Atomic force microscopy (AFM) in conjunction with a bioprobe developed using a polydopamine wet adhesive was used to directly measure the adhesive force between bacteria and different polymeric ...membrane surfaces. Bacterial cells of Pseudomonas putida and Bacillus subtilis were immobilized onto the tip of a standard AFM cantilever, and force measurements made using the modified cantilever on various membranes. Interaction forces measured with the bacterial probe were compared, qualitatively, to predictions by the extended Derjaguin–Landau–Verwey–Overbeek (XDLVO) theory with steric interactions included. The XDLVO theory predicted attractive interactions between low energy hydrophobic membranes with high energy hydrophilic bacterium (P. putida). It also predicted a shallow primary maximum with the most hydrophilic bacterium, B. subtilis. Discrepancies between predictions using the XDLVO theory and theory require involvement of factors such as bridging effects. Differences in interaction between P. putida and B. subtilis are attributed to acid–base interactions and steric interactions. P. putida is Gram negative with lipopolysaccharides present in the outer cell membrane. A variation in forces of adhesion for bacteria on polymeric membranes studied was interpreted in terms of hydrophilicity and interfacial surface potential calculated from physicochemical properties.
The health of older persons has not been a major priority in many African countries. Hypertension is one of the common health problems of older persons. However, there is little information on the ...prevalence of hypertension in older adults in Africa. This is in spite of the fact that Africa has the highest age-standardized prevalence of hypertension in the world. We therefore present this protocol to conduct a systematic review and meta-analysis on the prevalence of hypertension and the level of its awareness among older persons living in Africa.
Major databases (EMBASE, MEDLINE, Academic Search Complete, CINAHL, PsycINFO) and unpublished literature will be searched to identify population-based studies on hypertension in adults aged 50 years and older living in Africa. Eligible articles are those which use the 140/90-mmHg cutoff to diagnose hypertension and were published from 1980 to present. We will exclude subjects in restricted environments such as patients and refugees. Articles will be independently evaluated by two reviewers to determine if they meet the inclusion criteria. They will also evaluate the quality of included studies using a validated tool by Hoy and colleagues for prevalence studies. The main outcome is the prevalence of hypertension while the explanatory variables include demographic, socio-economic, dietary, lifestyle and behavioural factors. Effect sizes in bivariate and multivariate analyses will be presented as odds or prevalence ratios. We will explore for heterogeneity of the standard errors across the studies, and if appropriate, we will perform a meta-analysis using a random-effects model to present a summary estimate of the prevalence of hypertension in this population.
The estimates of the prevalence, the risk factors and the level of awareness of hypertension could help in galvanizing efforts at prioritizing the cardiovascular health of older persons in Africa.
PROSPERO CRD42017056474.
How much do preschool children look at print within storybooks when adults read to them? This study sought to answer this question as well as to examine the effects of adult verbal and nonverbal ...references to print on children's visual attention to print during storybook reading. Forty-four preschool-aged children participated in this study designed to determine the amount of visual attention children paid to print in 4 planned variations of storybook reading. Children's visual attention to print was examined when adults commented and questioned about print (verbal print condition) or pointed to and tracked the print (nonverbal print condition), relative to 2 comparison conditions (verbatim reading and verbal picture conditions). Results showed that children rarely look at print, with about 5%-6% of their fixations allocated to print in verbatim and verbal picture reading conditions. However, preschoolers' visual attention to print increases significantly when adults verbally and nonverbally reference print; both reading styles exerted similar effects. The authors conclude that explicit referencing of print is 1 way to increase young children's contacts with print during shared storybook reading.
Background and Aims
Despite the implementation of anemia control interventions in Ghana, anemia prevalence is still high in children under‐fives. Reducing the prevalence of anemia requires ...identifying and targeting associated critical risk factors. This study seeks to identify predictors of anemia among children under‐fives in Ghana.
Methods
Nationally representative data from the 2019 Ghana Malaria Indicator Survey was used in this study. Both fixed and random effects (multilevel) logistic regression models were applied to 2434 children to identify critical factors associated with anemia.
Results
In this study, 54% (95% confidence interval CI 52.0–57.0) of children under‐5 years were anemic. Infants were more likely to be anemic (66.7%) compared with other children below 5 years. In the multivariable multilevel model, the risk of anemia was found to be higher in younger children especially 6–11 months old (adjusted odds ratio aOR = 3.59, CI: 2.54–5.08) and 12–23 months old (aOR = 2.97, CI: 2.08–4.23), children who had malaria (aOR = 1.53, CI: 1.13–2.06), children whose mothers were not registered but not covered with health insurance (aOR = 1.45, CI: 1.21–1.74) or were not even registered for insurance (aOR = 1.49, CI: 1.15–1.93), children born to adolescent mothers (aOR = 2.21, CI: 1.36–3.57), children born to non‐Christian mothers (Islam aOR = 1.53, CI: 1.17–2.00), children born to families of poorer households (poorest aOR = 3.01, CI: 1.64–5.51; poorer aOR = 2.56, CI: 1.65–3.98); middle (aOR = 2.03, CI: 1.32–3.11) and richer (aOR = 1.78, CI: 1.19–2.64), and children who lived in either Upper East (aOR = 2.03, CI: 1.26–3.26) or Central (aOR = 2.52, CI: 1.42–4.47) regions. Significant unobserved community‐level differences in anemia prevalence were observed.
Conclusion
The probability of anemia in children under‐fives differs substantially from one community to another, and the prevalence remains high. The identified critical risk factors should be addressed. Multifaceted and targeted approaches are needed to help reduce the anemia prevalence in this setting to achieve the multiple United Nation's Sustainable Development Goals, which are related to risk and prevalence of anemia by 2030.
Chemically interfacing the inert basal plane of graphene with other materials has limited the development of graphene-based catalysts, composite materials, and devices. Here, we overcome this ...limitation by chemically activating epitaxial graphene on SiC(0001) using atomic oxygen. Atomic oxygen produces epoxide groups on graphene, which act as reactive nucleation sites for zinc oxide nanoparticle growth using the atomic layer deposition precursor diethyl zinc. In particular, exposure of epoxidized graphene to diethyl zinc abstracts oxygen, creating mobile species that diffuse on the surface to form metal oxide clusters. This mechanism is corroborated with a combination of scanning probe microscopy, Raman spectroscopy, and density functional theory and can likely be generalized to a wide variety of related surface reactions on graphene.
Classroom social networks are influential to young children’s cognitive, social–emotional, and language development, but assessment and analyses of social networks are complex. Findings have been ...mixed regarding whether different informants (teachers, children, researchers) are congruent in perceiving classroom social networks. There is also a lack of discussion about the roles of network transformation (converting value networks into binary networks), a required data step for widely used statistical network analyses. This study addressed these issues based on network data of 16 preschool children containing 240 potential dyadic interactions collected from teacher ratings, child nominations, and researcher observations across 44 observation cycles over four school days. Results showed that the three informants were congruent in perceiving the classroom social network, whereas the level of congruency between the teacher-report and the researcher-report networks was the highest. Binary transformation of social networks tended to decrease the level of congruency across informants, although the level of congruency tended to be higher when more stringent binary transformation thresholds were selected.
Invariant natural killer T cells (iNKT cells) express a semi-invariant T cell receptor that recognizes certain glycolipids (including α-galactosylceramide, αGC) bound to CD1d, and can induce potent ...antitumor responses. Here, we assessed whether αGC could enhance the efficacy of a GM-CSF-producing tumor cell vaccine in the transgenic SV40 T antigen-driven TRAMP prostate cancer model. In healthy mice, we initially found that optimal T cell responses were obtained with αGC-pulsed TRAMP-C2 cells secreting GM-CSF and milk fat globule epidermal growth factor protein-8 (MFG-E8) with an RGD to RGE mutation (GM-CSF/RGE TRAMP-C2), combined with systemic low dose IL-12. In a therapeutic model, transgenic TRAMP mice were then castrated at ~ 20 weeks, followed by treatment with the combination vaccine. Untreated mice succumbed to tumor by ~ 40 weeks, but survival was markedly prolonged by vaccine treatment, with most mice surviving past 80 weeks. Prostates in the treated mice were heavily infiltrated with T cells and iNKT cells, which both secreted IFNγ in response to tumor cells. The vaccine was not effective if the αGC, IL-12, or GM-CSF secretion was eliminated. Finally, immunized mice were fully resistant to challenge with TRAMP-C2 cells. Together these findings support further development of therapeutic vaccines that exploit iNKT cell activation.
The superlative electronic properties of graphene suggest its use as the foundation of next-generation integrated circuits. However, this application requires precise control of the interface between ...graphene and other materials, especially the metal oxides that are commonly used as gate dielectrics. Toward that end, organic seeding layers have been empirically shown to seed ultrathin dielectric growth on graphene via atomic layer deposition (ALD), although the underlying chemical mechanisms and structural details of the molecule/dielectric interface remain unknown. Here, confocal resonance Raman spectroscopy is employed to quantify the structure and chemistry of monolayers of 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) on graphene before and after deposition of alumina with the ALD precursors trimethyl aluminum (TMA) and water. Photoluminescence measurements provide further insight into the details of the growth mechanism, including the transition between layer-by-layer growth and island formation. Overall, these results reveal that PTCDA is not consumed during ALD, thereby preserving a well-defined and passivating organic interface between graphene and deposited dielectric thin films.
Understanding the heterogeneous genetic mechanisms of tumor initiation in lymphoid leukemias (LL) will lead to improvements in prognostic classification and treatment regimens. In previous studies of ...mouse leukemias, we showed that retroviral insertion at the ecotropic viral insertion site 32 locus leads to increased expression of Prdm14, a pluripotency gene implicated in the self-renewal capacity of embryonic stem cells and the early stages of breast cancer. Here, we show that PRDM14 is also overexpressed in ∼25% of human lymphoid neoplasms, with increased frequencies in T-cell acute LL and hyperdiploid precursor B-cell acute LL. To test if Prdm14 overexpression could initiate leukemia, mice were transduced with bone marrow cells transfected with a Prdm14 expression vector. LLs developed in 96% of female mice and 42% of male mice. Before the onset of leukemia, differentiation of transduced cells was biased up to 1000-fold toward cells with features of common lymphoid progenitors (CLPs), and lymphoid differentiation showed a relative block at the pro-B stage. Microarray gene expression analysis of expanded CLP-like cells before the onset of leukemia demonstrated upregulation of genes involved in pluripotency, tumor initiation, early B-lineage commitment, Wnt/Ras signaling and the epithelial-to-mesenchymal transition. Among the dysregulated genes were imprinted genes and non-coding RNAs including Dlk1 and Meg3, which are also key pluripotency mediators. Heightened expression of the estrogen-dependent oncogene, Myb, in tumors suggests a basis for the increased frequency of cancer in female mice. These data provide the first direct evidence for the association of Prdm14 with cancer initiation in an in vivo mouse model and in human lymphoid malignancies, while suggesting mechanisms for Prdm14's mode of action.
Mouse ENU Mutagenesis Justice, Monica J.; Noveroske, Janice K.; Weber, John S. ...
Human molecular genetics,
01/1999, Letnik:
8, Številka:
10
Journal Article
Recenzirano
Odprti dostop
The progress of human genome sequencing is driving genetic approaches to define gene function. Strategies such as gene traps and chemical mutagenesis will soon generate a large mutant mouse resource. ...Point mutations induced by N-ethyl-N-nitrosourea (ENU) provide a unique mutant resource because they: (i) reflect the consequences of single gene change independent of position effects; (ii) provide a fine-structure dissection of protein function; (iii) display a range of mutant effects from complete or partial loss of function to exaggerated function; and (iv) discover gene functions in an unbiased manner. Phenotype-driven ENU screens in the mouse are emphasizing relevance to human clinical disease by targeting cardiology, physiology, neurology, immunity, hematopoiesis and mammalian development. Such approaches are extremely powerful in understanding complex human diseases and traits: the base-pair changes may accurately model base changes found in human diseases, and subtle mutant alleles in a standard genetic background provide the ability to analyze the consequences of compound genotypes. Ongoing mouse ENU mutagenesis experiments are generating a treasure trove of new mutations to allow an in-depth study of a single gene, a chromosomal region or a biological system.
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