Machine learning ensemble method for discovering knowledge from big data

Big data, generated from various business internet and social media activities, has become a big challenge to researchers in the field of machine learning and data mining to develop new methods and techniques for analysing big data effectively and efficiently. Ensemble methods represent an attractive approach in dealing with the problem of mining large datasets because of their accuracy and ability of utilizing the divide-and-conquer mechanism in parallel computing environments. This research proposes a machine learning ensemble framework and implements it in a high performance computing environment. This research begins by identifying and categorising the effects of partitioned data subset size on ensemble accuracy when dealing with very large training datasets. Then an algorithm is developed to ascertain the patterns of the relationship between ensemble accuracy and the size of partitioned data subsets. The research concludes with the development of a selective modelling algorithm, which is an efficient alternative to static model selection methods for big datasets. The results show that maximising the size of partitioned data subsets does not necessarily improve the performance of an ensemble of classifiers that deal with large datasets. Identifying the patterns exhibited by the relationship between ensemble accuracy and partitioned data subset size facilitates the determination of the best subset size for partitioning huge training datasets. Finally, traditional model selection is inefficient in cases wherein large datasets are involved

Heterogeneous Ensemble for Imaginary Scene Classification

In data mining, identifying the best individual technique to achieve very reliable and accurate classification has always been considered as an important but non-trivial task. This paper presents a novel approach - heterogeneous ensemble technique, to avoid the task and also to increase the accuracy of classification. It combines the models that are generated by using methodologically different learning algorithms and selected with different rules of utilizing both accuracy of individual modules and also diversity among the models. The key strategy is to select the most accurate model among all the generated models as the core model, and then select a number of models that are more diverse from the most accurate model to build the heterogeneous ensemble. The framework of the proposed approach has been implemented and tested on a real-world data to classify imaginary scenes. The results show our approach outperforms other the state of the art methods, including Bayesian network, SVM an d AdaBoost

The heterogeneity of the functional, metabolic, and molecular responses of skeletal muscle and clinical adaptations to exercise training in pre-clinical and human models

Introduction: Exercise training triggers numerous physiological adaptations that promote individual general health, which were found to be mediated through myokines. Exercise training stimulates myokines expression from skeletal muscle and released into the circulation. However, individuals respond very differently to exercise training i.e. high responders to low/non-responders. The aims of the thesis were i) to explore the impact of Fndc5/irisin (a myokine) on skeletal muscle metabolism and fat remodelling, ii) to investigate how trainability, acute and chronic exercise effect the release of myokines, and lastly, iii) to test the existence of low/non-responder to all exercise training modes and the impact on health benefits. Methods: Fndc5 was locally overexpressed in rat hind-limb via in vivo electroporation technique. Molecular analysis were performed in control and overexpressed muscle and also adipose tissue. Inbred animal model, low responder (LRT) and high responder (HRT) trainers, was used to investigate trainability on myokines’ profiles, which were examined at baseline, following acute exercise, and after 3-weeks of training. Finally a novel human clinical intervention study was conducted wherein participants were studied following, 4-weeks of either endurance or resistance training, then crossed over following a 6-week washout. Findings: Fndc5 overexpression resulted in physiological levels of circulating irisin, which had minimal impact on skeletal metabolism and browning adipose tissue. Exercise training caused an acute elevation of myokines, while 3-weeks training increased/decreased myokines baseline concentrations and temporal responses area under the curve. In general, ‘myokine’ profiles were not able to clearly distinguish between LRT/HRT animals and explain their trainability. In the human cross-over study, the 6-weeks of detraining were enough to washout the enhanced mode specific adaptions. The adaptive responses varied from high to low/non responder with suggested mode preference for individual. Finally, the magnitude of fitness adaptive responses to training modes were not link to the extent of health benefits responses

Myokine Responses to Exercise in a Rat Model of Low/High Adaptive Potential

IntroductionAssuming myokines underlie some of the health benefits of exercise, we hypothesised that ‘high responder trainer’ (HRT) rats would exhibit distinct myokine profiles to ‘low responder trainers’ (LRT), reflecting distinct health and adaptive traits.MethodsBlood was collected from LRT and HRT (N=8) rats at baseline (BL), immediately (0h), 1h, and 3h after running; repeated after 3-wks training. Myokines were analysed by ELISA (i.e. BDNF/Fractalkine/SPARC/Irisin/FGF21/Musclin/IL-6).ResultsAt baseline, Musclin (LRT: 84 ± 24 vs HRT: 26 ± 3 pg/ml, P=0.05) and FGF21 (LRT: 133 ± 34 vs HRT: 63.5 ± 13 pg/ml, P=0.08) were higher in LRT than HRT. Training increased Musclin in HRT (26 ± 3 to 54 ± 9 pg/ml, P<0.05) and decreased FGF21 in LRT (133 ± 34 to 60 ± 28 pg/ml, P<0.05). Training increased SPARC (LRT: 0.8 ± 0.1 to 2.1 ± 0.6 ng/ml, P<0.05; HRT: 0.7 ± 0.06 to 1.8 ± 0.3 ng/ml, P=0.06) and Irisin (LRT 0.62 ± 0.1 to 2.6 ± 0.4 ng/ml, P<0.01; HRT 0.53 ± 0.1 to 2.8 ± 0.7 ng/ml, P<0.01) while decreasing BDNF (LRT: 2747 ± 293 to 1081 ± 330 pg/ml, P<0.01; HRT: 1976 ± 328 to 797 ± 160 pg/ml, P<0.05). Acute exercise response of Musclin (AUC) was higher in LRT vs HRT (306 ± 74 vs. 88 ± 12 pg/ml×3h-1, P<0.01) and elevated in HRT after training (221 ± 31 pg/ml×3h-1, P<0.01). Training elevated SPARC (LRT: 2.4 ± 0.1 to 7.7 ± 1.3 ng/ml×3h-1, P<0.05; HRT: 2.5 ± 0.13 to 11.2 ± 2.2 ng/ml×3h-1, P<0.001) and Irisin (LRT: 1.34 ± 0.3 to 9.6 ± 1.7 ng/ml×3h-1, P<0.001; HRT: 1.5 ± 0.5 to 12.1 ± 1.9 ng/ml×3h-1, P<0.0001).ConclusionExercise training alters how myokines are secreted in response to acute exercise. Myokine responses were not robustly linked to adaptive potential in aerobic capacity, making them an unlikely regulator of adaptive traits

Pharmacological hypogonadism impairs molecular transducers of exercise-induced muscle growth in humans

Background: The relative role of skeletal muscle mechano-transduction in comparison with systemic hormones, such as testosterone (T), in regulating hypertrophic responses to exercise is contentious. We investigated the mechanistic effects of chemical endogenous T depletion adjuvant to 6weeks of resistance exercise training (RET) on muscle mass, function, myogenic regulatory factors, and muscle anabolic signalling in younger men. Methods: Non-hypogonadal men (n=16; 18–30years) were randomized in a double-blinded fashion to receive placebo (P, saline n=8) or the GnRH analogue, Goserelin [Zoladex (Z), 3.6mg, n=8], injections, before 6weeks of supervised whole-body RET. Participants underwent dual-energy X-ray absorptiometry (DXA), ultrasound of m. vastus lateralis (VL), and VL biopsies for assessment of cumulative muscle protein synthesis (MPS), myogenic gene expression, and anabolic signalling pathway responses. Results: Zoladex suppressed endogenous T to within the hypogonadal range and was well tolerated; suppression was associated with blunted fat free mass [Z: 55.4±2.8 to 55.8±3.1kg, P=0.61 vs. P: 55.9±1.7 to 57.4±1.7kg, P=0.006, effect size (ES)=0.31], composite strength (Z: 40±2.3% vs. P: 49.8±3.3%, P=0.03, ES=1.4), and muscle thickness (Z: 2.7±0.4 to 2.69±0.36cm, P>0.99 vs. P: 2.74±0.32 to 2.91±0.32cm, P0.99 vs. P: 1.9 fold, P0.99 vs. P: 4.7 fold, P=0.0005, ES=0.68; myogenin: Z: 1.3 fold, P>0.99 vs. P: 2.7 fold, P=0.002, ES=0.72), RNA/DNA (Z: 0.47±0.03 to 0.53±0.03, P=0.31 vs. P: 0.50±0.01 to 0.64±0.04, P=0.003, ES=0.72), and RNA/ASP (Z: 5.8±0.4 to 6.8±0.5, P>0.99 vs. P: 6.5±0.2 to 8.9±1.1, P=0.008, ES=0.63) ratios, as well as acute RET-induced phosphorylation of growth signalling proteins (e.g. AKTser473: Z: 2.74±0.6, P=0.2 vs. P: 5.5±1.1 fold change, P0.99 vs. P: 3.6±1 fold change, P=0.002, ES=0.53). Both MPS (Z: 1.45±0.11 to 1.50±0.06%·day−1, P=0.99 vs. P: 1.5±0.12 to 2.0±0.15%·day−1, P=0.01, ES=0.97) and (extrapolated) muscle protein breakdown (Z: 93.16±7.8 vs. P: 129.1±13.8g·day−1, P=0.04, ES=0.92) were reduced with hypogonadism result in lower net protein turnover (3.9±1.1 vs. 1.2±1.1g·day−1, P=0.04, ES=0.95). Conclusions: We conclude that endogenous T sufficiency has a central role in the up-regulation of molecular transducers of RET-induced muscle hypertrophy in humans that cannot be overcome by muscle mechano-transduction alone

Global Perspectives on Task Shifting and Task Sharing in Neurosurgery.

BACKGROUND: Neurosurgical task shifting and task sharing (TS/S), delegating clinical care to non-neurosurgeons, is ongoing in many hospital systems in which neurosurgeons are scarce. Although TS/S can increase access to treatment, it remains highly controversial. This survey investigated perceptions of neurosurgical TS/S to elucidate whether it is a permissible temporary solution to the global workforce deficit. METHODS: The survey was distributed to a convenience sample of individuals providing neurosurgical care. A digital survey link was distributed through electronic mailing lists of continental neurosurgical societies and various collectives, conference announcements, and social media platforms (July 2018-January 2019). Data were analyzed by descriptive statistics and univariate regression of Likert Scale scores. RESULTS: Survey respondents represented 105 of 194 World Health Organization member countries (54.1%; 391 respondents, 162 from high-income countries and 229 from low- and middle-income countries [LMICs]). The most agreed on statement was that task sharing is preferred to task shifting. There was broad consensus that both task shifting and task sharing should require competency-based evaluation, standardized training endorsed by governing organizations, and maintenance of certification. When perspectives were stratified by income class, LMICs were significantly more likely to agree that task shifting is professionally disruptive to traditional training, task sharing should be a priority where human resources are scarce, and to call for additional TS/S regulation, such as certification and formal consultation with a neurosurgeon (in person or electronic/telemedicine). CONCLUSIONS: Both LMIC and high-income countries agreed that task sharing should be prioritized over task shifting and that additional recommendations and regulations could enhance care. These data invite future discussions on policy and training programs

Hepcidin, Serum Iron, and Transferrin Saturation in Full-Term and Premature Infants during the First Month of Life: A State-of-the-Art Review of Existing Evidence in Humans.

Neonates regulate iron at birth and in early postnatal life. We reviewed literature from PubMed and Ovid Medline containing data on umbilical cord and venous blood concentrations of hepcidin and iron, and transferrin saturation (TSAT), in human neonates from 0 to 1 mo of age. Data from 59 studies were used to create reference ranges for hepcidin, iron, and TSAT for full-term-birth (FTB) neonates over the first month of life. In FTB neonates, venous hepcidin increases 100% over the first month of life (to reach 61.1 ng/mL; 95% CI: 20.1, 102.0 ng/mL) compared with umbilical cord blood (29.7 ng/mL; 95% CI: 21.1, 38.3 ng/mL). Cord blood has a high concentration of serum iron (28.4 μmol/L; 95% CI: 26.0, 31.1 μmol/L) and levels of TSAT (51.7%; 95% CI: 46.5%, 56.9%). After a short-lived immediate postnatal hypoferremia, iron and TSAT rebounded to approximately half the levels in the cord by the end of the first month. There were insufficient data to formulate reference ranges for preterm neonates

Variation in postoperative outcomes of patients with intracranial tumors: insights from a prospective international cohort study during the COVID-19 pandemic

Background: This study assessed the international variation in surgical neuro-oncology practice and 30-day outcomes of patients who had surgery for an intracranial tumor during the COVID-19 pandemic. Methods: We prospectively included adults aged ≥18 years who underwent surgery for a malignant or benign intracranial tumor across 55 international hospitals from 26 countries. Each participating hospital recorded cases for 3 consecutive months from the start of the pandemic. We categorized patients’ location by World Bank income groups (high [HIC], upper-middle [UMIC], and low- and lower-middle [LLMIC]). Main outcomes were a change from routine management, SARS-CoV-2 infection, and 30-day mortality. We used a Bayesian multilevel logistic regression stratified by hospitals and adjusted for key confounders to estimate the association between income groups and mortality. Results: Among 1016 patients, the number of patients in each income group was 765 (75.3%) in HIC, 142 (14.0%) in UMIC, and 109 (10.7%) in LLMIC. The management of 200 (19.8%) patients changed from usual care, most commonly delayed surgery. Within 30 days after surgery, 14 (1.4%) patients had a COVID-19 diagnosis and 39 (3.8%) patients died. In the multivariable model, LLMIC was associated with increased mortality (odds ratio 2.83, 95% credible interval 1.37–5.74) compared to HIC. Conclusions: The first wave of the pandemic had a significant impact on surgical decision-making. While the incidence of SARS-CoV-2 infection within 30 days after surgery was low, there was a disparity in mortality between countries and this warrants further examination to identify any modifiable factors

The heterogeneity of the functional, metabolic, and molecular responses of skeletal muscle and clinical adaptations to exercise training in pre-clinical and human models

Introduction: Exercise training triggers numerous physiological adaptations that promote individual general health, which were found to be mediated through myokines. Exercise training stimulates myokines expression from skeletal muscle and released into the circulation. However, individuals respond very differently to exercise training i.e. high responders to low/non-responders. The aims of the thesis were i) to explore the impact of Fndc5/irisin (a myokine) on skeletal muscle metabolism and fat remodelling, ii) to investigate how trainability, acute and chronic exercise effect the release of myokines, and lastly, iii) to test the existence of low/non-responder to all exercise training modes and the impact on health benefits. Methods: Fndc5 was locally overexpressed in rat hind-limb via in vivo electroporation technique. Molecular analysis were performed in control and overexpressed muscle and also adipose tissue. Inbred animal model, low responder (LRT) and high responder (HRT) trainers, was used to investigate trainability on myokines’ profiles, which were examined at baseline, following acute exercise, and after 3-weeks of training. Finally a novel human clinical intervention study was conducted wherein participants were studied following, 4-weeks of either endurance or resistance training, then crossed over following a 6-week washout. Findings: Fndc5 overexpression resulted in physiological levels of circulating irisin, which had minimal impact on skeletal metabolism and browning adipose tissue. Exercise training caused an acute elevation of myokines, while 3-weeks training increased/decreased myokines baseline concentrations and temporal responses area under the curve. In general, ‘myokine’ profiles were not able to clearly distinguish between LRT/HRT animals and explain their trainability. In the human cross-over study, the 6-weeks of detraining were enough to washout the enhanced mode specific adaptions. The adaptive responses varied from high to low/non responder with suggested mode preference for individual. Finally, the magnitude of fitness adaptive responses to training modes were not link to the extent of health benefits responses

Synthesis and Characterization of Two Novel Organic-Inorganic Compounds Based on Tetrahexyl and Tetraheptyl Ammonium Ions and the Preyssler Anion and Their Catalytic Activities in the Synthesis of 4-Aminopyrazolo[3,4-d]- Pyrimidines

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