70 research outputs found
Characterizing the Role of Transcription Factor Hb9 in Glial Cell Development
Hb9 (Mnx1) is a transcription factor described as a spinal cord motor neuron-specific marker in embryonic development and a critical factor for the post-mitotic specification of these cells. As such, transgenic mice with mutations in the Hb9 gene are commonly used for the study of spinal cord motor neurons. To date, the expression of Hb9 in other cell types has not previously been reported. We performed a fate-mapping approach to examine the localization of Hb9-expressing cells and their progeny (‘Hb9-lineage cells’) within the embryonic and adult spinal cord. We found that Hb9-lineage cells are distributed in a gradient of increasing abundance throughout the rostro-caudal spinal cord axis during developmental and postnatal stages. Furthermore, although the majority of Hb9-lineage cells at cervical spinal cord levels are motor neurons, at more caudal levels, Hb9-lineage cells include astrocytes and oligodendrocytes, the macroglial cells of the central nervous system. In the peripheral nervous system, we observed a similar phenomenon with Hb9-lineage Schwann cells present in an increasing rostro-caudal gradient throughout the body. These observations have several exciting implications. Hb9 may play an important role not only in astrocyte and oligodendrocyte development, but also in development of Schwann cells, which are the glial cells associated with the peripheral nerves. Additionally, characterization of Hb9-lineage glial cells may reveal new functional roles for glia throughout the developing spinal cord. Through characterizing the role of Hb9 in glial cell development, describing the molecular pathways involved, and determining the differences in gene expression between Hb9+ and Hb9- spinal cord glial cells, the developmental function of Hb9 can be better understood
Comparison of Experimental Results with Numerical Simulations for Pulsed Thermographic NDE
This paper examines pulse thermographic nondestructive evaluation of flat bottom holes of isotropic materials. Different combinations of defect diameters and depths are considered. Thermographic Signal Reconstruction (TSR) method [1] is used to analyze these results. In addition, a new normalization procedure is used to remove the dependence of thermographic results on the material properties and instrumentation settings during these experiments. Hence the normalized results depend only on the geometry of the specimen and the defects. These thermographic NDE procedures were also simulated using finite element technique for a variety of defect configurations. The data obtained from numerical simulations were also processed using the normalization scheme. Excellent agreement was seen between the results obtained from experiments and numerical simulations. Therefore the scheme is extended to introduce a correlation technique by which numerical simulations are used to quantify the defect parameters
A Normalization Procedure and Sound Zone Determination for Pulse Thermographic NDE
Thermographic nondestructive evaluation is quick and effective in detecting damage particularly for composite structures. Pulse thermographic nondestructive evaluation (TNDE) technique can potentially provide information on defect dimensions, such as the depth at which the defect is located. However, there are a number of extraneous variables that affect the signal obtained during these tests, such as non-uniformity in the heat pulse applied and differences in the emissivity of the surfaces from specimen to specimen. In addition, the identification of defect free areas in the image is a challenge. As in other NDE procedures calibration specimens would be of help, but calibration specimens corresponding to complex damage states in composite materials are difficult to fabricate. Results from validated numerical simulations can complement calibration specimens. However, the thermo-mechanical properties of the test object as well as the amount of energy absorbed in the field tests are not readily available for such models. This paper presents an extension of the thermographic signal reconstruction (TSR) procedure [1] in which the temperature and the time scales are respectively normalized with equilibrium temperature and the break time. A benefit of such normalization is the ability to directly measure the defect depth as a fraction of plate thickness. In order to implement this normalization procedure, sound zone definition is required. A new approach for determining sound zone has been developed. Finally, determination of sound zone is affected by non-uniform heating, and a method of minimizing the effects of non-uniform heating [2] is proposed. The performance of these new approaches on actual experimental results are presented
A Normalization Procedure and Determination of Axisymmetric Defect Characters of Composite Panels
In Pulse Thermographic Nondestructive Evaluation (TNDE), the thermographic signals are heavily influenced by material directionalities, therefore comparison of thermographic results are challenging. In this study a normalization procedure is introduced which simplifies the analysis and requires only break time, equilibrium temperature, and diffusivity ratios of transverse to lateral diffusivity. The normalization for the composite panels was proved to be effective for quasi-isotropic carbon epoxy composite panels used in the study. A correlation method was utilized to estimate the defect diameter and depth of a composite panel. The correlation method utilizes several numerical models to estimate the correct defect parameter of the experimental specimen. Thermographic Signal Reconstruction (TSR) second derivatives [1] found to be effective in differentiating the defect parameters. Since this method was proved to be successful an additional advantage of this method of estimating the in-plane diffusivity of unknown composite panels also have been proposed
The validity of the menopause specific quality of life questionnaire in women with type 2 diabetes
OBJECTIVES:
To examine the validity and reliability of the Menopause-specific Quality of Life (MENQOL) questionnaire in a sample of women with diabetes in Malaysia, with the secondary aim of determining whether MENQOL domain scores were associated with depression and diabetes.
METHODS:
A total of 337 postmenopausal women (241 with diabetes, 96 controls) were evaluated. Construct validity was evaluated using principal components analysis (PCA) and comparing scale items against the mental component score of the Short Form-12 (SF-12 MCS), and against the Center for Epidemiologic Studies Depression Scale 10 (CES-D 10). Consistency assessment was conducted using Cronbach's α.
RESULTS:
The internal consistencies for the physical (PHS), psychosocial (PS), sexual (VSS) and vasomotor domains were 0.86, 0.79, 0.79 and 0.70, and 0.90 for the full scale of MENQOL. PCA revealed a four-factorial model. Diabetes and non-diabetes subjects experienced their first period (13.25 vs. 13.10 years, p = 0.680) and achieved menopause around the same age (49.35 vs. 48.87 years, p = 0.426). We found significant variations in the MENQOL's PHS and PS domain scores that could be explained by SF-12 PCS (25%) and SF-12 MCS (20%) sub-scales. The validity of the MENQOL domains was demonstrated through significant associations with the equivalent SF-12 MCS and PCS subscales. The PS domain of the MENQOL also predicted the likelihood of symptoms of depression (1.42, 95% confidence interval 1.01-2.02).
CONCLUSIONS:
This study confirms the validity and internal consistency of the MENQOL questionnaire for measuring quality of life in postmenopausal women with diabetes, suggesting that the instrument can be used to screen people for menopausal symptoms
Oxygen tension, H2S, and NO bioavailability:is there an interaction?
Molecular oxygen (O2) is an essential component for survival and development. Variation in O2 levels leads to changes in molecular signaling and ultimately affects the physiological functions of many organisms. Nitric oxide (NO) and hydrogen sulfide (H2S) are two gaseous cellular signaling molecules that play key roles in several physiological functions involved in maintaining vascular homeostasis including vasodilation, anti-inflammation, and vascular growth. Apart from the aforementioned functions, NO and H2S are believed to mediate hypoxic responses and serve as O2 chemosensors in biological systems. In this literature review, we briefly discuss NO and H2S and their roles during hypoxia
Traction for low-back pain with or without sciatica.
BACKGROUND: Traction is used to treat low-back pain (LBP), often with other treatments. OBJECTIVES: To determine traction's effectiveness, compared to reference treatments, placebo, sham traction or no treatment for LBP. SEARCH STRATEGY: We searched CENTRAL (The Cochrane Library 2006, issue 4), MEDLINE, EMBASE, and CINAHL to October 2006, references in relevant reviews and personal files. SELECTION CRITERIA: Randomized controlled trials (RCTs) involving traction to treat acute (less than four weeks duration), sub-acute (four to 12 weeks) or chronic (more than 12 weeks) non-specific LBP with or without sciatica. DATA COLLECTION AND ANALYSIS: Study selection, methodological quality assessment and data extraction were done independently by two authors. As there were insufficient data for statistical pooling, we performed a qualitative analysis. MAIN RESULTS: We included 25 RCTs (2206 patients; 1045 receiving traction). Five trials were considered high quality.For patients with mixed symptom patterns (acute, sub-acute and chronic LBP with and without sciatica) there is: strong evidence of no statistically significant difference in outcomes between traction as a single treatment and placebo, sham or no treatment; moderate evidence that traction as a single treatment is no more effective than other treatments; limited evidence of no significant difference in outcomes between a standard physical therapy program with or without continuous traction. For LBP patients with sciatica (with acute, sub-acute or chronic pain), there is conflicting evidence in several comparisons: autotraction compared to placebo, sham or no treatment; other forms of traction compared to other treatments; different forms of traction. In other comparisons, there were no statistically significant differences; the evidence is moderate for continuous or intermittent traction compared to placebo, sham or no treatment, and limited for light versus normal force traction. AUTHORS' CONCLUSIONS: Implications for practice: The results of the available studies involving mixed groups of acute, sub-acute and chronic patients with LBP with and without sciatica were quite consistent, indicating that continuous or intermittent traction as a single treatment for LBP is not likely effective for this group. Traction for patients with sciatica cannot be judged effective at present either, due to inconsistent results and methodological problems in most studies. We conclude that traction as a single treatment for LBP is probably not effective. Implications for research: Any future research on traction for patients with LBP should distinguish between symptom pattern and duration, and should be carried out according to the highest methodological standards
Development of a web-based insulin decision aid for the elderly: usability barriers and guidelines
In recent years, researchers have attempted to shift patient decision aids (PDAs) from paper-based to web-based to increase its accessibility. Insulin decision aids help diabetes patients, most of whom are elderly to make an informed decision to start insulin. However, the lack of usability guidelines applicable for such target group causes developers to struggle to answer the challenging question ‘How can such web service be made usable, and, ultimately, acceptable and accessible for elderly patients?’. Hence, the purpose of this study is to identify the common usability requirements that may facilitate good practices to empower elderly diabetes patients in utilizing a web-based insulin decision aid for their benefit. We set out an approach to use prototyping and retrospective think-aloud techniques to explore web usability barriers that elderly patients may encounter when using an insulin decision aid web site and use the feedback for improving the prototype. Usability requirements were captured iteratively through scoping, brainstorming, prototype, testing and evaluating. The study suggests that the insights from experts and users are equally important to assure the validity of the identified usability guidelines; they reflect the accessibility needs of the aging community while complementing the key requirements of an insulin decision aid. The study contributes to recommend web usability guidelines backed by a series of expert and user evaluations which could be a proactive resource to improve usability, acceptability and accessibility of online insulin decision aids for elderly with diabetes
Salivary Proteins Associated with Periodontitis in Patients with Type 2 Diabetes Mellitus
The objective of this study was to investigate the salivary proteins that are associated with periodontitis in patients with Type 2 diabetes mellitus (T2DM). Volunteers for the study were patients from the Diabetic Unit, University of Malaya Medical Centre, whose periodontal status was determined. The diabetic volunteers were divided into two groups, i.e., patients with periodontitis and those who were periodontally healthy. Saliva samples were collected and treated with 10% TCA/acetone/20 mM DTT to precipitate the proteins, which were then separated using two-dimensional polyacrylamide gel electrophoresis. Gel images were scanned using the GS-800TM Calibrated Densitometer. The protein spots were analyzed and expressed in percentage volumes. The percentage volume of each protein spot was subjected to Mann-Whitney statistical analysis using SPSS software and false discovery rate correction. When the expression of the salivary proteins was compared between the T2DM patients with periodontitis with those who were periodontally healthy, seven proteins, including polymeric immunoglobulin receptor, plastin-2, actin related protein 3, leukocyte elastase inhibitor, carbonic anhydrases 6, immunoglobulin J and interleukin-1 receptor antagonist, were found to be differentially expressed (p < 0.01304). This implies that the proteins may have the potential to be used as biomarkers for the prediction of T2DM patients who may be prone to periodontitis
A qualitative study on healthcare professionals’ perceived barriers to insulin initiation in a multi-ethnic population
Background: Nationwide surveys have shown that the prevalence of diabetes rates in Malaysia have almost doubled in the past ten years; yet diabetes control remains poor and insulin therapy is underutilized. This study aimed to explore healthcare professionals’ views on barriers to starting insulin therapy in people with type 2 diabetes. Methods: Healthcare professionals consisting of general practitioners (n = 11), family medicine specialists (n = 10), medical officers (n = 8), government policy makers (n = 4), diabetes educators (n = 3) and endocrinologists (n = 2) were interviewed. A semi-structured topic guide was used to guide the interviews by trained facilitators. The interviews were transcribed verbatim and analysed using a thematic analysis approach. Results: Insulin initiation was found to be affected by patient, healthcare professional and system factors. Patients’ barriers include culture-specific barriers such as the religious purity of insulin, preferred use of complementary medication and perceived lethality of insulin therapy. Healthcare professionals’ barriers include negative attitudes towards insulin therapy and the ‘legacy effect’ of old insulin guidelines; whilst system barriers highlight the lack of resources, language and communication challenges. Conclusions: Tackling the issue of insulin initiation should not only happen during clinical consultations. It requires health education to emphasise the progressive nature of diabetes and the eventuality of insulin therapy at early stage of the illness. Healthcare professionals should be trained how to initiate insulin and communicate effectively with patients from various cultural and religious backgrounds
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