The measurement of frequency characteristics, like magnitude and phase, related to a specific transfer function of DC–DC converters, can be a difficult task – especially when the measured signal approaches the boundary of a small-signal model validity (i:e. 1/3 of the switching frequency fS). It is hard to find a paper where authors mention the measurement techniques they use to draw frequency characteristics. Meanwhile the presence of noise in the output signal does not enable to directly measure the gain and the phase shift between the input and output signals. In such situations additional analysis is required in order to achieve a reliable result. This paper contains a description of a few methods that can be used to analyse measured signals in order to determine the gain and the phase shift of a specific transfer function. They enable to verify mathematical models in a wide range of frequencies (up to 1/3 fS). The methods use signals measured in the time domain and can be implemented in mathematical software such as Matlab or Scilab.

The paper presents research on the capability of the residual magnetic field (RMF) measurement system to be applied to the railway inspection for the early non-destructive detection of defects. The metal magnetic memory (MMM) phenomena are analysed using normal component Hy of self-magnetic flux leakage (SMFL), and its tangential component Hx, as well as their respective gradients. The measurement apparatus is described together with possible factors that may affect the results of measurement. The Type A uncertainty estimation and repeatability tests were performed. The results demonstrate that the system may be successfully applied to detection of head check flaws.

A new attack against the Kirchhoff-Law-Johnson-Noise (KLJN) secure key distribution system is studied with unknown parasitic DC-voltage sources at both Alice’s and Bob’s ends. This paper is the generalization of our earlier investigation with a single-end parasitic source. Under the assumption that Eve does not know the values of the parasitic sources, a new attack, utilizing the current generated by the parasitic dc-voltage sources, is introduced. The attack is mathematically analyzed and demonstrated by computer simulations. Simple defense methods against the attack are shown. The earlier defense method based solely on the comparison of current/voltage data at Alice’s and Bob’s terminals is useless here since the wire currents and voltages are equal at both ends. However, the more expensive version of the earlier defense method, which is based on in-situ system simulation and comparison with measurements, works efficiently.

The paper presents a novel implementation of a time-to-digital converter (TDC) in field-programmable gate array (FPGA) devices. The design employs FPGA digital signal processing (DSP) blocks and gives more than two-fold improvement in mean resolution in comparison with the common conversion method (carry chain-based time coding line). Two TDCs are presented and tested depending on DSP configuration. The converters were implemented in a Kintex-7 FPGA device manufactured by Xilinx in 28 nm CMOS process. The tests performed show possibilities to obtain mean resolution of 4.2 ps but measurement precision is limited to at most 15 ps mainly due to high conversion nonlinearities. The presented solution saves FPGA programmable logic blocks and has an advantage of a wider operation range when compared with a carry chain-based time coding line.

Coordinate Measurement Machines (CMMs) have been extensively used in inspecting mechanical parts with higher accuracy. In order to enhance the efficiency and precision of the measurement of aviation engine blades, a sampling method of profile measurement of aviation engine blade based on the firefly algorithm is researched. Then, by comparing with the equal arc-length sampling algorithm (EAS) and the equi-parametric sampling algorithm (EPS) in one simulation, the proposed sampling algorithm shows its better sampling quality than the other two algorithms. Finally, the effectiveness of the algorithm is verified by an experimental example of blade profile. Both simulated and experimental results show that the method proposed in this paper can ensure the measurement accuracy by measuring a smaller number of points.

In this paper the current status of microplasma devices and systems made in the LTCC technology is presented. The microplasma characteristics and applications are described.We discuss the properties of the LTCC materials, that are necessary for reliable operation of the sources. This material is well known for its good reliability and durability in harsh conditions. Still, only a few examples of such microplasma sources are described. Some of them have been developed by the authors and successfully used for chemical analysis and synthesis.

The non-contact current measurement method with magnetic sensors has become a subject of research. Unfortunately, magnetic sensors fail to distinguish the interested magnetic field from nearby interference and suffer from gauss white noise due to the intrinsic noise of the sensor and external disturbance. In this paper, a novel adaptive filtering-based current reconstruction method with a magnetic sensor array is proposed. Interference-rejection methods based on two classic algorithms, the least-mean-square (LMS) and recursive-least-square (RLS) algorithms, are compared when used in the parallel structure and regular triangle structure of three-phase system. Consequently, the measurement range of RLS-based algorithm is wider than that of LMS-based algorithm. The results of carried out simulations and experiments show that RLS-based algorithms can measure currents with an error of around 1%. Additionally, the RLS-based algorithm can filter the gauss white noise whose magnitude is within 10% of the linear magnetic field range of the sensor.

Rotation modulation can significantly improve the navigation accuracies of an inertial navigation system (INS) and a strap-down configuration dominating in this type of INS. However, this style of construction is not a good scheme since it has no servo loop to counteract a vehicle manoeuvre. This paper proposes a rotary upgrading method for a rotational INS based on an inertially stabilized platform. The servo control loop is reconstructed on a four-gimbal platform, and it has the functions of providing both a level stability relative to the navigation frame and an azimuth rotation at a speed of 1:2◦/s. With the platform’s rotation, the observability and the convergence speed of the estimation for the initial alignment can be improved, as well as the biases of the gyroscopes and accelerometers be modulated into zero-mean periodic values. An open-loop initial alignment method is designed, and its detailed algorithms are delivered. The experiment result shows that the newly designed rotational INS has reached an accuracy of 0.38 n mile/h (CEP, circular error probable). The feasibility and engineering applicability of the designed scheme have been validated.

Design closure, i.e., adjustment of geometry parameters to boost the performance, is a challenging stage of antenna design process. Given complexity of contemporary structures, reliable parameter tuning requires numerical optimization and can be executed using local algorithms. Yet, EM-driven optimization is a computationally expensive endeavour and reducing its cost is highly desirable. In this paper, a modification of the trust-region gradient search algorithm is proposed for accelerated optimization of antenna structures. The algorithm is based on sparse updates of antenna sensitivities involving various methods that include the Broyden formula used for selected parameters, as well as dimensionality- and convergence-dependent acceptance thresholds which enable additional speedup, and make the procedure easy to tune for various numbers of antenna parameters. Comprehensive verification executed for a set of benchmark antennas delivers consistent results and considerable cost reduction of up to 60 percent with respect to the reference algorithm. Experimental validation is also provided.

On the basis of induction heating, radiation heating and liquid nitrogen refrigeration, high-temperature, medium-temperature, normal-temperature and low-temperature heating/refrigeration furnaces were designed, respectively. An apparatus with a wide temperature range and high accuracy applied to test oxidation resistance of materials has been developed based on the thermogravimetric method and the heat transfer principle. The apparatus consists of four heating/cooling systems, a specimen fixture positioning unit, a laser positioning unit, vertical and horizontal moving guide rails, and a high-precision weighing balance. The apparatus, based on the thermogravimetric method, is able to test oxidation resistance of materials. In the test, the temperature range was −180∼3000◦C (the highest temperature is determined by material properties). The temperature control accuracy was ±5◦C. The accuracy of on-line weighing was ±0:1 mg. The measurement uncertainty was 0.2 mg. Compared with other relevant devices, this apparatus has its own advantages: simple operation, wide heating/cooling temperature range, sufficient specimen heating, high sensitivity and precision, and short heating/cooling time. The experimental results show that the developed apparatus presented in this study not only can be used for isothermal thermogravimetric tests, but also for thermal cycling tests and multi-step oxidation tests. With the effective integration of multiple heating apparatus and refrigeration apparatus, the apparatus breaks through the limitations of the heating/cooling temperature range of the existing devices, accomplishes the high-precision oxidation resistance test of materials in a wide temperature range, and will play a great role in improving the research of materials.

Adaptive locomotion over difficult or irregular terrain is considered as a superiority feature of walking robots over wheeled or tracked machines. However, safe foot positioning, body posture and stability, correct leg trajectory, and efficient path planning are a necessity for legged robots to overcome a variety of possible terrains and obstacles.Without these properties, anywalking machine becomes useless. Energy consumption is one of the major problems for robots with a large number of Degrees of Freedom (DoF). When considering a path plan ormovement parameters such as speed, step length or step height, it is important to choose the most suitable variables to sustain long battery life and to reach the objective or complete the task successfully.We change the settings of a hexapod robot leg trajectory for overcoming small terrain irregularities by optimizing consumed energy and leg trajectory during each leg transfer. The trajectory settings are implemented as a part of hexapod robot simulation model and tested through series of experiments with various terrains of differing complexity and obstacles of various sizes. Our results show that the proposed energy-efficient trajectory transformation is an effective method for minimizing energy consumption and improving overall performance of a walking robot.

The study aimed to examine the use of Geomagnetic Anomaly Detection (GAD) to locate the buried ferromagnetic pipeline defects without exposing them. However, the accuracy of GAD is limited by the background noise. In the present work, we propose an approximate entropy noise suppression (AENS) method based on Variational Mode Decomposition (VMD) for detection of pipeline defects. The proposed method is capable of reconstructing the magnetic field signals and extracting weak anomaly signals that are submerged in the background noise, which was employed to construct an effective detector of anomalous signals. The internal parameters of VMD were optimized by the Scale–Space algorithm, and their anti-noise performance was compared. The results show that the proposed method can remove the background noise in high-noise background geomagnetic field environments. Experiments were carried out in our laboratory and evaluation results of inspection data were analysed; the feasibility of GAD is validated when used in the application to detection of buried pipeline defects.

As a result of the development of modern vehicles, even higher accuracy standards are demanded. As known, Inertial Navigation Systems have an intrinsic increasing error which is the main reason of using integrating navigation systems, where some other sources of measurements are utilized, such as barometric altimeter due to its high accuracy in short times of interval. Using a Robust Kalman Filter (RKF), error measurements are absorbed when a Fault Tolerant Altimeter is implemented. During simulations, in order to test the Nonlinear RKF algorithm, two kind of measurement malfunction scenarios have been taken into consideration; continuous bias and measurement noise increment. Under the light of the results, some recommendations are proposed when integrated altimeters are used.

The free-living Acanthamoeba sp. causes various diseases. Treatment of them is very difficult and not always effective because of encystation, making it highly resistant to antiamoebic drugs. Gram-positive bacteria Staphylococcus aureus, Gram-negative bacteria Escherichia coli, and an yeast Candida albicans also exhibit outstanding resistance to antimicrobial substances. The search for new natural amoebicidal and antimicrobial agents of plant origin is still of current interest. The aim of the study was to investigate the amoebicidal activity of the extracts obtained from tissue culture and a field-grown plant of Chaenomeles japonica against pathogenic trophozoites of Acanthamoeba spp. and antimicrobial effect against S. aureus, E. coli, and C. albicans. The extracts of C. japonica had an inhibitory effect on the proliferation of Acanthamoeba trophozoites as compared to the non-treated control. Among the crude extracts tested, the extract of leaves, from both shoot culture and the field-grown plant had remarkable amoebicidal action against the trophozoites but also antibacterial activity against Gram-positive bacteria Staphylococcus aureus. The extract from leaves from shoot culture, already on the second and third days of treatment, showed an antiamoebicidal effect at a concentration of 1 mg mL-1 (inhibition of trophozoites 87.5% and 91.8%, respectively). In addition to leaves from shoot culture (a conc. 5 mg mL-1, 2nd day inhibition of trophozoites 85.7% and 3rd day 97.2%), leaves from a field-grown plant (a conc. 5 mg mL-1, 2nd day 91.0% and 3rd day 94.4%) and callus (a conc. 5 mg mL-1, 2nd day 90.0% and 3rd day – 95.4%) also exhibited a good antiamoebicidal activity. Out of the four extracts, the extracts from leaves from both shoot culture and a field-grown plant were reported to be the most active against Gram-positive S. aureus, which was determined by the values of MIC = 5.0 mg mL-1 and MIC = 2.5 mg mL-1, respectively. The inhibitory potential depends on the yield and composition of mainly bioactive compounds: pentacyclic terpenoids (mainly betulinic, ursolic, and oleanolic acids) and polyphenols (mainly chlorogenic acid and its isomers, epicatechin, dimeric, and trimeric proanthocyanidins, quercetin and kaempferol derivatives).

Incidence of colonic atresia in living infants ranges from 1:5,000 to 1:60,000 (average 1:20,000). It constitutes 1.8 to 15% of all cases of atresia of the gastrointestinal tract. In 58.56–75% of all cases is right-sided. We aim, through the presentation of two cases of colonic atresia which we encountered and after systematic research of the current literature, at addressing three major issues: diagnostic approach, operative strategy and management of the prognostic parameters of the colonic atresia. The common parameter in these two cases was the early diagnosis, which played a significant role in the uncomplicated postoperative course. The first case was a type I sigmoid atresia. Contrast’s escape during contrast enema examination due to accidental rupture of the distal part of the colon led to diagnosis. Side-to-side anastomosis, restoration of the rupture and a central loop sigmoidostomy were urgently performed. The second case was a type III atresia at the level of the ascending colon, which was early diagnosed via pregenital ultrasonography, in which colonic dilation was depicted. Restoration of the intestinal continuity early after birth was performed at a time. In conclusion, we believe that early diagnosis, selection of the appropriate operative strategy and prompt recognition of potential post-operative complications, especially rupture of the anastomosis, contribute to the optimization of the prognosis in patients with colonic atresia.

I n t r o d u c t i o n: Fecal calprotectin (FC) rises significantly in intestinal inflammation accompanied by neutrophil activation — such as Clostridium diffi cile infection (CDI). The aim of the study was to evaluate the benefi t of FC testing in assessing the severity of CDI.

Ma t e r i a l s a n d M e t h o d s: The study group included 76 patients with CDI hospitalized in the Jagiellonian University Hospital in Krakow from July 2017 till January 2018. FC levels were measured using an EIA (Enzyme Immunoassay). Demographic, clinical information and blood tests were recorded using standardized data collection forms. The selection of patients into non-severe and severe groups was carried out in accordance with the ESCMID criteria (European Society of Clinical Microbiology and Infectious Diseases) and some modifications to those criteria were proposed.

R e s u l t s: The studied population included 76 patients (39 men and 37 women) with CDI aged from 24 to 98 years (mean: 72). Median calprotectin level was 739 (Q25–Q75: 612–799 μg/g), characteristic of patients with colitis. A statistically signifi cant diff erence in FC concentration in patients with severe vs non-severe CDI was observed (severe — 770 vs non-severe — 659 μg/g, p = 0.009). FC directly correlated with platelets level; however, no correlation between FC level and the blood parameters prognostic for CDI (leukocyte, neutrophil count, albumin, creatinine levels) was found.

C o n c l u s i o n: FC level is an indication of ongoing intestinal inflammation in CDI patients. FC level significantly correlated with CDI severity, which demonstrates that FC could serve as a predictive marker for assessing CDI severity.

I n t r o d u c t i o n: RANTES regulates leukocyte recruitment to areas affected by the inflammatory process. Microvesicles (MVs) belong to a subpopulation of extracellular vesicles and show proangiogenic potential by transferring bioactive molecules to target cells.

Obj e c t i v e s: The aim of this study was to determine the relationship between circulating proangiogenic factors (MVs and RANTES) and diabetes complications in patients with different severities of diabetic retinopathy (DR). CCR5 (CD195) receptors transported by annexin V-labeled MVs were also investigated. Patients and Methods: Diabetic patients (n = 61), among whom 35 had confirmed DR classified according to guidelines, and controls (n = 25) were included. MVs were isolated by centrifugation and analyzed using flow cytometry, RANTES was assessed by ELISA.

R e s u l t s: T h e study group diff ered from the control group with respect to BMI, age, heart rate and systolic blood pressure. Additionally, glucose and creatinine concentrations were signifi cantly increased: 5.30 [5.09–5.62] vs. 9.38 [7.48–11.55] (p<0.0001) mmol/l and 74.59 [64–84] vs. 89.00 [77.11–105.44] μmol/l (p = 0.0005), respectively. RANTES concentrations were significantly increased in diabetic patients compared to those of controls (15.5 (9.7–18.1) vs. 8.9 (0.9–14.6) μg/ml (p = 0.011)), and RANTES concentration significantly increased with respect to nonproliferative DR progression. Moreover, the number of CCR5-positive MVs was significantly increased in patients with heavy nonproliferative diabetic retinopathy (HNPDR) compared to those with soft nonproliferative DR (SNPDR): 1178 [836–2254] vs. 394 [275–799] counts/μl.

C o n c l u s i o n s: Correlation of RANTES concentrations with the stage of nonproliferative DR and the statistically significant dependence of CCR5-positive MVs with disease progression suggest that MVs and RANTES can be considered new biomarkers.

B a c k g r o u n d: Articular cartilage is highly-organized nonvascularized tissue which is responsible in humans for pressure absorption under load, as well as for the smoothness of the opposite tangential bone surfaces.

The purpose of our research is to study structural and functional features of articular cartilage at lightoptical level by using state-of-the-art research methods of bone-cartilage tissue.

M a t e r i a l a n d M e t h o d s: The study was conducted on samples of femoral heads. Hyperfine sections were subject to hematoxylin and eosin, Van Gieson’s and PAS staining. In order to identify the receptor profile of chondrocytes and the features of protein arrangement in extracellular matrix we undertook an immunohistochemical study.

R e s u l t s: An articular cartilage is quite organized tissue. As any other organ, it has parenchyma and stroma. Parenchyma is represented by one type of cells — chondrocytes, which, depending on how deep they are located in cartilage, have a different shape, size and functional features. The chondrocytes and extracellular matrix have different degrees of receptors expression.

C o n c l u s i o n s: Th e cartilage is being constantly self-renewed, what is manifested by means of a rather slow division of the surface-located chondrocytes and programmed death of dystrophic-modified cells. The features of extracellular matrix structure determine the originality of cell location in different areas of cartilage tissue. Due to synthesis of specific proteins, chondrocytes self-regulate properties of cartilage tissue.

The anatomy of the human temporal bone is complex and, therefore, poses unique challenges for students. Furthermore, temporal bones are frequently damaged from handling in educational settings due to their inherent fragility. This report details the production of a durable physical replica of the adult human temporal bone, manufactured using 3D printing technology. The physical replica was printed from a highly accurate virtual 3D model generated from CT scans of an isolated temporal bone. Both the virtual and physical 3D models accurately reproduced the surface anatomy of the temporal bone. Therefore, virtual and physical 3D models of the temporal bone can be used for educational purposes in order to supplant the use of damaged or otherwise fragile human temporal bones.

Alcohol is a recognized teratogen that affects various aspects of fetal development. Tissue that is particularly susceptible to its teratogenicity is neuronal tissue. The effect of prenatal alcohol exposure (PAE) on the central nervous system has been extensively studied, yet the knowledge on the influence of PAE on the autonomic nervous system is scarce. The purpose of this article is to review the current state of knowledge about the impact of PAE on the autonomic nervous system. Studies conducted on the PAE animal model have shown that prenatal alcohol exposure is associated with significant alterations in the autonomic nervous system, but the mechanisms and consequences are not yet clearly defined. It was established that PAE causes decreased heart rate variability (HRV) in fetal cardiotocography. Several studies have revealed that later, in infancy and childhood, reduced parasympathetic activity with or without compensating sympathetic activity is observed. This may result in behavioral and attention disorders, as well as an increased predisposition to sudden infant death syndrome. Both animal and human studies indicate that the relationship between PAE and autonomic dysfunction exists, however large, well-designed, prospective studies are needed to confirm the causal relationship and characterize the nature of the observed changes.

The musculocutaneous nerve (C5–C7) is a terminal branch of the lateral cord of the brachial plexus and provides motor innervation to the anterior compartment of arm muscles. Both the musculocutaneous and median nerve may show numerous anatomical variations. Keeping in mind possible aberrations in the course of the upper limb nerves may increase the safety and success rate of surgical procedures. The presented report is a detailed anatomical study of the fusion between the median and musculocutaneous nerve, supplemented by intraneural fascicular dissection. In the presented case, the musculocutaneous nerve was not found in its typical location in the axillary cavity and upper arm during the preliminary assessment. However, a careful intraneural fascicular dissection revealed that musculocutaneous nerve was fused with the median nerve and with its lateral root; Those nerves were surrounded by a common epineurium, however they were separable. The muscular branch to the biceps brachii muscle arose from the trunk ( fascicular bundle) dissected out from the median nerve and corresponding to the musculocutaneous nerve. Such variation may be of utmost clinical importance, especially during reconstructions of the brachial plexus or its branches.

I n t r o d u c t i o n: Hydronephrosis is an actual pediatric problem, affecting children in the anteand neonatal periods. Intrinsic stenosis is due to external obstruction and creates a pathophysiological basis of this urological pathology. Co-localization of ureter with a renal vasculature also could not be omitted from this point of view. Mesenchymal cells, partially telocytes, are important for local fibrosis development and hydronephrosis formation as well. In the current study, we focused on identification of telocytes in the human ureters to hypothesize their role in hydronephrosis pathophysiology.

M a t e r i a l a n d Me t h o d s: The samples were taken from 18 surgically treated patients with hydronephrosis (due to ureteral obstruction and crossing renal vessel). The control group consisted of 10 patients suffered from a non-obstructive disease of the urinary tract — predominantly renal tumors. Tissue samples from a ureter were stained for c-kit, tryptase, CD34 and PDGFRα to identify telocytes. Routine histology was performed to analyze tissue morphology, collagen deposits and mast cell’s profile.

R e s u l t s: Telocytes were detected in the ureteral wall. In patients with hydronephrosis we revealed decreasing density of telocytes, the prevalence of collagen, rise in mast cells amount and the ureteral wall thickening. In ureters with crossing renal vessels as a primary etiologic factor more telocytes have been observed in comparison with the obstructive hydronephrosis.

C o n c l u s i o n s: A declined density of telocytes accompanied hydronephrosis development. Increased number of mast cells in the ureteral wall reflects a local inflammation, while detailed observation of collagen/muscle deposits and density of telocytes reveal a difference depended on etiologic factor (obstruction or crossing vessel) in patients with hydronephrosis.

Significant impact factor and psycho-emotional stress in the etiology of dysfunction indicate the need of the routine approach in the treatment of patients with temporomandibular joint disorders to be changed. The aim of the study was to obtain data, documented test results as to the efficiency of progressive muscle relaxation in the treatment of pain caused by temporomandibular joint disorders, as a supplement to previous methods using occlusal splint and other physical therapies. The study included 100 patients of both sexes, aged from 20 to 35 years who were diagnosed with pain due to temporomandibular joint disorders accompanied with high muscle tension of musticatory muscles which were treatment by relaxation therapy. All patients underwent physical examination, specialized functional examination of the masticatory system in accordance with the Polish version of the study RDC/TMD (The Research Diagnostic Criteria of Temporomandibular Disorders, Axis I — physical assessment, Axis II — assessment of psychosocial status and pain — related disability) and assessment of psycho emotional factor and stress, based on the survey developed for their own purpose. The results of the research were obtained using specialized statistical package “R” i386 3.2.3. The results of examinations aft er relaxation therapy showed a signifi cant reduction in the intensity of myofascial pain in all patients. Progressive muscle relaxation can be successfully used as an supportive therapy treatment of patient with dysfunction.