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Machining difficult-to-cut materials involves challenging machining conditions, including higher temperatures in the cutting zone, cutting forces and friction. Another important phenomenon is vibration, which is undesirable when manufacturing high quality workpieces. One way to reduce vibration in the cutting zone is to use cooling methods. Due to its environmentally friendly nature, the minimum quantity lubrication (MQL) method has already been widely used in metalworking. However, when combined with nanofluids, it improves the ability of the aerosol to dissipate more heat and increase lubrication in the cutting zone. This paper presents the effect of a polyol esterbased Al2O3 nanofluid due to the varying mass concentration of nanoparticles on the vibration during turning of Ti6Al4V alloy and compares the results with dry cutting and the MQL method without nanoparticles. Four concentrations (0.25-1 wt%), variable nanofluid flow rate E=0.388-1.182 g/min and air flow rate P=10-40 l/min were considered. According to the statistical analysis, the most important factor influencing tool vibration was the mass concentration of nanoparticles in the cutting fluid. By combining the MQL method with 0.5 wt% Al2O3, the vibration acceleration RMS values were found to be the lowest. When compared to the MQL method without nanoparticles, the RMS values for dry cutting ranged from 17.8% to 24.9%, and for wet cutting they were reduced by about 10.9-18.5%. [ABSTRACT FROM AUTHOR]

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In a placebo controlled double-blind study including 10 patients with heart failure the nisoldipine/digoxin interaction was studied. Nisoldipine was shown to elevate digoxin plasma concentrations significantly by about 15% (trough levels). During chronic combination therapy with nisoldipine trough levels and plasma concentrations 4 h after the morning dose of digoxin were 1.35 +/- 0.14 and 1.92 +/- 0.16 ng ml-1 respectively, whereas they averaged to 1.16 +/- 0.14 and 1.52 +/- 0.16 ng ml-1 with digoxin and placebo (P less than 0.05; mean +/- s.e. mean). Systolic time intervals were significantly altered by nisoldipine co-administration compared with digoxin plus placebo. In certain patients the elevation of digoxin plasma levels due to nisoldipine co-administration could be of clinical relevance. [ABSTRACT FROM AUTHOR]

Introduction: It is unclear whether it is possible to determine the training load on the basis of the 6-minute walk test (6-MWT) in patients after cardiac surgery with low tolerance of physical exercise., Aim: Use of the 6-MWT to determine an individual initial training load in walking training on a treadmill in the early phase of cardiac rehabilitation in men after coronary artery bypass graft (CABG) surgery., Material and Methods: Twenty-two men aged 54 to 74 years, up to 3 months after CABG surgery participated in walking training on a treadmill (12-15 sessions). Patients underwent the initial and final treadmill exercise stress test (TEST) and the 6-MWT. Based on 6-MWT results, the initial training load was prescribed. Before the 6-MWT and 3 minutes after its completion, lactate concentration was determined., Results: The 6-MWT distance increased from 420 ±80 m to 519 ±61 m ( p < 0.001), and the energy expenditure from 4.4 ±1.4 MET to 6.3 ±1.3 MET ( p < 0.001). There was a positive correlation between 6-MWT distance and energy expenditure in the TEST before rehabilitation ( r = 0.60, p = 0.005), and after rehabilitation ( r = 0.75, p < 0.001). A negative correlation was found between the baseline 6-MWT distance and distance increment in the final 6-MWT ( r = -0.66, p = 0.002). The 6-MWT did not induce hyperlactatemia., Conclusions: The 6-MWT can be used in exercise intensity prescription, especially for determining the individual initial training load, load progression, as well as its correction during follow-up tests., Competing Interests: The authors report no conflict of interest., (Copyright: © 2021 Polish Society of Cardiothoracic Surgeons (Polskie Towarzystwo KardioTorakochirurgów) and the editors of the Polish Journal of Cardio-Thoracic Surgery (Kardiochirurgia i Torakochirurgia Polska).)

Introduction: Walking training is a good alternative to the commonly used cycle ergometer training. It is still necessary to develop rehabilitation programs based on walking characterized by a high degree of safety and effectiveness., Aim: Application of continuous walking training as an alternative to interval cycle ergometer training in men after coronary artery bypass graft (CABG) surgery, using the 6-minute walk test (6-MWT) to determine the initial training load., Material and Methods: Forty-four men aged 45 to 76 years, up to 3 months after CABG surgery, were randomly assigned to continuous training on a treadmill (study group) or interval training on a cycle ergometer (control group), performed 6 times per week (12-15 sessions). Participants underwent the treadmill exercise stress test (TEST) and 6-MWT at the begining and after completion of the rehabilitation program. Before and 3 minutes after the 6 th and 12 th training session blood lactate concentration was determined., Results: Energy expenditure in TEST increased from 4.4 to 6.3 MET in the study group and from 5.0 to 6.5 MET in the control group. Distance walked in 6-MWT increased from 420 to 519 m and from 438 to 510 m, respectively. Resting heart rate (HR) and double product (DP) decreased only in the study group as well as systolic blood pressure (SBP), HR and DP at peak exercise load in baseline TEST. Mean energy expenditure during training sessions was 2.6 MET in the study group and 2.8 MET in the control group (NS). Exercise blood lactate concentration did not exceed 2.0 mmol/l in both groups., Conclusions: Both rehabilitation programs were of similar effectiveness and their intensity did not exceed the anaerobic threshold., Competing Interests: Authors report no conflict of interest., (Copyright © 2020 Polish Society of Cardiothoracic Surgeons (Polskie Towarzystwo KardioTorakochirurgów) and the editors of the Polish Journal of Cardio-Thoracic Surgery (Kardiochirurgia i Torakochirurgia Polska).)

Walking is regarded as one of the most common and utilitarian activities of everyday life. Rehabilitation programs developed on the basis of this form of activity often constitute the primary method of rehabilitating patients after coronary artery bypass grafting. This paper provides a review of literature concerning various forms of walking training, discussing their impact on the parameters of exercise capacity and verifying the training methods with regard to the current guidelines. Attention is drawn to the diversity of the exercise protocols applied during the early and late stages of rehabilitation and pre-rehabilitation programs including: treadmill walking, walking down the corridor, treadmill walking enriched with virtual reality, and walking as an element of training sessions consisting of many different forms of activities. Exercise protocols were also analyzed in terms of their safety, especially in the case of high-intensity interval training. Despite the variety of the available rehabilitation programs, the training methodology requires constant improvement, particularly in terms of load dosage and the supervision of training sessions.

Objective: The aim of this study was to assess the 1-yr follow-up effects of inpatient rehabilitation and its prolongation with an ambulatory training program on blood pressure and metabolic risk factors in patients after an acute coronary syndrome., Design: A controlled (n = 20) prospective study was undertaken. The study group consisted of 54 consecutive patients participating in a 3-wk inpatient rehabilitation. Of these, 14 chose to continue the training for 3 mos (CR&#95;In+Amb group) and 40 declined (CR&#95;In group)., Results: Body mass index increased in the CR&#95;In and control groups. The magnitude of change was greater in controls (2.2 ± 2.14 vs. 0.7 ± 1.70 kg/m; P < 0.05). Waist circumference increased only in the control group, and at 12 mos, it was higher than in the CR&#95;In and CR&#95;In+Amb groups (P < 0.05). Mean systolic and diastolic blood pressure increased in the CR&#95;In (from 121/76 to 130/82 mm Hg; P < 0.01) and control (from 122/74 to 139/87 mm Hg; P < 0.01) groups. At 12 mos, blood pressure in the CR&#95;In group was lower than in the control group but higher than in the CR&#95;In+Amb group (119/77 mm Hg; P < 0.05). Total cholesterol, low-density lipoprotein cholesterol level, and triglyceride level at 12 mos were higher in the control group than in the CR&#95;In and CR&#95;In+Amb groups (P < 0.05). C-reactive protein decreased in the CR&#95;In and CR&#95;In+Amb groups (P < 0.01)., Conclusions: Inpatient rehabilitation was associated with beneficial effects on blood lipids and C-reactive protein in coronary patients and attenuated the rise in blood pressure and adiposity indices observed in nonparticipants. Prolongation of rehabilitation with an ambulatory program improved blood pressure control.

Objective: To investigate the effects of Nordic Walking training supplemental to a standard, early rehabilitation programme on exercise capacity and physical fitness in men after an acute coronary syndrome., Design: A controlled trial., Setting: Cardiac rehabilitation service of a provincial hospital., Subjects: Eighty men 2-3 weeks after an acute coronary syndrome, with good exercise tolerance., Interventions: Three-week, inpatient cardiac rehabilitation programme (control group) supplemented with Nordic Walking (Nordic Walking group), or with traditional walking training (walking training group)., Main Measures: Exercise capacity was assessed as peak energy cost (in metabolic equivalents) in symptom-limited treadmill exercise test, and physical fitness with the Fullerton Functional Fitness Test., Results: Exercise capacity after the rehabilitation programme was higher in the Nordic Walking group than in the control group (10.8 +/- 1.8 versus 9.2 +/- 2.2 metabolic equivalents, P =0.025). The improvement in exercise capacity in the Nordic Walking group was higher than in the control group (1.8 +/- 1.5 versus 0.7 +/- 1.4 metabolic equivalents, P =0.002). In contrast to the control group, the results of all components of the Fullerton test improved in the Nordic Walking and walking training groups. After the programme, lower body endurance, and dynamic balance were significantly better in the Nordic Walking group in comparison with the walking training and control groups, and upper body endurance was significantly better in the Nordic Walking and walking training groups than in the control group., Conclusions: Nordic Walking may improve exercise capacity, lower body endurance and coordination of movements in patients with good exercise tolerance participating in early, short-term rehabilitation after an acute coronary syndrome.

Background: The value of cardiac rehabilitation in patients with coronary artery disease has been well established. The main problem is a low attendance of patients qualified for rehabilitation., Aim: To assess differences between subjects attending outpatient cardiac rehabilitation (OutCR) after completing an early inpatient programme (InCR), and patients refusing participation in OutCR; to investigate factors determining patients' decisions., Methods: Seventy-two patients (mean age 57 +/- 9.4 years; 53 men) 2-3 weeks after an acute coronary syndrome (ACS) treated with primary PCI were enrolled. On admission to the cardiac rehabilitation ward, the following parameters were assessed: quality of life (EuroQol-5D questionnaire), psychological status (Beck's, SOPER and STAI questionnaires), marital status, education, economic status, employment, place of living, smoking status, and comorbidities (a questionnaire prepared by the authors). Additionally, patients' opinions on outpatient and inpatient cardiac rehabilitation were noted. The inpatient programme lasted 2-3 weeks. At discharge, the assessment was repeated, and patients were proposed to enrol in a 12-week outpatient programme. In the case of refusal, patients were asked to give the reason., Results: Two men failed to complete the inpatient program. Of the remaining 70 subjects, 16 attended and completed the outpatient programme. In the group participating in OutCR, there were fewer patients with depression before InCR (12 vs. 39% in the group without OutCR, p = 0.0484). Subjects in the OutCR group had a higher score for mood after InCR (7.7 +/- 1.25 vs. 6.7 +/- 1.69, p = 0.0365), lower score for emotional stress before and after InCR (before InCR: 4.4 +/- 1.09 vs. 5.3 +/- 1.34, p = 0.0188; after InCR: 3.8 +/- 1.51 vs. 4.8 +/- 1.4, p = 0.0262), and lower score for anxiety before InCR (3.1 +/- 1.75 vs. 4.4 +/- 2.12, p = 0.0426). Patients in the two groups differed with regard to employment (p = 0.0256) and smoking status (p = 0.0517). In both groups, most patients (ł 80%) preferred inpatient rehabilitation. Continuous medical care, lack of commuting problems, and convenience were the most frequently given advantages of inpatient rehabilitation, while commuting problems and conflict with job were the most frequently perceived barriers to outpatient rehabilitation., Conclusions: Only a small proportion of patients after an ACS decides to participate in outpatient rehabilitation after completing a short-term inpatient programme. Psychological status, employment and smoking status are among the factors that differentiate OutCR attenders and non-attenders. Continuous medical care, lack of commuting problems, and convenience were the most frequently given advantages of inpatient rehabilitation, while commuting problems and conflict with job were the most frequently perceived barriers to outpatient rehabilitation.

Background: Education on behavioural risk factors and lifestyle modification is one of the core components of comprehensive cardiac rehabilitation., Aim: To assess the level of knowledge of cardiovascular risk factors and recommended lifestyle changes in patients rehabilitated after an acute coronary syndrome (ACS)., Methods: The study group consisted of 31 consecutive patients (22 males, 56.6+/-10.9 years) participating in short-term, early, comprehensive cardiac rehabilitation. On admission, at discharge and 3 months after discharge patients' knowledge was assessed with a questionnaire worked out by the authors., Results: On admission, patients had poor knowledge of cardiovascular risk factors and recommended lifestyle modifications, especially concerning diabetes, hypertension, and diet. After completing the rehabilitation programme, significantly higher percentage of patients gave correct answers to questions concerning diabetes and cholesterol-rich diet as cardiovascular risk factors, and substitution of vegetable fat for animal fat as a lifestyle modification, and significantly higher proportion of patients gave the correct value for elevated systolic blood pressure., Conclusions: Patients after ACS have poor knowledge of cardiovascular risk factors and recommended lifestyle modifications. The level of knowledge improves after short-term, stationary cardiac rehabilitation; however, the degree of this improvement is not completely satisfactory.

Background: Cardiovascular diseases are the main cause of death in the adult Polish population. Beside lipid disorders and cigarette smoking, hypertension represents the most important risk factor leading to cardiovascular complications. Representative studies conducted in Poland in 1994-2002 showed that in 2002 the number of respondents in the survey who stated they knew their own blood pressure values dropped by 3.5 million, compared with 1994. This decrease was predominantly seen in small towns and in the countryside. Preventive programmes should therefore be addressed mainly to the most vulnerable communities. Modern methods of social marketing may play a substantial role in the creation of a healthy lifestyle., Aim: The aim of the Polish Four Cities Programme (PP4M), conducted in 2000-2001, was to develop the most effective methods of detection of and improvement in treatment for hypertension among the residents of small towns and rural areas. One of the programme tasks was to compare the effectiveness of a standard medical screening intervention with a similar approach combined with the use of social marketing methods.Methods. The programme was conducted by an interdisciplinary team in three small Polish towns -- Kartuzy, Oborniki Wlkp. and Braniewo, as well as in one of the districts of a large city Łódź -- Olechów. Medical intervention combined with social marketing (community intervention) took place in Oborniki Wlkp. whereas the residents of Kartuzy and Łódź were subjected only to the traditional medical intervention. Braniewo served as a control location -- neither medical nor community intervention was implemented. Community intervention with elements of social marketing consisted of a three-month, intensive education and information campaign, initiated four weeks prior to the start of medical intervention. Epidemiological situation was assessed in all the four cities before and after the completion of the preventive interventions (screening), using representative surveys, with the objective to assess the changes in the awareness of one's own blood pressure values, detection of hypertension and knowledge concerning cardiovascular risk factors.Results. In two survey locations -- Kartuzy and Łódź - awareness of one's own blood pressure values after the medical intervention did not significantly change (61% and 67.6% at baseline versus 62.1% and 71.6% after the intervention, respectively). In contrast, social marketing activities conducted in Oborniki significantly increased this parameter from 61.5% to 79.8% (p<0.01). While medical intervention did not change the proportion of non-diagnosed hypertension in a small town (a non-significant decrease from 49% to 45% in Kartuzy), its effect in a large city was clearly visible (a decrease from 46% to 28% in Łódź). In Oborniki Wlkp. (medical intervention combined with social marketing) the effects were the most noticeable -- a reduction from 50% to 27% was achieved. The efficacy of hypertension treatment at baseline was low (4.7% in Kartuzy, 6.6% in Oborniki, and 6.5% in Łódź), but it then improved significantly (a twofold increase in Kartuzy and Oborniki, and more than twofold increase in Łódź). When the target value of blood pressure was set at 160/95 mmHg, the highest efficacy of hypotensive therapy was observed directly after the completion of medical and community intervention in Oborniki (an almost twofold increase in treatment efficacy)., Conclusions: 1. Medical intervention combined with a community intervention and marketing campaign leads to a statistically significant improvement in self-awareness of blood pressure values among residents of small towns. 2. Medical intervention combined with community intervention brings the detection rate of hypertension in small towns up to the level observed in large cities. 3. Medical intervention, especially when combined with community intervention, improves the efficacy of the treatment of hypertension, regardless of the size of agglomeration.

Background: It has been shown that short-term exercise training improves insulin resistance parameters in patients with ischaemic heart disease. The effects of such a rehabilitation programme in patients with hypertension have not been well established., Aim: To assess whether short-term endurance training after coronary artery bypass grafting (CABG) may improve metabolic parameters and reduce blood pressure in patients with hypertension., Methods: The study group consisted of 30 male patients (15 with hypertension and 15 normotensive) aged 55+/-2.1 years who underwent CABG 1 to 6 months before the initiation of a 3-week endurance training. Glucose, insulin and C-peptide blood levels as well as binding and degradation of 125I-insulin by erythrocyte receptors were assessed before and after the training programme. The effects of training on blood pressure values were also evaluated., Results: A significant improvement (p<0.01) in the insulin resistance parameters, i.e. binding and degradation of labelled insulin was noted only in patients with hypertension. This was accompanied by a significant (p<0.05) increase in the HDL-cholesterol level. In the subgroup with hypertension, both the exercise systolic and diastolic pressures decreased significantly (p<0.05 and p<0.01, respectively), and similar changes were noted in the resting systolic and diastolic blood pressures values (p<0.05)., Conclusions: Rehabilitation after CABG based on the endurance training was especially effective in patients with hypertension in whom beneficial changes in some metabolic risk factors of ischaemic heart disease as well as the reduction in the blood pressure values were observed.

Aims: Our study was aimed at determining whether beneficial modification of carbohydrate metabolism can be obtained after a short-term training program and whether it is associated with an increase in binding and degradation of (125)I-insulin by erythrocyte receptors that suggests a decrease in insulin resistance., Methods: The study was conducted in a group of 20 patients aged 56 +/- 1.9 years (mean +/- SEM), within 1 to 6 months after coronary bypass surgery. All patients completed 15 training sessions based on 30 min of cycling with a constant load. Before and after a 3-week training program, glucose, insulin, and C-peptide blood levels, as well as binding and degradation of (125)I-insulin by erythrocyte receptors, were determined., Results: A statistically significant decrease was found in the blood glucose level, from 111.2 +/- 4.2 to 97.8 +/- 3.5 mg/dL (p < 0.01); this decrease was not accompanied by significant insulin concentration changes. There was also a significant increase in insulin binding, from 0.535 +/- 0.059 to 0.668 +/- 0.042 pg (125)I/10(11) RBCs (p < 0.01), and degradation from 7.64 +/- 0.54 to 9.49 +/- 0.58 pg (125)I/10(11) RBCs (p < 0.05)., Conclusion: The results indicated that even short-term endurance training in patients rehabilitated after coronary bypass surgery induced favorable modification of glucose metabolism, presumably caused by a decrease in insulin resistance.

Glucosamine has a major influence on the impairment of some metabolic mechanisms in the human body. As shown in vitro experiments, it takes part in inducing mechanisms of insulin resistance. Therefore, the purpose of our study was to evaluate glucosamine levels in the serum of patients who suffered myocardial infarction (MI) and who either had or didn't have diagnosed type II diabetes in relation to healthy people. The levels of glucosamine, immunoreactive insulin, C-peptide, glucose and lipid indexes were measured in venous blood in investigated patients. In patients with MI without diabetes the highest concentrations of glucosamine, insulin and C-peptide were noted as compared to the results obtained from other groups of patients. In patients with diabetes, on the other hand, the highest glucose levels were noted as compared to the results of other patients. There were no statistically differences of lipid indexes between two groups of patients following MI. A negative correlation between glucosamine levels and glucose concentrations in patients without diabetes may suggest that glucose does not directly determine glucosamine levels. The returning of insulin levels to normal in patients with hyperinsulinemia (antidiabetic drugs) may play a role in the lowering of glucosamine induced peripheral insulin resistance.

This paper presents results of 3 weeks physical training on glucosamine level in serum of male patients after myocardial infarction (MI) aged between 38 and 61. Patients were randomised in two groups: the training group (n = 21), staying in Cardiac Rehabilitation Department and the control group (n = 11), discharged home for 3 weeks. Each group received identical dietary instructions. The training group performed exercises every day: on bicycle ergometer during 30 minutes (5 times a week), overall-conditioning exercises for 30 minutes daily and 30 to 60 minutes of walking each day. Before administering of the therapy and 3 weeks later all MI patients performed the bicycle ergometer exercise test until the ventilatory threshold was reached. Before that test and 3 minutes after its termination capillary and venous blood samples were drawn. In the capillary blood samples indices of acid-base balance, lactate level, and glucose level were determined. In venous blood samples the serum levels of immunoreactive insulin, C-peptide and glucosamine were determined as well as binding of 125I-insulin to erythrocyte receptors. Obtained results show that administered therapy increased physical fitness and decreased of glucosamine concentration, insulinaemia and insulin resistance.

In this study, we investigated the influence of glucose administration on binding and degradation of 125I-insulin by receptors on erythrocytes as well as on insulin and C-peptide serum levels in 15 patients after myocardial infarction and in 15 age-matched healthy persons. Venous blood samples were taken directly before and at 30, 60 and 120 minutes after oral administration of 75 g of glucose. In the collected blood samples serum glucose, insulin and C-peptide levels were determined. Binding and degradation of 125I-insulin by specific receptors on red blood cells were evaluated using the method described by Gambhir and modified by the authors. Serum insulin and C-peptide levels were significantly higher while binding of 125I-insulin to erythrocytes was decreased in patients after myocardial infarction. These results seem to support the hypothesis that insulin resistance and hyperinsulinism play a role in the pathogenesis of ischaemic heart disease. Impaired degradation of 125I-insulin during the oral glucose tolerance test in the patients after myocardial infarction indicates that insulin resistance is located at the receptor level.

Following administration of digitoxin, 1 mg intravenously, the pharmacokinetics of this glycoside were studied in eight healthy volunteers and in eight patients with hepatorenal insufficiency (mean creatinine clearance 19.6 +/- 2.9 ml/min; antipyrine clearance 25.6 +/- 3.2 ml/min; means +/- SEM). Liver cirrhosis of the patients was confirmed by liver biopsy. Plasma protein binding of digitoxin (means +/- SEM) was 95.1 +/- 0.7% in the patients and 95.6 +/- 1.2% in the volunteers (NS). Total body clearance of digitoxin was 0.0530 +/- 0.0040 ml/min/kg of body weight in the patients and 0.0547 +/- 0.0043 ml/min/kg of body weight in the healthy subjects (NS). When elimination half-lives of the patients and the volunteers were compared, there was also no significant difference (7.0 +/- 0.77 days in the patient group and 7.8 +/- 0.8 days in the volunteers). Our data concerning digitoxin kinetics in patients with hepatorenal insufficiency do not indicate an accumulation of the drug in these patients.