Medical staff monitoring in interventional cardiology: over apron dosemeter placement based on measurements and simulations.

Interventional cardiology is characterized by high radiation exposure for both the patient and the operator. Adequate shielding and monitoring of the operator are fundamental to comply with radiation protection principles. In a previous work, the effect on the dose of the dosemeter position on the chest was studied. In this paper, the investigation has been completed, employing an anthropomorphic thorax phantom, equipped with arms. Although there are differences between the Monte Carlo simulations and the measurements, similar trends are observed, showing that the reduction in dose, due to the arms, is between 20 and 60%, compared with the situation without arms. For that reason, considering a dosemeter placed on the chest, the upper position, which is the least affected by the arms, should be preferred while the extreme lateral position, near the armpit, should be avoided.

Robust SrTiO3 Passivation of Silicon Photocathode by Reduced Graphene Oxide for Solar Water Splitting.

Development of a robust photocathode using low-cost and high-performing materials, e.g., p-Si, to produce clean fuel hydrogen has remained challenging since the semiconductor substrate is easily susceptible to (photo)corrosion under photoelectrochemical (PEC) operational conditions. A protective layer over the substrate to simultaneously provide corrosion resistance and maintain efficient charge transfer across the device is therefore needed. To this end, in the present work, we utilized pulsed laser deposition (PLD) to prepare a high-quality SrTiO3 (STO) layer to passivate the p-Si substrate using a buffer layer of reduced graphene oxide (rGO). Specifically, a very thin (3.9 nm ∼10 unit cells) STO layer epitaxially overgrown on rGO-buffered Si showed the highest onset potential (0.326 V vs RHE) in comparison to the counterparts with thicker and/or nonepitaxial STO. The photovoltage, flat-band potential, and electrochemical impedance spectroscopy measurements revealed that the epitaxial photocathode was more beneficial for charge separation, charge transfer, and targeted redox reaction than the nonepitaxial one. The STO/rGO/Si with a smooth and highly epitaxial STO layer outperforming the directly contacted STO/Si with a textured and polycrystalline STO layer showed the importance of having a well-defined passivation layer. In addition, the numerous pinholes formed in the directly contacted STO/Si led to the rapid degradation of the photocathode during the PEC measurements. The stability tests demonstrated the soundness of the epitaxial STO layer in passivating Si against corrosion. This study provided a facile approach for preparing a robust protection layer over a photoelectrode substrate in realizing an efficient and, at the same time, durable PEC device.

Tiling the Silicon for Added Functionality: PLD Growth of Highly Crystalline STO and PZT on Graphene Oxide-Buffered Silicon Surface.

The application of two-dimensional (2D) materials has alleviated a number of challenges of traditional epitaxy and pushed forward the integration of dissimilar materials. Besides acting as a seed layer for van der Waals epitaxy, the 2D materials─being atom(s) thick─have also enabled wetting transparency in which the potential field of the substrate, although partially screened, is still capable of imposing epitaxial overgrowth. One of the crucial steps in this technology is the preservation of the quality of 2D materials during and after their transfer to a substrate of interest. In the present study, we show that by honing the achievements of traditional epitaxy and wet chemistry a hybrid approach can be devised that offers a unique perspective for the integration of functional oxides with a silicon platform. It is based on SrO-assisted deoxidation and controllable coverage of silicon surface with a layer(s) of spin-coated graphene oxide, thus simultaneously allowing both direct and van der Waals epitaxy of SrTiO3 (STO). We were able to grow a high-quality STO pseudo-substrate suitable for further overgrowth of functional oxides, such as PbZr1-xTixO3 (PZT). Given that the quality of the films grown on a reduced graphene oxide-buffer layer was almost identical to that obtained on SiC-derived graphene, we believe that this approach may provide new routes for direct and "remote" epitaxy or layer-transfer techniques of dissimilar material systems.

Assessment of the Frequency, Causes, Degree and Consequences of Violence against Health Workers in Psychiatric Institutions.

(1) Background: The prevalence of workplace violence within the health sector varies between 50 and 88%. Depending on the health care environment, the percentages mentioned can be much higher. (2) The aim of this study was to determine the prevalence, characteristics, factors, and consequences of violence against healthcare workers (physicians, nurses, and technicians) in psychiatric institutions in the Republic of Serbia. Additionally, this study should validate the Serbian version of the aggression questionnaire, which could be a significant tool in recognizing and assessing any type of violence against health care workers in psychiatric institutions. (3) Methods: This study was designed as an observational questionnaire study that included 191 health workers (physicians, medical technicians, workers in kitchens or maintenance, and others) from three psychiatric institutions. As an instrument, this study validated and used the Serbian version of the aggression standardized questionnaire. We observed the primary and secondary outcomes of potential violence in psychiatric institutions against healthcare workers using different parameters. (4) Results: The internal consistency of each item as well as the instrument was very good (the mean Cronbach alfa = 0.91). A total of 104 of the participants never experienced physical violence, while more than five times that had 20 health workers (10.5%). We observed the statistical significance of gender, age, working status (permanent/limited) and professional status (physician/medical technician/worker etc.) on physical attack incidence. (5) Conclusions: The incidence of violence against healthcare workers is very high, especially in terms of physical assault and threats in the workplace. The majority of the victims were women who work as medical technicians, attacked by male patients with unknown motivation. A number of changes in the structure and organizational culture of the hospital are required. All hospital employees, employers, patients, and their families share responsibility for the creation of a safe workplace.

Strain-Engineered Metal-to-Insulator Transition and Orbital Polarization in Nickelate Superlattices Integrated on Silicon.

Epitaxial growth of SrTiO3 (STO) on silicon greatly accelerates the monolithic integration of multifunctional oxides into the mainstream semiconductor electronics. However, oxide superlattices (SLs), the birthplace of many exciting discoveries, remain largely unexplored on silicon. In this work, LaNiO3 /LaFeO3 SLs are synthesized on STO-buffered silicon (Si/STO) and STO single-crystal substrates, and their electronic properties are compared using dc transport and X-ray absorption spectroscopy. Both sets of SLs show a similar thickness-driven metal-to-insulator transition, albeit with resistivity and transition temperature modified by the different amounts of strain. In particular, the large tensile strain promotes a pronounced Ni 3 d x 2 - y 2 orbital polarization for the SL grown on Si/STO, comparable to that reported for LaNiO3 SL epitaxially strained to DyScO3 substrate. Those results illustrate the ability to integrate oxide SLs on silicon with structure and property approaching their counterparts grown on STO single crystal, and also open up new prospects of strain engineering in functional oxides based on the Si platform.

Integration of Single Oriented Oxide Superlattices on Silicon Using Various Template Techniques.

To benefit from the diverse functionalities of perovskite oxides in silicon-based complementary metal oxide semiconductor (CMOS) technology, integrating oxides into a silicon platform has become one of the major tasks for oxide research. Using the deposition of LaMnO3/SrTiO3 (STO) superlattices (SLs) as a case study, we demonstrate that (001) single oriented oxide SLs can be integrated on Si using various template techniques, including a single-layer buffer of STO prepared by molecular beam epitaxy (MBE) and pulsed laser deposition, a multilayer buffer of Y-stabilized zirconia/CeO2/LaNiO3/STO, and STO-coated two-dimensional nanosheets of Ca2Nb3O10 (CNO) and reduced graphene oxide. The textured SL grown on STO-coated CNO nanosheets shows the highest crystallinity, owing to the small lattice mismatch between CNO and STO as well as less clamping from a Si substrate. The epitaxial SL grown on STO buffer prepared by MBE suffers the largest thermal strain, giving rise to a strongly suppressed saturation magnetization but an enhanced coercive field, as compared to the reference SL grown on an STO single crystal. These optional template techniques used for integrating oxides on Si are of significance to fulfill practical applications of oxide films in different fields.

Absorbed dose in the operator's brain in interventional radiology practices: evaluation through KAP value conversion factors.

In order to address the recent concerns over a possible increasing in brain tumour mortality among interventional radiologists and cardiologist, this work evaluated the exposure conditions of the operator's brain during interventional procedures using Monte Carlo simulations with anthropomorphic phantoms. The absorbed doses in several predefined segments of the operator's brain were estimated in a typical interventional radiology irradiation scenario. The doses were normalized to the KAP values simulated for ten X-ray beam qualities and four projections (PA, RAO 25°, LAO 25° and CRA 25°). For the interventional radiology scenario, because of the position of the operator, no difference was found in the exposure between the left and right regions of the brain for the first operator. However, for the second operator standing at a farer distance from the tube, the exposure of the left part of the brain is up to two times higher than that of the right part. The results are in agreement with dose measurements reported in the literature. The conversion factors, obtained as the absorbed dose per KAP, can be used to obtain a first estimate of the exposure of the brain of the operators during interventional procedures.

Simultaneous heteroepitaxial growth of SrO (001) and SrO (111) during strontium-assisted deoxidation of the Si (001) surface.

Epitaxial integration of transition-metal oxides with silicon brings a variety of functional properties to the well-established platform of electronic components. In this process, deoxidation and passivation of the silicon surface are one of the most important steps, which in our study were controlled by an ultra-thin layer of SrO and monitored by using transmission electron microscopy (TEM), electron energy-loss spectroscopy (EELS), synchrotron X-ray diffraction (XRD) and reflection high energy electron diffraction (RHEED) methods. Results revealed that an insufficient amount of SrO leads to uneven deoxidation of the silicon surface i.e. formation of pits and islands, whereas the composition of the as-formed heterostructure gradually changes from strontium silicide at the interface with silicon, to strontium silicate and SrO in the topmost layer. Epitaxial ordering of SrO, occurring simultaneously with silicon deoxidation, was observed. RHEED analysis has identified that SrO is epitaxially aligned with the (001) Si substrate both with SrO (001) and SrO (111) out-of-plane directions. This observation was discussed from the point of view of SrO desorption, SrO-induced deoxidation of the Si (001) surface and other interfacial reactions as well as structural ordering of deposited SrO. Results of the study present an important milestone in understanding subsequent epitaxial integration of functional oxides with silicon using SrO.

Hydrogen Absorption in Pd-Ag Systems: A TPD and Electrical Resistivity Study.

Hydrogen retention in Pd-Ag (silver 21 wt. %) thin foil has been tested by means of temperature-programmed desorption (TPD) in the temperature range 25-200 °C and compared to the resistivity measurements for the purpose of explaining the characteristic S-shaped resistivity curve and its minimum observed in the same temperature range. The TPD results indicated that the highest uptake of hydrogen was between 65 °C and 105 °C, with a maximum at ~85 °C. Furthermore, in all examined cases, the hydrogen desorption peak was between 140 °C and 180 °C. The resistivity measurements in argon, hydrogen, and vacuum allowed us to examine the influence of hydrogen on the resistivity of a Pd-Ag alloy. The results showed evidence of two kinds of hydrides: (1) a weak absorption at low temperature (T < 70 °C) with the hydrogen present mainly in tetrahedral sites, and (2) a strong absorption up to 150 °C with the hydrogen present mainly in octahedral sites. The behaviour of the electrical resistivity and the minimum between 90 °C and 110 °C can be explained by the two kinds of hydrogen uploaded into the metal lattice.

In situ synthesis of potassium tungstophosphate supported on BEA zeolite and perspective application for pesticide removal.

Potassium tungstophosphate is supported on BEA zeolite by in situ synthesis for glyphosate removal. Spectroscopic measurements identified hydrogen bonding as a primal interaction of potassium salt and BEA zeolite. Composites are evaluated for glyphosate herbicide removal and adsorption process is analyzed using two isotherm models. Obtained adsorption capacities for all prepared composites lay between 45.2 and 92.2 mg of glyphosate per gram of investigated composite. Suspension acidity revealed that glyphosate is adsorbed mainly in the zwitter-ion form at the composite surface while the amount of potassium salt in the composites is crucial for the adsorption application. Exceptional adsorption behavior is postulated to come from a high degree of homogeneity among surface active sites which is confirmed by different experimental methods. Temperature programmed desorption of glyphosate coupled with mass spectrometer detected one broad, high-temperature peak which represents overlapped desorption processes from active sights of similar strength. Introduction of potassium tungstophosphate affects active sites present in BEA zeolite for glyphosate desorption and significantly increases the amount of adsorbed pesticide in comparison to BEA zeolite. Supporting of potassium tungstophosphate on BEA zeolite via in situ synthesis procedure enables the formation of highly efficient adsorbents and revealed their perspective environmental application.

Effect of the radiation protective apron on the response of active and passive personal dosemeters used in interventional radiology and cardiology.

In fluoroscopy guided interventional procedures, workers use protective garments and often two personal dosemeters, the readings of which are used for the estimation of the effective dose; whereas the dosemeter above the protection can be used for the estimation of the equivalent dose of the lens of the eye. When a protective apron is worn the scattered field that reaches the dosemeter is different from the case where no protection is used; this study analyses the changes in the response of seven passive and eight active personal dosemeters (APDs) when they are placed above a lead or lead equivalent garment for S-Cs and x-ray diagnostic qualities. Monte Carlo simulations are used to support the experimental results. It is found that for passive dosemeters, the influence on the dosemeter's response to the lead or lead equivalent was within the range 15%-38% for the x-ray qualities. This effect is smaller, of the order of 10%, when lead-free garments are used, and much smaller, within 1%-10%, for most of the APDs used in the study. From these results it is concluded that when comparing passive and active dosemeter measurements worn above the protection, a difference of 20%-40% is expected. The effect is small when deriving the effective dose from double dosimetry algorithms, but it can be of major importance when eye lens monitoring is based on the use of the dosemeter worn above the protection.

Management, Diagnostic and Prognostic Significance of Acetylcholinesterase as a Biomarker of the Toxic Effects of Pesticides in People Occupationally Exposed.

AIM: The paper presents research on the most common causes of exposure that leads to disorders of cholinesterase activity, as well as an overview of the results of cholinesterase activity with the poisoned people. MATERIAL AND METHODS: In a group of 35 acute poisoned patients by organophosphate compounds has led to inhibition of AchE. A total number of examined workers are 175 in the chemical industry and agricultural production in the area of Rasina District-Serbia. RESULTS: The results showed that among workers who are constantly exposed to pesticides, acetylcholinesterase is within the reference value. Having examined the medical records of these workers, it is noted that, at 72%, there is a slight fall of AchE activity, each year. The workers who had been exposed to pesticides at the time of testing had acetylcholinesterase regarding reference value, but 52% of them had a few years ago significantly reduced the value of the activity of acetylcholinesterase, which was treated and then transferred to other jobs. The 48% of these workers had acetylcholinesterase regarding benchmarks or were transferred to other jobs, for a variety of other health problems. CONCLUSION: Using each pesticide should only deal with people who are well versed in the way of its use, as well as the way of protecting them from poisoning.

Monte Carlo study of the scattered radiation field near the eyes of the operator in interventional procedures.

Interventional radiology and cardiology guarantee high benefits for patients, but are known to be associated with a high level of radiation exposure of medical staff. The recently suggested decrease of the annual dose limit for the eye lens, from 150 to 20 mSv, caused a need for a reconsideration of practices ensuring sufficient protection for the lens of the eyes of medical staff. In such context the study of the scattered radiation around the operator's head could help in finding the best solutions to be adopted for the ceiling-suspended shield and lead glasses in the most common situations in interventional practices. MCNPX Monte Carlo code was employed with anthropomorphic mathematical phantoms to simulate interventional practice projections. For each projection the effect of changing selected parameters on the evaluated scattered radiation towards the operator's head has been calculated. The variety of modelled situations provides plentiful material regarding the spatial distribution of the scattered radiation, useful to improve eye lens radiation protection, such as the following:  (a) Glasses, which provide shielding from both lateral and bottom-up scattered radiation, can reduce by ten times the exposure to the most exposed eyes;  (b) The ceiling-suspended shield offers valuable protection, but such effectiveness can diminish by 90% if the shielding is not correctly positioned;  (c) The transition from femoral to radial access usually intensifies the scattered radiation toward the operator head (a factor of 1.5 for AP projection), but for RAO projections, a reduction of the order by two to three times, in the case of radial access, can be seen, due to the protection provided by the image receptor. The detailed fluence outcomes show that there is a preferential direction of the impinging scattered radiation that should be considered when radiation protection options are evaluated or when a dedicated eye lens dosemeter is used for monitoring.

Silicon surface deoxidation using strontium oxide deposited with the pulsed laser deposition technique.

The epitaxial growth of functional oxides on silicon substrates requires atomically defined surfaces, which are most effectively prepared using Sr-induced deoxidation. The manipulation of metallic Sr is nevertheless very delicate and requires alternative buffer materials. In the present study the applicability of the chemically much more stable SrO in the process of native-oxide removal and silicon-surface stabilization was investigated using the pulsed-laser deposition technique (PLD), while the as-derived surfaces were analyzed in situ using reflection high-energy electron diffraction and ex situ using X-ray photoelectron spectroscopy, X-ray reflectivity, and atomic force microscopy. After the deposition of the SrO over Si/SiO2, in a vacuum, different annealing conditions, with the temperature ranging up to 850 °C, were applied. Because the deposition took place in a vacuum, a multilayer composed of SrO, Sr-silicate, modified Si, and Si as a substrate was initially formed. During the subsequent annealing the topmost layer epitaxially orders in the form of islands, while a further increase in the annealing temperature induced rapid desorption and surface deoxidation, leading to a 2 × 1 Sr-reconstructed silicon surface. However, the process is accompanied by distinctive surface roughening, and therefore the experimental conditions must be carefully optimized to minimize the effect. The results of the study revealed, for the first time, an effective pathway for the preparation of a SrO-induced buffer layer on a silicon substrate using PLD, which can be subsequently utilized for the epitaxial growth of functional oxides.

Mechanism of Zn Particle Oxidation by H2O and CO2 in the Presence of ZnO.

In this work we investigate the mechanism of Zn oxidation with CO2 and/or H2O to produce solar derived fuels (CO and/or H2) as part of the Zn/ZnO thermochemical redox cycle. It has been observed that the ZnO contamination of Zn produced by solar thermal reduction of ZnO (solar Zn) facilitates oxidation of the metallic Zn by CO2 and H2O, allowing for nearly complete conversion at temperatures as low as 350 °C. Reaching the same reaction extent starting with pure Zn requires considerably higher temperatures which imposes use of unconventional hard-to-operate reaction configurations utilizing Zn as vapor. The mechanism of this enhancement is investigated by studying the oxidation of solid Zn diluted with ZnO or Al2O3 at 350-400 °C utilizing thermogravimetry. It is found that ZnO acts as the site for the oxidation of Zn originating from the vapor phase, thereby serving as a sink for Zn vapor and maintaining the driving force for sustainable Zn sublimation. As this Zn sublimation competes with the growth of an impervious ZnO scale over the surface of the remaining solid Zn, the presence of the ZnO increases the reaction extent according to the magnitude of its surface area. This mechanism is supported by energy-dispersive X-ray (EDX) spectroscopy, revealing a substantial deposition of produced ZnO over the surface of the ZnO-seeded Al2O3 diluent.

The frequency of dyscalculia among primary school children.

BACKGROUND: Formal education, daily living activities and jobs require knowledge and application skills of counting and simple mathematical operations. Problems with mathematics start in primary school and persist till adulthood. This is known as dyscalculia and its prevalence in the school population ranges from 3 to 6.5%. SUBJECTS AND METHODS: The study included 1424 third-grade students (aged 9-10) of all primary schools in the City of Kragujevac, Serbia. Tests in mathematics were given in order to determine their mathematical achievement. 1078 students (538 boys and 540 girls) completed all five tests. RESULTS: The frequency of dyscalculia in the sample was 9.9%. The difference between boys and girls according to the total score on the test was statistically significant (p<0.005). The difference between students according to their school achievement (excellent, very good, good, sufficient and insufficient) was statistically significant for all tests (p<0.0005). The influence of place of residence/school was significant for all tests (p<0.0005). Independent prognostic variables associated with dyscalculia are marks in mathematics and Serbian language. CONCLUSION: Frequency of dyscalculia of 9.9% in the sample is higher than in the other similar studies. Further research should identify possible causes of such frequency of dyscalculia in order to improve students` mathematical abilities.