Biomass valorization toward sustainable asphalt pavements: Progress and prospects

To cope with the global climate crisis and assist in achieving the carbon neutrality, the use of biomass materials to fully or partially replace petroleum-based products and unrenewable resources is expected to become a widespread solution. Based on the analysis of the existing literature, this paper firstly classified biomass materials with potential application prospects in pavement engineering according to their application and summarized their respective preparation methods and characteristics. The pavement performance of asphalt mixtures with biomass materials was analyzed and summarized, and the economic and environmental benefits of bio-asphalt binder were evaluated. The analysis shows that pavement biomass materials with potential for practical application can be divided into three categories: bio-oil, bio-fiber, and bio-filler. Adding bio-oil to modify or extend the virgin asphalt binder can mostly improve the low temperature performance of asphalt binder. Adding styrene-butadienestyrene (SBS) or other preferable bio-components for composite modification will have a further improved effect. Most of the asphalt mixtures prepared by using bio-oil modified asphalt binders have improved the low temperature crack resistance and fatigue resistance of asphalt mixtures, but the high temperature stability and moisture resistance may decrease. As a rejuvenator, most bio-oils can restore the high and low temperature performance of aged asphalt and recycled asphalt mixture, and improve fatigue resistance. Adding bio-fiber could significantly improve the high temperature stability, low temperature crack resistance and moisture resistance of asphalt mixtures. Biochar as a bio-filler can slow down the asphalt aging process and some other bio-fillers can improve the high temperature stability and fatigue resistance of asphalt binders. Through calculation, it is found that the cost performance of bio-asphalt has the ability to surpass conventional asphalt and has economic benefits. The use of biomass materials for pavements not only reduces pollutants, but also reduces the dependence on petroleum-based products. It has significant environmental benefits and development potential.

Central systolic blood pressure (cSBP) to brachial systolic blood pressure (brachSBP) ratio reproducibility during antihypertensive therapy

OBJECTIVES

Higher CSBP than brachial SBP in individual patient increases cardiovascular (CV) risk. For follow-up it is important to assess the reproducibility of such measurements. The aim of this study was to assess the reproducibility of these differences, expressed as a CSBP/BrachSBP ratios.

SUBJECTS AND METHODS

Eighty-three patients on antihypertensive therapy were analysed for the reproducibility of such ratios after time interval of several month up to several years. For CSBP estimation, we used the Arteriograph (Tensiomed Ltd.), based on blood pressure measurements by cuff on oscillometric principle, using pulse wave analysis (PWA) for assessment of CSBP.

RESULTS

The proportion of patients retained the same characteristics (either higher central or higher peripheral SBP) between the first and second measurement was 71.1 %. The association between 1st and 2nd measurement, was statistically significant, p < 0.001.

CONCLUSION

In our study, a high proportion (60 %) of treated hypertensive patients had CSBP higher than brachial SBP, which may adversely influence their prognosis. This characteristic is highly reproducible. Taking into the account these differences may increase the exactness of CV risk estimation and may contribute to explanation of residual risk of individual patient (Tab. 3, Fig. 1, Ref. 28).

Central systolic blood pressure increases with aortic stiffness

OBJECTIVES

Central systolic blood pressure (CSBP) is the pressure in the root of aorta, which directly influences organs such as brain, heart and kidneys and is related to organ damage. Its value increases with the aortic stiffness. The aim of this study was to analyze the relationships of CSBP to aortic stiffness parameters.

METHODS

Central blood pressure (BP) and related parameters were measured by Arteriograph, working based on oscillometric principle, using pulse wave analysis (PWA) approach. We examined 123 patients (69 females, 54 males) with a primary hypertension.

RESULTS

Using a linear correlation analysis, we found that CSBP was correlated to aortic pulse wave velocity (PWV), aortic and brachial pulse pressure (PP), aortic augmentation index, return time of reflected pressure wave (RT) and aortic and brachial augmentation indexes. Multivariate analysis defines the aortic pulse pressure (PPao) as the most powerful parameter influencing CSBP. By an individual analysis of BP in each patient separately, we defined two different types of central hemodynamics; those with a higher CSBP than brachial SBP occur in stiffer aorta.

CONCLUSION

The CSBP increases with aortic PP, the most powerful stiffness parameter of aorta. Higher CSBP than brachial SBP usually accompanies a stiffer aorta (Tab. 5, Ref. 19).

Holter ECG findings in diabetics with medial arterial calcification

OBJECTIVES

Medial arterial calcification (MAC) is a nonobstructive condition leading to reduced arterial compliance. The disease most commonly occurs in diabetes mellitus. Decreased ankle-brachial pressure index (ABI) is a well-known marker of increased cardiovascular mortality. However, also the values of ABI above 1.3, typical in MAC, are associated with increased mortality.

METHODS

By means of Holter ECG monitoring, we investigated 41 patients (25 men, 16 women) with mean age of 59±8 years, suffering of type 2 diabetes mellitus and identified as having MAC, and Holter ECG monitoring with an average duration of recording 22.36 hours, was carried out by GE-Marquette MARS ECG Holter system.

RESULTS

We found frequent incidence of cardiac arrhythmias and myocardial ischemia in 22 patients (53.7 %). Only 19 patients (46.3 %) had normal Holter ECG recordings. ABI values were significantly higher in patients with abnormal ECG Holter recordings.

CONCLUSION

Our results confirm the importance of ABI estimation in clinical practice. As the central goal of therapy for patients with myocardial ischemia and/or complex forms of cardiac arrhythmias is the reduction or elimination of these episodes. Ambulatory Holter ECG monitoring plays an important role in the management of these patients (Tab. 7, Ref. 16).

Atherogenic versus non-atherogenic lipoprotein profiles in healthy individuals. is there a need to change our approach to diagnosing dyslipidemia?

The electrophoretic separation of lipoproteins on polyacrylamide gels enables the quantification of nonatherogenic and atherogenic plasma lipoproteins including small dense low density lipoprotein (sdLDL) particles, which represent the atherogenic lipoprotein subpopulations in plasma. This methodology could help distinguish between nonatherogenic hyperlipidemia, normolipidemia with an atherogenic lipoprotein profile, non-atherogenic normolipidemia, and atherogenic hyperlipidemia. According to our pilot research of a normolipidemic population, the atherogenic lipoprotein profile might be present in about 6% of normolipidemic young healthy individuals. Therefore, if confirmed by other studies, it will be necessary to consider a different diagnostic approach and risk stratification for patients with atherogenic normolipidemia (as well as non-atherogenic hypercholesterolemia).

Risk factors in diabetic nephropathy progression at present

Diabetic nephropathy is becoming an increasingly important cause of morbidity and mortality worldwide as a consequence of increasing prevalence of type 2 diabetes and obesity. The glomeruli of patients with diabetes are characterized by glomerular hypertrophy, widening of the glomerular basement membrane, mesangial expansion, podocytopenia leading to nodular (Kimmelstiel-Wilson) glomerulosclerosis. Many studies have reported the initiation and progression of incipient nephropathy in type 1 diabetes patients, but only limited data are available in type 2 diabetes patients. The information on the risk factors and conversion rate of normal renal function to proteinuria in type 2 diabetes patients is sparse. In this report, we review risk factors of diabetic nephropathy progression in type 2 diabetes patients (Ref. 50).

Vasculitides as a rare cause of intermittent claudication

Intermittent claudication of the lower extremities is a common symptom described in older patients with atherosclerotic peripheral arterial disease. Peripheral arterial disease due to atherosclerosis is known to be associated with a higher risk of myocardial infarction, stroke and all-cause mortality. However, if intermittent claudication appears in a younger group of patients or older patients in absence of traditional risk factors for atherosclerosis such as smoking, dyslipidemia, arterial hypertension and diabetes mellitus other causes than atherosclerosis must be considered. These conditions include vasculitides, fibromuscular dysplasia, cystic adventitial disease, excentric vascular compression by tumor, popliteal artery entrapment syndrome, trauma or dissection. Vasculitides present a heterogenous group of disorders characterized by inflammatory destruction of blood vessels. Although often not a leading symptom intermittent claudication could be a part of a clinical picture in giant-cell arteritis, Takayasu´s arteritis, Buerger´s disease, polyarteritis nodosa or Behçet disease. Limb claudication is usually of rapid onset, progressive and bilateral. Each of the mentioned vasculitides is specific in ethiology and clinical manifestation with a variable prognosis for the patient. Increased awareness of the presence of different causes of limb claudication and their early diagnosis with a prompt initiation of appropriate treatment may help to avoid clinical progression that can lead to vascular surgery or even limb loss (Ref. 37).

Influence of infection on clinical picture of diabetic foot syndrome

The aim of our study was to analyse the foot infections in diabetic patients. We analysed foot ulcerations in 124 diabetics who attended outpatient foot clinic, or were hospitalized in the period from 1996 to 2006. Basic neuropathy screening examination was made with cotton wisp, pin-prick, tuning fork, and monofilament. For evaluation of leg ischemia, besides the evaluation of the presence of pedal pulses, the ankle-brachial pressure index was measured. If the infection of foot ulceration was clinically present, bacteriology examinations was performed. In the case of deep wound infection, x-ray examination was made. If bone destruction was present, osteomyelitis was diagnosed by technecium bone scanning and by technecium-labelled leukocyte scan. Deformation and destruction of the bone without infection was appoited as Charcot neuroarthropathy. Foot ulcer infection was found in 58 % diabetic patients, wounds were more often deep (80 %). Infection was not associated with special location of foot ulcer. Two-third of the total infected wounds were associated with leg ischemia and 30.6 % of infected ulcer ended with leg amputation. More foot ulcer infections were found in the diabetics with HbAlc over 8 %. Infection was coupled with diabetic retinopathy (in 63 % patients) (p=0.023), and also with diabetic nephropathy (in 66 % patients) (p=0.012). Bacteriology examination revealed most often Staphylococci (45.8 %), antibiotic therapy was made most often with chinolones. Osteomyelitis was present in 34.7 % of foot ulcer infections. In 14 diabetics (56 %) after antibiotic therapy it was not necessary to perform a leg amputation. HbAlc seems to be a significant predictor of osteomyelitis (p<0.02; OR=1.76). In conclusion, we confirmed that diabetic foot infections, especially on ischemic leg, in diabetics with poor metabolic control and chronic diabetic microvascular complications, are associated with a higher risk of leg amputations. Further, it is possible to cure osteomyelitis successfully without surgery in more than half the cases (Tab. 1, Ref. 24). Full Text in free PDF www.bmj.sk.

The importance of ambulatory blood pressure monitoring (ABPM) in patients with tinnitus

Arterial hypertension belongs to the most important factors of origin and lasting of tinnitus. We have studied 18 subjects suffering from tinnitus without the history of diagnosed or treated arterial hypertension. ABPM method was used for diagnosing arterial hypertension. 12 patients (66%) fulfilled the criteria for arterial hypertension. Our results illustrate that arterial hypertension diagnosis is devoted an insufficient attention in patients with tinnitus. ABPM should therefore be used in all patients with tinnitus, immediately after its manifestation and also repeatedly during its course. With early diagnosis and treatment of hypertension, some complications, such as myocardial infarction, stroke, heart and/or kidney failure can be thus prevented (Tab. 1, Fig. 5, Ref. 10). Full Text in free PDF www.bmj.sk.

[Obesity and arterial hypertension]

Obesity is an independent risk factor for the development and progression of hypertension, cardiovascular disease and chronic kidney disease. There is growing evidence that obesity and associated metabolic abnormalities may induce and accelerate renal complications in essential hypertension. The clustering of obesity and other features of the metabolic syndrome might have important implications for prevention, particularly with regard to whether interventions targeted at visceral obesity would have beneficial effects on cardiovascular and renal morbidity.

[Prevention and treatment of extremity vascular ischemic disease]

Extremitovascular ischemic disease (peripheral arterial disease of extremities - PAD) is an important manifestation of systemic atherosclerosis and other arterial diseases of vascular system. The lower the anklebrachial pressure index, the greater the risk of serious cardiovascular events (e.g., acute myocardial infarction, stroke). Prevention and treatment ofextremitovascular disease is discussed in this article.

[Characteristics of foot ulcers in diabetic patients]

INTRODUCTION

Diabetic foot syndrome is often presented as a skin lesion in diabetics. The aim of our study was to analyse foot ulcerations in diabetics, together with ethiopatogenesis, location and grade of impairment.

METHODS

We analysed foot ulcerations in 124 diabetics who attended outpatient foot clinic, or were hospitalized in the period from 1996 to 2006. Basic neuropathy screening examination was made with cotton wisp, pin-prick, tuning fork, and monofilament. Beside the evaluation of the presence of pedal pulses, the ankle-brachial pressure index was measured. If the infection of foot ulceration was present, bacteriology examinations was performed. Wagner and University of Texas classifications of foot ulcerations were applied, moreover, location of ulcerations was analysed.

RESULTS

Neuropathic ulcer was diagnosed in 46 patients of the total number of 124 (37%), neuroischemic in 76 patients (61%) and pure ischemic ulcer only in 2 patients (2%). Neuropathy was present in 122 (98%) patients with diabetic foot, limb ischemia in 78 patients (63%). Fifty four per cent of foot ulcers were located on toes and 43% ulcers on plantar surface. Foot ulcer infection was detected in 72 patients (58%). We found 48 superficial ulcers (38.7%) and 76 deep ulcers (61.3%). In diabetics without foot ischemia and infection 39% deep ulcers were present whereas in the group with ischemia and infection the proportion amounted to 80% (p < 0.05).

CONCLUSION

Diabetic foot syndrom was present more often in type-2 diabetics with longer disease duration, in those on insulin treatment, in men of older age, further in the diabetics with pure glycemic control and/or with chronic microvascular diabetic complications.

Photosynthetic activity of homoiochlorophyllous desiccation tolerant plant Haberlea rhodopensis during dehydration and rehydration

The functional state of the photosynthetic apparatus of flowering homoiochlorophyllous desiccation tolerant plant Haberlea rhodopensis during dehydration and subsequent rehydration was investigated in order to characterize some of the mechanisms by which resurrection plants survive drought stress. The changes in the CO2 assimilation rate, chlorophyll fluorescence parameters, thermoluminescence, fluorescence imaging and electrophoretic characteristics of the chloroplast proteins were measured in control, moderately dehydrated (50% water content), desiccated (5% water content) and rehydrated plants. During the first phase of desiccation the net CO2 assimilation decline was influenced by stomatal closure. Further lowering of net CO2 assimilation was caused by both the decrease in stomatal conductance and in the photochemical activity of photosystem II. Severe dehydration caused inhibition of quantum yield of PSII electron transport, disappearance of thermoluminescence B band and mainly charge recombination related to S2QA- takes place. The blue and green fluorescence emission in desiccated leaves strongly increased. It could be suggested that unchanged chlorophyll content and amounts of chlorophyll-proteins, reversible modifications in PSII electron transport and enhanced probability for non-radiative energy dissipation as well as increased polyphenolic synthesis during desiccation of Haberlea contribute to drought resistance and fast recovery after rehydration.

Aplasia cutis congenita after methimazole exposure in utero

We describe a patient who was exposed to the antithyroid drug methimazole during the first 6 weeks of gestation and was born prematurely with scalp and skull defects associated with facial asymmetry. A review of the literature seems to support the hypothesis that methimazole is a potential teratogen. Although the risk of birth defects is low with clinically applied doses of the drug, it cannot be regarded as safe and should therefore be avoided in the treatment of pregnant women.

[Holter ECG monitoring during gastroscopy in patients with chronic atrial fibrillation]

The authors present their results obtained with Holter ECG monitoring during gastroscopy in a group of patients with chronic atrial fibrillation. In one third of the group, endoscopic procedure induced complex cardiac arrhythmias and also significant myocardial ischaemia. These findings can have serious hemodynamic consequences. Therefore previous evaluation of cardiac findings and extemporaneous for urgent therapeutical intervention are necessary. To these patients, especially to those with cardiac arrhythmias--including atrial fibrillation--it is necessary to devote intensified attention and precaution with interdisciplinary co-operation.