A new resonant circuit for 2.45 GHz LC VCO with linear frequency tuning

A new MOS varactor bank is proposed to implement a 2.45 GHz SiGe BiCMOS LC-tank voltage controlled oscillator (VCO) with linear frequency tuning. Compared to a conventional VCO, the proposed technique improves the quality factor of the LC-tank while preserving the linearity of the circuit. Realized in 0.25-μm SiGe BiCMOS technology, VCO exhibits 35% VCO gain (KVCO) variation from 2.29 to 2.66 GHz with a 16% tuning ratio. The VCO also exhibits a phase noise of -113 dBc/Hz at 1 MHz offset frequency and consumes 1.7 mA from 1.8 V supply

A high power handling capability CMOS T/R switch for x-band phased array antenna systems

This paper presents a single-pole double-throw (SPDT) transmit/receive (T/R) switch fabricated in 0.25-μm SiGe BiCMOS process for X-Band (8 – 12 GHz) phased array radar applications. The switch is based on series-shunt topology with combination of techniques to improve insertion loss (IL), isolation and power handling capability (P1dB). These techniques include optimization of transistor widths for lower insertion loss and parallel resonance technique to improve isolation. In addition, DC biasing of input and output ports, on-chip impedance transformation networks (ITN) and resistive body-floating are used to improve P1dB of the switch. All these design techniques resulted in a measured IL of 3.6 dB, isolation of 30.8 dB and P1dB of 28.2 dBm at 10 GHz. The return losses at both input and output ports are better than 16 dB from 8 to 12 GHz. To our knowledge, this work presents the highest P1dB at X-Band compared to other reported single-ended CMOS T/R switches in the literature

SiGe BiCMOS front-end circuits for X-Band phased arrays

The current Transmit/Receive (T/R) modules have typically been implemented using GaAs- and InP-based discrete monolithic microwave integrated circuits (MMIC) to meet the high performance requirement of the present X-Band phased arrays. However their cost, size, weight, power consumption and complexity restrict phased array technology only to certain military and satellite applications which can tolerate these limitations. Therefore, next generation X-Band phased array radar systems aim to use low cost, silicon-based fully integrated T/R modules. For this purpose, this thesis explores the design of T/R module front-end building blocks based on new approaches and techniques which can pave the way for implementation of fully integrated X-Band phased arrays in low-cost SiGe BiCMOS process. The design of a series-shunt CMOS T/R switch with the highest IP1dB, compared to other reported works in the literature is presented. The design focuses on the techniques, primarily, to achieve higher power handling capability (IP1dB), along with higher isolation and better insertion loss of the T/R switch. Also, a new T/R switch was implemented using shunt NMOS transistors and slow-wave quarter wavelength transmission lines. It presents the utilization of slow-wave transmissions lines in T/R switches for the first time in any BiCMOS technology to the date. A fully integrated DC to 20 GHz SPDT switch based on series-shunt topology was demonstrated. The resistive body oating and on-chip impedance transformation networks (ITN) were used to improve power handling of the switch. An X-Band high performance low noise ampli er (LNA) was implemented in 0.25 μm SiGe BiCMOS process. The LNA consists of inductively degenerated two cascode stages with high speed SiGe HBT devices to achieve low noise gure (NF), high gain and good matching at the input and output, simultaneously. The performance parameters of the LNA collectively constitute the best Figure-of-Merit value reported in similar technologies, to the best of author's knowledge. Furthermore, a switched LNA was implemented SiGe BiCMOS process for the first time at X-Band. The resistive body floating technique was incorporated in switched LNA design, for the first time, to improve the linearity of the circuit further in bypass mode. Finally, a complete T/R module with a state-of-the-art performance was implemented using the individually designed blocks. The simulations results of the T/R module is presented in the dissertation. The state-of-the-art performances of the presented building blocks and the complete module are attributed to the unique design methodologies and techniques

Comparison of botox and lateral internal sphincterotomy treatment outcomes in chronic anal fissures

Objective: Both botox and lateral internal sfinkterotomi are treatment technics used in chronic anal fissure; provide the relaxation of anal sphincter and as a result of this, healing occurs. Aim of this study is to compare efficacy of botox and LIS treatment in chronic anal fissure and discussing with the literature. Methods: 60 of 66 patients who has chronic anal fissure, that we reached, treated but not healed with medical therapy, appealed to the Dr. Sami Ulus Hospital included the study. Gender, age, fissure localization, complaints (pain, bleeding, itching, constipation), complaint length, recurrences after treatment, continence conditions and complications of patients were registered. Results: Sixty patients were enrolled the study. Of the 60 patients; 38(63.3%) were male and 22 (27.7%) were female. Mean age of all patients was 35.93 ± 11.45 (21 -60). Pain was the common complaint of the all patients. 10 (32.3%) recurrence were detected in botox treatment group (Group-I), only 1 (3.4%) recurrence was in LIS group (Group-II). There was no complication as an incontinence in group-I but 3 cases with incontinence (10.39%) were obtained in group-II. In the evaluation of these 3 cases by Cleveland Clinic Continence Scoring System, 2 cases classified as gas incontinence and 1 case as moderate fecal incontinence. Conclusion: Although botulinum toxin injection seen as an alternative treatment method with low complication rates such as incontinence, high recurrence is an important shortcoming of this technic. LIS performed by experienced surgeons remained the most popular treatment modality with low complication rates and great deal of healing success

Development of insect resistant tobacco lines expressing cry1Ac and cry2A genes

Bu tez çalışmasına Ömer Halisdemir Üniversitesi Bilimsel Araştırma Projeleri (BAP) birimine ait FEB314/10-BAEP6 numaralı proje ile finansal destek sağlanmıştır.Türkiye, şark tütünü piyasasında dünyada önemli bir yere sahiptir. Tütün üretimini sınırlandıran en büyük sebeplerden biri de zararlı böceklerdir. Bu tez çalışmasında, gen piramit stratejesi kullanarak cry1Ac ve cry2A isimli iki adat böcek dirençlilik sağlayan genlerin Agrobacterium tumefaciens aracılığıyla, Basma ve Nail Türk tütün hatlarına aktarılarak böceklere karşı dayanıklı tütün hatları geliştirilmiştir. Çalışmada, gen aktarım amacıyla kullanılan pK2AC plazmidi, 35S promotoru, T-DNA bölgesinde ayrıca npt-II ve GUS-INT genlerinide içermektedir. Elde edilen analizler sonucunda, Basma hattına ait 22 adet ve Nail hattına ait ise 3 adet bitkisinde hem GUS pozitif ekspresiyonu hemde genomik PCR ile cry1Ac, cry2A ve npt-II genlerinin bitki genomlarında entegrasyonu teyit edilmiştir. ELISA testi de transgenik bitkilerin cry1Ac proteinini 0,017-0,607 µg/g konsantrasyonları arasında sentezlediğini göstermiştir. Transgenik hatlarında, yapılan biyoanaliz testleri sonucunda elde edilen transgenik hatların patates güvesi (Phthorimea operculella) karşı dirençli olduğu görülmüştür. Hatların her ikisine ait bitkilerde T1 nesilde de kanamisin içeren MS ortamında antibiyotiğe karşı direnç göstererek yabancı genin başarıyla bir sonraki nesle aktarılabildiğini göstermiştir. Transgenin varlığını sürderen transgenik tütün hatları bir tütün ıslahı programı için mükemmel gen kaynakları olabilirler.Turkey, has an important place in the world trade of oriental tobacco. One of the main constraints in agricultural production of tobacco is huge damages incurred by insects. The study aimed to transform two tobacco lines Basma and Nail to encode insect resistance using pyramid gene transfer strategy. The plasmid pK2AC contained both genes under control of 35S promoter; that also harbored GUS-INT with in T-DNA region for earlier screening of putative transformants. Consequently, the genomic PCR results confirmed integration of cry1Ac, cry2A and nptII genes in 22 plants from line Basma and 3 plants from Nail. ELISA results showed variation in expression of cry1Ac protein among transgenic plants varying from 0,017 µg/g of fresh tissue weight to 0,607. Bioassay results with potato tuber moth (Phthorimea operculella) showed significant mortality of targeted pest on primary transformants. Furthermore, T1 transgenic progeny also confirmed resistance on MS selection medium containing kanamycin. These transgenic lines can serve as an excellent source of germplasm for an efficient tobacco breeding programme

Tracheotomy in pediatric patients: In operating room or intensive care unit?

Giriş: Pediatrik trakeotomilerde, trakea ve boynun çocuklarda zedelenmeye daha duyarlı olması ve daha küçük bir insizyondan cerrahi yapma gereksiniminden dolayı, işlemin morbidite ve mortalitesi erişkin trakeotomilere oranla daha yüksektir. Birçok klinikte bu işlem ameliyathanede yapılmaktadır. Çalışmada; aynı kulak burun boğaz ve baş boyun cerrahı tarafından, yoğun bakım ünitesinde veya ameliyathanede traketomi açılan hastaların cerrahi komplikasyonları, ailelerinin uygulamaya yaklaşımları ile beraber, operasyon yerinin uygulama güçlükleri üzerindeki etkisi araştırılmıştır. Gereç ve Yöntem: Çalışmamızda, Haziran 2012 ile Temmuz 2013 tarihleri arasında çeşitli nedenlerle trakeotomi açtığımız 39 olgu prospektif olarak değerlendirildi. Hastaların yaşı, cinsiyeti, primer patolojisi, trakeotomi endikasyonu, trakeotominin açılma yeri, ailelerden işlem öncesi alınan onam için geçen süre, peroperatif komplikasyonlar ve dekanülasyon durumları kayıt altına alındı. Bulgular: Toplam 39 pediatrik trakeotomi olgusu çalışmaya dahil edildi. Hastaların 20’si erkek, 19’u ise kız çocuğuydu. Hastaların yaş aralığı ise 4 ay ile 204 ay arasında değişmekte olup ortalaması 49,9±52,5 ay olarak bulundu. Olgulardan 19’una (%45,0) ameliyathanede, 20’sine (%54,5) ise yoğun bakımda hasta başında trakeotomi açıldı. Ameliyathane (%48,7) ve yoğun bakımda (%51,3) trakeotomi açılan hastalar arasında komplikasyonlar açısından istatistiksel olarak anlamlı bir fark saptanmadı. Ailelerden alınan onam süreleri yoğun bakımda açılanlar lehine anlamlı bulundu. Sonuç: Yoğun bakım şartlarında, hasta başında açılan trakeotomiler, ameliyathanede açılanlar kadar güvenlidir. Aileler; çocuklarına yoğun bakım şartlarında, yerinden oynatılmadan ameliyathaneye alınmadan yapılacak işlemlere daha kolay ve hızlı onam vermektedirler.Introduction: The morbidity and mortality rates of tracheotomy are higher in the pediatric population because the incision is small and the trachea is more prone to surgical trauma. Tracheotomy procedure is mostly performed in operating room in most institutions. The aim of the study is to compare the outcomes of tracheotomy procedures between intensive care unit (ICU) and operating room (OR) in terms of pitfalls, complications and family preferences. Materials and Methods: In between June 2012 and July 2013, at a single institution, 39 patients were prospectively analyzed for age, gender, primary pathology, tracheotomy indications, location of operation, the duration of family consent, perioperative complications and presence of decanulation. Results: Male/female ratio was 20/19. Mean age was 49.9±52.5 (4-204) months. Tracheotomy procedure was performed in OR in 19 patients (45%) and in ICU in 20 (54.5%) patients. There was no statistically significant difference between groups in terms of complications (OR-48.7%, ICU-51.3%). The time of informed consent was significantly shorter in ICU patients. Conclusions: There is no significant difference in terms of safety for tracheotomy procedure in ICU or OR. Parents give approval to a bedside invasive procedure faster. The words ‘Surgery’ and ‘Operating room’ can easily confuse the parents, extend the duration for endolaryngeal intubation, and increase the cost and labour loss

Compact X-band SiGe power amplifier for single-chip phased array radar applications

An X-band power amplifier (PA) is presented for single-chip phased array radar applications. In this work, the choice of optimum circuit topology for X-band PA design is discussed and possible stability issues for high and low frequencies are analysed. The PA features a two-stage cascode architecture that includes both high-speed (low breakdown) and high breakdown (low-speed) SiGe transistors. It consists of two stages providing a 23.2 dBm saturated output power with a 28% power-added efficiency at 9 GHz. The output 1-dB compression point (P-1dB) is higher than 20 dBm in a 3 GHz bandwidth and has a maximum value of 22.2 dBm. The small-signal gain is 25.5 dB with a 3-dB bandwidth of 3.2 GHz (7.3-10.5 GHz). The PA has been fabricated using 0.25 mu m SiGe BiCMOS process provided by IHP Microelectronics. The PA occupies 1 mm x 0.6 mm chip area and consumes 120 mA from a 4 V supply voltage. These results demonstrate comparable or better performance than other reported PAs and suitable performance for single-chip phased array applications

A fully integrated, highly linear CMOS T/R switch for x-band phased array radars

This paper presents the design and implementation of a single-pole, double-throw transmit/receive (T/R) switch for X-Band (8-12 GHz) phased array radar applications. The T/R switch was fabricated in a 0.25-mu m SiGe BiCMOS process and occupies 0.44-mm(2) chip area, including pads. The design focuses on the techniques, primarily, to achieve higher power handling capability (P-1dB), along with higher isolation and better insertion loss (IL) of the T/R switch. These techniques include resistive-body floating, using on-chip impedance transformation networks and DC biasing of all terminals of the T/R switch. In addition, optimization of transistor widths and parallel resonance technique are used to improve IL and isolation, respectively. All these design techniques resulted in a measured IL of 3.6 dB, isolation of 34.8 dB and IP1dB of 28.2 dBm at 10 GHz. The return losses at both input and output ports are better than 16 dB from 8 to 12 GHz. To our knowledge, this paper presents the single-ended CMOS T/R switch with the highest IP1dB, competitive isolation and comparable IL at X-Band, compared to other reported works in the literature and attributed to the unique design methodologies and techniques