be attributed to one risk haplotype. We also identified 12 potentially novel loci at p<5×10−6. However, we were unable to replicate any of these novel associations in the replication cohort.</p>
<p>Interpretation - Our results show that, although genetic variants can be detected in patients with ischaemic stroke when compared with controls, all associations we were able to confirm are specific to a stroke subtype. This finding has two implications. First, to maximise success of genetic studies in ischaemic stroke, detailed stroke subtyping is required. Second, different genetic pathophysiological mechanisms seem to be associated with different stroke subtypes.</p>
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