515 research outputs found
Stack-run adaptive wavelet image compression
We report on the development of an adaptive wavelet image coder based on stack-run representation of the quantized coefficients. The coder works by selecting an optimal wavelet packet basis for the given image and encoding the quantization indices for significant coefficients and zero runs between coefficients using a 4-ary arithmetic coder. Due to the fact that our coder exploits the redundancies present within individual subbands, its addressing complexity is much lower than that of the wavelet zerotree coding algorithms. Experimental results show coding gains of up to 1:4dB over the benchmark wavelet coding algorithm
Evaluation of three accelerometer devices for physical activity measurement amongst south Asians and Europeans
We recruited 62 South Asians and 40 Europeans aged 25 to 75 years, to assess the potential validity of three physical activity accelerometers for use amongst South Asians. Participants completed an exercise treadmill test (following Bruce protocol) while wearing the 3 accelerometers: Actigraph GT3X+ [GT3X+] and Geneactiv [GA] on ankle, waist and wrist; and Actiheart [AH] on chest. We compared relationships between energy expenditure (EE) measured by accelerometers (Measured) and actual EE on the treadmill (Actual) in the two ethnicities and tested for potential confounding effects. All accelerometers under-reported EE. Difference between Measured and Actual EE was smallest for GT3X+ankle (Measured – Actual at peak exercise [Mets]: GT3X+ankle –6.52 (1.77); GT3X+waist –8.46 (1.29); GT3X+wrist –11.17 (1.03); GAankle –8.17 (1.19); GAwaist –10.24 (0.64); GAwrist –11.21 (1.10); AHchest –9.09 (1.43), P 0.05). Relationship between Measured and Actual EE was not influenced by age, gender, height, waist, weight or waist-hip ratio (all P > 0.05). Amongst the devices and positions tested, GT3X+ankle is the most accurate device for measuring EE during an exercise treadmill test. Accelerometer performance is similar in South Asians and Europeans and is not influenced by anthropometric differences between the two populations
Crop-based irrigation operations in the North West Frontier Province of Pakistan. Vol.II: Research approach and interpretation. Final Report
Irrigation management / Crop-based irrigation / Research / Irrigation canals / Water demand / Performance evaluation / Agricultural production / Pakistan / North West Frontier Province
Prevalence and patterns of physical activity among school aged adolescents in Pakistan: A systematic review and meta-analysis
Less than one fifth of Pakistani adolescents, aged 13–15, years achieve recommended activity levels. This systematic review and meta-analysis was conducted to determine a pooled estimate of the prevalence of PA, and to systematically evaluate the literature available on PA among adolescents in Pakistan. A systemic search of databases was conducted. In addition, hand search of references of all the included relevant publications was performed. Random effects meta-analysis was used to get weighted prevalence of PA among adolescents. Quality of undertaken studies was assessed using New-Castle Ottawa Scale. After removing duplicates, reviewing titles and abstracts and screening full texts, 15 articles were included for analysis. All studies were conducted in school setting, with a total sample size of 10,651. Weighted pooled prevalence of PA among adolescents was 36.0% with high heterogeneity (99.28%). Most of the studies met study quality assessment criteria except for comparability of subjects in different outcome groups and assessment of outcome. Prevalence of PA among adolescents is low in Pakistan. Formal strategies are needed for promoting PA among adolescents for their improved health and for reducing future burden of NCDs
A young boy with abdominal pain
At times, acute diffuse abdominal pain can be a diagnostic dilemma, especially when the symptoms appear to be out of proportion to the findings on physical examination. The case of a young boy with abdominal pain is presented
The clinical utility of prostate cancer heterogeneity using texture analysis of multiparametric MRI
Purpose
To determine if multiparametric MRI (mpMRI) derived filtration-histogram based texture analysis (TA) can differentiate between different Gleason scores (GS) and the D’Amico risk in prostate cancer.
Methods
We retrospectively studied patients whose pre-operative 1.5T mpMRI had shown a visible tumour and who subsequently underwent radical prostatectomy (RP). Guided by tumour location from the histopathology report, we drew a region of interest around the dominant visible lesion on a single axial slice on the T2, Apparent Diffusion Coefficient (ADC) map and early arterial phase post-contrast T1 image. We then performed TA with a filtration-histogram software (TexRAD -Feedback Medical Ltd, Cambridge, UK). We correlated GS and D’Amico risk with texture using the Spearman’s rank correlation test.
Results
We had 26 RP patients with an MR-visible tumour. Mean of positive pixels (MPP) on ADC showed a significant negative correlation with GS at coarse texture scales. MPP showed a significant negative correlation with GS without filtration and with medium filtration. MRI contrast texture without filtration showed a significant, negative correlation with D’Amico score. MR T2 texture showed a significant, negative correlation with the D’Amico risk, particularly at textures without filtration, medium texture scales and coarse texture scales.
Conclusion
ADC map mpMRI TA correlated negatively with GS, and T2 and post-contrast images with the D’Amico risk score. These associations may allow for better assessment of disease prognosis and a non-invasive method of follow-up for patients on surveillance. Further, identifying clinically significant prostate cancer is essential to reduce harm from over-diagnosis and over-treatment
CT-based texture analysis potentially provides prognostic information complementary to interim fdg-pet for patients with hodgkin's and aggressive non-hodgkin's lymphomas
OBJECTIVES: The purpose of this study was to investigate the ability of computed tomography texture analysis (CTTA) to provide additional prognostic information in patients with Hodgkin's lymphoma (HL) and high-grade non-Hodgkin's lymphoma (NHL).
METHODS: This retrospective, pilot-study approved by the IRB comprised 45 lymphoma patients undergoing routine 18F-FDG-PET-CT. Progression-free survival (PFS) was determined from clinical follow-up (mean-duration: 40 months; range: 10-62 months). Non-contrast-enhanced low-dose CT images were submitted to CTTA comprising image filtration to highlight features of different sizes followed by histogram-analysis using kurtosis. Prognostic value of CTTA was compared to PET FDG-uptake value, tumour-stage, tumour-bulk, lymphoma-type, treatment-regime, and interim FDG-PET (iPET) status using Kaplan-Meier analysis. Cox regression analysis determined the independence of significantly prognostic imaging and clinical features.
RESULTS: A total of 27 patients had aggressive NHL and 18 had HL. Mean PFS was 48.5 months. There was no significant difference in pre-treatment CTTA between the lymphoma sub-types. Kaplan-Meier analysis found pre-treatment CTTA (medium feature scale, p=0.010) and iPET status (p<0.001) to be significant predictors of PFS. Cox analysis revealed that an interaction between pre-treatment CTTA and iPET status was the only independent predictor of PFS (HR: 25.5, 95% CI: 5.4-120, p<0.001). Specifically, pre-treatment CTTA risk stratified patients with negative iPET.
CONCLUSION: CTTA can potentially provide prognostic information complementary to iPET for patients with HL and aggressive NHL
Oral health behind the bars: oral health seeking behavior among jail prisoners at central jail of Peshawar, Pakistan: a cross-sectional study
Background: The oral health care-seeking behavior among prison inmates is an overlooked area, often leading to deteriorating general health due to the prisoners’ limited awareness of oral hygiene practices. It is crucial to address this issue and understand the factors associated with oral healthcare-seeking behavior in prisons. Objective: To assess the oral healthcare-seeking behavior of prison inmates at Central Prisoner Jail, Peshawar Pakistan and to look the factors associated with their dental care utilization. Material and Methods: This cross-sectional study was conducted at Central Prisoner Jail, Peshawar Khyber Pakhtunkhwa, Pakistan from November 2021 to April 2022. A consecutive sampling technique was used to collect data from both convicted and under-trial prisoners by using a pre-tested WHO Basic Oral Health Survey 2013 tool. Our outcome variable was “Visit to a dentist in the last 12 months (Never/Once or more than one visit). Chi-square test was used to determine univariate association with other explanatory variables while multivariable logistic regression was performed to adjust for potential confounders. Result: A total of 225 participants were recruited to the study with a mean (SD) age of 32.9(11.4). More than two-thirds of 200(88.9%) of the participants were males. One-third of the sample never visited the dentist75(33.3). Participants who completed college/university education and never visited the dentist in the last 12 months constituted a smaller proportion (17.6%) compared to those who visited the dentist once or more than once n = 28(82.4%, p-value = 0.003). Individuals who were using toothbrushes were most frequently visiting the dentist n = 130(72.6%=p value = 0.001) as compared to never visitors. Multivariate logistic regression analysis revealed that Participants who experienced teeth pain or discomfort had 0.42 times lower odds of visiting the dentist compared to those who did not experience any pain or discomfort [AOR 0.42 (95% CI 0.17–0.80), p = 0.04]. Similarly, Participants who do not use any denture have 4.06 times higher odds[AOR 4.06(95% CI 1.76–9.36), p = 0.001] of visiting the dentist compared to those who use a denture. Conclusion: Our result demonstrates that those prisoners who were experiencing tooth pain or discomfort and not using dentures were the strong predictors with lower dental visit frequency to seek oral health care
Numerical and experimental investigation of the effect of process parameters on sheet deformation during the electromagnetic forming of AA6061-T6 alloy.
Electromagnetic forming is a high-speed sheet metal forming technique to form metallic sheets by applying magnetic forces. In comparison to the conventional sheet metal forming process, electromagnetic forming is a process with an extremely high velocity and strain rate, which can be effectively used for the forming of certain difficult-to-form metals. During electromagnetic forming, it is important to recognise the effects of process parameters on the deformation and sheet thickness variation of the sheet metal. This research focuses on the development of a numerical model for aluminium alloy (AA6061-T6) to analyse the effects of three process parameters, namely voltage, sheet thickness and number turns of the coils, on the deformation and thickness variation of the sheet. A two-dimensional fully coupled finite-element (FE) model consisting of an electrical circuit, magnetic field and solid mechanics was developed and used to determine the effect of changing magnetic flux and system inductance on sheet deformation. Experiment validation of the results was performed on a 28 KJ electromagnetic forming system. The Taguchi orthogonal array approach was used for the design of experiments using the three input parameters (voltage, sheet thickness and number of turns of the coil). The maximum error between numerical and experimental values for sheet thickness variation was observed to be 4.9 %. Analysis of variance (ANOVA) was performed on the experimental results. Applied voltage and sheet thickness were the significant parameters, while the number of turns of the coil had an insignificant effect on sheet deformation. The contribution ratio of voltage and sheet thickness was 46.21 % and 45.12 % respectively. The sheet deformation from simulations was found to be in good agreement with the experimental results
ATF4 regulates arsenic trioxide-mediated NADPH oxidase, ER-mitochondrial crosstalk and apoptosis
Arsenic is a mitochondrial toxin, and its derivatives, such as arsenic trioxide (ATO), can trigger endoplasmic reticulum (ER) and the associated unfolded protein response (UPR). Here, we show that arsenic induction of the UPR triggers ATF4, which is involved in regulating this ER-mitochondrial crosstalk that is important for the molecular pathogenesis of arsenic toxicity. Employing ATF4+/+ and ATF4−/− MEFs, we show that ATO induces UPR and impairs mitochondrial integrity in ATF4+/+ MEF cells which is largely ablated upon loss of ATF4. Following ATO treatment, ATF4 activates NADPH oxidase by promoting assembly of the enzyme components Rac-1/P47phox/P67phox, which generates ROS/superoxides. Furthermore, ATF4 is required for triggering Ca++/calpain/caspase-12-mediated apoptosis following ATO treatment. The IP3R inhibitor attenuates Ca++/calpain-dependent apoptosis, as well as reduces m-ROS and MMP disruption, suggesting that ER-mitochondria crosstalk involves IP3R-regulated Ca++ signaling. Blockade of m-Ca++ entry by inhibiting m-VDAC reduces ATO-mediated UPR in ATF4+/+ cells. Additionally, ATO treatment leads to p53-regulated mitochondrial apoptosis, where p53 phosphorylation plays a key role. Together, these findings indicate that ATO-mediated apoptosis is regulated by both ER and mitochondria events that are facilitated by ATF4 and the UPR. Thus, we describe novel mechanisms by which ATO orchestrates cytotoxic responses involving interplay of ER and mitochondria.
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