Assessments of Process Parameters on Cutting Force and Surface Roughness during Drilling of AA7075/TiB2 In Situ Composite.

Reinforced aluminum composites are the basic class of materials for aviation and transport industries. The machinability of these composites is still an issue due to the presence of hard fillers. The current research is aimed to investigate the drilling topographies of AA7075/TiB2 composites. The samples were prepared with 0, 3, 6, 9 and 12 wt.% of fillers and experiments were conducted by varying the cutting speed, feed, depth of cut and tool nose radius. The machining forces and surface topographies, the structure of the cutting tool and chip patterns were examined. The maximum cutting force was recorded upon increase in cutting speed because of thermal softening, loss of strength discontinuity and reduction of the built-up-edge. The increased plastic deformation with higher cutting speed resulted in the excess metal chip. In addition, the increase in cutting speed improved the surface roughness due to decrease in material movement. The cutting force was decreased upon high loading of TiB2 due to the deterioration of chips caused by fillers. Further introduction of TiB2 particles above 12 wt.% weakened the composite; however, due to the impact of the microcutting action of the fillers, the surface roughness was improved.

Compression after Impact Behaviour and Failure Analysis of Nanosilica-Toughened Thin Epoxy/GFRP Composite Laminates.

Nanosilica particles were utilized as secondary reinforcement to enhance the strength of the epoxy resin matrix. Thin glass fibre reinforced polymer (GFRP) composite laminates of 3 ± 0.25 mm were developed with E-Glass mats of 610 GSM and LY556 epoxy resin. Nanosilica fillers were mixed with epoxy resin in the order of 0.25, 0.5, 0.75 and 1 wt% through mechanical stirring followed by an ultrasonication method. Thereafter, the damage was induced on toughened laminates through low-velocity drop weight impact tests and the induced damage was assessed through an image analysis tool. The residual compression strength of the impacted laminates was assessed through compression after impact (CAI) experiments. Laminates with nanosilica as secondary reinforcement exhibited enhanced compression strength, stiffness, and damage suppression. Results of Fourier-transform infrared spectroscopy revealed that physical toughening mechanisms enhanced the strength of the nanoparticle-reinforced composite. Failure analysis of the damaged area through scanning electron microscopy (SEM) evidenced the presence of key toughening mechanisms like damage containment through micro-cracks, enhanced fiber-matrix bonding, and load transfer.

Measurement of range of motions of L3-L4 healthy spine through offsetting reflective markers and in silico analysis of meshed model.

Degenerative disc disease (DDD) is a common condition in elderly population that can be painful and can significantly affect individual's quality of life. Diagnosis of DDD allows prompt corrective actions but it is challenging due to the absence of any symptoms at early stages. In studying disc degeneration, measurement of the range of motion (RoM) and loads acting on the spine are crucial factors. However, direct measurement of RoM involves increased instrumentation and risk. In this paper, an innovative method is proposed for calculating RoM, emphasizing repeatability and reliability by considering the posterior thickness of the spine. This is achieved by offsetting the position of markers in relation to the actual vertebral loci. Three geometrically identical finite element models of L3-L4 are developed from a CT scan with different types of elements, and thereafter, mesh element-related metrics are provided for the assessment of the quality of models. The model with the best mesh quality is used for further analysis, where RoM are within ranges as reported in literature and in vivo experiment results. Various kinds of stresses acting on individual components including facet joints are analysed for normal and abnormal loading conditions. The results showed that the stresses in abnormal load conditions for all components including cortical (76.67 MPa), cancellous (69.18 MPa), annulus (6.30 MPa) and nucleus (0.343 MPa) are significantly greater as compared to normal loads (49.96 MPa, 44.2 MPa, 4.28 MPa and 0.23 MPa respectively). However, stress levels for both conditions are within safe limits (167-215 MPa for cortical, 46 MPa for the annulus and 3 MPa for facets). The results obtained could be used as a baseline motion and stresses of healthy subjects based on their respective lifestyles, which could benefit clinicians to suggest corrective actions for those affected by DDD.

Development of Rheumatoid Arthritis Classification from Electronic Image Sensor Using Ensemble Method.

Rheumatoid arthritis (RA) is an autoimmune illness that impacts the musculoskeletal system by causing chronic, inflammatory, and systemic effects. The disease often becomes progressive and reduces physical function, causes suffering, fatigue, and articular damage. Over a long period of time, RA causes harm to the bone and cartilage of the joints, weakens the joints' muscles and tendons, eventually causing joint destruction. Sensors such as accelerometer, wearable sensors, and thermal infrared camera sensor are widely used to gather data for RA. In this paper, the classification of medical disorders based on RA and orthopaedics datasets using Ensemble methods are discussed. The RA dataset was gathered from the analysis of white blood cell classification using features extracted from the image of lymphocytes acquired from a digital microscope with an electronic image sensor. The orthopaedic dataset is a benchmark dataset for this study, as it posed a similar classification problem with several numerical features. Three ensemble algorithms such as bagging, Adaboost, and random subspace were used in the study. These ensemble classifiers use k-NN (K-nearest neighbours) and Random forest (RF) as the base learners of the ensemble classifiers. The data classification is accessed using holdout and 10-fold cross-validation evaluation methods. The assessment was based on set of performance measures such as precision, recall, F-measure, and receiver operating characteristic (ROC) curve. The performance was also measured based on the comparison of the overall classification accuracy rate between different ensembles classifiers and the base learners. Overall, it was found that for Dataset 1, random subspace classifier with k-NN shows the best results in terms of overall accuracy rate of 97.50% and for Dataset 2, bagging-RF shows the highest overall accuracy rate of 94.84% over different ensemble classifiers. The findings indicate that the efficiency of the base classifiers with ensemble classifier have substantially improved.

EEG-Based Control for Upper and Lower Limb Exoskeletons and Prostheses: A Systematic Review.

Electroencephalography (EEG) signals have great impact on the development of assistive rehabilitation devices. These signals are used as a popular tool to investigate the functions and the behavior of the human motion in recent research. The study of EEG-based control of assistive devices is still in early stages. Although the EEG-based control of assistive devices has attracted a considerable level of attention over the last few years, few studies have been carried out to systematically review these studies, as a means of offering researchers and experts a comprehensive summary of the present, state-of-the-art EEG-based control techniques used for assistive technology. Therefore, this research has three main goals. The first aim is to systematically gather, summarize, evaluate and synthesize information regarding the accuracy and the value of previous research published in the literature between 2011 and 2018. The second goal is to extensively report on the holistic, experimental outcomes of this domain in relation to current research. It is systematically performed to provide a wealthy image and grounded evidence of the current state of research covering EEG-based control for assistive rehabilitation devices to all the experts and scientists. The third goal is to recognize the gap of knowledge that demands further investigation and to recommend directions for future research in this area.

A Follow-Up Study of the Prevalence of Valvular Heart Abnormalities in Hyperprolactinemic Patients Treated With Cabergoline.

CONTEXT: Uncertainty exists whether the long-term use of ergot-derived dopamine agonist (DA) drugs for the treatment of hyperprolactinemia may be associated with clinically significant valvular heart disease and whether current regulatory authority guidelines for echocardiographic screening are clinically appropriate. OBJECTIVE: Our objective was to provide follow-up echocardiographic data on a previously described cohort of patients treated with DA for lactotrope pituitary tumors and to explore possible associations between structural and functional valve abnormalities with the cumulative dose of drug used. DESIGN: Follow-up echocardiographic data were collected from a proportion of our previously reported cohort of patients; all had received continuous DA therapy for at least 2 years in the intervening period. Studies were performed according to British Society of Echocardiography minimum standards for adult transthoracic echocardiography. Generalized estimating equations with backward selection were used to determine odds ratios of valvular heart abnormalities according to tertiles of cumulative cabergoline dose, using the lowest tertile as the reference group. SETTING: Thirteen centers of secondary/tertiary endocrine care across the United Kingdom were included. RESULTS: There were 192 patients (81 males; median age, 51 years; interquartile range [IQR], 42-62). Median (IQR) cumulative cabergoline doses at the first and second echocardiograms were 97 mg (20-377) and 232 mg (91-551), respectively. Median (IQR) duration of uninterrupted cabergoline therapy between echocardiograms was 34 months (24-42). No associations were observed between cumulative doses of dopamine agonist used and the age-corrected prevalence of any valvular abnormality. CONCLUSION: This large UK follow-up study does not support a clinically significant association between the use of DA for the treatment of hyperprolactinemia and cardiac valvulopathy.

Antiarthritic activity of a polyherbal formulation against Freund's complete adjuvant induced arthritis in Female Wistar rats.

OBJECTIVES: To formulate a polyherbal formulation and evaluate its antiarthritic activity against Freund's complete adjuvant induced arthritis in Female Wistar rats. MATERIALS AND METHODS: Glycosmis pentaphylla, Tridax procumbens, and Mangifera indica are well-known plants available throughout India and they are commonly used for the treatment of various diseases including arthritis. The polyherbal formulation was formulated using the ethanol extracts of the stem bark of G. pentaphylla , whole plant of T. procumbens, and leaves of M. indica. The polyherbal formulation contains the ethanol extracts of G. pentaphylla, T. procumbens, and M. indica in the ratio of 2:2:1. The quality of the finished product was evaluated as per the World Health Organization's guidelines for the quality control of herbal materials. Arthritis was induced in female Wistar rats using Freund's complete adjuvant (FCA), and the antiarthritic effect of polyherbal formulation was studied at doses of 250 and 500 mg/kg. The effects were compared with those of indomethacin (10 mg/kg). At the end of the study, blood samples were collected for biochemical and hematological analysis. The radiological examination was carried out before terminating the study. RESULTS: Polyherbal formulation showed significant antiarthritic activity at 250 and 500 mg/kg, respectively, and this effect was comparable with that of indomethacin. The antiarthritic activity of polyherbal formulation is supported by biochemical and hematological analysis. CONCLUSION: The polyherbal formulation showed signinicant antiarthritic activity against FCA-induced arthritis in female Wistar rats.

Evaluation of the antihypertensive activity and alpha adrenergic receptor interaction of cleistanthins A and B.

Hypertension was induced in male Sprague Dawley rats with twice weekly administration of deoxycorticosterone acetate (DOCA) salt (20 mg/kg s.c) for 4 weeks. They were divided into eight groups of six animals each viz., hypertensive control, standard (prazosin 1 mg/kg), cleistanthin A 12.5, 25, 50 mg/kg and cleistanthin B 12.5, 25 mg/kg, and 50 mg/kg. One more group served as normal control. The hypertension was induced in 4 weeks, and the animals were given assigned treatment in 5(th) week. The alteration in blood pressure (BP) was recorded weekly using a rodent noninvasive blood pressure system. At the end of the experiment alpha-adrenergic receptor response of drugs like adrenaline, nor adrenaline, dopamine (doses 1 µg and 2 µg) was recorded invasively. Two-way repeated measures ANOVA followed by Bonferroni post-hoc test was used to analyze the data. The systolic BP and diastolic BP of test groups rose to a higher level after DOCA administration and fell to the normal range (P < 0.05) following the administration of cleistanthins A and B. There were no differences in the weekly heart rate among the groups. In the test group animals pretreated with prazosin and cleistanthins, adrenaline, noradrenaline and dopamine failed to raise the mean arterial pressure and the end-diastolic pressure from baseline (P > 0.05) cleistanthins A and B exert a significant antihypertensive effect through alpha-adrenergic receptor blockade similar to prazosin.

Anti-arthritic activity of ethanolic extract of Tridax procumbens (Linn.) in Sprague Dawley rats.

OBJECTIVE: To determine the anti-arthritic effect of whole plant ethanolic extract of Tridax procumbens (Asteraceae) in female Sprague Dawley (SD) rats using the Freund's Complete Adjuvant (FCA) model. MATERIALS AND METHODS: The plant was collected from different regions of Madurai District, Tamil Nadu, and the phytoconstituents were identified through chemical tests. Ethanol (95%) was used to obtain the whole plant extraction through Soxhlet extractor. Female SD rats were used for anti-arthritic screening. Arthritis was induced using FCA, and the anti-arthritic effect of the ethanolic extract of T. procumbens was studied at doses of 250 and 500 mg/kg. The effects were compared with those of indomethacin (10 mg/kg). At the end of the study, the liver enzyme levels were determined and a radiological examination was carried out. RESULT: The preliminary phytochemical analysis of the ethanolic extract of T. procumbens indicated the presence of alkaloids, tannins, flavonoids and saponins. T. procumbens at 250 and 500 mg/kg significantly inhibited the FCA-induced arthritis in the rats. This was manifested by as a decrease in the paw volume. The arthritic control animals exhibited a significant decrease in body weight compared with control animals without arthritis. T. procumbens animals showed dose dependent reduction in decrees in body weight and arthritis. At the same time, T. procumbens significantly altered the biochemical and haematological changes induced by FCA (P < 0.05). The anti-arthritic effect of T. procumbens was comparable with that of indomethacin. CONCLUSION: The whole plant extract of T. procumbens showed significant anti-arthritic activity against FCA-induced arthritis in female SD rats.

Antidiabetic and antihyperlipidemic effects of an ethanolic extract of the whole plant of Tridax procumbens (Linn.) in streptozotocin-induced diabetic rats.

OBJECTIVE: To study the antidiabetic and antihyperlipidemic effects of an ethanolic extract of the whole plant of Tridax procumbens (Asteraceae) in streptozotocin-induced diabetic rats. MATERIALS AND METHODS: The whole plant of T. procumbens was collected in different regions of Madurai districts, Tamil Nadu. The air dried whole plant of T. procumbens was extracted with ethanol (95%) in a Soxhlet apparatus for 72 h. Diabetes was induced in male Wistar rats by streptozotocin (50 mg/jk, i.p.) and nicotinamide (120 mg/kg, i.p) injection. The dry mass of the extract was used for preliminary phytochemical and pharmacological analysis. Diabetic rats were treated with glibenclamide (0.25 mg/kg, p.o.) or T. procumbens extract (250 and 500 mg/k, p.o.) for 21 consecutive days. The blood samples were collected at regular intervals to access hypoglycemic effect of an ethanolic extract of the whole plant of T. procumbens. At the end of the experiment, serum lipid profile and liver enzymes levels were analyzed for all the experimental animals and compared with diabetic control. RESULTS: The preliminary phytochemical analysis of an ethanolic extract of the whole plant of T. procumbens indicated the presence of alkaloids, tannins, flavonoids, saponins, and phenolic compounds. The ethanolic extract of the whole plant of T. procumbens at 250 and 500 mg/kg has significant antidiabetic and antihyperlipidemic activities. The diabetic control animals exhibited a significant decrease in body weight compared with control animals. T. procumbens inhibited streptozotocin-induced weight loss and significantly alter the lipid levels. CONCLUSION: The ethanolic extract of the whole plant of T. procumbens showed significant antidiabetic and antihyperlipidemic activities against streptozotocin-induced diabetes in rats.

Diuretic effects of cleistanthin a and cleistanthin B from the leaves of cleistanthus collinus in wistar rats.

To study the diuretic effects of cleistanthin A and cleistanthin B, phytoconstituents were isolated from the leaves of Cleistanthus collinus in Wistar rats. The in vivo diuretic effects of cleistanthins A and B were determined according to the Lipschitz test. Prior to the experiment, the animals were fasted for 5 h and placed individually in metabolic cages. Cleistanthins A and B (12.5, 25, and 50 mg/kg) and furosemide (5 mg/kg) were suspended in 0.5% w/v carboxymethyl cellulose and administered orally. The urine was collected up to 5 h after administration and subsequently up to 24 h after administration. The acidity and urine volume were measured immediately. The urinary sodium and potassium levels were determined using a flame photometer, and the chloride level was determined by argentometric titration. The diuretic index and diuretic activity were calculated mathematically. While cleistanthins A and B showed a diuretic index of more than one, the diuretic activity of these compounds was less than one, indicating inferior activity compared with furosemide. Both cleistanthin A and B produced a significant increase in the urine volume and alterations in urinary electrolyte levels. However, the effect of the compounds was not dose dependent. Cleistanthin A and cleistanthin B exert diuretic effects in male Wistar rats without affecting the urinary acidity.

Evaluation of oxidative stress and antioxidant status in patients with cardiovascular disease in rural populations of the nilgiris, South India.

Objective. The objective of this work was to study the risk factors of ischaemic heart disease (IHD) in rural populations of the Nilgiris, south India, with stress on the various social habits and oxidant stress. Methods. A total of 72 patients with cardiovascular disease (CVD) and 12 healthy volunteers were screened. Forty-seven patients with CVD (intervention group) and 10 healthy volunteers (control group) were randomly selected for the study. Written informed consent was obtained from all the participants, and their demographic details were collected. A 6 mL blood sample was collected from each of the participants, and the serum was separated in the samples. The levels of enzymic (superoxide dismutase, catalase) and nonenzymic antioxidants (ascorbic acid) in the plasma were determined biochemically. The level of thiobarbituric acid species (TBARS), which is a predictor of lipid peroxidation, was measured. Results. The participants of the study were stratified as according to demographic and social variables. The values of all the antioxidants and TBARS were statistically compared. Significantly reduced antioxidant levels and increased TBARS levels were found in the intervention group compared with the control group. The results suggest that the lowered antioxidant level may be a result of the oxidant stress of the disease. Statistically significant differences were not found in the antioxidant and TBARS levels when comparing smokers versus nonsmokers, alcoholics versus nonalcoholics, and vegetarians versus nonvegetarians. Conclusion. The major causes of CVD amongst the rural populations of the Nilgiris, south India, are preventable causes such as smoking and high fat intake, all of which cause oxidative stress, as seen in our study through various serum markers.

Role of community pharmacists in improving knowledge and glycemic control of type 2 diabetes.

OBJECTIVE: To study the role of the community pharmacists in improving knowledge and glycemic control in patients with type 2 diabetes residing in villages of Coimbatore district, Tamil Nadu. MATERIALS AND METHODS: Fifty patients were interviewed, of whom 39 subjects were included in the study. The literate and chronic diabetic patients were included in the study and illiterate, children below 12 years of age, pregnant women, nursing mothers and subjects with any other chronic disorders were excluded from the study. The subjects were interviewed and divided randomly into two groups. There were 20 subjects in the control group and 19 in the intervention group. The study protocol was explained to all the participants, and written informed consent was obtained from them. Before the initiation of the study, the subjects were interviewedfor 20-40 min to educate them about diabetes. Subjects in the intervention group received continuous counselling and medical advice to improve their awareness about the disease and drugs. During the study period, the Diabetes Care Profile (a questionnaire developed by J.J. Fitzgerald of the Michigan Diabetes Research and Training Center, University of Michigan Medical School, Michigan) was performed to each subject. The interval between visits was 2 months. All the values are expressed in mean ± standard deviation. RESULTS: The intervention group showed better progress in the recovery of diabetics because of the continuous counselling and monitoring. There were significant changes in Diabetes Care Profile subscale scores in both the control and the intervention groups at the end of the study, viz. 1.8 ± 4.52 to 2.75 ± 6.62 and 3.10 ± 3.23 to 1.53 ± 2.66. Similarly, the knowledge test score was found to be increased in the intervention group compared with the baseline values (8.53 ± 1.81 to 12.16 ± 1.34). CONCLUSIONS: At the end of the study period, the patients of the intervention group had very good glycemic control. Their health status and understanding of diabetes and its management were better, and they had fewer problems such as episodes of hyperglycemia or hypoglycemia.

Effect of cleistanthin A and B on adrenergic and cholinergic receptors.

OBJECTIVE: The aim was to study the in vitro and in silico interactions of cleistanthin A and B on the adrenergic and cholinergic receptors using isolated animal tissues and bioinformatics tools. MATERIALS AND METHODS: The alpha adrenergic receptor activities of cleistanthin A and B were studied in vitro using a guinea pig vas deferens preparation. The beta adrenergic receptor activities of cleistanthin A and B on an isolated rat heart were studied in vitro using a modified Langendorff apparatus. The effects of cleistanthin A and B on the nicotinic and muscarinic cholinergic receptors were studied in vitro using rabbit vas deferens and rabbit jejunum, respectively. All the drug responses were recorded using a data acquisition system through a variable force transducer. The receptor-ligand interactions of cleistanthin A and B with adrenergic and cholinergic receptor proteins were determined using the ArgusLab molecular modeling and drug docking program. RESULTS: Cleistanthin A and B significantly inhibited the actions of the alpha adrenergic receptor and the nicotinic cholinergic receptor. Cleistanthin A and B shifted the dose-response curve to the right with an increased EC(50) value of phenylephrine and acetylcholine. Both cleistanthin A and B did not have any significant effect on the beta adrenergic and muscarinic cholinergic receptors. CONCLUSION: Cleistanthin A and B block the alpha adrenergic and nicotinic cholinergic receptors, but these compounds do not interact at all with the beta adrenergic and muscarinic cholinergic receptors.