501 research outputs found
Low cuticle deposition rate in ‘Apple’ mango increases elastic strain, weakens the cuticle and increases russet
Russeting compromises appearance and downgrades the market value of many fruitcrops, including of the mango cv. ‘Apple’. The objective was to identify the mechanistic basis of ‘Apple’ mango’s high susceptibility to russeting. We focused on fruit growth, cuticle deposition, stress/strain relaxation analysis and the mechanical properties of the cuticle. The non-susceptible mango cv. ‘Tommy Atkins’ served for comparison. Compared with ‘Tommy Atkins’, fruit of ‘Apple’ had a lower mass, a smaller surface area and a lower growth rate. There were little differences between the epidermal and hypodermal cells of ‘Apple’ and ‘Tommy Atkins’ including cell size, cell orientation and cell number. Lenticel density decreased during development, being lower in ‘Apple’ than in ‘Tommy Atkins’. The mean lenticel area increased during development but was consistently greater in ‘Apple’ than in ‘Tommy Atkins’. The deposition rate of the cuticular membrane was initially rapid but later slowed till it matched the area expansion rate, thereafter mass per unit area was effectively constant. The cuticle of ‘Apple’ is thinner than that of ‘Tommy Atkins’. Cumulative strain increased sigmoidally with fruit growth. Strains released stepwise on excision and isolation (εexc+iso), and on wax extraction (εextr) were higher in ‘Apple’ than in ‘Tommy Atkins’. Membrane stiffness increased during development being consistently lower in ‘Apple’ than in ‘Tommy Atkins’. Membrane fracture force (Fmax) was low and constant in developing ‘Apple’ but increased in ‘Tommy Atkin’. Membrane strain at fracture (εmax) decreased linearly during development but was lower in ‘Apple’ than in ‘Tommy Atkins’. Frequency of membrane failure associated with lenticels increased during development and was consistently higher in ‘Apple’ than in ‘Tommy Atkins’. The lower rate of cuticular deposition, the higher strain releases on excision, isolation and wax extraction and the weaker cuticle account for the high russet susceptibility of ‘Apple’ mango
ASD-Associated De Novo Mutations in Five Actin Regulators Show Both Shared and Distinct Defects in Dendritic Spines and Inhibitory Synapses in Cultured Hippocampal Neurons
Many actin cytoskeleton-regulating proteins control dendritic spine morphology and density, which are cellular features often altered in autism spectrum disorder (ASD). Recent studies using animal models show that autism-related behavior can be rescued by either manipulating actin regulators or by reversing dendritic spine density or morphology. Based on these studies, the actin cytoskeleton is a potential target pathway for developing new ASD treatments. Thus, it is important to understand how different ASD-associated actin regulators contribute to the regulation of dendritic spines and how ASD-associated mutations modulate this regulation. For this study, we selected five genes encoding different actin-regulating proteins and induced ASD-associated de novo missense mutations in these proteins. We assessed the functionality of the wild-type and mutated proteins by analyzing their subcellular localization, and by analyzing the dendritic spine phenotypes induced by the expression of these proteins. As the imbalance between excitation and inhibition has been suggested to have a central role in ASD, we additionally evaluated the density, size and subcellular localization of inhibitory synapses. Common for all the proteins studied was the enrichment in dendritic spines. ASD-associated mutations induced changes in the localization of alpha-actinin-4, which localized less to dendritic spines, and for SWAP-70 and SrGAP3, which localized more to dendritic spines. Among the wild-type proteins studied, only alpha-actinin-4 expression caused a significant change in dendritic spine morphology by increasing the mushroom spine density and decreasing thin spine density. We hypothesized that mutations associated with ASD shift dendritic spine morphology from mushroom to thin spines. An M554V mutation in alpha-actinin-4 (ACTN4) resulted in the expected shift in dendritic spine morphology by increasing the density of thin spines. In addition, we observed a trend toward higher thin spine density withmutations inmyosin IXb and SWAP-70. Myosin IIb and myosin IXb expression increased the proportion of inhibitory synapses in spines. The expression of mutated myosin IIb (Y265C), SrGAP3 (E469K), and SWAP-70 (L544F) induced variable changes in inhibitory synapses.Peer reviewe
Cesarean delivery in Nigeria: Prevalence and associated factors -a population-based cross-sectional study
Objective To investigate the prevalence and factors associated with caesarean delivery in Nigeria. Design This is a secondary analysis of the nationally representative 2013 Nigeria Demographic and Health Survey (NDHS) data. We carried out frequency tabulation, χ2 test, simple logistic regression and multivariable binary logistic regression analyses to achieve the study objective. Setting Nigeria. Participants A total of 31 171 most recent live deliveries for women aged 15–49 years (mother–child pair) in the 5 years preceding the 2013 NDHS was included in this study. Outcome measure Caesarean mode of delivery. Results The prevalence of caesarean section (CS) was 2.1% (95% CI 1.8 to 2.3) in Nigeria. At the region level, the South-West had the highest prevalence of 4.7%. Factors associated with increased odds of CS were urban residence (adjusted OR (AOR): 1.51, 95% CI 1.15 to 1.97), maternal age ≥ 35 years (AOR: 2.12, 95% CI 1.08 to 4.11), large birth size (AOR: 1.39, 95% CI 1.10 to 1.74) and multiple births (AOR: 4.96, 95% CI 2.84 to 8.62). Greater odds of CS were equally associated with maternal obesity (AOR: 3.16, 95% CI 2.30 to 4.32), Christianity (AOR: 2.06, 95% CI 1.58 to 2.68), birth order of one (AOR: 3.86, 95% CI 2.66 to 5.56), husband’s secondary/higher education level (AOR: 2.07, 95% CI 1.29 to 3.33), health insurance coverage (AOR: 2.01, 95% CI 1.37 to 2.95) and ≥ 4 antenatal visits (AOR: 2.84, 95% CI 1.56 to 5.17). Conclusions The prevalence of CS was low, indicating unmet needs in the use of caesarean delivery in Nigeria. Rural–urban, regional and socioeconomic differences were observed, suggesting inequitable access to the obstetric surgery. Intervention efforts need to prioritise women living in rural areas, the North-East and the North-West regions, as well as women of the Islamic faith
A selective synthesis of taon nanoparticles and their comparative study of photoelectrochemical properties
A simplified ammonolysis method for synthesizing single phase TaON nanoparticles is presented and the resulting photoelectrochemical properties are compared and contrasted with as-synthesized Ta2O5 and Ta3N5. The protocol for partial nitridation of Ta2O5 (synthesis of TaON) offers a straightforward simplification over existing methods. Moreover, the present protocol offers extreme reproducibility and enhanced chemical safety. The morphological characterization of the as-synthesized photocatalysts indicate spherical nanoparticles with sizes 30, 40, and 30 nm Ta2O5, TaON, and Ta3N5 with the absorbance onset at ~320 nm, 580 nm, and 630 nm respectively. The photoactivity of the catalysts has been examined for the degradation of a representative cationic dye methylene blue (MB) using xenon light. Subsequent nitridation of Ta2O5 yields significant increment in the conversion (ζ: Ta2O5 95% ζ for a lower (0.1 g) loading and with a lamp with lower Ultraviolet (UV) content. Improved Photoelectrochemical performance is noted after a series of chronoamperometry (J/t), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS) measurements. Finally, stability experiments performed using recovered and treated photocatalyst show no loss of photoactivity, suggesting the photocatalysts can be successfully recycled
Biospectroscopy of Nanodiamond-Induced Alterations in Conformation of Intra- and Extracellular Proteins: A Nanoscale IR Study
The toxicity of nanomaterials raises major concerns because of the impact that nanomaterials may have on health,
which remains poorly understood. We need to explore the fate of individual nanoparticles in cells at nano and molecular levels to
establish their safety. Conformational changes in secondary protein structures are one of the main indicators of impaired biological
function and hence, the ability to identify these changes at a nanoscale level offers unique insights into the nanotoxicity of materials.
Here, we used nanoscale infrared spectroscopy and demonstrated for the first time that nanodiamonds induced alterations in
both extra- and intracellular secondary protein structures, leading to the formation of antiparallel β-sheet, β-turns, intermolecular β-
sheet and aggregation of proteins. These conformational changes of the protein structure may result in the loss of functionality of
proteins and in turn lead to adverse effects
Quasi-normal modes of Schwarzschild-de Sitter black holes
The low-laying frequencies of characteristic quasi-normal modes (QNM) of
Schwarzschild-de Sitter (SdS) black holes have been calculated for fields of
different spin using the 6th-order WKB approximation and the approximation by
the P\"{o}shl-Teller potential. The well-known asymptotic formula for large
is generalized here on a case of the Schwarzchild-de Sitter black hole. In the
limit of the near extreme term the results given by both methods are
in a very good agreement, and in this limit fields of different spin decay with
the same rate.Comment: 9 pages, 1 ancillary Mathematica(R) noteboo
Home childbirth among young mothers aged 15–24 years in Nigeria: a national population-based cross-sectional study
Objective To estimate the prevalence and identify factors associated with home childbirth (delivery) among young mothers aged 15–24 years in Nigeria. Design A secondary analysis of cross-sectional data from the 2013 Nigeria Demographic and Health Survey (NDHS). Setting Nigeria. Participants A total of 7543 young mothers aged 15–24 years. Outcome measure Place of delivery. Results The prevalence of home delivery among young mothers aged 15–24 years was 69.5% (95% CI 67.1% to 71.8%) in Nigeria—78.9% (95%CI 76.3% to 81.2%) in rural and 43.9% (95%CI 38.5% to 49.5%, p<0.001) in urban Nigeria. Using the Andersen’s behavioural model, increased odds of home delivery were associated with the two environmental factors: rural residence (adjusted OR, AOR: 1.39, 95% CI 1.06 to 1.85) and regions of residence (North-East: AOR: 1.97, 95% CI 1.14 to 3.34; North-West: AOR: 2.94, 95% CI 1.80 to 4.83; and South-South: AOR: 3.81, 95% CI 2.38 to 6.06). Three of the enabling factors (lack of health insurance: AOR: 2.34, 95% CI 1.16 to 4.71; difficulty with distance to healthcare facilities: AOR: 1.48, 95% CI 1.15 to 1.88; and <4 times antenatal attendance: AOR: 3.80, 95% CI 3.00 to 4.85) similarly increased the odds of home delivery. Lastly, six predisposing factors—lack of maternal and husband’s education, poor wealth index, Islamic religion, high parity and low frequency of listening to radio—were associated with increased odds of home delivery. Conclusions Young mothers aged 15–24 years had a higher prevalence of home delivery than the national average for all women of reproductive age in Nigeria. Priority attention is required for young mothers in poor households, rural areas, North-East, North-West and South-South regions. Faith-based interventions, a youth-oriented antenatal care package, education of girls and access to health insurance coverage are recommended to speed up the reduction of home delivery among young mothers in Nigeria
The structure of the extreme Schwarzschild-de Sitter space-time
The extreme Schwarzschild-de Sitter space-time is a spherically symmetric
solution of Einstein's equations with a cosmological constant Lambda and mass
parameter m>0 which is characterized by the condition that 9 Lambda m^2=1. The
global structure of this space-time is here analyzed in detail. Conformal and
embedding diagrams are constructed, and synchronous coordinates which are
suitable for a discussion of the cosmic no-hair conjecture are presented. The
permitted geodesic motions are also analyzed. By a careful investigation of the
geodesics and the equations of geodesic deviation, it is shown that specific
families of observers escape from falling into the singularity and approach
nonsingular asymptotic regions which are represented by special "points" in the
complete conformal diagram. The redshift of signals emitted by particles which
fall into the singularity, as detected by those observers which escape, is also
calculated.Comment: 19 pages, 10 figures, LaTeX, to appear in Gen. Rel. Gra
Systematic Review of Health Literacy and Health Promotion in School-Aged Adolescents
Background: The literature has identified gaps in adolescent health literacy (AHL) measurements, as well as how the health literacy (HL) level is related to health promotion (HP) aspects. This study aimed to examine the tools used to measure HL and determine its relation with HP among adolescents. Methods: Three online databases (HINARI, PubMed, and DOAJ) were searched to conduct a systematic assessment of papers published between January 1, 2016, and January 1, 2021. In this review, 373 articles were identified from these databases. After removing duplicates and screening titles and abstracts of articles, 49 full texts were selected for full-text reading. After comprehensive reading, 23 papers were appraised for qualitative synthesis. Results: Of the 23 reviewed papers, 21 focused on assessing AHL measures, and 15 addressed the association between AHL and HP. Seven studies used the HL School-Aged Children instrument. The findings suggested that the methodological and conceptual underpinnings of HL measures are insufficient. Furthermore, HL acts as an independent and positive mediator for many facets of HP. Conclusion: This review offers a warning to practitioners and educationists interested in measuring HL as the number of measurement tools is quite huge with different tools applying different scales
- …