55 research outputs found
A Personalized Zero-Shot ECG Arrhythmia Monitoring System: From Sparse Representation Based Domain Adaption to Energy Efficient Abnormal Beat Detection for Practical ECG Surveillance
This paper proposes a low-cost and highly accurate ECG-monitoring system
intended for personalized early arrhythmia detection for wearable mobile
sensors. Earlier supervised approaches for personalized ECG monitoring require
both abnormal and normal heartbeats for the training of the dedicated
classifier. However, in a real-world scenario where the personalized algorithm
is embedded in a wearable device, such training data is not available for
healthy people with no cardiac disorder history. In this study, (i) we propose
a null space analysis on the healthy signal space obtained via sparse
dictionary learning, and investigate how a simple null space projection or
alternatively regularized least squares-based classification methods can reduce
the computational complexity, without sacrificing the detection accuracy, when
compared to sparse representation-based classification. (ii) Then we introduce
a sparse representation-based domain adaptation technique in order to project
other existing users' abnormal and normal signals onto the new user's signal
space, enabling us to train the dedicated classifier without having any
abnormal heartbeat of the new user. Therefore, zero-shot learning can be
achieved without the need for synthetic abnormal heartbeat generation. An
extensive set of experiments performed on the benchmark MIT-BIH ECG dataset
shows that when this domain adaptation-based training data generator is used
with a simple 1-D CNN classifier, the method outperforms the prior work by a
significant margin. (iii) Then, by combining (i) and (ii), we propose an
ensemble classifier that further improves the performance. This approach for
zero-shot arrhythmia detection achieves an average accuracy level of 98.2% and
an F1-Score of 92.8%. Finally, a personalized energy-efficient ECG monitoring
scheme is proposed using the above-mentioned innovations.Comment: Software implementation: https://github.com/MertDuman/Zero-Shot-EC
Delaying histone deacetylase response to injury accelerates conversion into repair Schwann cells and nerve regeneration
The peripheral nervous system (PNS) regenerates after injury. However, regeneration is often compromised in the case of large lesions, and the speed of axon reconnection to their target is critical for successful functional recovery. After injury, mature Schwann cells (SCs) convert into repair cells that foster axonal regrowth, and redifferentiate to rebuild myelin. These processes require the regulation of several transcription factors, but the driving mechanisms remain partially understood. Here we identify an early response to nerve injury controlled by histone deacetylase 2 (HDAC2), which coordinates the action of other chromatin-remodelling enzymes to induce the upregulation of Oct6, a key transcription factor for SC development. Inactivating this mechanism using mouse genetics allows earlier conversion into repair cells and leads to faster axonal regrowth, but impairs remyelination. Consistently, short-term HDAC1/2 inhibitor treatment early after lesion accelerates functional recovery and enhances regeneration, thereby identifying a new therapeutic strategy to improve PNS regeneration after lesion
Super Neurons
Self-Organized Operational Neural Networks (Self-ONNs) have recently been proposed as new-generation neural network models with nonlinear learning units, i.e., the generative neurons that yield an elegant level of diversity; however, like its predecessor, conventional Convolutional Neural Networks (CNNs), they still have a common drawback: localized (fixed) kernel operations. This severely limits the receptive field and information flow between layers and thus brings the necessity for deep and complex models. It is highly desired to improve the receptive field size without increasing the kernel dimensions. This requires a significant upgrade over the generative neurons to achieve the “non-localized kernel operations” for each connection between consecutive layers. In this article, we present superior (generative) neuron models (or super neurons in short) that allow random or learnable kernel shifts and thus can increase the receptive field size of each connection. The kernel localization process varies among the two super-neuron models. The first model assumes randomly localized kernels within a range and the second one learns (optimizes) the kernel locations during training. An extensive set of comparative evaluations against conventional and deformable convolutional, along with the generative neurons demonstrates that super neurons can empower Self-ONNs to achieve a superior learning and generalization capability with a minimal computational complexity burden. PyTorch implementation of Self-ONNs with super-neurons is now publically shared.Peer reviewe
EEF1A1 Deacetylation Enables Transcriptional Activation of Remyelination
Remyelination of the peripheral and central nervous systems (PNS and CNS, respectively) is a prerequisite for functional recovery after lesion. However, this process is not always optimal and becomes inefficient in the course of multiple sclerosis. Here we show that, when acetylated, eukaryotic elongation factor 1A1 (eEF1A1) negatively regulates PNS and CNS remyelination. Acetylated eEF1A1 (Ac- eEF1A1) translocates into the nucleus of myelinating cells where it binds to Sox10, a key transcription factor for PNS and CNS myelination and remyelination, to drag Sox10 out of the nucleus. We show that the lysine acetyltransferase Tip60 acetylates eEF1A1, whereas the histone deacetylase HDAC2 deacetylates eEF1A1. Promoting eEF1A1 deacetylation maintains the activation of Sox10 target genes and increases PNS and CNS remyelination efficiency. Taken together, these data identify a major mechanism of Sox10 regulation, which appears promising for future translational studies on PNS and CNS remyelination
Injured axons instruct schwann cells to build constricting actin spheres to accelerate axonal disintegration
After a peripheral nerve lesion, distal ends of injured axons disintegrate into small fragments that are subsequently cleared by Schwann cells and later by macrophages. Axonal debris clearing is an early step of the repair process that facilitates regeneration. We show here that Schwann cells promote distal cut axon disintegration for timely clearing. By combining cell-based and in vivo models of nerve lesion with mouse genetics, we show that this mechanism is induced by distal cut axons, which signal to Schwann cells through PlGF mediating the activation and upregulation of VEGFR1 in Schwann cells. In turn, VEGFR1 activates Pak1, leading to the formation of constricting actomyosin spheres along unfragmented distal cut axons to mediate their disintegration. Interestingly, oligodendrocytes can acquire a similar behavior as Schwann cells by enforced expression of VEGFR1. These results thus identify controllable molecular cues of a neuron-glia crosstalk essential for timely clearing of damaged axons
Ülkelerin nereye ihracat yaptığı önemlidir: Türkiye'nin ihracat sofistikasyonu ve ihracat partnerleri üzerine yorumlamalar
Bu yüksek lisans tezi temel olarak Türkiye'nin ihracat partnerlerinin ihracat sepetinin sofistikasyonu üzerindeki etkilerini araştırmaktadır. 1998-2011 dönemini içeren ve HS6 sınıflandırma sistemi ile elde edilen veriler kullanılarak ülke gruplarının Türkiye'nin toplam ihracatından aldıkları pay ile Türkiye'nin ihracat sepetinin niteliği arasındaki ilişkinin araştırıldığı çalışmada ayrıca, ihracat partnerlerinin ihraç mallarındaki teknoloji kullanımı üzerindeki etkisi de araştırılmaya çalışılmıştır. Bu çalışma, Türkiye'nin ihracat partnerlerinin hem ihracat sepetinin sofistikasyonu hem de ihraç ürünlerinin teknoloji kullanımı üzerinde etkileri olduğunu göstermektedir. Örneğin, Avrupa Birliği'nin Türkiye'nin toplam ihracatından aldığı payın artması hem Türkiye'nin ihracat sepetinin sofistikasyonunu hem de ihraç ürünlerinde orta-ileri ve ileri teknoloji kullanımını arttırırken bu durum MENA Bölgesi için tam tersidir. Türkiye'nin diğer ihracat partnerlerinin ihracat sepetinin sofistikasyonu ve ihraç ürünlerinin teknoloji kullanımı üzerindeki etkileri de çalışmada ayrıca sunulmuştur.This master thesis mainly aims to clarify the effects of export destinations of Turkey on product sophistication of its export basket with using Export data of Turkey between 1998 and 2011 with HS6 classification. Besides, effects of export destinations on technology usage of export products and how export products could be structured within country groups are also analyzed in this study by the light of the presence of relationship between export destinations and product sophistication. This study shows that export destinations of Turkey significantly matter on sophistication and technology usage of export products such that as share of European Union from Turkey's total export increases, both share of mid-high and high technology export commodities from total volume and product sophistication of export basket increase whilst it is in the opposite way for MENA. Moreover, effects of other export destinations of Turkey on both sophistication and technology usage of export products are analyzed in the study
Türkiye reasürans ve sigorta sektöründeki gelişmenin yabancı sermaye sektörüne etkisi
ÖZETTÜRKĠYE SĠGORTA VE REASÜRANS SEKTÖRÜNDEKĠGELĠġMENĠN YABANCI SERMAYE GĠRĠġĠNE ETKĠSĠÜlkelerin sosyoekonomik ve kültürel yaşamlarıyla iç içe ve hem riskyönetiminde hem de ekonomik gelişme ve büyümede önemli bir enstrüman olan sigortasektörü yapısının ve faaliyetlerinin rasyonel küresel faaliyetler olması gerekir.Ülkemizde bir yandan sektörün çağdaşlaşması yaşanırken bir yandan da sektörünkurumsal yapısının giderek yabancı şirketlerin ağırlık kazandığı bir yapıyadönüşmesinin, bir finans kurumu olarak gelecekte ülkeye etkileri neler olacaktır sorusuönem taşımaktadır.Türkiye sigorta sektöründe kurumsal yapının ve üretim faaliyetlerinin ülkeekonomisine ve Ödemeler Dengesine etkilerinin neler olabileceği, bu gelişmelerinYabancı Sermaye girişine etkileri, gerekçeleri ve önemi tez boyunca çeşitli açılardanincelenmiş; tüm bölümlerdeki bilgilerden çeşitli sonuçlara varılmıştır. Bölümlerdekiveriler en az beş yıllık olup çoğu on yıllıktır. Bu verilerin ışığında Türkiye‟de sektörünkurumsal yapısının giderek yabancı sermayenin yönetimine geçtiği ve buna rağmenüretimde son iki yıla dek önemli bir artışın olmadığı saptanmıştır.Özellikle Ödemeler Dengesi üzerinden sigorta girdi ve çıktılarıkarşılaştırıldığında aralıksız yıllar boyu Yabancı Sermaye artışı ile parasal çıkışlarıngirişlerden daha fazla olduğu dolayısıyla sektörün Ödemeler Dengesi açıklarınınkapatılmasına bir katkısının olmadığı ve neredeyse tamamen Yabancı Sermayekontrolüne geçtiği açığa çıkarılmıştır.Bazı bölümlerde analiz yöntemine yer verilse bile tezin tümünde tüme varımyöntemi kullanılmıştır. Veriler ve özellikle istatistikler için hem Dünya‟da hem deülkemizde güvenilirlikleri tartışılmayan kaynaklar kullanılmıştır.--------------------ABSTRACTEFFECT OF DEVELOPMENT IN INSURANCE AND REINSURANCEINDUSTRY IN TURKEY OVER FOREIGN INVESTMENT INCREASEThe insurance sector, which is an important instrument in the risk managementand economic development and growth, intertwined with the socioeconomic andcultural lives of the countries, must be rational global activities.. While themodernization of the sector is experienced in our country on the one hand, the questionof what will be the effects of the institutional structure of the sector to become astructure where foreign companies gain weight is important as a financial institution inthe future..Turkey institutional structure and production activities in the insurance sectorto the national economy and the Balance of Payments of what might be the effects, theeffects of foreign capital inflows from these developments, rationale and importance ofthis has been examined from various angles throughout the thesis; from theinformations in all sections various conclusions were reached. The data in the sectionsare at least five years and most of them are ten years. In the light of this data that theinstitutional structure of the sector in Turkey now increasingly getting under the controlof the management of foreign capital and it is found that until 2 years ago there werenot a significant increase in the production.In particular, when the insurance inputs and outputs were compared over theBalance of Payments, it was revealed that the increase in Foreign Capital and themonetary outflows were higher than the inflows for years, thus the sector did notcontribute to the closing of the Balance of Payments deficits and almost completelyunder the control of Foreign Capital.Even though the analysis method is included in some chapters, inductionmethod were used in the whole thesis. For the data and especially the statistics, thesources whose reliability was not discussed both in the world and in our country wereuse
Ortaöğretim Öğrencilerinde Kariyer Karar Verme Öz-Yeterliğinin Yordayıcıları Olarak Benlik Saygısı ve Algılanan Sosyal Destek
Bu araştırmanın amacı, ortaöğretim öğrencilerinde benlik saygısı ve algılanan sosyal
desteğin kariyer karar verme öz-yeterliğini yordamadaki rolünü incelemektir. Araştırmanın
çalışma grubu, 2016-2017 eğitim-öğretim yılında, Uşak ili merkezinde bulunan üç farklı
ortaöğretim kurumunda öğrenim görmekte olan ve araştırmaya gönüllü olarak katılmayı kabul
eden toplam 417 öğrenciden (249 kız – 168 erkek) oluşmaktadır. Araştırma, ilişkisel tarama
modeline uygun olarak gerçekleştirilmiştir. Bu çalışmada katılımcıların kariyer karar verme özyeterliği düzeylerini belirlemek amacıyla “Kariyer Karar Verme Öz-Yeterliği Ölçeği-Kısa
Form”, benlik saygısı düzeylerini belirlemek amacıyla “Rosenberg Benlik Saygısı Ölçeği” ve
algılanan sosyal destek düzeylerini belirleyebilmek için de “Çok Boyutlu Algılanan Sosyal
Destek Ölçeği” kullanılmıştır. Analizler, SPSS 17.0 paket programı aracılığıyla .05 ve .01
anlamlılık düzeyinde test edilmiştir. Veriler korelasyon, çoklu regresyon ve bağımsız
örneklemler t-testi teknikleri kullanılarak analiz edilmiştir. Araştırmanın bulgularında benlik
saygısı ve kariyer karar verme öz-yeterliği arasında pozitif yönlü anlamlı bir ilişkiye
rastlanmıştır. Benzer şekilde, algılanan sosyal destek ile kariyer karar verme öz-yeterliği
arasında da pozitif yönlü anlamlı bir ilişkiye rastlanmıştır. Bulgular, ortaöğretim öğrencilerinin
kariyer karar verme öz-yeterlikleri üzerinde benlik saygısı ve algılanan sosyal desteğin
yordayıcı rolünü ortaya koymuştur. Araştırmadan elde edilen bulgular, ilgili alanyazın ışığında
tartışılmış ve bazı önerilerde bulunulmuştur
Electrospinning of nanofibrous polycaprolactone (PCL) and collagen-blended polycaprolactone for wound dressing and tissue engineering
Fabrication of nanofibrous biomaterials based on natural materials through various techniques is a popular research topic, particularly for biomedical applications. Electrospinning, a well-established technique for nanofiber production has also been extended for producing nanofibrous structures of natural materials that mimic natural extracellular matrix of mammalian tissues. Collagen nanofiber production utilizes hexafluoro propanol (HFP) as a solvent for electrospinning. A novel cost-effective electrospun nanofibrous membrane is established for wound dressing and allogeneic cultured epidermal substitute through the cultivation of human dermal keratinocytes for skin defects. Several synthetic polymers such as polycaprolactone (PCL) are generally electrospun for tissue engineering applications because of their remarkable mechanical stability and slow degradation rates. The large surface area of the polymer nanofibers with specific modifications facilitates cell adhesion and control of their cellular functions. The objectives of this study were to optimize fabrication parameters of electrospun nanofibrous membranes from biodegradable PCL and collagen-blended nanofibrous membranes to combine mechanical integrity and spinnability of PCL with high biocompatibility of collagen, and to examine keratinocyte attachment, morphology, proliferation, and cell-matrix interactions. Results prove that the porous nanofibrous PCL and modified PCL-blended collagen nanofibrous membranes are suitable for the attachment and proliferation of keratinocytes, and might have the potential to be applied as wound dressing as well as in tissue engineering as an epidermal substitute for the treatment of skin defects and burn wounds
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