Ultralow noise optical clock for high speed sampling aplications

Methods and systems for using a laser type clock to produce a train of ultra-stable optical pulses. The methods and systems include generating an approximately 10 GHz ultralow noise pulse train from a harmonically modelocked laser having an intracavity Fabry-Perot etalon filter from a semiconductor lasers such as ring lasers, and the like. System output can have residual phase modulation(PM) noise values of approximately 18 fs and amplitude modulation(AM) noise values of approximately 0.05% RMS, and residual phase modulation(PM) noise values of approximately 94 fs and amplitude modulation(AM) noise values of approximately 0.05% RMS

Photonic Arbitrary Waveform Generation and Photonic Synthesis

Photonic arbitrary waveform methods and generation by manipulating the phase-locked longitudinal modes of an approximately 12.4 GHz fundamentally modelocked external-cavity semiconductor laser are demonstrated. Photonically synthesized sine waves (center frequency of approximately 37.2 GHz, linewidth less than approximately 100 Hz, dynamic range approximately 50 dB at approximately 100 Hz resolution bandwidth) and complex, arbitrarily shaped optical/microwave frequency waveforms with instantaneous bandwidths up to approximately 75 GHz are shown. A WDM filter can be used to separate individual longitudinal modes of a modelocked laser. Photonic arbitrary generation occurs through the modulation of individual channels before recombining the channels, followed by amplifying the output

Self-Supervised MRI Reconstruction with Unrolled Diffusion Models

Magnetic Resonance Imaging (MRI) produces excellent soft tissue contrast, albeit it is an inherently slow imaging modality. Promising deep learning methods have recently been proposed to reconstruct accelerated MRI scans. However, existing methods still suffer from various limitations regarding image fidelity, contextual sensitivity, and reliance on fully-sampled acquisitions for model training. To comprehensively address these limitations, we propose a novel self-supervised deep reconstruction model, named Self-Supervised Diffusion Reconstruction (SSDiffRecon). SSDiffRecon expresses a conditional diffusion process as an unrolled architecture that interleaves cross-attention transformers for reverse diffusion steps with data-consistency blocks for physics-driven processing. Unlike recent diffusion methods for MRI reconstruction, a self-supervision strategy is adopted to train SSDiffRecon using only undersampled k-space data. Comprehensive experiments on public brain MR datasets demonstrates the superiority of SSDiffRecon against state-of-the-art supervised, and self-supervised baselines in terms of reconstruction speed and quality. Implementation will be available at https://github.com/yilmazkorkmaz1/SSDiffRecon

Effects of polyglecaprone 25, silk and catgut suture materials on oral mucosa wound healing in diabetic rats : an evaluation of nitric oxide dynamics

Objectives: The purpose of this study is to investigate the effects of monocryl (Polyglecaprone 25), silk and catgut suture materials on wound healing in diabetic rats and to evaluate NO (nitric oxide) dynamics. Study desing: Fourty-eight male Wistar-Albino rats weighting 220-270 g were used in this study. The rats were categorized into 2 groups, as control group (n=24) and streptozotocin (STZ) induced diabetic group (n=24). For each group, incision wounds were created on the inner cheeck mucosa of the animals and wounds were closed primarily with three different types of sutures. These materials were sized 3-0 monocryl (polyglecaprone 25), silk and catgut sutures swaged on. Excisional biopsies were performed at 2nd, 7th, 14th and 21st day (2 rats per day) from the initial surgical procedure. Effects of these suture materials on wound healing and NOS (nitric oxide synthase) activities were compared immunohistochemically in the study. eNOS and iNOS (Endothelial and induced nitric oxide synthase) activities were classified as mild (+), moderate (++) and severe (+++). Results: Mild eNOS activities were seen in both diabetic and control groups at 2nd day specimens. Activities of silk and catgut were similar both in diabetic and control groups at 14th day, this activity in monocryl was mild. 21st day specimens revealed that monocryl has mild eNOS activity than silk and catgut sutures. iNOS activities in diabetic group were greater than control groups and the degrees of the activity in monocryl, silk and catgut sutures were mild, severe and moderate at the 7th day. At the 14th day there was no iNOS activity in diabetic monocryl group. Conclusion: All of the materials have the potential capacity to be well tolerated however monocryl seemed to have more benefical effects on wound healing in diabetic subjects

Safety and efficacy of using advanced electrosurgical bipolar vessel sealing during vaginal hysterectomy in morbidly obese patients: a retrospective cohort analysis

Objectives: To assess the safety and efficacy of electrosurgical bipolar vessel sealing during vaginal hysterectomy in morbidly obese patients Material and methods: A total of 105 morbidly obese patients who underwent vaginal hysterectomy due to benign gynecologic pathologies between January 2010 and April 2017 were included in the study. Patients were divided into two groups according to whether conventional suture ligation technique (n = 64) or electrosurgical bipolar vessel sealing (n = 41) were used during vaginal hysterectomy. The surgical procedure was performed with the same technique in both study groups. The primary outcomes were duration of surgery and estimated blood loss. The secondary outcomes were intra-operative complications and post-operative complications. Results: The duration of surgery and estimated blood loss in the vessel sealing group was significantly less than in the conventional suture group (p < 0.05). No significant difference was present between the two groups in the rate of intra-operative and post-operative complications. Conclusions: The primary outcome of our study is that the EBVS system can be used equally and even more effectively in some aspects; and as safe an alternative approach to conventional suture ligation technique during vaginal hysterectomies performed specifically on morbidly obese patients with reduced operation times and blood loss, and without increasing the complication rates

Relationship between CHA2DS2-VASc and CHADS2 scores with pulmonary hypertension in patients with acute pulmonary embolism

Introduction: Pulmonary hypertension (PH) is the most important prognostic factor after acute pulmonary embolism (PE). Therefore, determination of patients who will develop PH after acute PE is crucial.  The aim of the present study was to evaluate the predictive value of the CHADS2 and CHA2DS2-VASc scores for PH in patients with acute PE.Material and methods: Seventy-nine adults who presented with acute PE, had an admission systolic pulmonary artery pressure (sPAP) measured on echocardiogram and no previous history of PE, were retrospectively identified from the computerized database. 31 patients who had sPAP ≤ 40 mm Hg were categorized as a  “normal pulmonary pressure” group, whereas 48 patients who had sPAP > 40 mm Hg were categorized as a “PH” group.Results: SPAP was > 40 mm Hg in 48 patients (60.8%), with a mean sPAP of 60.9 ± 16.1 mm Hg (median = 60, min–max = 41–100 mm Hg). In multivariate logistic regression models adjusted for CHADS2 and CHA2DS2-VASc score components, only age was found to be related with the development of PH. SPAP was weakly positively correlated with CHADS2 (p = 0.047; r = 0.224) and CHA2DS2-VASc (p = 0.023; r = 0.256) scores. SPAP values were increasing with the severity of the scores.Conclusions: Both CHADS2 and CHA2DS2-VASc scores could be useful in the determination of which patients should be closely followed up in order to prevent the development of PH after acute PE

ÇELİK LAMALAR VE KORNİYERLER İLE GÜÇLENDİRİLMİŞ BETONARME ÇERÇEVELERİN YATAY YÜK TAŞIMA KAPASİTESİNİN İNCELENMESİ

ÇELİK LAMALAR VE KORNİYERLER İLE GÜÇLENDİRİLMİŞ BETONARME ÇERÇEVELERİN YATAY YÜK TAŞIMA KAPASİTESİNİN İNCELENMESİÖzetÜlkemiz büyük çoğunluğu deprem kuşağında yer alan bir ülkedir. Geçmiş yıllarda yaşanan depremlerden dolayı çok fazla can ve mal kaybı yaşanmıştır. Depremlerin oluşturduğu yıkıcı etki ile çağımız yapım tekniklerinden uzak, güncel yönetmeliklerin kriterlerini taşımayan yapılarda ciddi hasarlar oluşmaktadır. Yönetmelik kriterlerini sağlamayan bu tür binalar ülkemizin yapı stoğunda önemli bir bölüm oluşturmaktadır. Bu yapıların gelecek yıllarda yaşanabilecek olası depremlerde can kayıplarına neden olmaması için günümüz yönetmelik kriterlerini sağlayacak şekilde deprem performanslarının artırılması gerekmektedir. Yapılarda güçlendirmenin esas hedefi yapının yatay yük taşıma kapasitesini artırmak, sünekliği artırmak, rijitliği artırmak olarak sıralanabilir. Yapılan güçlendirmelerde bu temel kriterlerden hangisine yapıda ihtiyaç duyulduğunu belirlemek ve yapıya uygun güçlendirme tekniğine karar vermek oldukça önemlidir. Son yıllarda yapıların güçlendirilmesi ve deprem performanslarının iyileştirilmesi üzerine çok fazla çalışma yapılmaktadır. Bu çalışma da 3 tane betonarme çerçeve numunesi hazırlanmıştır. Bunlardan birisi mevcut yapı stoğundaki hataları yansıtacak şekilde üretilmiş betonarme çerçevedir. Diğer numuneler ise çelik lamalar ve korniyerler ile güçlendirilmiştir. Yatay yük uygulanan numunelerin yatay yük taşıma kapasiteleri elde edilmiştir. Güçlendirme yöntemlerinin yatay yük taşıma kapasitesi üzerinde etkili olduğu görülmüştür.Anahtar Kelimeler: Çelik Lamalar ve Korniyerler, Deprem Davranışı, Güçlendirme, Betonarme ÇerçevelerINVESTIGATION OF THE SEİSMİC LOAD CARRYING CAPACITY OF REINFORCED CONCRETE FRAMES STRENGTHENED WITH STEEL ANGLE AND FLAT STEELAbstractThe majority of our country is located in the earthquake zone. There has been much loss of life and property due to earthquakes in the past years. Due to the devastating effect of earthquakes, serious damage to structure which do not build with the criteria of current regulations and modern construction techniques. Such structure which do not build the criteria of the current regulation constitute an important part of the structure stock of our country. In order to prevent the loss of life in the earthquakes that may occur in the coming years, earthquake performance should be increased in order to upgrade to the criteria of current regulations. The main objective of strengthening structures is increasing the seismic load carrying capacity of the structure, the ductility and the stiffness. It is very important to determine which of these basic criteria are needed in the reinforcements and decide the appropriate reinforcement technique. In recent years, a lot of studies has been performed on strengthening structures and improving earthquake performances. In this study, 3 reinforced concrete frame samples were prepared. One of them is the reinforced concrete frame which is produced to reflect the general faults in the existing building stock. Other samples are reinforced with steel angle and flat steel. Seismic load carrying capacity of the samples are obtained by loading as quasi-static. Strengthening methods have been found to be effective on seismic load carrying capacity.Keywords: Steel Angle and Flat, Earthquake Behavior, Strengthening, Reinforced Concrete Fram

Adaptive Diffusion Priors for Accelerated MRI Reconstruction

Deep MRI reconstruction is commonly performed with conditional models that de-alias undersampled acquisitions to recover images consistent with fully-sampled data. Since conditional models are trained with knowledge of the imaging operator, they can show poor generalization across variable operators. Unconditional models instead learn generative image priors decoupled from the imaging operator to improve reliability against domain shifts. Recent diffusion models are particularly promising given their high sample fidelity. Nevertheless, inference with a static image prior can perform suboptimally. Here we propose the first adaptive diffusion prior for MRI reconstruction, AdaDiff, to improve performance and reliability against domain shifts. AdaDiff leverages an efficient diffusion prior trained via adversarial mapping over large reverse diffusion steps. A two-phase reconstruction is executed following training: a rapid-diffusion phase that produces an initial reconstruction with the trained prior, and an adaptation phase that further refines the result by updating the prior to minimize reconstruction loss on acquired data. Demonstrations on multi-contrast brain MRI clearly indicate that AdaDiff outperforms competing conditional and unconditional methods under domain shifts, and achieves superior or on par within-domain performance

BETONARME ÇERÇEVELERİN GÜÇLENDİRİLMESİ VE DEPREM PERFORMASININ İYİLEŞTİRİLMESİ

BETONARME ÇERÇEVELERİN GÜÇLENDİRİLMESİ VE DEPREM PERFORMASININ İYİLEŞTİRİLMESİÖzetYapıların deprem etkisi altındaki davranışları deprem mühendisliği için önemli bir çalışma alanıdır. Deprem etkisi altında yapılardan beklenen en önemli unsurlar yeterli rijitlik, yeterli dayanım ve sünekliktir. Yapıların bu temel kriterleri sağlaması deprem etkisi altında ağır hasarlar görmesini önleyecektir. Ancak ülkemizde bulunan yapıların önemli bir kısmı yapım kusurları ve proje hataları nedeniyle bu kriterleri sağlamamaktadır. Bu nedenle geçmiş yıllarda yaşanan depremlerde çok fazla can ve mal kaybı yaşanmıştır. Deprem performansı yetersiz yapıların depremlerde ağır hasar alması nedeniyle yapıların güçlendirilmesi konusu son yıllarda büyük önem kazanmıştır. Deprem performansı yetersiz yapılar için birçok güçlendirme tekniği geçmiş yıllardaki çalışmalar doğrultusunda ortaya atılmıştır. Bu çalışmada iki farklı güçlendirme yöntemi denenmiştir. Bir tanesi referans numunesi olmak üzere üç tane betonarme çerçeve numune hazırlanarak yatay yük altındaki davranışları incelenmiştir. Numunelerde yapılarda görülen genel kusurlara yer verilmiştir. Seçilen yöntemlerin yatay yük taşıma kapasitesini artırması yanında deplasman yapabilme kabiliyetini de artırması göz önüne alınmıştır. Bu sayede çerçevelerin sünekliğinin artırılması amaçlanmıştır. Seçilen güçlendirme teknikleri sayesinde hem yatay yük taşıma kapasitesinde artış hem de süneklik yani çerçevenin yaptığı deplasmanda artış sağlanmıştır.  Anahtar Kelimeler: Güçlendirme Teknikleri, Deprem Performansı, Çelik Çapraz ile Güçlendirme, Betonarme ÇerçevelerSTRENGTHENING THE REINFORCED CONCRETE FRAMES AND ENHANCING THE EARTHQUAKE PERFORMANCEAbstractBehavior of buildings under earthquake is an important area for earthquake engineering. The most important elements expected from the structures under earthquakes are adequate stiffness, strength and ductility. The fact that the structures meet these basic criteria will prevent the heavy damage under the earthquake effect. However, a significant part of the buildings in our country have the construction defects and project errors. Therefore, many life and property losses were experienced in the earthquakes in the past years. Strengthening the structures has gained importance due to insufficient structures of earthquake performance damaged in past earthquakes. Many strengthening techniques for inadequate structures of earthquake performance have been put forward in line with previous studies. In this study, two different strengthening methods were tried. Three reinforced concrete frame samples, one of which is a reference sample, were prepared and their behavior under lateral load was examined. General defects seen in the existing structures are given in the samples. In addition to increasing the seismic load carrying capacity of the selected methods, it is also considered to increase the displacement characteristics. In this way, it is aimed to increase the ductility of the frames.  Through the selected reinforcement techniques, obtained both the increase in the seismic load carrying capacity and the ductility.Keywords: Strengthening Techniques, Seismic Performance, Strengthening with Steel Brace, Reinforced Concrete Fram

Range resolved lidar for long distance ranging with sub-millimeter resolution

A lidar technique employing temporally stretched, frequency chirped pulses from a 20 MHz mode locked laser is presented. Sub-millimeter resolution at a target range of 10.1 km (in fiber) is observed. A pulse tagging scheme based on phase modulation is demonstrated for range resolved measurements. A carrier to noise ratio of 30 dB is observed at an unambiguous target distance of 30 meters in fiber