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Design, simulation and measurement results of a tunable planar bandpass filter with a tapped combline topology using diodes as active devices for varactor effect is given. Tunable planar bandpass filter that can operate from 900MHz to 1.6GHz with an enhanced attenuation characteristics are obtained. Diodes are used with an applied bias voltage to have capacitance variation from 0.84 [pF] to 5.08 [pF]. The proposed method eliminates the need for using different active devices and bias voltages and simplifies the geometry that eases implementation. The simulation and measurement results are compared and found in agreement. The method presented in this paper can be integrated in RFID systems to improve the common leakage problem in TX-RX due to poor isolation in circulators.

Fire safety design of buildings is essential to safeguard lives and minimize the loss of damage to properties. Light-weight cold-formed steel channel sections along with fire resistive plasterboards are used to construct light gauge steel frame floor systems to provide the required fire resistance rating. However, simply adding more plasterboard layers is not an efficient method to increase FRR. Hence this research focuses on using joists with improved joist section profiles such as hollow flange sections to increase the structural capacity of floor systems under fire conditions and thus their FRR. In this research, the structural and thermal behaviour of LSF floor systems made of LiteSteel Beams with different plasterboard and insulation configurations was investigated using four full scale tests under standard fires. Based on the ultimate failure load of the floor joist at ambient temperature, transient state fire tests were conducted for different Load Ratios. These fire tests showed that the new LSF floor system has improved the FRR well above that of those made of lipped channel sections. The joist failure was predominantly due to local buckling of LSB compression flanges near mid-span with severe yielding of tension flanges. Fire tests have provided valuable structural and thermal performance data of tested floor systems that included time-temperature profiles, and failure times and temperatures. Average failure temperatures of LSB joists and reduced yield strengths were used to predict their ultimate moment capacities, which were compared with corresponding test capacities. This allowed an assessment in relation to the accuracy of current design rules for steel joists at elevated temperatures. This paper presents the details of full scale fire tests of LSF floor systems made of LSB joists with different plasterboard and insulation configurations and their results along with some important findings.

This paper reports the details of an experimental study of cold-formed steel hollow section columns at ambient and elevated temperatures. In this study the global buckling behaviour of cold-formed Square Hollow Section (SHS) slender columns under axial compression was investigated at various uniform elevated temperatures up to 700℃. The results of these column tests are reported in this paper, which include the buckling/failure modes at elevated temperatures, and ultimate load versus temperature curves. Finite element models of tested columns were also developed and their behaviour and ultimate capacities at ambient and elevated temperatures were studied. Fire design rules given in European and American standards including the Direct Strength Method (DSM) based design rules were used to predict the ultimate capacities of tested columns at elevated temperatures. Elevated temperature mechanical properties and stress-strain models given in European steel design standards and past researches were used with design rules and finite element models to investigate their effects on SHS column capacities. Comparisons of column capacities from tests and finite element analyses with those predicted by current design rules were used to determine the accuracy of currently available column design rules in predicting the capacities of SHS columns at elevated temperatures and the need to use appropriate elevated temperature material stress-strain models. This paper presents the important findings derived from the comparisons of these column capacities.

BACKGROUND: Several studies have demonstrated that patients with childhood acute lymphoblastic leukemia presenting with mild anemia at diagnosis have an increased risk of poor outcome compared to patients with more severe anemia. However, it has not been reported whether there is any correlation between degree of anemia and leukemia subtype. DESIGN AND METHODS: In a cohort of 1162 patients with childhood acute lymphoblastic leukemia we analyzed whether there was a correlation between degree of anemia and leukemia subtype. We also studied the association between degree of anemia and event-free survival within the subtypes. RESULTS: Hemoglobin levels at diagnosis were distributed in a non-random pattern. The degree of anemia was significantly different for three distinct groups of patients compared to the remaining patients (mean hemoglobin; T-cell leukemia: 106 g/L versus 76 g/L (precursor B-cell acute lymphoblastic leukemia); within precursor B-cell ALL: TEL-AML1 positive: 68 g/L versus 79 g/L; BCR-ABL positive: 93 g/L versus 76 g/L; each p<0.05). Furthermore, in contrast to the entire study group, patients with T-cell leukemia, TEL-AML1(+), and BCR-ABL(+) precursor B-cell leukemia had a more favorable prognosis if presenting with a higher hemoglobin level (>/=80 g/L). CONCLUSIONS: These observations indicate that the formerly reported direct correlation between severity of anemia and survival in childhood acute lymphoblastic leukemia mainly reflects differences in the degree of anemia between distinct biological subgroups with different treatment outcomes. On the other hand, the inverse relationship between severity of anemia and survival found within specific subgroups suggests that very low hemoglobin levels at diagnosis are associated with more advanced disease in these subgroups.