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1.
Artículo en Inglés | MEDLINE | ID: mdl-37184092

RESUMEN

PURPOSE: Recent evidence suggests that the ciliary muscle apical fibres are most responsive to accommodative load; however, the structure of the ciliary muscle in individuals with accommodative insufficiency is unknown. This study examined ciliary muscle structure in individuals with accommodative insufficiency (AI). We also determined the response of the ciliary muscle to accommodative/vergence therapy and increasing accommodative demands to investigate the muscle's responsiveness to workload. METHODS: Subjects with AI were enrolled and matched by age and refractive error with subjects enrolled in another ciliary muscle study as controls. Anterior segment optical coherence tomography was used to measure the ciliary muscle thickness (CMT) at rest (0D), maximum thickness (CMTMAX) and over the area from 0.75 mm (CMT0.75) to 3 mm (CMT3) posterior to the scleral spur of the right eye. For those with AI, the ciliary muscle was also measured at increasing levels of accommodative demand (2D, 4D and 6D), both before and after accommodative/vergence therapy. RESULTS: Sixteen subjects with AI (mean age = 17.4 years, SD = 8.0) were matched with 48 controls (mean age = 17.8 years, SD = 8.2). On average, the controls had 52-72 µm thicker ciliary muscles in the apical region at 0D than those with AI (p = 0.03 for both CMTMAX and CMT 0.75). Differences in thickness between the groups in other regions of the muscle were not statistically significant. After 8 weeks of accommodative/vergence therapy, the CMT increased by an average of 22-42 µm (p ≤ 0.04 for all), while AA increased by 7D (p < 0.001). CONCLUSIONS: This study demonstrated significantly thinner apical ciliary muscle thickness in those with AI and that the ciliary muscle can thicken in response to increased workload. This may explain the mechanism for improvement in signs and symptoms with accommodative/vergence therapy.

2.
BMC Infect Dis ; 23(1): 60, 2023 Jan 31.
Artículo en Inglés | MEDLINE | ID: mdl-36721102

RESUMEN

BACKGROUND: The Coronavirus Infectious Disease 2019 (COVID-19) pandemic has continuously affected human life with several devastating effects. Currently, there are effective vaccines to protect people from COVID-19 and the World Health Organization (WHO) has highlighted strategies to influence COVID-19 vaccine uptake in hard-to-reach communities in Ghana. However, prior studies on COVID-19 vaccine acceptability in Ghana are online surveys targeting the literates and those in urban areas, leaving residents in far-flung communities. We assessed knowledge, attitude and acceptability of COVID-19 vaccine among residents in rural communities in Ghana. METHODS: This study was a community-based cross-sectional study and was conducted at three selected regions in Ghana (Northern, Ashanti and Western North) from May to November, 2021. This study included residents 15-81 years, living in the selected rural communities for more than 1 year. Study participants were recruited and questionnaires administered to collect data on knowledge, attitude and acceptance of the COVID-19 vaccine. Statistical analyses were performed using Statistical Package for Social Science (SPSS) version 26.0 and GraphPad Prism Version 8.0 software. RESULTS: Of the 764 participants included in this study, more than half had inadequate knowledge (55.0%), poor attitudes (59.4%) and bad perception about COVID-19 vaccine (55.4%). The acceptability of COVID-19 vaccine in this study was 41.9%. The acceptability of COVID-19 vaccine in Ashanti, Northern and Western North regions were 32.5%, 26.2% and 29.6% respectively. In a multivariate logistic regression analysis, receiving recent or previous vaccine such as HBV vaccine [aOR = 1.57, 95% CI (1.23-3.29), p = 0.002], having good attitude towards COVID-19 vaccine [aOR = 61.47, 95% CI (29.55-127.86), p < 0.0001] and having good perception about the COVID-19 vaccine [aOR = 3.87, 95% CI (1.40-10.72), p < 0.0001] were independently associated with higher odds of accepting COVID-19 vaccine. CONCLUSION: More than half of residents in Ghanaian rural communities have inadequate knowledge, poor attitudes and bad perception about COVID-19 vaccine. The acceptability of COVID-19 vaccine is generally low among rural residents in Ashanti, Northern and Western North regions of Ghana. Residents living in hard-to-reach communities must be educated about the benefits of COVID-19 vaccine to achieve effective vaccination program.


Asunto(s)
COVID-19 , Enfermedades Transmisibles , Humanos , Vacunas contra la COVID-19 , Ghana/epidemiología , Estudios Transversales , Conocimientos, Actitudes y Práctica en Salud , Población Rural , COVID-19/epidemiología , COVID-19/prevención & control
3.
Heliyon ; 8(12): e12217, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36578397

RESUMEN

Macrophomina root rot disease (MRRD) caused by Macrophomina phaseolina is an emerging threat to the profitable cowpea production in northern Ghana. Recommended control methods including the use of fungicides are ineffective and expensive for resource poor farmers whilst biocontrol options are not commercially available. An integrated method based on host plant resistance is considered the cheapest and most effective method of managing the disease. This study sought to confirm and characterize previously identified MRRD isolates from Northern Ghana using molecular technology, and to identify cowpea with potential sources of resistance to the MRRD. A PCR assay of ten isolates of the cowpea root rot pathogen revealed all isolates belonged to the species M. phaseolina, whilst a nucleotide BLAST of eight isolates showed 98% similarity with the sequences of Macrophomina isolates from other host available in GenBank. A sick pot method evaluation of 49 cowpea lines found 10 lines resistant to MRRD on a 1-9 disease severity scale (disease score, less than 5). A selection of eight resistant lines (Suvita 2, Abagbaala, IT97K573-1-1, IT93K-503-1-1, Hewale, AV2 3224, Nhyira and T2T4), and a susceptible check (Songotra) were evaluated against 10 isolates of M. phaseolina using a sick pot method. All the genotypes except for the susceptible check were resistant to MRRD. Thus, these genotypes could be used in cowpea MRRD resistance breeding programs.

4.
Artículo en Inglés | MEDLINE | ID: mdl-36286324

RESUMEN

INTRODUCTION: Maddox suggested that there were four convergence subtypes, each driven by a different stimulus. The purpose of this study was to assess the neural correlates for accommodative convergence, proximal convergence (convergence stimulus provided), disparity convergence and voluntary convergence (no specific convergence stimulus provided) using functional magnetic resonance imaging (fMRI). METHODS: Ten subjects (mean age = 24.4 years) with normal binocular vision participated. The blood oxygenation level-dependent (BOLD) signals of the brain from fMRI scans were measured when subjects made vergence eye movements while: (1) alternately viewing letters monocularly where one eye viewed through a -2.00 D lens, (2) alternately viewing Difference of Gaussian targets monocularly at distance and near, (3) viewing random dot stereograms with increasing disparity and (4) voluntarily converging the eyes with binocular viewing. RESULTS: The accommodative convergence paradigm resulted in activation on the right side in the right fusiform cortex and the right middle occipital cortex. The proximal convergence stimulus mainly activated areas in the right occipital lobe. The disparity stimulus activated areas in the left occipital cortex and the left frontal cortex. Finally, the voluntary convergence paradigm resulted in activation primarily in the occipital lobe and mostly bilaterally. CONCLUSION: The accommodative, proximal, disparity and voluntary convergence paradigms resulted in activation in unique areas in the brain with functional MRI. Activation was found in more areas in the proximal and voluntary conditions compared with the accommodative and disparity conditions.

5.
Heliyon ; 8(7): e09852, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35847611

RESUMEN

Global climate change is expected to further intensify the already harsh conditions in the dry savannah ecological zones of sub-Saharan Africa, posing serious threats to food and income security of millions of smallholder farmers. Breeding cowpea for improved earliness could help minimize this risk, by ensuring that the crops complete their lifecycle before the cessation of rainfall. In this study, we crossed two sets of cowpea lines showing contrasting phenotypes for earliness in terms of days to 50% flowering (DFF). One set of the lines comprised three extra-early parents (viz.: Sanzi-Nya, Tobonaa and CB27, 30-35 DFF), and the other set consisted of three early-to-medium maturity lines (viz.: Kirkhouse-Benga, Wang-Kae and Padi-Tuya, 42-45 DFF). The derived crosses and their parents were evaluated for key earliness-related traits at Nyankpala and Manga sites of CSIR-Savanna Agricultural Research Institute (SARI), Ghana. To unravel the genetic control of measured traits, we compared the appropriateness of Chi-square goodness of fit tests using classical Mendelian ratios, and frequency distribution (histogram)-related statistics such as skewness and kurtosis. The Chi-square test suggested a single dominant gene mode of inheritance for earliness, whereas the quantitative methods implicated duplicate epistasis and complementary epistatic gene actions. Our results show that coercing segregating lines to fit into classical Mendelian ratios to determine the genetic control of earliness could be misleading, due to its subjectivity. Thus, the genetic control of earliness in cowpea is governed by complementary and duplicate epistasis. The most applicable breeding approach for traits influenced by duplicate epitasis is selection of desirable recombinants from segregating populations developed from bi-parental crosses. Complementary epitasis, as found in the Wang-Kae × CB27 cross, could be exploited in developing improved extra-early lines through backcrossing. Heritability and genetic advance estimates were high for days to first flower appearance (DFFA) and days to 95 % pod maturity (DNPM) in the Padi-Tuya × CB27 and Kirkhouse-Benga x CB27 crosses, indicating that breeding for extra-earliness is feasible. CB27 could be a good donor for introgression of earliness into medium to late maturing improved cowpea varieties, because crosses developed from it had high heritability and genetic advance estimates.

6.
PLoS One ; 16(6): e0252787, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34138900

RESUMEN

Suboptimal cataract surgery outcomes remain a challenge in most developing countries. In Ghana, about 2 million people have been reported to be blind due to cataract with about 20% new cases being recorded yearly. The aim of this study was to evaluate postoperative correction of refractive errors after cataract surgery in a selected eye hospital in Ashanti Region, Ghana. This was a retrospective study where medical records of patients (aged 40-100) who reported to an eye hospital in Ghana from 2013-2018 were reviewed. Included in the study were patients aged ≥40 years and patients with complete records. Data on patient demographics, type of surgery, intra-ocular lens (PCIOL) power, availability of biometry, postoperative refraction outcomes, pre- and postoperative visual acuity were analyzed. Data of two hundred and thirteen eyes of 190 patients who met the inclusion criteria were analyzed. Descriptive analysis and Chi-square test were carried out to determine the mean, median, standard deviation and relevant associations. The mean ± SD age was 67.21±12.2 years (51.2% were females). Small Incision Cataract Surgery (99.5%) with 100% IOL implants was the main cataract surgery procedure in this study. Pre-operative biometry was performed for 38.9% of all patients on their first eye surgery and 41.5% for second eye surgeries. About 71% eyes in this study were blind (presenting VA<3/60) before surgery; 40.4% had post-operative VA <3/60. Pre-existing ocular comorbidities discovered post- surgery, attributed to suboptimal visual outcomes. More than half (55.3%) of patients did not undergo postoperative refraction due to loss to follow-up. Year of surgery (p = .017), follow up visits< 2months (p < .0001) and discovered comorbidity post-surgery (p = .035) were the factors significantly associated with postoperative refraction. Myopia and compound myopic astigmatism were the dominant refractive error outcomes. The timing of post-operative refraction had a significant effect on postoperative refraction done. These findings indicate a clinically meaningful significance between completion of postoperative care and postoperative refraction done. Consequently, with settings in most developing countries, where less biometry is done, it is appropriate that post-operative refractive services are encouraged and done earlier to enhance the patients' expectations while increasing cataract surgery patronage.


Asunto(s)
Extracción de Catarata/métodos , Catarata/prevención & control , Evaluación de Resultado en la Atención de Salud/estadística & datos numéricos , Errores de Refracción/prevención & control , Procedimientos Quirúrgicos Refractivos/métodos , Adulto , Anciano , Anciano de 80 o más Años , Catarata/fisiopatología , Femenino , Ghana , Humanos , Implantación de Lentes Intraoculares/métodos , Masculino , Persona de Mediana Edad , Evaluación de Resultado en la Atención de Salud/métodos , Periodo Posoperatorio , Refracción Ocular/fisiología , Errores de Refracción/fisiopatología , Estudios Retrospectivos , Agudeza Visual/fisiología
7.
Heliyon ; 7(9): e07890, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34522801

RESUMEN

Experimental studies were conducted to evaluate 16 advanced breeding lines of cowpea (Vigna unguiculata (L) Walp) for genetic variability, heritability and correlation between maturity and yield related traits. The genotypes exhibited significant (P < 0.05) differences for the eight traits evaluated viz., number of days to 50 % flowering, number of days to 90 % pod maturity, plant height at maturity, number of pods per plant, number of seeds per pod, pod yield, grain yield and hundred seed weight. SARI-3-11-100, SARI-6-2-6, SARVX-09-004 and IT07K-299-6 had grain yields of 1.99 ± 0.30, 1.88 ± 0.20, 1.95 ± 0.30 and 1.91 ± 0.20 t/ha, respectively, which were significantly higher than the check (Songotra) (1.68 ± 0.01 t/ha). In addition, SARI-5-5-5 matured significantly earlier than the check but no significant difference was observed for grain yield. The higher value of phenotypic component compared to the corresponding genotypic component for all the traits suggest that there was an environmental influence on the performance of the genotypes. Hence, the need for multi-location evaluation of the promising lines for onward release if found stable. The information provided in this study, can be exploited in cowpea breeding program.

8.
ScientificWorldJournal ; 2020: 9390287, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32802007

RESUMEN

Information on combining ability and reciprocal effects (REC) facilitates efficient utilization of genetic materials in a breeding program. This study was conducted (at the CSIR-Savanna Agricultural Research Institute, Ghana) to determine general combining ability (GCA) and specific combining ability (SCA), heritability, genetic advance, GCA, and SCA effects as well as the relationship between parents per se performance and progenies for yield components and maturity traits in cowpea. The test populations were derived using a 5 × 5 complete diallel cross of parents with different yield attributes and maturity durations. The results indicated that GCA was predominant for number of days to 90% pod maturity, plant height at maturity, and hundred-seed weight. This showed that genes with additive effects conditioned these traits. Padi-Tuya, Songotra, and IT86D-610 were identified as good general combiners for grain yield, while Sanzi-Nya was identified as a general combiner for developing extra-early duration cowpea varieties. Crosses Songotra × Sanzi-Nya, SARC-1-57-2 × IT86D-610, Songotra × SARC-1-57-2, and Padi-Tuya × Songotra were identified as good specific combiners for days to 50% flowering, pod length, pods per plant, pod yield, grain yield, and seeds per pod. The findings from this study provide useful information on the inheritance of early maturity and yield traits in cowpea. This can be exploited to develop high yielding and early maturing cowpea varieties as climate smart strategy to mitigate climate change via breeding methods such as pedigree selection and marker assisted backcrossing (MABC). Pedigree selection method is being used to develop varieties from the hybrid with high and significant SCA for grain yield, whereas the development of extra-early duration varieties via MABC with Sanzi-Nya (general combiner for earliness traits) as a donor parent is ongoing.


Asunto(s)
Vigna/crecimiento & desarrollo , Vigna/genética , Alelos , Productos Agrícolas/genética , Productos Agrícolas/crecimiento & desarrollo , Productos Agrícolas/fisiología , Variación Genética , Genotipo , Ghana , Semillas/genética , Vigna/fisiología
9.
Sci Eng Ethics ; 26(1): 325-349, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-30868376

RESUMEN

Construction process stages are argued to be vulnerable to the prevalence of corrupt practices. However, the validity of this argument has not been empirically explored in the extant literature of construction management. Therefore, this study examines the stages of the construction process susceptibility to corruption and its most prominent forms of corrupt activities (within the respective stages). A total of forty-four project-related professionals were involved in an expert survey to assess such susceptibilities and the criticality of the identified corrupt activities at each stage. A comparative study of expert views from developing regions against experts from developed regions is conducted. Expert scoring results revealed that three stages are most susceptible, namely: project execution, pre-qualification and tender stages. Such results were confirmed by application of the Mann-Whitney U test statistics tool, showing wide disparities in seven out of eleven identical stages. This study is intended to incite polemic discussions and greater empirical, evidence-based research from scholars in both developed and developing countries. This study adds to the extant literature corruption-related works on the construction process through deeper understanding of the dynamic nature of corrupt practices involved in the stages of the construction process in developing countries. Practically, it intends to offer a veritable plethora of information on the critical stages of the construction process for industry practitioners, policymakers and anti-corruption bodies to careen their attention towards the fight against corruption.


Asunto(s)
Industria de la Construcción/ética , Industria de la Construcción/organización & administración , Crimen , Mala Conducta Profesional , Industria de la Construcción/legislación & jurisprudencia , Países Desarrollados , Países en Desarrollo , Investigación Empírica , Humanos , Incidencia , Prevalencia , Encuestas y Cuestionarios
10.
Clin Lab ; 65(1)2019 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-30775895

RESUMEN

BACKGROUND: The authors report a clinical case where biological interference rendered the electrophoretic trace of serum proteins obtained by capillary electrophoresis as uninterpretable. METHODS: Electrophoresis of serum proteins and immunotyping immunoassay were performed on Capillary 2 Flex Piercing® Sebia. RESULTS: A 72-year-old male patient was hospitalized in the clinical hematology department for deep lymphadenopathies with hepatocellular failure. The biological assessment revealed chronic renal failure stage G3b, icteric cholestasis with alkaline phosphatase levels, and hepatic cytolysis. Electrophoresis of serum proteins showed a thickening at the base of albumin peak on its anodic slope but, in particular, it revealed the appearance of a super-numerary split peak between albumin and α1 globulins. These peaks made it impossible to identify and integrate peaks. Based on the clinical information, immunotyping immunoassay was performed on the same sample. The comparison of the different curves with the reference curve does not show any monoclonal immunoglobulinopathy but eliminates all the supernumerary peaks. Suspecting an interference, a Hydrasys 2 Scan® agarose gel electrophoresis (Sebia) was run on the same sample; however, it did not show qualitative anomalies interfering with identification and integration of all the peaks. CONCLUSIONS: Our clinical case emphasizes the importance of the knowledge of certain endogenous interferences that may be the origin of unusual images when interpreting electrophoretic profiles, especially in capillary electrophoresis.


Asunto(s)
Albúminas/análisis , Proteínas Sanguíneas/análisis , Electroforesis Capilar/métodos , Fallo Renal Crónico/metabolismo , Anciano , Humanos , Fallo Renal Crónico/diagnóstico , Masculino
11.
Sci Eng Ethics ; 25(1): 1-31, 2019 02.
Artículo en Inglés | MEDLINE | ID: mdl-29129014

RESUMEN

The development of efficient and strategic anti-corruption measures can be better achieved if a deeper understanding and identification of the causes of corruption are established. Over the past years, many studies have been devoted to the research of corruption in construction management (CM). This has resulted in a significant increase in the body of knowledge on the subject matter, including the causative factors triggering these corrupt practices. However, an apropos systematic assessment of both past and current studies on the subject matter which is needful for the future endeavor is lacking. Moreover, there is an absence of unified view of the causative factors of corruption identified in construction project management (CPM). This paper, therefore, presents a comprehensive review of the causes of corruption from selected articles in recognized construction management journals to address the mentioned gaps. A total number of 44 causes of corruption were identified from 37 publications and analyzed in terms of existing causal factors of corruption, annual trend of publications and the thematic categorization of the identified variables. The most identifiable causes were over close relationships, poor professional ethical standards, negative industrial and working conditions, negative role models and inadequate sanctions. A conceptual framework of causes of corruption was established, after categorizing the 44 variables into five unique categories. In descending order, the five constructs are Psychosocial-Specific Causes, Organizational-Specific Causes, Regulatory-Specific Causes, Project-Specific Causes and Statutory-Specific Causes. This study extends the current literature of corruption research in construction management and contributes to a deepened understanding of the causal instigators of corruption identified in CPM. The findings from this study provide valuable information and extended knowledge to industry practitioners and policymakers as well as anti-corruption agencies in the formulation and direction of anti-corruption measures. To corruption researchers in CM, this study is vital for further research.


Asunto(s)
Industria de la Construcción/ética , Ética en los Negocios , Ética Profesional , Humanos , Principios Morales
12.
Clin Case Rep ; 5(12): 2044-2046, 2017 12.
Artículo en Inglés | MEDLINE | ID: mdl-29225853

RESUMEN

We are highlighting on the particularity of a clinical picture of pulmonary embolism revealing light-chain myeloma in a 56-year-old male patient. Myeloma remains a rare affection. Even though its revelation through pulmonary embolism remains rare, it can be explained by hyperviscosity syndrome accompanying it.

13.
Int J Environ Res Public Health ; 12(7): 7814-38, 2015 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-26184257

RESUMEN

Exposure to traffic-generated ultrafine particles (UFP; particles <100 nm) is likely a risk factor for cardiovascular disease. We conducted a trial of high-efficiency particulate arrestance (HEPA) filtration in public housing near a highway. Twenty residents in 19 apartments living <200 m from the highway participated in a randomized, double-blind crossover trial. A HEPA filter unit and a particle counter (measuring particle number concentration (PNC), a proxy for UFP) were installed in living rooms. Participants were exposed to filtered air for 21 days and unfiltered air for 21 days. Blood samples were collected and blood pressure measured at days 0, 21 and 42 after a 12-hour fasting period. Plasma was analyzed for high sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6), tumor necrosis factor alpha-receptor II (TNF-RII) and fibrinogen. PNC reductions ranging from 21% to 68% were recorded in 15 of the apartments. We observed no significant differences in blood pressure or three of the four biomarkers (hsCRP, fibrinogen, and TNF-RII) measured in participants after 21-day exposure to HEPA-filtered air compared to measurements after 21-day exposure to sham-filtered air. In contrast, IL-6 concentrations were significantly higher following HEPA filtration (0.668 pg/mL; CI = 0.465-0.959) compared to sham filtration. Likewise, PNC adjusted for time activity were associated with increasing IL-6 in 14- and 21-day moving averages, and PNC was associated with decreasing blood pressure in Lags 0, 1 and 2, and in a 3-day moving average. These negative associations were unexpected and could be due to a combination of factors including exposure misclassification, unsuccessful randomization (i.e., IL-6 and use of anti-inflammatory medicines), or uncontrolled confounding. Studies with greater reduction in UFP levels and larger sample sizes are needed. There also needs to be more complete assessment of resident time activity and of outdoor vs. indoor source contributions to UFP exposure. HEPA filtration remains a promising, but not fully realized intervention.


Asunto(s)
Contaminantes Atmosféricos/efectos adversos , Enfermedades Cardiovasculares/prevención & control , Material Particulado/efectos adversos , Vivienda Popular , Adulto , Biomarcadores , Proteína C-Reactiva , Sistema Cardiovascular/efectos de los fármacos , Estudios Cruzados , Método Doble Ciego , Femenino , Filtración , Humanos , Interleucina-6 , Masculino , Factores de Riesgo , Emisiones de Vehículos/envenenamiento
14.
Artículo en Inglés | MEDLINE | ID: mdl-23543021

RESUMEN

BACKGROUND: Particulate air pollution, including from motor vehicles, is associated with cardiovascular disease. OBJECTIVES: To describe lessons learned from installing air filtration units in public housing apartments next to a major highway. METHODS: We reviewed experience with recruitment, retention, and acceptance of the air filtration units. RESULTS: Recruitment and retention have been challenging, but similar to other studies in public housing. Equipment noise and overheated apartments during hot weather have been notable complaints from participants. In addition, we found that families with members with Alzheimer's or mental disability were less able to tolerate the equipment. CONCLUSIONS: For this research, the primary lesson is that working closely with each participant is important. A future public health program would need to address issues of noise and heat to make the intervention more acceptable to residents.


Asunto(s)
Enfermedades Cardiovasculares/prevención & control , Ruido/efectos adversos , Material Particulado/efectos adversos , Vivienda Popular , Filtros de Aire , Enfermedades Cardiovasculares/etiología , Investigación Participativa Basada en la Comunidad , Humanos , Ruido/prevención & control , Emisiones de Vehículos/prevención & control , Ventilación/instrumentación , Ventilación/métodos , Ventilación/normas
15.
Acta Crystallogr Sect E Struct Rep Online ; 69(Pt 11): o1655-6, 2013 Oct 19.
Artículo en Inglés | MEDLINE | ID: mdl-24454094

RESUMEN

The title compound, C12H12O2, lies across an inversion centre. The mol-ecular structure suggests that the meth-oxy groups in the 1- and 5-positions of the naphthalene moiety do not significantly distort the planar conformation of the ring system, which has a maximum deviation of 0.0025 (9) Å. In the crystal, mol-ecules pack in a herringbone arrangement in layers parallel to (100) and with chains propagating along [101] formed by very weak C-H⋯O inter-actions.

16.
Org Biomol Chem ; 1(19): 3464-9, 2003 Oct 07.
Artículo en Inglés | MEDLINE | ID: mdl-14584812

RESUMEN

A new bisurea gelator derived from 2,6-diaminopyridine has been developed. It efficiently gelates common organic and liquid crystalline (LC) solvents by forming elongated self-assembled fibres in solvents. X-Ray crystallography and 1H NMR measurements reveal that two urea groups in pyridine-based bisurea compounds form different hydrogen bonding patterns. One of two urea units is involved in intramolecular hydrogen bonding with the pyridyl nitrogen, while the other urea unit forms bifurcated intermolecular hydrogen bonding. This hydrogen-bonded structure is key for the fibrous self-assembly along with the efficient gelation. In addition, LC gels based on the pyridine-based gelator exhibit good electrooptic properties. These results indicate that the pyridine-based bisurea compound is a good gelator not only effective in gelation but also useful as a component of functional soft materials.

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