Novel Approach to Design Ultra Wideband Microwave Amplifiers: Normalized Gain Function Method

In this work, we propose a novel approach called as “Normalized Gain Function (NGF) method” to design low/medium power single stage ultra wide band microwave amplifiers based on linear S parameters of the active device. Normalized Gain Function TNGF is defined as the ratio of T and |S21|^2, desired shape or frequency response of the gain function of the amplifier to be designed and the shape of the transistor forward gain function, respectively. Synthesis of input/output matching networks (IMN/OMN) of the amplifier requires mathematically generated target gain functions to be tracked in two different nonlinear optimization processes. In this manner, NGF not only facilitates a mathematical base to share the amplifier gain function into such two distinct target gain functions, but also allows their precise computation in terms of TNGF=T/|S21|^2 at the very beginning of the design. The particular amplifier presented as the design example operates over 800-5200 MHz to target GSM, UMTS, Wi-Fi and WiMAX applications. An SRFT (Simplified Real Frequency Technique) based design example supported by simulations in MWO (MicroWave Office from AWR Corporation) is given using a 1400mW pHEMT transistor, TGF2021-01 from TriQuint Semiconductor

Significant benefits of AIP testing and clinical screening in familial isolated and young-onset pituitary tumors

Context Germline mutations in the aryl hydrocarbon receptor-interacting protein (AIP) gene are responsible for a subset of familial isolated pituitary adenoma (FIPA) cases and sporadic pituitary neuroendocrine tumors (PitNETs). Objective To compare prospectively diagnosed AIP mutation-positive (AIPmut) PitNET patients with clinically presenting patients and to compare the clinical characteristics of AIPmut and AIPneg PitNET patients. Design 12-year prospective, observational study. Participants & Setting We studied probands and family members of FIPA kindreds and sporadic patients with disease onset ≤18 years or macroadenomas with onset ≤30 years (n = 1477). This was a collaborative study conducted at referral centers for pituitary diseases. Interventions & Outcome AIP testing and clinical screening for pituitary disease. Comparison of characteristics of prospectively diagnosed (n = 22) vs clinically presenting AIPmut PitNET patients (n = 145), and AIPmut (n = 167) vs AIPneg PitNET patients (n = 1310). Results Prospectively diagnosed AIPmut PitNET patients had smaller lesions with less suprasellar extension or cavernous sinus invasion and required fewer treatments with fewer operations and no radiotherapy compared with clinically presenting cases; there were fewer cases with active disease and hypopituitarism at last follow-up. When comparing AIPmut and AIPneg cases, AIPmut patients were more often males, younger, more often had GH excess, pituitary apoplexy, suprasellar extension, and more patients required multimodal therapy, including radiotherapy. AIPmut patients (n = 136) with GH excess were taller than AIPneg counterparts (n = 650). Conclusions Prospectively diagnosed AIPmut patients show better outcomes than clinically presenting cases, demonstrating the benefits of genetic and clinical screening. AIP-related pituitary disease has a wide spectrum ranging from aggressively growing lesions to stable or indolent disease course

AN INTELLIGENT DECISION SUPPORT TOOL FOR EARLY DIAGNOSIS OF FUNCTIONAL PITUITARY ADENOMAS

In this work, a web based integrated Medical Decision Support System (MDSS) tool for mainly early diagnosis of functional pituitary adenomas (i.e., somatotrophinoma, corticotrophinoma and prolactinoma) is developed. In the MDSS tool, hormone diseases are described by means of well-classified set of attributes generated from the typical sign and symptoms of disorders.The proposed tool is based on a stationary linear stochastic system model which specifically predicts the selected hormone diseases employing certain system parameters. The MDSS tool is user friendly which includes questions and answers at the opening session of the self-test. Questions and answers session will be completed by "yes" or "no" type of simple-responses. Based on our clinical results, MDSS tool yields more than 99% correct decisions on the selected hormone diseases. It is expected that effective use of the proposed MDSS tool will save substantial amount of valuable time of an expert endocrinologists and minimizes the cost of diagnosis. Furthermore, it will provide the opportunity for early diagnosis for the patient and the expert medical doctor to take the necessary preventive measures

Value of petrosal sinus sampling: coexisting acromegaly, empty sella and meningioma

Simultaneous occurrence of an intracranial meningioma and a growth hormone (GH)-producing pituitary adenoma is exceedingly rare, as is coexistence of an empty sella and acromegaly. We report all these rare entities in the same patient. We evaluated the role of inferior petrosal sinus sampling for lateralisation of an adenoma in this patient

On numerical design technique of wideband microwave amplifiers based on GaN small-signal device model

This work presents an application of Normalized Gain Function (NGF) method to the design of linear wideband microwave amplifiers based on small-signal model of a device. NGF has been originally developed to be used together with an S-parameter (*.s2p) file, whereas this work enables the NGF to be able to work with explicit S-parameter formulae derived from the small-signal model of the device. This approach provides the designer to be able to use simple set of S-parameter equations instead of S-parameter file of the device. Representation of the device simply by several model equations not only eliminates the need of carrying large number of data but also provides the capability of equation-based easy, realistic and equispaced S-parameter data generation in any desired resolution in frequency axis without requiring interpolation. NGF is defined as the ratio of T and |S-21|(2), i.e. T-N = T/|S-21|(2), gain function of the amplifier to be designed and transistor forward gain function, respectively. Synthesis of output/input matching networks (OMN/IMN) of the amplifier requires two target gain functions in terms of T-N, to be used in two sequential non-linear optimization procedures, respectively. An amplifier with a flat gain of similar to 10 dB operating in 0.8-2.35 GHz is designed using a small-signal model of an experimental GaN-HEMT. Theoretical amplifier performance obtained in Matlab is shown to be in excellent agreement with the simulated performance in MWO (Microwave Office, AWR Inc.). A prototype low-power amplifier having a similar to 10 to 12 dB gain, operating in (0.9-1.5 GHz) is also produced and measured which yielded good performance results.The work reported here has been carried out at Isik University and Istanbul University. We here thank to Sedat Kilinc, of Istanbul University, for his invaluable contributions in simulations, layout design, prototyping and VNA measurements. We also thank to Dr. Koray Gurkan, of Istanbul University, for his great assistance in pcb board manufacturing via prototyping machine. We also appreciate the Scientific Research Projects Unit (BAP) of Istanbul University which supported this work with the project code 18549Publisher's Versio

Morphing for motion estimation

A new approach is presented for motion estimation and modeling. The proposed method morphs the final frame of a sequence of motion frames from the initial frame. The morphing parameters are estimated using the intermediate frames. The morphing algorithm uses the warping and cross-dissolve techniques used in the recent morphing algorithms. However, rather then using the displacement of line pairs, a set of control points is used. A new method is proposed for the identification of the control points. For this purpose, the moving pixels are identified and clustered. The cluster centers of the moving pixels are labeled as control points. The number of control points and the motion detection thresholds are identified during the morphing by minimizing the sum of square error between the actual and generated image. The experimental results are very promising and yield very high compression ratios