538 research outputs found
PTPN11 mutation manifesting as LEOPARD syndrome associated with hypertrophic plexi and neuropathic pain.
BACKGROUND: LEOPARD syndrome (LS) belongs to the family of neuro-cardio-facio-cutaneous syndromes, which include Neurofibromatosis-1 (NF1), Noonan syndrome, Costello Syndrome, cardio-facio-cutaneous syndrome, Noonan-like syndrome with loose anagen hair and Legius syndrome. These conditions are caused by mutations in genes encoding proteins involved in the RAS-MAPK cellular pathway. Clinical heterogeneity and phenotype overlaps across those different syndromes is already recognized.
CASE PRESENTATION: We hereby report a heterozygous de novo mutation in the PTPN11 gene (c.1403C > T) manifesting with a clinical picture of LS during childhood, and later development of neuropathic pain with hypertrophic plexi, which are typically observed in NF1 but have not been reported in LS.
CONCLUSION: LS caused by PTPN11 mutations may be associated with hypertrophic roots and plexi. Consequently, clinicians should be aware of the possible development of neuropathic pain and consider specific diagnostic work-up and management
Stability of sub-surface oxygen at Rh(111)
Using density-functional theory (DFT) we investigate the incorporation of
oxygen directly below the Rh(111) surface. We show that oxygen incorporation
will only commence after nearly completion of a dense O adlayer (\theta_tot =
1.0 monolayer) with O in the fcc on-surface sites. The experimentally suggested
octahedral sub-surface site occupancy, inducing a site-switch of the on-surface
species from fcc to hcp sites, is indeed found to be a rather low energy
structure. Our results indicate that at even higher coverages oxygen
incorporation is followed by oxygen agglomeration in two-dimensional
sub-surface islands directly below the first metal layer. Inside these islands,
the metastable hcp/octahedral (on-surface/sub-surface) site combination will
undergo a barrierless displacement, introducing a stacking fault of the first
metal layer with respect to the underlying substrate and leading to a stable
fcc/tetrahedral site occupation. We suggest that these elementary steps,
namely, oxygen incorporation, aggregation into sub-surface islands and
destabilization of the metal surface may be more general and precede the
formation of a surface oxide at close-packed late transition metal surfaces.Comment: 9 pages including 9 figure files. Submitted to Phys. Rev. B. Related
publications can be found at http://www.fhi-berlin.mpg.de/th/paper.htm
Preconditioning triggered by carbon monoxide (CO) provides neuronal protection following perinatal hypoxia-ischemia
Perinatal hypoxia-ischemia is a major cause of acute mortality in newborns and cognitive and motor impairments in children. Cerebral hypoxia-ischemia leads to excitotoxicity and necrotic and apoptotic cell death, in which mitochondria play a major role. Increased resistance against major damage can be achieved by preconditioning triggered by subtle insults. CO, a toxic molecule that is also generated endogenously, may have a role in preconditioning as low doses can protect against inflammation and apoptosis. In this study, the role of CO-induced preconditioning on neurons was addressed in vitro and in vivo. The effect of 1 h of CO treatment on neuronal death (plasmatic membrane permeabilization and chromatin condensation) and bcl-2 expression was studied in cerebellar granule cells undergoing to glutamate-induced apoptosis. CO's role was studied in vivo in the Rice-Vannucci model of neonatal hypoxia-ischemia (common carotid artery ligature +75 min at 8% oxygen). Apoptotic cells, assessed by Nissl staining were counted with a stereological approach and cleaved caspase 3-positive profiles in the hippocampus were assessed. Apoptotic hallmarks were analyzed in hippocampal extracts by Western Blot. CO inhibited excitotoxicity-induced cell death and increased Bcl-2 mRNA in primary cultures of neurons. In vivo, CO prevented hypoxia-ischemia induced apoptosis in the hippocampus, limited cytochrome c released from mitochondria and reduced activation of caspase-3. Still, Bcl-2 protein levels were higher in hippocampus of CO pre-treated rat pups. Our results show that CO preconditioning elicits a molecular cascade that limits neuronal apoptosis. This could represent an innovative therapeutic strategy for high-risk cerebral hypoxia-ischemia patients, in particular neonates
Immunohistochemical localization of a specificileal peptide in the pig
The tissue distribution of a polypeptide purified from pig ileal mucosa tentatively called porcine ileal polypeptide (PIP) and known to have potent acid secretagogue activity has been studied with immunohistochemical methods together with extraction of different tissues followed by radioimmunoassay for PIP content. Histochemically the peptide is found in superficial epithelial cells in the mucosa of the distal 20% of the small intestine and to some extent in the mucosa of the urinary tract. There is no staining of goblet cells or crypt cells. The staining in the urinary tract mucosa is due to antigenic peptides with Mr identical to PIP. While the presence of PIP in the ileum is compatible with a function as an enterooxyntin, it is not possible at present to explain the physiologic role of PIP entirely as a hormone regulating acid secretion in light of the immunohistochemical distribution.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47406/1/418_2004_Article_BF00492352.pd
Inequality and violent crime: evidence from data on robbery and violent theft
This article argues that the link between income inequality and violent property crime might be spurious, complementing a similar argument in prior analysis by the author on the determinants of homicide. In contrast, Fajnzylber, Lederman & Loayza (1998; 2002a, b) provide seemingly strong and robust evidence that inequality causes a higher rate of both homicide and robbery/violent theft even after controlling for country-specific fixed effects. Our results suggest that inequality is not a statistically significant determinant, unless either country-specific effects are not controlled for or the sample is artificially restricted to a small number of countries. The reason why the link between inequality and violent property crime might be spurious is that income inequality is likely to be strongly correlated with country-specific fixed effects such as cultural differences. A high degree of inequality might be socially undesirable for any number of reasons, but that it causes violent crime is far from proven
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Barriers and enablers to diabetic retinopathy screening attendance: Protocol for a systematic review
BACKGROUND: Diabetic retinopathy is a serious complication of diabetes which, if left untreated, can result in blindness. Population screening among people with diabetes has been shown to be clinically effective; however, suboptimal attendance with wide demographic disparities has been reported. To develop quality improvement interventions to maximise attendance, it is important to understand the theoretical determinants (i.e. barriers and enablers) of screening behaviour. The aim of this systematic review is to identify and synthesise the modifiable barriers and enablers associated with diabetic retinopathy screening attendance.
METHODS/DESIGN: Primary and secondary studies will be included if they report perceived barriers/enablers of diabetic retinopathy screening attendance, from the perspectives of people with diabetes and healthcare providers. There will be no restrictions on study design. Studies will be identified from published and grey literature through multiple sources. Bibliographic databases will be searched using synonyms in four search domains: diabetic retinopathy; screening; barriers/enablers; and theoretical constructs relating to behaviour. Search engines and established databases of grey literature will be searched to identify additional relevant studies. Extracted data will include: participant quotations from qualitative studies, statistical analyses from questionnaire and survey studies, and interpretive descriptions and summaries of results from reports. All extracted data will be coded into domains from the Theoretical Domains Framework (TDF) and (for organisational level data) the Consolidated Framework of Implementation Research (CFIR); with domains representing theoretical barriers/enablers proposed to mediate behaviour change. The potential role of each domain in influencing retinopathy screening attendance will be investigated through thematic analysis of the TDF/ CFIR coding. Domain importance will be identified using pre-specified criteria: "frequency" and "expressed importance". Variations in perceived barriers and enablers between demographic groups (e.g., socio-economic, ethnic) will be explored.
DISCUSSION: This review will identify important barriers and enablers likely to influence attendance for diabetic retinopathy screening. The results will be used to assess the extent to which existing interventions targeting attendance address the theoretical determinants of attendance behaviour. Findings will inform recommendations for future intervention design.
SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42016032990
Cybersecurity behavior among government employees: The role of protection motivation theory and responsibility in mitigating cyberattacks
This study examines the factors influencing government employees’ cybersecurity behavior in Malaysia. The country is considered the most vulnerable in Southeast Asia. Applying the protection motivation theory, this study addresses the gap by investigating how government employees behave toward corresponding cyberrisks and threats. Using partial least-squares structural equation modeling (PLS-SEM), 446 respondents participated and were analyzed. The findings suggest that highly motivated employees with high severity, vulnerability, response efficacy, and self-efficacy exercise cybersecurity. Incorporating the users’ perceptions of vulnerability and severity facilitates behavioral change and increases the understanding of cybersecurity behavior’s role in addressing cybersecurity threats—particularly the impact of the threat response in predicting the cybersecurity behavior of government employees. The implications include providing robust information security protection to the government information systems
The effect of whatsapp usage on employee innovative performance at the workplace: Perspective from the stressor–strain–outcome model
Social media applications have increasingly become a valuable platform for personal communication and knowledge sharing in working life. Several researchers have considered the direct role of social media usage in influencing job performance. However, limited studies explore how social media use may impact employees’ job performance, especially in innovativeness. Moreover, inconsistencies in the findings exist in the literature regarding whether social media improves employees’ job performance or causes harm. By adapting the stressor–strain–outcome (SSO) model, the present study investigates how WhatsApp use at work can predict social media overloads that might induce technostress and, subsequently, affect employees’ innovative job performance. Thus, 206 Malaysian employees from the government and private sectors participated in this study and the data were analyzed using partial least squares structural equation modeling (PLS-SEM). The findings show that social media, predominantly WhatsApp, used at work has a mild but statistically significant influence on information overload, communication overload, and social overload. In addition, information overload and communication overload positively influence technostress, except for social overload. Subsequently, technostress does not have an impact on innovative job performance. This study provides theoretical and practical implications for extending the knowledge and mitigating plans and efforts to improve employees’ performance at work. Therefore, this study helps mitigate the dearth of research pertaining to the roles of social media use at work on employees’ innovative job performance
Understanding social media usage at work from the perspective of social capital theory
With the pervasive use of social media (SM) in organizations, it is regarded as a relevant driver that can influence an employee’s job performance. This study fills in the gap that extends the job performance concept by discovering the role of SM in innovative performance in introducing new ideas beyond standard specifications to produce novel and valuable organizational outcomes. By adopting the social capital theory (SCT), the present study investigates the roles of social media use at work in predicting social capital (network ties, shared vision, and trust) that might promote work engagement and subsequently affect employees’ innovative job performance. The data was collected through an online survey, and 291 Malaysian employees participated. The partial least square structural equation modelling (PLS-SEM) technique was applied in data analysis for the measurement model and structural model used in this study. Findings show that SM use at work significantly predicts network ties, shared vision, and trust. Besides, network ties and trust positively promoted work engagement except for shared vision. Subsequently, work engagement was associated with innovative job performance. This study provides theoretical and practical implications for extending knowledge, as well as mitigating plans and efforts to resolve employees’ performance concerning the issues of SM use at work
Differential Photoelectron Holography: A New Approach for Three-Dimensional Atomic Imaging
We propose differential holography as a method to overcome the long-standing
forward-scattering problem in photoelectron holography and related techniques
for the three-dimensional imaging of atoms. Atomic images reconstructed from
experimental and theoretical Cu 3p holograms from Cu(001) demonstrate that this
method suppresses strong forward-scattering effects so as to yield more
accurate three-dimensional images of side- and back-scattering atoms.Comment: revtex, 4 pages, 2 figure
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