2,845 research outputs found
Evaluation of herbal ointment formulation of Milicia excelsa (Welw) C.C berg for wound healing
The wound healing effect of Milicia excelsa ointment was evaluated in three groups of rats using the excision wound model. Also the antibacterial effect of M. excelsa extract on Pseudomonas aeruginosa and Staphylococcus aureus was investigated. The result of the study showed that the ointment of M. excelsa significantly enhanced wound contraction and epithelialization. The epithelialization time in the M. excelsa ointment treated group was significantly shorter than time of epithelialization in the base treated group. On day 7, wound sections of rats treated with M. excelsa ointment showed abundant neutrophils, few macrophages and few fibroblasts while in the base treated rats, abundant neutrophils, few macrophages and few fibroblasts were seen. By day 14, wound sections of M. excelsa ointment treated rats showed abundant fibroblasts, mild collagenization, moderate macrophages and vascularization whereas moderate neutrophils, few macrophages and few fibroblasts were seen in the sections of base treated rats. M. excelsa extract at 100, 50, 25 and 12.5 mg/ml inhibited the growth of S. aureus but not P. aeruginosa. In this study, daily application of M. excelsa ointment enhanced wound contraction, epithelialization and fibroplasia. These results provide scientific evidence showing the efficacy of M. excelsa leaves in wound healing.Keywords: Milicia excelsa, ointment, excision wounds, contraction, epithelializationAfrican Journal of Biotechnology Vol. 12(21), pp. 3351-335
Photo-electromotive-force from volume speckle pattern vibration with large amplitude
We report an accurate mathematical model describing the photo-electromotive-force signal produced by a speckle pattern of light vibrating in the volume of a photorefractive crystal with a large transverse amplitude. Our model shows that, for vibrations much faster than the material response time, the first harmonic term of the photo-electromotive-force signal exhibits a maximum at a characteristic value of the vibration-amplitude-to-speckle-size ratio that depends on the dark-to-photoconductivity ratio in the material. The theoretical results are in good agreement with experimental data from a vanadium-doped photorefractive CdTe (CdTe:V) crystal under 1064 nm wavelength illumination. (C) 2008 American Institute of Physics.1031
Pulmonary ventilation imaging based on 4-dimensional computed tomography: comparison with pulmonary function tests and SPECT ventilation images.
PURPOSE: 4-dimensional computed tomography (4D-CT)-based pulmonary ventilation imaging is an emerging functional imaging modality. The purpose of this study was to investigate the physiological significance of 4D-CT ventilation imaging by comparison with pulmonary function test (PFT) measurements and single-photon emission CT (SPECT) ventilation images, which are the clinical references for global and regional lung function, respectively. METHODS AND MATERIALS: In an institutional review board-approved prospective clinical trial, 4D-CT imaging and PFT and/or SPECT ventilation imaging were performed in thoracic cancer patients. Regional ventilation (V4DCT) was calculated by deformable image registration of 4D-CT images and quantitative analysis for regional volume change. V4DCT defect parameters were compared with the PFT measurements (forced expiratory volume in 1 second (FEV1; % predicted) and FEV1/forced vital capacity (FVC; %). V4DCT was also compared with SPECT ventilation (VSPECT) to (1) test whether V4DCT in VSPECT defect regions is significantly lower than in nondefect regions by using the 2-tailed t test; (2) to quantify the spatial overlap between V4DCT and VSPECT defect regions with Dice similarity coefficient (DSC); and (3) to test ventral-to-dorsal gradients by using the 2-tailed t test. RESULTS: Of 21 patients enrolled in the study, 18 patients for whom 4D-CT and either PFT or SPECT were acquired were included in the analysis. V4DCT defect parameters were found to have significant, moderate correlations with PFT measurements. For example, V4DCT(HU) defect volume increased significantly with decreasing FEV1/FVC (R=-0.65, P<.01). V4DCT in VSPECT defect regions was significantly lower than in nondefect regions (mean V4DCT(HU) 0.049 vs 0.076, P<.01). The average DSCs for the spatial overlap with SPECT ventilation defect regions were only moderate (V4DCT(HU)0.39 ± 0.11). Furthermore, ventral-to-dorsal gradients of V4DCT were strong (V4DCT(HU) R(2) = 0.69, P=.08), which was similar to VSPECT (R(2) = 0.96, P<.01). CONCLUSIONS: An 18-patient study demonstrated significant correlations between 4D-CT ventilation and PFT measurements as well as SPECT ventilation, providing evidence toward the validation of 4D-CT ventilation imaging
Aharonov-Bohm interferences from local deformations in graphene
One of the most interesting aspects of graphene is the tied relation between
structural and electronic properties. The observation of ripples in the
graphene samples both free standing and on a substrate has given rise to a very
active investigation around the membrane-like properties of graphene and the
origin of the ripples remains as one of the most interesting open problems in
the system. The interplay of structural and electronic properties is
successfully described by the modelling of curvature and elastic deformations
by fictitious gauge fields that have become an ex- perimental reality after the
suggestion that Landau levels can form associated to strain in graphene and the
subsequent experimental confirmation. Here we propose a device to detect
microstresses in graphene based on a scanning-tunneling-microscopy setup able
to measure Aharonov-Bohm inter- ferences at the nanometer scale. The
interferences to be observed in the local density of states are created by the
fictitious magnetic field associated to elastic deformations of the sample.Comment: Some bugs fixe
“Man in the driving seat”:A grounded theory study of the psychosocial experiences of Black African and Black Caribbean men treated for prostate cancer and their partners
Objective: Evidence suggests that treatment side‐effects of prostate cancer (CaP) substantially affect the psychosocial well‐being of affected men and their partners. However, this phenomenon is poorly understood among high risk (1 in 4) Black African (BA)/Black Caribbean (BC) men and their partners, as they are currently under‐represented in global research on CaP survivorship. This study explored the psychosocial experiences of BA/BC men with CaP and their partners in the United Kingdom as they lived through the side effects of CaP treatment within their own sociocultural and marital contexts. Methods: Using constructivist grounded theory methodology, interviews and focus groups were conducted with eligible men (n = 25), partners (n = 11), and health care professionals (HCPs) (n = 11) recruited in England. Data were iteratively analysed using constant comparison following the key stages of initial, focused, and theoretical coding until saturation was achieved. Results: Data analysis culminated in the development of a substantive theory “man in the driving seat,” which describes the experiences of BA/BC men with CaP and their partners within their context. Culturally informed gender roles and identities influenced how men and partners responded and coped with the side effects of CaP treatment. There was a hierarchy of power within the BA/BC relationship, in which men were dominantly positioned as leaders, whilst partners mostly operated from a supportive but “accepting” position. Conclusion: Inclusive and culturally sensitive individual and couple‐focused psychosocial support, which is devoid of stereotyping and recognises the experiences of both BA/BC men and their partners is recommended
Parton Fragmentation within an Identified Jet at NNLL
The fragmentation of a light parton i to a jet containing a light energetic
hadron h, where the momentum fraction of this hadron as well as the invariant
mass of the jet is measured, is described by "fragmenting jet functions". We
calculate the one-loop matching coefficients J_{ij} that relate the fragmenting
jet functions G_i^h to the standard, unpolarized fragmentation functions D_j^h
for quark and gluon jets. We perform this calculation using various IR
regulators and show explicitly how the IR divergences cancel in the matching.
We derive the relationship between the coefficients J_{ij} and the quark and
gluon jet functions. This provides a cross-check of our results. As an
application we study the process e+ e- to X pi+ on the Upsilon(4S) resonance
where we measure the momentum fraction of the pi+ and restrict to the dijet
limit by imposing a cut on thrust T. In our analysis we sum the logarithms of
tau=1-T in the cross section to next-to-next-to-leading-logarithmic accuracy
(NNLL). We find that including contributions up to NNLL (or NLO) can have a
large impact on extracting fragmentation functions from e+ e- to dijet + h.Comment: expanded introduction, typos fixed, journal versio
Pattern of childhood and adolescent malignancies at a tertiary health institution in South-east Nigeria : A ten year study
Background: Cancer remains a major cause of death in children and adolescents, and differs in adults in nature, distribution and prognosis1. A culture of case documentation is lacking in our environment and many cases go unreported.Study objectives: To document the pattern of childhood and adolescent malignancies at a tertiary health institution in south-east Nigeria over a ten year period (January 2004 to December 2013)Methodology: Details of all children and adolescents aged 18 years and below treated for malignancy were extracted from the cancer registry and the records unit of the histopathology department for the period beginning at January 2004 to December 2013 at Nnamdi Azikiwe University Teaching Hospital (NAUTH), Nnewi, Nigeria. Information retrieved was verified against the hospital admission register, as well as the medical and histopathology records for all cancer patients over the period of interest.Results: Eighty-five cases of childhood and adolescent malignancy were treated at NAUTH, Nnewi between January 2004 and December 2013. Median age of the study population was 9years, with a range of 0.1– 18years, more males (56.50%) than females (43.50%). Commonest tumours were the Lymphomas (11.76%) comprising Non- Hodgkin’s lymphoma (80%), Hodgkin’s lymphoma (10%) and Large-cell lymphoma (10%), the Leukaemias (11.76%) comprising Acute myeloblastic leukaemia (80%) and Acute lymphoblastic leukaemia (20%). Others were Rhabdomyosarcoma (11.76%), Nephroblastoma (11.76%), Retinoblastoma (5.88%), Ovarian tumours (4.71%), the Soft tissue sarcomas-excluding rhabdomyosarcoma (3.53%) and Osteogenic sarcoma (3.35%)’.Conclusion: Study findings suggest that lymphoma, leukaemia, rhabdomyosarcoma and nephroblastoma are the commonest childhood and adolescent malignancies in south-east Nigeria.Keywords: Childhood, Adolescent, Malignanc
Global parameter search reveals design principles of the mammalian circadian clock
Background: Virtually all living organisms have evolved a circadian (~24 hour) clock that controls physiological and behavioural processes with exquisite precision throughout the day/night cycle. The suprachiasmatic nucleus (SCN), which generates these ~24 h rhythms in mammals, consists of
several thousand neurons. Each neuron contains a gene-regulatory network generating molecular oscillations, and the individual neuron oscillations are synchronised by intercellular coupling, presumably via neurotransmitters. Although this basic mechanism is currently accepted and has
been recapitulated in mathematical models, several fundamental questions about the design principles of the SCN remain little understood. For example, a remarkable property of the SCN is that the phase of the SCN rhythm resets rapidly after a 'jet lag' type experiment, i.e. when the light/ dark (LD) cycle is abruptly advanced or delayed by several hours.
Results: Here, we describe an extensive parameter optimization of a previously constructed simplified model of the SCN in order to further understand its design principles. By examining the top 50 solutions from the parameter optimization, we show that the neurotransmitters' role in generating the molecular circadian rhythms is extremely important. In addition, we show that when
a neurotransmitter drives the rhythm of a system of coupled damped oscillators, it exhibits very robust synchronization and is much more easily entrained to light/dark cycles. We were also able to recreate in our simulations the fast rhythm resetting seen after a 'jet lag' type experiment.
Conclusion: Our work shows that a careful exploration of parameter space for even an extremely simplified model of the mammalian clock can reveal unexpected behaviours and non-trivial predictions. Our results suggest that the neurotransmitter feedback loop plays a crucial role in the
robustness and phase resetting properties of the mammalian clock, even at the single neuron level
Fleming's penicillin producing streain is not Penicillium chrysogenum but P. rubens
Penicillium chrysogenum is a commonly occurring mould in indoor environments and foods, and has gained much attention for its use in the production of the antibiotic penicillin. Phylogenetic analysis of the most important penicillin producing P. chrysogenum isolates revealed the presence of two highly supported clades, and we show here that these two clades represent two species, P. chrysogenum and P. rubens. These species are phenotypically similar, but extrolite analysis shows that P. chrysogenum produces secalonic acid D and F and/or a metabolite related to lumpidin, while P. rubens does not produce these metabolites. Fleming’s original penicillin producing strain and the full genome sequenced strain of P. chrysogenum are re-identified as P. rubens. Furthermore, the well-known claim that Alexander Fleming misidentified the original penicillin producing strain as P. rubrum is discussed
Analysis of DAX1 (NR0B1) and steroidogenic factor-1 (NR5A1) in children and adults with primary adrenal failure: Ten years' experience
Context: Primary adrenal failure is a life-threatening condition that can be caused by a range of etiologies, including autoimmune, metabolic, and developmental disorders. The nuclear receptors DAX1 (NR0B1) and steroidogenic factor-1 (SF1/Ad4BP, NR5A1) play an important role in adrenal development and function, and mutations in these transcription factors have been found in patients with adrenal hypoplasia.Objective: Our objective was to investigate the prevalence of DAX1 and SF1 mutations in children and adults with primary adrenal failure of unknown etiology (i.e. not caused by congenital adrenal hyperplasia, adrenoleukodystrophy, or autoimmune disease).Patients: One hundred seventeen patients were included. Eighty-eight individuals presented in infancy or childhood with adrenal hypoplasia or primary adrenal failure of unknown etiology (n = 64 46, XY phenotypic males; n = 17 46, XY gonadal dysgenesis/ impaired androgenization; n = 7 46, XX females). Twenty-nine individuals presented in adulthood with Addison's disease of unknown etiology.Methods: Mutational analysis of DAX1 ( NR0B1) ( including exon 2 alpha/1A) and SF1 ( NR5A1) was done by direct sequencing.Results: DAX1 mutations were found in 58% ( 37 of 64) of 46, XY phenotypic boys referred with adrenal hypoplasia and in all boys ( eight of eight) with hypogonadotropic hypogonadism and a family history suggestive of adrenal failure in males. SF1 mutations causing adrenal failure were found in only two patients with 46, XY gonadal dysgenesis. No DAX1 or SF1 mutations were identified in the adult-onset group.Conclusions: DAX1 mutations are a relatively frequent cause of adrenal failure in this group of boys. SF1 mutations causing adrenal failure in humans are rare and are more likely to be associated with significant underandrogenization and gonadal dysfunction in 46, XY individuals
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