ASSESSMENT OF BIOCLIMATIC VARIABILITY ON REGIONAL AND LOCAL SCALES IN CENTRAL EUROPE USING UCTI

The paper presents new approach to study spatial and temporal variability of bioclimatic conditions. The new Universal Thermal Climate Index UTCI was applied in this purpose. UTCI bases on multi-note human heat balance Fiala model and it represents heat stress in man caused by meteorological conditions. The seasonal and regional variability of bioclimate was assessed on an example of selected European cities: Kołobrzeg, Warsaw, Świeradów, Prague, Budapest, Ljubljana and Milan. Daily meteorological data (air temperature, vapour pressure, wind speed and total cloud cover) for the period 1991-2000 was used in this purpose. Annual course of UTCI values and the frequency of UTCI categories are discussed. Significant regional differences between studied cities were found. The results confirm frequent occurrence of unfavourable thermal conditions in Mediterranean region in summer months. However, heat stress was frequently observed in summer in all compared stations. Spatial variability in detail local scale was studied on the examples of selected regions of Poland (Mazovia Lowland, Warsaw). The results show that occurrence of strong heat stress depends not only on general meteorological conditions but also on land use. The greatest heat stress is observed mostly in urbanised areas especially in the central parts of cities and inside industrial districts

Impact force generator: self-synchronization and regularity of motion

Abstract Impacts in multibody mechanical systems are an object of interest for many scientists in the world. In this paper, we present a principle of operation of the impact force generator being an element of the rotor of the heat exchanger. In this machine, step disturbances of the rotational velocity of the generator cause rapid changes of the rotational velocity of the exchanger rotor, which leads to the intensi®cation of the heat exchange process. We show the phenomenon of self-synchronization, regular motion of the system, and in a special case: chaotic motion of the rotor.

3D Raman imaging of systemic endothelial dysfunction in the murine model of metastatic breast cancer

It was recently reported in the murine model of metastatic breast cancer (4T1) that tumor progression and development of metastasis is associated with systemic endothelial dysfunction characterized by impaired nitric oxide (NO) production. Using Raman 3D confocal imaging with the analysis of the individual layers of the vascular wall combined with AFM endothelial surface imaging, we demonstrated that metastasis-induced systemic endothelial dysfunction resulted in distinct chemical changes in the endothelium of the aorta. These changes, manifested as a significant increase in the protein content (18 %) and a slight decrease in the lipid content (4 %), were limited to the endothelium and did not occur in the deeper layers of the vascular wall. The altered lipid to protein ratio in the endothelium, although more pronounced in the fixed vascular wall, was also observed in the freshly isolated unfixed vascular wall samples in the aqueous environment (12 and 7 % change of protein and lipid content, respectively). Our results support the finding that the metastasis induces systemic endothelial dysfunction that may contribute to cancer progression

Modification of internal hernia classification system after laparoscopic Roux-en-Y bariatric surgery

INTRODUCTION: The occurrence of internal hernia is not an uncommon late complication following the laparoscopic bariatric Roux-en-Y gastric bypass procedure. In some instances, it can be life threatening if not treated in a timely manner. Although there are numerous publications in the literature addressing internal hernia, they are mostly retrospective, and focus mainly on describing the different reconstructive orientation as far as the bowel is concerned. AIM: Our study aim is to address the relationship between the three basic elements of internal hernia, namely: intestinal mesentery defect, the involved intestine and herniated loop direction. Although a developed and widely accepted classification system of internal hernia has not been established yet, we hope this study can help the system to be established. MATERIAL AND METHODS: We studied all patients who underwent revision bariatric operations in the Freiburg and Lübeck University Hospitals (2007–2013). A single surgeon performed and documented all revision procedures for internal hernia. The post-operative follow-up period is up to 6 years. All patients with internal hernias were included whether their primary surgery was performed in our center or performed in other institutions, being referred to our center for further management. The presence of hernia defect, the type of herniated intestinal loop and the direction by which the herniated intestinal loop migrated were analyzed. RESULTS: Twenty-five patients with internal hernia were identified; in 2 patients more than one hernia type coexisted. The most frequent constellation of internal hernias was BP limb herniation into the Brolin space and migrating from left to right direction (28%). The highest incidence of internal hernia was found to be following Roux-en-Y gastric bypass (68%); the biliopancreatic limb (BP) limb was the most commonly involved intestine (51.9%). The incidence of Petersen hernia was the highest (59.3%), and left-right direction was more common. The most common hernia direction of the biliopancreatic limb was from left to right (92.6%), but alimentary limb (AL; 57.1%) and common channel (CC; 66.7%) often favor the other course. CONCLUSIONS: There are existing different types of internal hernias after bariatric operations including separate mesenterial spaces, various intestine parts and herniation direction. Our SDL classification system may offer a useful pathway that facilitates the understanding, and systematic approach to internal hernia, which can be used by bariatric quality registers

Nonlinear dynamic analysis of an optimal particle damper

We study the dynamical behavior of a single degree of freedom mechanical system with a particle damper. The particle (granular) damping was optimized for the primary system operating condition by using an appropriate gap size for a prismatic enclosure. The particles absorb the kinetic energy of the vibrating structure and convert it into heat through the inelastic collisions and friction. This results in a highly nonlinear mechanical system. Considering linear signal analysis, state space reconstruction, Poincar\'e sections and the determination of maximal Lyapunov exponents, the motion of the granular system inside the enclosure is characterized for a wide frequency range. With the excitation frequency as control parameter, either regular and chaotic motion of the granular bed are found and their influence on the damping is analyzed.Comment: 18 pages, 8 figures. arXiv admin note: text overlap with arXiv:1105.030

Use of control to maintain period-1 motions during wind-up or wind-down operations of an impacting driven beam

We consider the dynamical response of a thin beam held fixed at one end while excited by an external driving force. A motion limiting constraint, or stop, causes the beam to impact. During wind-up or wind-down operations, in which the driving frequency is continuously altered, the system can undergo complicated motions close to the value of frequency at which impacts may first occur, the grazing bifurcation. In this region, the beam may experience several impacts within a long period-repeating solution or even chaotic behavior which, in practical terms, may be undesirable to the long-term integrity of the system. The first task is to identify the zones in the space of parameters (forcing amplitude or, alternatively, the gap between the beam and the stop) in which period-1 motions can be guaranteed. In this paper, in the areas in which complicated or chaotic motion occurs, a control strategy is proposed which stabilises unstable period-1 motions. As a consequence, numerical simulations indicate that, for any choice of parameter in the range, simple period-1 motions can be maintained, limiting the number of impacts (together with their velocity)

Deriving the operational procedure for the Universal Thermal Climate Index (UTCI)

The Universal Thermal Climate Index (UTCI) aimed for a one-dimensional quantity adequately reflecting the human physiological reaction to the multi-dimensionally defined actual outdoor thermal environment. The human reaction was simulated by the UTCI-Fiala multi-node model of human thermoregulation, which was integrated with an adaptive clothing model. Following the concept of an equivalent temperature, UTCI for a given combination of wind speed, radiation, humidity and air temperature was defined as the air temperature of the reference environment, which according to the model produces an equivalent dynamic physiological response. Operationalising this concept involved (1) the definition of a reference environment with 50% relative humidity (but vapour pressure capped at 20 hPa), with calm air and radiant temperature equalling air temperature and (2) the development of a one-dimensional representation of the multivariate model output at different exposure times. The latter was achieved by principal component analyses showing that the linear combination of 7 parameters of thermophysiological strain (core, mean and facial skin temperatures, sweat production, skin wettedness, skin blood flow, shivering) after 30 and 120 min exposure time accounted for two-thirds of the total variation in the multi-dimensional dynamic physiological response. The operational procedure was completed by a scale categorising UTCI equivalent temperature values in terms of thermal stress, and by providing simplified routines for fast but sufficiently accurate calculation, which included look-up tables of pre-calculated UTCI values for a grid of all relevant combinations of climate parameters and polynomial regression equations predicting UTCI over the same grid. The analyses of the sensitivity of UTCI to humidity, radiation and wind speed showed plausible reactions in the heat as well as in the cold, and indicate that UTCI may in this regard be universally useable in the major areas of research and application in human biometeorology