Design methodology for graphene tunable filters at the sub–millimeter–wave frequencies

Tunable components and circuits, allowing for the fast switching between the states of operation, are among the basic building blocks for future communications and other emerging applications. Based on the previous thorough study of graphene based resonators, the design methodology for graphene tunable filters has been devised, outlined, as well as explained through an example of the fifth order filter. The desired filtering responses can be achieved with the material loss not higher than the loss corresponding to the previously studied single resonators, depending mostly on the quantity of graphene per resonator. The proposed design method relies on the detailed design space mapping; obtained data gives an immediate assessment of the feasibility of specifications with a particular filter order, maximal passband ripple level, desired bandwidth, and acceptable losses. The design process could be further automated by the knowledge based approach using the collected design space data

GERMINATION OF SOYBEAN AND FORAGE PEA SEED UNDER DIFFERENT pH OF WATER SOLUTIONS

U laboratorijskim uvjetima ispitivan je utjecaj različitih pH vrijednosti vodene otopine na energiju klijanja, klijavost, dužinu korjenova i izdanaka klijanaca dvije jednogodišnje krmne leguminoze s ciljem procjene tolerantnosti vrsta i kultivara na stresne uvjete nižeg ili višeg pH u najranijim fazama rasta. Po dva kultivara soje (Anica i Ika) i dva kultivara krmnog graška (Zekon i Timo) različite krupnoće sjemena testirana su na četiri razine pH vodene otopine (5, 6, 7 i 8). Sjeme svih ispitivanih kultivara proizvedeno je 2003. godine. Energija klijanja i klijavost nisu se značajno mijenjali zavisno od pH vodene otopine. Dužina korjenova i izdanaka klijanaca obje vrste bila je pod značajnim utjecajem pH vrijednosti vodene otopine (p=0,01). Najveće vrijednosti za dužinu korijena (8,01 cm) dobivene su pri pH=6. Izdanci su bili najduži pri pH=6 i 7 gdje je njihova dužina iznosila 7,53 cm, odnosno 7,07 cm. Najniža prosječna vrijednost za korijen (5,72 cm) utvrđena je pri pH=7, a za izdanak pri pH=5 i 8 (6,02 cm i 6,07 cm). U prosjeku za pH vrijednosti razlike između kultivara su bile značajne (p=0,01) za sva ispitivana svojstva. Kultivar soje Ika imao je najveću energiju klijanja (70,1%), a Anica najveću klijavost (80,8%). Najveće prosječne vrijednosti za dužinu korijena (8,17 cm) i izdanka (10,18 cm) imao je kultivar krmnog graška Timo.Influence of different pH values of water solution on germination energy, germination, seedlings root length and stem height of two annual forage legumes was tested in laboratory conditions in order to evaluate tolerance of species and cultivars to stress conditions caused by lower or higher pH in the earliest phases of growth. Two soybean cultivars (Anica and Ika) and two forage pea cultivars (Zekon and Timo), which differentiated in seed size were tested at four pH levels of water solution (5, 6, 7and 8). Seed of all investigated cultivars was produced in 2003. Germination energy and germination were not significantly affected by the pH of water solution. Root length and stem height of seedlings of both species were significantly affected (p=0.01) by the pH of water solution. The highest values for root length were found at pH=6 (8.01 cm). Stem was highest in both species at pH=6 and 7 (7.53 and 7.07 cm).The lowest average root length value (5.72) was found at pH=7. The lowest average stem height (6.02 and 6.07 cm) was at pH=5 and 8. Differences among all investigated traits of cultivars for pH values in average were significant (p=0.01). Soybean cultivar Ika had the highest germination energy (70.1%), and soybean cultivar Anica had the highest germination (80.8%). Forage pea cultivar Timo had the highest average value of root length and stem height (8.17 and 10.18 cm, respectively)

Treatment of Supracondylar Humerus Fractures in Children: Minimal Possible Duration of Immobilization

In the period from January 1980 until December 1990 we treated 147 children and adolescents with supracondylar humerus fracture, and followed the outcome in 127 of them. Three (2.4%) patients had no displacement of fractured bones and were treated only with plaster cast immobilization. Twenty three (18.1%) underwent closed reduction of fragments and application of a plaster cast. The majority (97; 76.4%) required manual reduction and the fixation of segments with Kirschner\u27s wires laterally and medially. Four (3.1%) patients were treated with open reduction and fixation with Kirschner\u27s wires. Both plaster cast immobilization and fragment fixation with Kirschner\u27s wires lasted only 14 days and were immediately followed by rehabilitation. Such a short immobilization of extremities or fixation of fragments did not result in any complication. Of 56 children available for long-term follow-up, we achieved excellent treatment results in 43 (76.6%) of the patients, good and fair in 12 (21.5%), and a poor result in only 1 patient (1.8%). There were no permanent vascular or neurological complications apart from slight weakness of the ulnar nerve in 3 patients. In conclusion 14 days seemed to be the biological minimum of time needed for this type of fracture to heal in children and adolescents. Fixation of the fragments with Kirschner\u27s wires and immobilization of the extremity for only 14 days brings a significant reduction of total treatment expenses, avoids repeated x-ray examination, facilitates early physical therapy and returns the child to its family

Graphene-based waveguide resonators for submillimeter-wave applications

Utilization of graphene covered waveguide inserts to form tunable waveguide resonators is theoretically explained and rigorously investigated by means of full-wave numerical electromagnetic simulations. Instead of using graphene-based switching elements, the concept we propose incorporates graphene sheets as parts of a resonator. Electrostatic tuning of the graphene surface conductivity leads to changes in the electromagnetic field boundary conditions at the resonator edges and surfaces, thus producing an effect similar to varying the electrical length of a resonator. The presented outline of the theoretical background serves to give phenomenological insight into the resonator behavior, but it can also be used to develop customized software tools for design and optimization of graphene-based resonators and filters. Due to the linear dependence of the imaginary part of the graphene surface impedance on frequency, the proposed concept was expected to become effective for frequencies above 100 GHz, which is confirmed by the numerical simulations. A frequency range from 100 GHz up to 1100 GHz, where the rectangular waveguides are used, is considered. Simple, all-graphene-based resonators are analyzed first, to assess the achievable tunability and to check the performance throughout the considered frequency range. Graphene–metal combined waveguide resonators are proposed in order to preserve the excellent quality factors typical for the type of waveguide discontinuities used. Dependence of resonator properties on key design parameters is studied in detail. Dependence of resonator properties throughout the frequency range of interest is studied using eight different waveguide sections appropriate for different frequency intervals. Proposed resonators are aimed at applications in the submillimeter-wave spectral region, serving as the compact tunable components for the design of bandpass filters and other devices

Normal and Cut-Off Values of the Cytokinesis-Block Micronucleus Assay on Peripheral Blood Lymphocytes in the Croatian General Population

Mikronukleus (MN) test na limfocitima periferne krvi jedna je od najvažnijih metoda koje se primjenjuju u citogenetičkom nadzoru. Osnovni preduvjet za primjenu nekog testa u svrhu nadzora profesionalno izloženih populacija jest poznavanje normalnih vrijednosti promatranoga biološkog pokazatelja (biomarkera) u kontrolnoj populaciji. Baze podataka na razini opće populacije moraju se redovito obnavljati novim podacima. Cilj ovog istraživanja bio je utvrditi normalne i granične vrijednosti MN-testa na limfocitima periferne krvi 200 zdravih ispitanika obaju spolova iz opće populacije Republike Hrvatske te ispitati koji čimbenici pridonose spontanom nastanku MN. Na razini istražene populacije utvrđeno je prosječno (6,90±3,32) MN (medijan 7 MN), dok je raspon pojedinačnih vrijednosti iznosio 0 do 18 MN u 1000 binuklearnih stanica. Gornja granična vrijednost dobivena izračunavanjem 95. percentila za cjelokupnu promatranu populaciju iznosi 12,5 MN na 1000 limfocita. Utvrđeno je da na spontani nastanak MN utječu spol, dob i navika pušenja. Žene u prosjeku imaju više vrijednosti svih parametara MN-testa od muškaraca, a u njih je bio i naglašeniji porast vrijednosti citogenetičkog nalaza zbog navike pušenja. Kako su literaturni podaci o utjecaju pušenja cigareta na nastanak MN kontradiktorni, planiran je nastavak istraživanja radi razjašnjavanja utjecaja dnevno utrošenog broja cigareta i ukupnog trajanja pušačkog staža na vrijednosti parametara MN-testa. Usporedba rezultata s literaturnim podacima potvrdila je da su dobivene vrijednosti u skladu s vrijednostima MN-testa zabilježenim na općoj populaciji u drugim svjetskim laboratorijima. Normalne i granične vrijednosti MN-testa utvrđene u ovome istraživanju poslužit će kao osnova za usporedbu i tumačenje nalaza MN-testa u ispitanika izloženih populacija te daljnju nadogradnju laboratorijske baze podataka.The cytokinesis-block micronucleus (CBMN) assay on peripheral blood lymphocytes is one of the most important methods employed in cytogenetic biomonitoring. For the purposes of biological dosimetry, it is important to kno the spontaneous frequency of a biomarker and its normal values in general population. These values are used for population databases, which should be updated regularly. In this study, MN levels were investigated in cytokinesis-blocked lymphocytes of 200 healthy male and female blood donors selected at random from the general population of Croatia. The aim was to assess the variability and determine possible infl uences of external and/or internal factors on the background levels of MN and to establish the cut-off value for the CBMN assay. The background frequency of MN was (6.90±3.32) MN (median 7 MN) and the range was 0 to 18 MN per 1000 binuclear lymphocytes. The cut-off value, which corresponds to 95th percentile of the distribution of 200 individual values, was 12.5 MN. Spontaneous formation of MN was infl uenced by sex, age, and smoking. Women had higher MN levels than men. However, only age and smoking signifi cantly increased the values of all parameters evaluated by the CBMN assay. Since the existing literature data on smoking-related formation of MN are contradictory, we will continue these investigations to resolve how the number of cigarettes smoked per day and the duration of smoking in years infl uence the results of the CBMN assay. Our results are consistent with the background MN frequencies reported by other cytogenetic laboratories worldwide. Normal and cut-off values estimated in this study will be used to update the current general population data and as reference for occupationally or accidental exposure

Stark widths and shifts of triply ionized argon spectral lines

The Stark widths and shifts of 18 triply ionized argon (Ar IV) spectral lines have been measured at an electron density of 1.9 1023 m-3 and electron temperature of 22 500 K in a linear pulsed-arc discharge-containing argon-helium mixture. The measured values were compared to the existing calculated and experimental data

Chromosomal Aberrations in Subjects Exposed to Ionizing Radiation

Occupational exposure to low doses of ionizing radiation is a particularly delicate subject for investigation, due to the cumulative effects of chronic exposure. It is extremely important to consider and to measure the biological response to given conditions of exposure. The aim of this study was to establish possible recovery from DNA damage in subjects professionally exposed to radiation in their working area by examinations for chromosomal aberrations (CA) at two different times. The first group (I) was composed of 30 professionally exposed subjects in whom unstable CA (dicentrics, ring, acentric fragments, chromatid, chromosomal breaks, and chromatid interchanges) were identified at time zero. After removal from the radiation area, they were re-examined 9 months later. The second group (H) contained 64 healthy individuals, not professionally exposed to ionizing radiation or other known mutagenic agents. In the group of exposed individuals, five (16.67%)) subjects exhibited permanent unstable CAs, even after 9 months absence from the radiation. When the nonexposed and exposed groups were compared, an increase of unstable aberrations (p < 0.05) was observed in the exposed group. Nevertheless, a statistically significant decrease of dicentrics, acentric fragments, and ring frequencies was observed in exposed individuals after 9 months away from the radiation area. However, chromatid and isochromatid break frequencies increased slightly but not significantly after 9 months. The detected CAs corresponded to the total effective doses of radiation measured in our subjects. The existence of CAs in some individuals even after absence from the radiation area suggests that the time necessary for the damaged DNA to recover is extremely variable and indicates interindividual differences in radiosensitivity as well as differences in the cellular-reparation response.nul

Chromosomal Aberrations in Subjects Exposed to Ionizing Radiation

Occupational exposure to low doses of ionizing radiation is a particularly delicate subject for investigation, due to the cumulative effects of chronic exposure. It is extremely important to consider and to measure the biological response to given conditions of exposure. The aim of this study was to establish possible recovery from DNA damage in subjects professionally exposed to radiation in their working area by examinations for chromosomal aberrations (CA) at two different times. The first group (I) was composed of 30 professionally exposed subjects in whom unstable CA (dicentrics, ring, acentric fragments, chromatid, chromosomal breaks, and chromatid interchanges) were identified at time zero. After removal from the radiation area, they were re-examined 9 months later. The second group (H) contained 64 healthy individuals, not professionally exposed to ionizing radiation or other known mutagenic agents. In the group of exposed individuals, five (16.67%)) subjects exhibited permanent unstable CAs, even after 9 months absence from the radiation. When the nonexposed and exposed groups were compared, an increase of unstable aberrations (p < 0.05) was observed in the exposed group. Nevertheless, a statistically significant decrease of dicentrics, acentric fragments, and ring frequencies was observed in exposed individuals after 9 months away from the radiation area. However, chromatid and isochromatid break frequencies increased slightly but not significantly after 9 months. The detected CAs corresponded to the total effective doses of radiation measured in our subjects. The existence of CAs in some individuals even after absence from the radiation area suggests that the time necessary for the damaged DNA to recover is extremely variable and indicates interindividual differences in radiosensitivity as well as differences in the cellular-reparation response.nul