The surgical stress response: should it be prevented?

DEFF Research Database (Denmark)

Kehlet, H

1991-01-01

clinical trials have demonstrated a reduction in various aspects of postoperative morbidity by such a nociceptive blockade. Although a causal relationship has still to be demonstrated, these findings strongly argue the concept of "stress-free anesthesia and surgery" as an important instrument in improving......Postoperative complications such as myocardial infarction, pulmonary infection, thromboembolism and fatigue are probably related to increased demands, hypermetabolism, catabolism and other physiologic changes included in the global "surgical stress response." Strategies have been developed...... to suppress the detrimental components of the stress response so as to improve postoperative outcome. Of the various techniques to reduce the surgical stress response, afferent neural blockade with regional anesthesia to relieve pain is the most effective, although not optimal. Data from numerous controlled...

Modeling and simulation of permanent magnet synchronous motor based on neural network control strategy

Science.gov (United States)

Luo, Bingyang; Chi, Shangjie; Fang, Man; Li, Mengchao

2017-03-01

Permanent magnet synchronous motor is used widely in industry, the performance requirements wouldn't be met by adopting traditional PID control in some of the occasions with high requirements. In this paper, a hybrid control strategy - nonlinear neural network PID and traditional PID parallel control are adopted. The high stability and reliability of traditional PID was combined with the strong adaptive ability and robustness of neural network. The permanent magnet synchronous motor will get better control performance when switch different working modes according to different controlled object conditions. As the results showed, the speed response adopting the composite control strategy in this paper was faster than the single control strategy. And in the case of sudden disturbance, the recovery time adopting the composite control strategy designed in this paper was shorter, the recovery ability and the robustness were stronger.

The incidence, root-causes, and outcomes of adverse events in surgical units: implication for potential prevention strategies

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Groenewegen Peter P

2011-05-01

Full Text Available Abstract Background We need to know the scale and underlying causes of surgical adverse events (AEs in order to improve the safety of care in surgical units. However, there is little recent data. Previous record review studies that reported on surgical AEs in detail are now more than ten years old. Since then surgical technology and quality assurance have changed rapidly. The objective of this study was to provide more recent data on the incidence, consequences, preventability, causes and potential strategies to prevent AEs among hospitalized patients in surgical units. Methods A structured record review study of 7,926 patient records was carried out by trained nurses and medical specialist reviewers in 21 Dutch hospitals. The aim was to determine the presence of AEs during hospitalizations in 2004 and to consider how far they could be prevented. Of all AEs, the consequences, responsible medical specialty, causes and potential prevention strategies were identified. Surgical AEs were defined as AEs attributable to surgical treatment and care processes and were selected for analysis in detail. Results Surgical AEs occurred in 3.6% of hospital admissions and represented 65% of all AEs. Forty-one percent of the surgical AEs was considered to be preventable. The consequences of surgical AEs were more severe than for other types of AEs, resulting in more permanent disability, extra treatment, prolonged hospital stay, unplanned readmissions and extra outpatient visits. Almost 40% of the surgical AEs were infections, 23% bleeding, and 22% injury by mechanical, physical or chemical cause. Human factors were involved in the causation of 65% of surgical AEs and were considered to be preventable through quality assurance and training. Conclusions Surgical AEs occur more often than other types of AEs, are more often preventable and their consequences are more severe. Therefore, surgical AEs have a major impact on the burden of AEs during hospitalizations

A review of current strategies to reduce intraoperative bacterial contamination of surgical wounds

OpenAIRE

Dohmen, Pascal M.; Konertz, Wolfgang

2007-01-01

Surgical site infections are a mean topic in cardiac surgery, leading to a prolonged hospitalization, and substantially increased morbidity and mortality. One source of pathogens is the endogenous flora of the patient?s skin, which can contaminate the surgical site. A number of preoperative skin care strategies are performed to reduce bacterial contamination like preoperative antiseptic showering, hair removal, antisepsis of the skin, adhesive barrier drapes, and antimicrobial prophylaxis. Fu...

Surgical data processing for smart intraoperative assistance systems

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Stauder Ralf

2017-09-01

Full Text Available Different components of the newly defined field of surgical data science have been under research at our groups for more than a decade now. In this paper, we describe our sensor-driven approaches to workflow recognition without the need for explicit models, and our current aim is to apply this knowledge to enable context-aware surgical assistance systems, such as a unified surgical display and robotic assistance systems. The methods we evaluated over time include dynamic time warping, hidden Markov models, random forests, and recently deep neural networks, specifically convolutional neural networks.

Multimodal strategies to improve surgical outcome

DEFF Research Database (Denmark)

Kehlet, Henrik; Wilmore, Douglas W

2002-01-01

OBJECTIVE: To evaluate the effect of modifying perioperative care in noncardiac surgical patients on morbidity, mortality, and other outcome measures. BACKGROUND: New approaches in pain control, introduction of techniques that reduce the perioperative stress response, and the more frequent use...... anesthesia in elective operations, and pilot studies of fast track surgical procedures using the multimodality approach. RESULTS: The introduction of newer approaches to perioperative care has reduced both morbidity and mortality in surgical patients. In the future, most elective operations will become day...... surgical procedures or require only 1 to 2 days of postoperative hospitalization. Reorganization of the perioperative team (anesthesiologists, surgeons, nurses, and physical therapists) will be essential to achieve successful fast track surgical programs. CONCLUSIONS: Understanding perioperative...

Inter-progenitor pool wiring: An evolutionarily conserved strategy that expands neural circuit diversity.

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Suzuki, Takumi; Sato, Makoto

2017-11-15

Diversification of neuronal types is key to establishing functional variations in neural circuits. The first critical step to generate neuronal diversity is to organize the compartmental domains of developing brains into spatially distinct neural progenitor pools. Neural progenitors in each pool then generate a unique set of diverse neurons through specific spatiotemporal specification processes. In this review article, we focus on an additional mechanism, 'inter-progenitor pool wiring', that further expands the diversity of neural circuits. After diverse types of neurons are generated in one progenitor pool, a fraction of these neurons start migrating toward a remote brain region containing neurons that originate from another progenitor pool. Finally, neurons of different origins are intermingled and eventually form complex but precise neural circuits. The developing cerebral cortex of mammalian brains is one of the best examples of inter-progenitor pool wiring. However, Drosophila visual system development has revealed similar mechanisms in invertebrate brains, suggesting that inter-progenitor pool wiring is an evolutionarily conserved strategy that expands neural circuit diversity. Here, we will discuss how inter-progenitor pool wiring is accomplished in mammalian and fly brain systems. Copyright © 2017 Elsevier Inc. All rights reserved.

Age-specific neural strategies to maintain motor performance after an acute social stress bout.

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Mehta, Ranjana K; Rhee, Joohyun

2017-07-01

Stress due to cognitive demands and fatigue have shown to impair motor performance in older adults; however, the effect of social stress and its influence on prefrontal cortex (PFC) functioning in older adults during upper extremity motor performance tasks is not known. The present study explored the after-effects of an acute social stress bout on neural strategies, measured using PFC and hand/arm muscle activation, and adopted by younger and older adults to maintain handgrip force control. Nine older [74.1 (6.5) years; three men, six women] and ten younger [24.2 (5.0) years, four men, six women] adults performed handgrip force control trials at 30% maximum voluntary contractions before and after the Trier Social Stress Test (TSST). PFC activity was measured using functional near infrared spectroscopy and muscle activity from the flexor and extensor carpi radialis (FCR/ECR) was measured using electromyography. In general, aging was associated with decreased force steadiness and force complexity with a concomitant increase in bilateral PFC activity. While motor performance remained comparable before and after the TSST stress session in both age groups, the associated neural strategies differed between groups. While the stress condition was associated with lower FCR and ECR activity in younger adults despite no change in the PFC activation, stress was associated with increases in FCR activity in older adults. This stress-related compensatory neural strategy of increasing hand/arm muscle activation, potentially via the additional recruitment of the stress-motor neural circuitry, may have played a role in maintaining motor performance in older adults.

Training strategy for convolutional neural networks in pedestrian gender classification

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Ng, Choon-Boon; Tay, Yong-Haur; Goi, Bok-Min

2017-06-01

In this work, we studied a strategy for training a convolutional neural network in pedestrian gender classification with limited amount of labeled training data. Unsupervised learning by k-means clustering on pedestrian images was used to learn the filters to initialize the first layer of the network. As a form of pre-training, supervised learning for the related task of pedestrian classification was performed. Finally, the network was fine-tuned for gender classification. We found that this strategy improved the network's generalization ability in gender classification, achieving better test results when compared to random weights initialization and slightly more beneficial than merely initializing the first layer filters by unsupervised learning. This shows that unsupervised learning followed by pre-training with pedestrian images is an effective strategy to learn useful features for pedestrian gender classification.

Overview of current surgical strategies for aortic disease in patients with Marfan syndrome.

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Miyahara, Shunsuke; Okita, Yutaka

2016-09-01

Marfan syndrome is a heritable, systemic disorder of the connective tissue with a high penetrance, named after Dr. Antoine Marfan. The most clinically important manifestations of this syndrome are cardiovascular pathologies which cause life-threatening events, such as acute aortic dissections, aortic rupture and regurgitation of the aortic valve or other artrioventricular valves leading to heart failure. These events play important roles in the life expectancy of patients with this disorder, especially prior to the development of effective surgical approaches for proximal ascending aortic disease. To prevent such catastrophic aortic events, a lower threshold has been recommended for prophylactic interventions on the aortic root. After prophylactic root replacement, disease in the aorta beyond the root and distal to the arch remains a cause for concern. Multiple surgeries are required throughout a patient's lifetime that can be problematic due to distal lesions complicated by dissection. Many controversies in surgical strategies remain, such as endovascular repair, to manage such complex cases. This review examines the trends in surgical strategies for the treatment of cardiovascular disease in patients with Marfan syndrome, and current perspectives in this field.

Cognitive and neural strategies during control of the anterior cingulate cortex by fMRI neurofeedback in patients with schizophrenia

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Julia S Cordes

2015-06-01

Full Text Available Cognitive functioning is impaired in patients with schizophrenia, leading to significant disabilities in everyday functioning. Its improvement is an important treatment target. Neurofeedback (NF seems a promising method to address the neural dysfunctions underlying those cognitive impairments. The anterior cingulate cortex (ACC, a central hub for cognitive processing, is one of the dysfunctional brain regions in schizophrenia. Here we conducted NF training based on real-time functional magnetic resonance imaging (fMRI in patients with schizophrenia to enable them to control their ACC activity. Training was performed over three days in a group of 11 patients with schizophrenia and 11 healthy controls. Social feedback was provided in accordance with the evoked activity in the selected region of interest (ROI. Neural and cognitive strategies were examined off-line. Both groups learned to control the activity of their ACC but used different neural strategies: Patients activated the dorsal and healthy controls the rostral subdivision. Patients mainly used imagination of music to elicit activity and the control group imagination of sports. However, the difference in neural control did not result from the differences in cognitive strategies but from diagnosis alone. Based on social reinforcers, schizophrenia patients can learn to regulate localized brain activity. Cognitive strategies and neural network location differ, however, from healthy controls. These data emphasize that for therapeutic interventions in schizophrenia compensatory strategies may emerge. Specific cognitive skills or specific dysfunctional networks should be addressed to train impaired skills. Social neurofeedback based on fMRI may be one method to accomplish precise learning targets.

[Ladder step strategy for surgical repair of congenital concealed penis in children].

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Wang, Fu-Ran; Zhong, Hong-Ji; Chen, Yi; Zhao, Jun-Feng; Li, Yan

2016-11-01

To assess the feasibility of the ladder step strategy in surgical repair of congenital concealed penis in children. This study included 52 children with congenital concealed penis treated in the past two years by surgical repair using the ladder step strategy, which consists of five main steps: cutting the narrow ring of the foreskin, degloving the penile skin, fixing the penile skin at the base, covering the penile shaft, and reshaping the prepuce. The perioperative data of the patients were prospectively collected and statistically described. Of the 52 patients, 20 needed remodeling of the frenulum and 27 received longitudinal incision in the penoscrotal junction to expose and deglove the penile shaft. The advanced scrotal flap technique was applied in 8 children to cover the penile shaft without tension, the pedicled foreskin flap technique employed in 11 to repair the penile skin defect, and excision of the webbed skin of the ventral penis performed in another 44 to remodel the penoscrotal angle. The operation time, blood loss, and postoperative hospital stay were 40－100 minutes, 5－30 ml, and 3－6 days, respectively. Wound bleeding and infection occurred in 1 and 5 cases, respectively. Follow-up examinations at 3 and 6 months after surgery showed that all the children had a satisfactory penile appearance except for some minor complications (2 cases of penile retraction, 2 cases of redundant ventral skin, and 1 case of iatrogenic penile curvature). The ladder step strategy for surgical repair of congenital concealed penis in children is a simple procedure with minor injury and satisfactory appearance of the penis.

Relationship between job stress level and coping strategies used by Hong Kong nurses working in an acute surgical unit.

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Wang, Wenru; Kong, Amelia Wai Man; Chair, Sek Ying

2011-11-01

The aim of this study is to explore the relationship between job stress and coping strategies of Hong Kong nurses working in an acute surgical unit. This is a descriptive correlational study. Data were collected from 98 Hong Kong surgical nurses using the Nursing Stress Scale and the Jalowiec Coping Scale. Results showed that workload (M = 15.36), lack of support (M = 13.32), and inadequate preparation (M = 12.33) are the most common stressors for Hong Kong surgical nurses. The most frequent strategies used by nurses to cope with stress can be characterized as evasive (M = 19.23), confrontive (M = 17.46), and optimistic (M = 15.81), all of which are also rated as the most effective strategies in reducing stress levels. Only the confrontive, optimistic, supportant, and emotive coping strategies reveal significant correlations (p stress levels of nurses, whereas the evasive, fatalistic, palliative, and self-reliant strategies showed no significant correlation with stress levels (p > .05). Recognizing the impacts of job-related stress and making use of effective coping methods play a vital role in reducing nurse's stress. A change in leadership styles from the managerial level and reallocation of manpower may help reduce job stress. The use of confrontive and optimistic coping strategies in reducing job-related stress for surgical nurses should be advocated and promoted in their daily work. Copyright © 2011 Elsevier Inc. All rights reserved.

Proposed health state awareness of helicopter blades using an artificial neural network strategy

Science.gov (United States)

Lee, Andrew; Habtour, Ed; Gadsden, S. A.

2016-05-01

Structural health prognostics and diagnosis strategies can be classified as either model or signal-based. Artificial neural network strategies are popular signal-based techniques. This paper proposes the use of helicopter blades in order to study the sensitivity of an artificial neural network to structural fatigue. The experimental setup consists of a scale aluminum helicopter blade exposed to transverse vibratory excitation at the hub using single axis electrodynamic shaker. The intent of this study is to optimize an algorithm for processing high-dimensional data while retaining important information content in an effort to select input features and weights, as well as health parameters, for training a neural network. Data from accelerometers and piezoelectric transducers is collected from a known system designated as healthy. Structural damage will be introduced to different blades, which they will be designated as unhealthy. A variety of different tests will be performed to track the evolution and severity of the damage. A number of damage detection and diagnosis strategies will be implemented. A preliminary experiment was performed on aluminum cantilever beams providing a simpler model for implementation and proof of concept. Future work will look at utilizing the detection information as part of a hierarchical control system in order to mitigate structural damage and fatigue. The proposed approach may eliminate massive data storage on board of an aircraft through retaining relevant information only. The control system can then employ the relevant information to intelligently reconfigure adaptive maneuvers to avoid harmful regimes, thus, extending the life of the aircraft.

How are things adding up? Neural differences between arithmetic operations are due to general problem solving strategies.

Science.gov (United States)

Tschentscher, Nadja; Hauk, Olaf

2014-05-15

A number of previous studies have interpreted differences in brain activation between arithmetic operation types (e.g. addition and multiplication) as evidence in favor of distinct cortical representations, processes or neural systems. It is still not clear how differences in general task complexity contribute to these neural differences. Here, we used a mental arithmetic paradigm to disentangle brain areas related to general problem solving from those involved in operation type specific processes (addition versus multiplication). We orthogonally varied operation type and complexity. Importantly, complexity was defined not only based on surface criteria (for example number size), but also on the basis of individual participants' strategy ratings, which were validated in a detailed behavioral analysis. We replicated previously reported operation type effects in our analyses based on surface criteria. However, these effects vanished when controlling for individual strategies. Instead, procedural strategies contrasted with memory retrieval reliably activated fronto-parietal and motor regions, while retrieval strategies activated parietal cortices. This challenges views that operation types rely on partially different neural systems, and suggests that previously reported differences between operation types may have emerged due to invalid measures of complexity. We conclude that mental arithmetic is a powerful paradigm to study brain networks of abstract problem solving, as long as individual participants' strategies are taken into account. Copyright © 2014 Elsevier Inc. All rights reserved.

Control Strategy Based on Wavelet Transform and Neural Network for Hybrid Power System

Directory of Open Access Journals (Sweden)

Y. D. Song

2013-01-01

Full Text Available This paper deals with an energy management of a hybrid power generation system. The proposed control strategy for the energy management is based on the combination of wavelet transform and neural network arithmetic. The hybrid system in this paper consists of an emulated wind turbine generator, PV panels, DC and AC loads, lithium ion battery, and super capacitor, which are all connected on a DC bus with unified DC voltage. The control strategy is responsible for compensating the difference between the generated power from the wind and solar generators and the demanded power by the loads. Wavelet transform decomposes the power difference into smoothed component and fast fluctuated component. In consideration of battery protection, the neural network is introduced to calculate the reference power of battery. Super capacitor (SC is controlled to regulate the DC bus voltage. The model of the hybrid system is developed in detail under Matlab/Simulink software environment.

A Parallel Strategy for Convolutional Neural Network Based on Heterogeneous Cluster for Mobile Information System

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Jilin Zhang

2017-01-01

Full Text Available With the development of the mobile systems, we gain a lot of benefits and convenience by leveraging mobile devices; at the same time, the information gathered by smartphones, such as location and environment, is also valuable for business to provide more intelligent services for customers. More and more machine learning methods have been used in the field of mobile information systems to study user behavior and classify usage patterns, especially convolutional neural network. With the increasing of model training parameters and data scale, the traditional single machine training method cannot meet the requirements of time complexity in practical application scenarios. The current training framework often uses simple data parallel or model parallel method to speed up the training process, which is why heterogeneous computing resources have not been fully utilized. To solve these problems, our paper proposes a delay synchronization convolutional neural network parallel strategy, which leverages the heterogeneous system. The strategy is based on both synchronous parallel and asynchronous parallel approaches; the model training process can reduce the dependence on the heterogeneous architecture in the premise of ensuring the model convergence, so the convolution neural network framework is more adaptive to different heterogeneous system environments. The experimental results show that the proposed delay synchronization strategy can achieve at least three times the speedup compared to the traditional data parallelism.

Strategies for memory-based decision making: Modeling behavioral and neural signatures within a cognitive architecture.

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Fechner, Hanna B; Pachur, Thorsten; Schooler, Lael J; Mehlhorn, Katja; Battal, Ceren; Volz, Kirsten G; Borst, Jelmer P

2016-12-01

How do people use memories to make inferences about real-world objects? We tested three strategies based on predicted patterns of response times and blood-oxygen-level-dependent (BOLD) responses: one strategy that relies solely on recognition memory, a second that retrieves additional knowledge, and a third, lexicographic (i.e., sequential) strategy, that considers knowledge conditionally on the evidence obtained from recognition memory. We implemented the strategies as computational models within the Adaptive Control of Thought-Rational (ACT-R) cognitive architecture, which allowed us to derive behavioral and neural predictions that we then compared to the results of a functional magnetic resonance imaging (fMRI) study in which participants inferred which of two cities is larger. Overall, versions of the lexicographic strategy, according to which knowledge about many but not all alternatives is searched, provided the best account of the joint patterns of response times and BOLD responses. These results provide insights into the interplay between recognition and additional knowledge in memory, hinting at an adaptive use of these two sources of information in decision making. The results highlight the usefulness of implementing models of decision making within a cognitive architecture to derive predictions on the behavioral and neural level. Copyright © 2016 Elsevier B.V. All rights reserved.

Complete Expulsion of Testicular Prosthesis via the Scrotum: A Case-Based Review of the Preventive Surgical Strategies

Directory of Open Access Journals (Sweden)

Jack Donati-Bourne

2015-01-01

Full Text Available Testicular prostheses are regularly used in urological surgery and are important for postoperative psychological well-being in many patients undergoing orchiectomy. One of the recognised complications of this procedure is graft extrusion, which can result in significant morbidity for patients and require operative reintervention. Whilst most cases of extrusion involve upward graft migration to the external inguinal ring or direct displacement through the scrotal skin, we present an unusual case of complete expulsion of testicular implant three weeks postoperatively through a previously healthy scrotum. During surgical insertion of testicular prostheses, the urological surgeon must carefully consider the different surgical strategies at each step of the operation to prevent future extrusion of the graft. A stepwise review of the preventive surgical strategies to reduce the risk of graft extrusion encompasses the choice of optimal surgical incision, the technique of dissection to create the receiving anatomical pouch, the method of fixation of the implant within the receiving hemiscrotum, and the adoption of good postoperative care measures in line with the principles of sound scrotal surgery.

PREDIKSI CHURN DAN SEGMENTASI PELANGGAN MENGGUNAKAN BACKPROPAGATION NEURAL NETWORK BERBASIS EVOLUTION STRATEGIES

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Junta Zeniarja

2015-05-01

Full Text Available Pelanggan merupakan bagian penting dalam memastikan keunggulan dan kelangsungan hidup perusahaan. Oleh karena itu perlu untuk memiliki sistem manajemen untuk memastikan pelanggan tetap setia dan tidak pindah ke pesaing lain, yang dikenal sebagai manajemen churn. Prediksi churn pelanggan adalah bagian dari manajemen churn, yang memprediksi perilaku pelanggan dengan klasifikasi pelanggan setia dan mana yang cenderung pindah ke kompetitor lain. Keakuratan prediksi ini mutlak diperlukan karena tingginya tingkat migrasi pelanggan ke perusahaan pesaing. Hal ini penting karena biaya yang digunakan untuk meraih pelanggan baru jauh lebih tinggi dibandingkan dengan mempertahankan loyalitas pelanggan yang sudah ada. Meskipun banyak studi tentang prediksi churn pelanggan yang telah dilakukan, penelitian lebih lanjut masih diperlukan untuk meningkatkan akurasi prediksi. Penelitian ini akan membahas penggunaan teknik data mining Backpropagation Neural Network (BPNN in hybrid dengan Strategi Evolution (ES untuk atribut bobot. Validasi model dilakukan dengan menggunakan validasi Palang 10-Fold dan evaluasi pengukuran dilakukan dengan menggunakan matriks kebingungan dan Area bawah ROC Curve (AUC. Hasil percobaan menunjukkan bahwa hibrida BPNN dengan ES mencapai kinerja yang lebih baik daripada Basic BPNN. Kata kunci: data mining, churn, prediksi, backpropagation neural network, strategi evolusi.

Surgical orthodontics.

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Strohl, Alexis M; Vitkus, Lauren

2017-08-01

The article reviews some commonly used orthodontic treatments as well as new strategies to assist in the correction of malocclusion. Many techniques are used in conjunction with surgical intervention and are a necessary compliment to orthognathic surgery. Basic knowledge of these practices will aid in the surgeon's ability to adequately treat the patient. Many orthodontists and surgeons are eliminating presurgical orthodontics to adopt a strategy of 'surgery first' orthodontics in orthognathic surgery. This has the benefit of immediate improvement in facial aesthetics and shorter treatment times. The advent of virtual surgical planning has helped facilitate the development of this new paradigm by making surgical planning faster and easier. Furthermore, using intraoperative surgical navigation is improving overall precision and outcomes. A variety of surgical and nonsurgical treatments may be employed in the treatment of malocclusion. It is important to be familiar with all options available and tailor the patient's treatment plan accordingly. Surgery-first orthodontics, intraoperative surgical navigation, virtual surgical planning, and 3D printing are evolving new techniques that are producing shorter treatment times and subsequently improving patient satisfaction without sacrificing long-term stability.

The Shift from a Response Strategy to Object-in-Place Strategy during Learning Is Accompanied by a Matching Shift in Neural Firing Correlates in the Hippocampus

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Lee, Inah; Kim, Jangjin

2010-01-01

Hippocampal-dependent tasks often involve specific associations among stimuli (including egocentric information), and such tasks are therefore prone to interference from irrelevant task strategies before a correct strategy is found. Using an object-place paired-associate task, we investigated changes in neural firing patterns in the hippocampus in…

Addressing the burden of post-conflict surgical disease - strategies from the North Caucasus.

Science.gov (United States)

Lunze, Karsten; Lunze, Fatima I

2011-01-01

The 2004 terror attack on a school in Beslan, North Caucasus, with more than 1300 children and their families taken hostage and 334 people killed, ended after extreme violence. Following the disaster, many survivors with blast ear injuries developed complications because no microsurgery services were available in the region. Here, we present our strategies in North Ossetia to strengthen subspecialty surgical care in a region of instable security conditions. Disaster modifies disease burden in an environment of conflict-related health-care limitations. We built on available secondary care and partnered international with local stakeholders to reach and treat victims of a humanitarian disaster. A strategy of mutual commitment resulted in treatment of all consenting Beslan victims with blast trauma sequelae and of non disaster-related patients. Credible, sustained partnerships and needs assessments beyond the immediate phases after a disaster are essential to facilitate a meaningful transition from humanitarian aid to capacity building exceeding existing insufficient standards. Psychosocial impacts of disaster might constitute a barrier to care and need to be assessed when responding to the burden of surgical disease in conflict or post-conflict settings. Involving local citizen groups in the planning process can be useful to identify and access vulnerable populations. Integration of our strategy into broader efforts might strengthen the local health system through management and leadership.

Place of surgical resection in the treatment strategy of gastrointestinal neuroendocrine tumors.

Science.gov (United States)

Gaujoux, Sébastien; Sauvanet, Alain; Belghiti, Jacques

2012-09-01

Neuroendocrine tumors (NET) are usually slow-growing neoplasms carrying an overall favorable prognosis. Surgery, from resection to transplantation, remains the only potential curative option for these patients, and should always be considered. Nevertheless, because of very few randomized controlled trials available, the optimal treatment for these patients remains controversial, especially regarding the place of surgery. We herein discuss the place of surgical resection in the treatment strategy in neuroendocrine tumors of the digestive tract.

Surgical strategy for giant pituitary adenoma based on evaluation of fine feeding system and angioarchitecture

Directory of Open Access Journals (Sweden)

Yoshikazu Ogawa, M.D., Ph.D.

2017-06-01

Conclusion: Major blood supply was different from the normal supply to the anterior pituitary gland and did not necessarily correspond to tumor shape and extension. Surgical strategy should be established based on the tumor feeding systems and hemodynamics in giant pituitary adenomas.

Cooperating attackers in neural cryptography.

Science.gov (United States)

Shacham, Lanir N; Klein, Einat; Mislovaty, Rachel; Kanter, Ido; Kinzel, Wolfgang

2004-06-01

A successful attack strategy in neural cryptography is presented. The neural cryptosystem, based on synchronization of neural networks by mutual learning, has been recently shown to be secure under different attack strategies. The success of the advanced attacker presented here, called the "majority-flipping attacker," does not decay with the parameters of the model. This attacker's outstanding success is due to its using a group of attackers which cooperate throughout the synchronization process, unlike any other attack strategy known. An analytical description of this attack is also presented, and fits the results of simulations.

Connectivity strategies for higher-order neural networks applied to pattern recognition

Science.gov (United States)

Spirkovska, Lilly; Reid, Max B.

1990-01-01

Different strategies for non-fully connected HONNs (higher-order neural networks) are discussed, showing that by using such strategies an input field of 128 x 128 pixels can be attained while still achieving in-plane rotation and translation-invariant recognition. These techniques allow HONNs to be used with the larger input scenes required for practical pattern-recognition applications. The number of interconnections that must be stored has been reduced by a factor of approximately 200,000 in a T/C case and about 2000 in a Space Shuttle/F-18 case by using regional connectivity. Third-order networks have been simulated using several connection strategies. The method found to work best is regional connectivity. The main advantages of this strategy are the following: (1) it considers features of various scales within the image and thus gets a better sample of what the image looks like; (2) it is invariant to shape-preserving geometric transformations, such as translation and rotation; (3) the connections are predetermined so that no extra computations are necessary during run time; and (4) it does not require any extra storage for recording which connections were formed.

A NEURAL NETWORK BASED TRAFFIC-AWARE FORWARDING STRATEGY IN NAMED DATA NETWORKING

OpenAIRE

Parisa Bazmi; Manijeh Keshtgary

2016-01-01

Named Data Networking (NDN) is a new Internet architecture which has been proposed to eliminate TCP/IP Internet architecture restrictions. This architecture is abstracting away the notion of host and working based on naming datagrams. However, one of the major challenges of NDN is supporting QoS-aware forwarding strategy so as to forward Interest packets intelligently over multiple paths based on the current network condition. In this paper, Neural Network (NN) Based Traffic-aware Forwarding ...

Strategies to Prevent Surgical Site Infections in Acute Care Hospitals: 2014 Update

Science.gov (United States)

Anderson, Deverick J.; Podgorny, Kelly; Berríos-Torres, Sandra I.; Bratzler, Dale W.; Dellinger, E. Patchen; Greene, Linda; Nyquist, Ann-Christine; Saiman, Lisa; Yokoe, Deborah S.; Maragakis, Lisa L.; Kaye, Keith S.

2014-01-01

PURPOSE Previously published guidelines are available that provide comprehensive recommendations for detecting and preventing healthcare-associated infections (HAIs). The intent of this document is to highlight practical recommendations in a concise format designed to assist acute care hospitals in implementing and prioritizing their surgical site infection (SSI) prevention efforts. This document updates “Strategies to Prevent Surgical Site Infections in Acute Care Hospitals,”1 published in 2008. This expert guidance document is sponsored by the Society for Healthcare Epidemiology of America (SHEA) and is the product of a collaborative effort led by SHEA, the Infectious Diseases Society of America (IDSA), the American Hospital Association (AHA), the Association for Professionals in Infection Control and Epidemiology (APIC), and The Joint Commission, with major contributions from representatives of a number of organizations and societies with content expertise. The list of endorsing and supporting organizations is presented in the introduction to the 2014 updates.2 PMID:24799638

Tracking-by-detection of surgical instruments in minimally invasive surgery via the convolutional neural network deep learning-based method.

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Zhao, Zijian; Voros, Sandrine; Weng, Ying; Chang, Faliang; Li, Ruijian

2017-12-01

Worldwide propagation of minimally invasive surgeries (MIS) is hindered by their drawback of indirect observation and manipulation, while monitoring of surgical instruments moving in the operated body required by surgeons is a challenging problem. Tracking of surgical instruments by vision-based methods is quite lucrative, due to its flexible implementation via software-based control with no need to modify instruments or surgical workflow. A MIS instrument is conventionally split into a shaft and end-effector portions, while a 2D/3D tracking-by-detection framework is proposed, which performs the shaft tracking followed by the end-effector one. The former portion is described by line features via the RANSAC scheme, while the latter is depicted by special image features based on deep learning through a well-trained convolutional neural network. The method verification in 2D and 3D formulation is performed through the experiments on ex-vivo video sequences, while qualitative validation on in-vivo video sequences is obtained. The proposed method provides robust and accurate tracking, which is confirmed by the experimental results: its 3D performance in ex-vivo video sequences exceeds those of the available state-of -the-art methods. Moreover, the experiments on in-vivo sequences demonstrate that the proposed method can tackle the difficult condition of tracking with unknown camera parameters. Further refinements of the method will refer to the occlusion and multi-instrumental MIS applications.

3D bioprinting: A new insight into the therapeutic strategy of neural tissue regeneration.

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Hsieh, Fu-Yu; Hsu, Shan-hui

2015-01-01

Acute traumatic injuries and chronic degenerative diseases represent the world's largest unmet medical need. There are over 50 million people worldwide suffering from neurodegenerative diseases. However, there are only a few treatment options available for acute traumatic injuries and neurodegenerative diseases. Recently, 3D bioprinting is being applied to regenerative medicine to address the need for tissues and organs suitable for transplantation. In this commentary, the newly developed 3D bioprinting technique involving neural stem cells (NSCs) embedded in the thermoresponsive biodegradable polyurethane (PU) bioink is reviewed. The thermoresponsive and biodegradable PU dispersion can form gel near 37 °C without any crosslinker. NSCs embedded within the water-based PU hydrogel with appropriate stiffness showed comparable viability and differentiation after printing. Moreover, in the zebrafish embryo neural deficit model, injection of the NSC-laden PU hydrogels promoted the repair of damaged CNS. In addition, the function of adult zebrafish with traumatic brain injury was rescued after implantation of the 3D-printed NSC-laden constructs. Therefore, the newly developed 3D bioprinting technique may offer new possibilities for future therapeutic strategy of neural tissue regeneration.

Towards reducing thrombogenicity of LVAD therapy: optimizing surgical and patient management strategies

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Chivukula, Venkat Keshav; Lafzi, Ali; Mokadam, Nahush; Beckman, Jennifer; Mahr, Claudius; Aliseda, Alberto

2017-11-01

Unfavourable hemodynamics in heart failure patients implanted with left ventricular assist devices (LVAD), due to non-optimal surgical configurations and patient management, strongly influence thrombogenicity. This is consistent with the increase in devastating thromboembolic complications (specifically thrombosis and stroke) in patients, even as the risk of thrombosis inside the device decreases with modern designs. Inflow cannula and outflow graft surgical configurations have been optimized via patient-specific modeling that computes the thrombogenic potential with a combination of Eulerian (endothelial) wall shear stress and Lagrangian (platelet shear history) tracking. Using this view of hemodynamics, the benefits of intermittent aortic valve opening (promoting washout and reducing stagnant flow in the aortic valve region) have been assessed in managing the patient's residual native cardiac output. The use of this methodology to understand the contribution of the hemodynamics in the flow surrounding the LVAD itself to thrombogenesis show promise in developing holistic patient-specific management strategies to minimize stroke risk and enhance efficacy of LVAD therapy. Funded in part by an AHA postdoctoral fellowship 16POST30520004.

Economic and clinical contributions of an antimicrobial barrier dressing: a strategy for the reduction of surgical site infections.

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Leaper, David; Nazir, Jameel; Roberts, Chris; Searle, Richard

2010-01-01

In patients at risk of surgical site infection (SSI), there is evidence that an antimicrobial barrier dressing (Acticoat* ) applied immediately post-procedure is effective in reducing the incidence of infection. The objective of this study was to assess when it is appropriate to use an antimicrobial barrier dressing rather than a post-operative film dressing, by evaluating the net cost and budget impact of the two strategies. An economic model was developed, which estimates expected expenditure on dressings and the expected costs of surgical site infection during the initial inpatient episode, based on published literature on the pre-discharge costs of surgical infection and the efficacy of an antimicrobial barrier dressing in preventing SSI. At an SSI risk of 10%, an antimicrobial barrier dressing strategy is cost neutral if the incidence of infection is reduced by at least 9% compared with a post-operative film dressing. At 35% efficacy, expenditure on dressings would be higher by £30,760 per 1000 patients, and the cost of treating infection would be lower by £111,650, resulting in a net cost saving of £80,890. The break-even infection risk for cost neutrality is 2.6%. Although this cost analysis is based on published data, there are limitations in methodology: the model is dependent on and subject to the limitations of the data used to populate it. Further studies would be useful to increase the robustness of the conclusions, particularly in a broader range of surgical specialties. A strategy involving the use of an antimicrobial barrier dressing in patients at moderate (5-10%) or high (>10%) risk of infection appears reasonable and cost saving in light of the available clinical evidence.

Biomedical engineering strategies for peripheral nerve repair: surgical applications, state of the art, and future challenges.

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Pfister, Bryan J; Gordon, Tessa; Loverde, Joseph R; Kochar, Arshneel S; Mackinnon, Susan E; Cullen, D Kacy

2011-01-01

Damage to the peripheral nervous system is surprisingly common and occurs primarily from trauma or a complication of surgery. Although recovery of nerve function occurs in many mild injuries, outcomes are often unsatisfactory following severe trauma. Nerve repair and regeneration presents unique clinical challenges and opportunities, and substantial contributions can be made through the informed application of biomedical engineering strategies. This article reviews the clinical presentations and classification of nerve injuries, in addition to the state of the art for surgical decision-making and repair strategies. This discussion presents specific challenges that must be addressed to realistically improve the treatment of nerve injuries and promote widespread recovery. In particular, nerve defects a few centimeters in length use a sensory nerve autograft as the standard technique; however, this approach is limited by the availability of donor nerve and comorbidity associated with additional surgery. Moreover, we currently have an inadequate ability to noninvasively assess the degree of nerve injury and to track axonal regeneration. As a result, wait-and-see surgical decisions can lead to undesirable and less successful "delayed" repair procedures. In this fight for time, degeneration of the distal nerve support structure and target progresses, ultimately blunting complete functional recovery. Thus, the most pressing challenges in peripheral nerve repair include the development of tissue-engineered nerve grafts that match or exceed the performance of autografts, the ability to noninvasively assess nerve damage and track axonal regeneration, and approaches to maintain the efficacy of the distal pathway and targets during the regenerative process. Biomedical engineering strategies can address these issues to substantially contribute at both the basic and applied levels, improving surgical management and functional recovery following severe peripheral nerve injury.

Glycemic control strategies and the occurrence of surgical site infection: a systematic review.

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Domingos, Caroline Maria Herrero; Iida, Luciana Inaba Senyer; Poveda, Vanessa de Brito

2016-01-01

To analyze the evidence available in the scientific literature regarding the relationship between the glycemic control strategies used and the occurrence of surgical site infection in adult patients undergoing surgery. This is a systematic review performed through search on the databases of CINAHL, MEDLINE, LILACS, Cochrane Database of Systematic Reviews and EMBASE. Eight randomized controlled trials were selected. Despite the diversity of tested interventions, studies agree that glycemic control is essential to reduce rates of surgical site infection, and should be maintained between 80 and 120 mg/dL during the perioperative period. Compared to other strategies, insulin continuous infusion during surgery was the most tested and seems to get better results in reducing rates of surgical site infection and achieving success in glycemic control. Tight glycemic control during the perioperative period benefits the recovery of surgical patients, and the role of the nursing team is key for the successful implementation of the measure. Analisar as evidências disponíveis na literatura científica sobre a relação entre as estratégias de controle glicêmico efetuadas e a ocorrência de infecção do sítio cirúrgico em pacientes adultos submetidos à cirurgia. Trata-se de revisão sistemática, por meio das bases de dados CINAHL, MEDLINE, LILACS, Cochrane Database of Systematic Reviews e EMBASE. Foram selecionados oito ensaios clínicos randomizados. Apesar da diversidade de intervenções testadas, os estudos concordam que o controle glicêmico é essencial para a redução das taxas de infecção do sítio cirúrgico e deve ser mantido entre 80 e 120 mg/dL durante o perioperatório. A infusão contínua de insulina no transoperatório foi a mais testada e parece obter melhores resultados na redução das taxas de infecção do sítio cirúrgico e sucesso no controle glicêmico comparada às demais estratégias. O controle glicêmico rigoroso durante o perioperat

[The "window" surgical exposure strategy of the upper anterior cervical retropharyngeal approach for anterior decompression at upper cervical spine].

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Wu, Xiang-Yang; Zhang, Zhe; Wu, Jian; Lü, Jun; Gu, Xiao-Hui

2009-11-01

To investigate the "window" surgical exposure strategy of the upper anterior cervical retropharyngeal approach for the exposure and decompression and instrumentation of the upper cervical spine. From Jan. 2000 to July 2008, 5 patients with upper cervical spinal injuries were treated by surgical operation included 4 males and 1 female with and average age of 35 years old ranging from 16 to 68 years. There were 2 cases of Hangman's fractures (type II ), 2 of C2.3 intervertebral disc displacement and 1 of C2 vertebral body tuberculosis. All patients underwent the upper cervical anterior retropharyngeal approach through the "window" between the hypoglossal nerve and the superior laryngeal nerve and pharynx and carotid artery. Two patients of Hangman's fractures underwent the C2,3 intervertebral disc discectomy, bone graft fusion and internal fixation. Two patients of C2,3 intervertebral disc displacement underwent the C2,3 intervertebral disc discectomy, decompression bone graft fusion and internal fixation. One patient of C2 vertebral body tuberculosis was dissected and resected and the focus and the cavity was filled by bone autografting. C1 anterior arch to C3 anterior vertebral body were successful exposed. Lesion resection or decompression and fusion were successful in all patients. All patients were followed-up for from 5 to 26 months (means 13.5 months). There was no important vascular and nerve injury and no wound infection. Neutral symptoms was improved and all patient got successful fusion. The "window" surgical exposure surgical technique of the upper cervical anterior retropharyngeal approach is a favorable strategy. This approach strategy can be performed with full exposure for C1-C3 anterior anatomical structure, and can get minimally invasive surgery results and few and far between wound complication, that is safe if corresponding experience is achieved.

[The clinical features and surgical treatment strategies of cervical kyphosis].

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Fang, Jia-hu; Jia, Lian-shun; Zhou, Xu-hui; Song, Li-jun; Cai, Wei-hua; Li, Xiang

2010-10-15

To analyze the clinical characteristics and the surgical treatment strategy of cervical kyphosis. From March 2006 to October 2009, 31 cases of cervical kyphosis were treated. According to the clinical features and imaging findings, different treatment methods were used. There were 9 patients in operation group, including 4 male and 5 female patients, aged from 17 to 72 years (average age of 35 years). Among them, 5 cases were idiopathic kyphosis and 4 cases were caused by laminectomy or other reasons. There were 22 patients in conservative treatment group, including 11 male and 11 female patients, aged from 14 to 40 years (average age of 29 years), who were all idiopathic cervical kyphosis. Before and 1 week after operation, clinical assessment were taken for the patients in operation group using Spinal Cord Injuries Classification Standard of American Spinal Injury Association (AISA). During the periodic review, the anteroposterior, normal sagittal films of cervical spine were taken. At 1 week and every 6 months after operation, MRI films were also taken. These films were studied to evaluate the effects of the operations. In the conservative group, assessment of treatment results by studying anteroposterior and normal lateral views of cervical spine were were taken every month. The clinical characteristics and the surgical treatment strategies of these patients were analyzed. In operation group, 9 cases were followed up for 6 to 18 months, all patients did not failed in internal fixation and fusion. AISA neurological score and neurological function significantly improved. Three days after operation the average Cobb angle was -1.29 ° (preoperative 54.24 °). In conservative group, the average Cobb angle was -5.41 ° (before treatment 11.20 °) 4 months after the treatment. The symptoms of neck shoulder and back pain disappeared, and all patients were followed up for 3 to 24 months, with no recurrence of symptoms. In the early period of cervical kyphosis, adopt

Secular trends in mortality associated with new therapeutic strategies in surgical critical illness.

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Hartl, Wolfgang H; Wolf, Hilde; Schneider, Christian P; Küchenhoff, Helmut; Jauch, Karl-Walter

2007-10-01

Since 1999 randomized controlled trials have shown that new therapeutic strategies, such as strict glycemic control, increased use of noninvasive ventilation and of lung-protective ventilation, and early goal-oriented shock therapy, may reduce mortality in selected groups of critically ill patients. Whether these benefits can be translated to a surgical clinical setting is unclear. We wanted to evaluate longitudinally the successive routine implementation of new therapeutic measures and its effect on postsurgical patients admitted to the intensive care unit. We performed a retrospective analysis on data collected prospectively from March 1, 1993 through February 28, 2005. A cohort of 1,802 consecutive cases requiring intensive care therapy for more than 4 days was analyzed. A significant decrease in mortality was observed in the last years of the study. With adjustment for relevant covariates, treatment after the implementation of new therapeutic strategies was identified as an independent factor linked with a reduced risk of death (odds ratio [OR] .518; 95% confidence interval [CI] .337-.796), whereas older age (OR 1.030; 95% CI 1.015-1.045), a high severity score on admission (OR 1.155; 95% CI 1.113-1.198) or during intensive care unit stay (OR 1.187; 95% CI 1.145-1.231), a high number of failing organs (OR 1.918; 95% CI 1.635-2.250), and peritonitis (OR 3.277; 95% CI 2.046-5.246) were independently associated with death. Implementing of a variety of new therapeutic measures into routine care of critically ill surgical patients was associated with improved survival after 2001.

Surgical management of spinal intramedullary tumors: radical and safe strategy for benign tumors.

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Takami, Toshihiro; Naito, Kentaro; Yamagata, Toru; Ohata, Kenji

2015-01-01

Surgery for spinal intramedullary tumors remains one of the major challenges for neurosurgeons, due to their relative infrequency, unknown natural history, and surgical difficulty. We are sure that safe and precise resection of spinal intramedullary tumors, particularly encapsulated benign tumors, can result in acceptable or satisfactory postoperative outcomes. General surgical concepts and strategies, technical consideration, and functional outcomes after surgery are discussed with illustrative cases of spinal intramedullary benign tumors such as ependymoma, cavernous malformation, and hemangioblastoma. Selection of a posterior median sulcus, posterolateral sulcus, or direct transpial approach was determined based on the preoperative imaging diagnosis and careful inspection of the spinal cord surface. Tumor-cord interface was meticulously delineated in cases of benign encapsulated tumors. Our retrospective functional analysis of 24 consecutive cases of spinal intramedullary ependymoma followed for at least 6 months postoperatively demonstrated a mean grade on the modified McCormick functional schema of 1.8 before surgery, deteriorating significantly to 2.6 early after surgery ( 6 months after surgery). The risk of functional deterioration after surgery should be taken into serious consideration. Functional deterioration after surgery, including neuropathic pain even long after surgery, significantly affects patient quality of life. Better balance between tumor control and functional preservation can be achieved not only by the surgical technique or expertise, but also by intraoperative neurophysiological monitoring, vascular image guidance, and postoperative supportive care. Quality of life after surgery should inarguably be given top priority.

Novel Strategy for Discrimination of Transcription Factor Binding Motifs Employing Mathematical Neural Network

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Sugimoto, Asuka; Sumi, Takuya; Kang, Jiyoung; Tateno, Masaru

2017-07-01

Recognition in biological macromolecular systems, such as DNA-protein recognition, is one of the most crucial problems to solve toward understanding the fundamental mechanisms of various biological processes. Since specific base sequences of genome DNA are discriminated by proteins, such as transcription factors (TFs), finding TF binding motifs (TFBMs) in whole genome DNA sequences is currently a central issue in interdisciplinary biophysical and information sciences. In the present study, a novel strategy to create a discriminant function for discrimination of TFBMs by constituting mathematical neural networks (NNs) is proposed, together with a method to determine the boundary of signals (TFBMs) and noise in the NN-score (output) space. This analysis also leads to the mathematical limitation of discrimination in the recognition of features representing TFBMs, in an information geometrical manifold. Thus, the present strategy enables the identification of the whole space of TFBMs, right up to the noise boundary.

Failed medial patellofemoral ligament reconstruction: Causes and surgical strategies

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Sanchis-Alfonso, Vicente; Montesinos-Berry, Erik; Ramirez-Fuentes, Cristina; Leal-Blanquet, Joan; Gelber, Pablo E; Monllau, Joan Carles

2017-01-01

Patellar instability is a common clinical problem encountered by orthopedic surgeons specializing in the knee. For patients with chronic lateral patellar instability, the standard surgical approach is to stabilize the patella through a medial patellofemoral ligament (MPFL) reconstruction. Foreseeably, an increasing number of revision surgeries of the reconstructed MPFL will be seen in upcoming years. In this paper, the causes of failed MPFL reconstruction are analyzed: (1) incorrect surgical indication or inappropriate surgical technique/patient selection; (2) a technical error; and (3) an incorrect assessment of the concomitant risk factors for instability. An understanding of the anatomy and biomechanics of the MPFL and cautiousness with the imaging techniques while favoring clinical over radiological findings and the use of common sense to determine the adequate surgical technique for each particular case, are critical to minimizing MPFL surgery failure. Additionally, our approach to dealing with failure after primary MPFL reconstruction is also presented. PMID:28251062

Distinct neural and neuromuscular strategies underlie independent evolution of simplified advertisement calls.

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Leininger, Elizabeth C; Kelley, Darcy B

2013-04-07

Independent or convergent evolution can underlie phenotypic similarity of derived behavioural characters. Determining the underlying neural and neuromuscular mechanisms sheds light on how these characters arose. One example of evolutionarily derived characters is a temporally simple advertisement call of male African clawed frogs (Xenopus) that arose at least twice independently from a more complex ancestral pattern. How did simplification occur in the vocal circuit? To distinguish shared from divergent mechanisms, we examined activity from the calling brain and vocal organ (larynx) in two species that independently evolved simplified calls. We find that each species uses distinct neural and neuromuscular strategies to produce the simplified calls. Isolated Xenopus borealis brains produce fictive vocal patterns that match temporal patterns of actual male calls; the larynx converts nerve activity faithfully into muscle contractions and single clicks. In contrast, fictive patterns from isolated Xenopus boumbaensis brains are short bursts of nerve activity; the isolated larynx requires stimulus bursts to produce a single click of sound. Thus, unlike X. borealis, the output of the X. boumbaensis hindbrain vocal pattern generator is an ancestral burst-type pattern, transformed by the larynx into single clicks. Temporally simple advertisement calls in genetically distant species of Xenopus have thus arisen independently via reconfigurations of central and peripheral vocal neuroeffectors.

Simulation-Based Learning Strategies to Teach Undergraduate Students Basic Surgical Skills: A Systematic Review.

Science.gov (United States)

Theodoulou, Iakovos; Nicolaides, Marios; Athanasiou, Thanos; Papalois, Apostolos; Sideris, Michail

2018-02-16

We aimed to identify and critically appraise all literature surrounding simulation-based learning (SBL) courses, to assess their relevance as tools for undergraduate surgical education, and create a design framework targeted at standardizing future SBL. We performed a systematic review of the literature using a specific keyword strategy to search at MEDLINE database. Of the 2371 potentially eligible titles, 472 were shortlisted and only 40 explored active interventions in undergraduate medical education. Of those, 20 were conducted in the United States, 9 in Europe and 11 in the rest of the world. Nineteen studies assessed the effectiveness of SBL by comparing students' attributes before and after interventions, 1 study assessed a new tool of surgical assessment and 16 studies evaluated SBL courses from the students' perspectives. Of those 40 studies, 12 used dry laboratory, 7 wet laboratory, 12 mixed, and 9 cadaveric SBL interventions. The extent to which positive results were obtained from dry, wet, mixed, and cadaveric laboratories were 75%, 57%, 92%, and 100%, respectively. Consequently, the SBL design framework was devised, providing a foundation upon which future SBL interventions can be designed such that learning outcomes are optimized. SBL is an important step in surgical education, investing in a safer and more efficient generation of surgeons. Standardization of these efforts can be accelerated with SBL design framework, a comprehensive guide to designing future interventions for basic surgical training at the undergraduate level. Copyright © 2018 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

Horizontal infection control strategy decreases methicillin-resistant Staphylococcus aureus infection and eliminates bacteremia in a surgical ICU without active surveillance.

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Traa, Maria X; Barboza, Lorena; Doron, Shira; Snydman, David R; Noubary, Farzad; Nasraway, Stanley A

2014-10-01

Methicillin-resistant Staphylococcus aureus infection is a significant contributor to morbidity and mortality in hospitalized patients worldwide. Numerous healthcare bodies in Europe and the United States have championed active surveillance per the "search and destroy" model. However, this strategy is associated with significant economic, logistical, and patient costs without any impact on other hospital-acquired pathogens. We evaluated whether horizontal infection control strategies could decrease the prevalence of methicillin-resistant S. aureus infection in the ICU, without the need for active surveillance. Retrospective, observational study in the surgical ICU of a tertiary care medical center in Boston, MA, from 2005 to 2012. A total of 6,697 patients in the surgical ICU. Evidence-based infection prevention strategies were implemented in an iterative fashion, including 1) hand hygiene program with refresher education campaign, 2) chlorhexidine oral hygiene program, 3) chlorhexidine bathing, 4) catheter-associated bloodstream infection program, and 5) daily goals sheets. The prevalence of methicillin-resistant S. aureus infection fell from 2.66 to 0.69 per 1,000 patient days from 2005 to 2012, an average decrease of 21% per year. The biggest decline in rate of infection was detected in 2008, which may suggest that the catheter-associated bloodstream infection prevention program was particularly effective. Among 4,478 surgical ICU admissions over the last 5 years, not a single case of methicillin-resistant S. aureus bacteremia was observed. Aggressive multifaceted horizontal infection control is an effective strategy for reducing the prevalence of methicillin-resistant S. aureus infection and eliminating methicillin-resistant S. aureus bacteremia in the ICU without the need for active surveillance and decontamination.

A NEURAL NETWORK BASED TRAFFIC-AWARE FORWARDING STRATEGY IN NAMED DATA NETWORKING

Directory of Open Access Journals (Sweden)

Parisa Bazmi

2016-11-01

Full Text Available Named Data Networking (NDN is a new Internet architecture which has been proposed to eliminate TCP/IP Internet architecture restrictions. This architecture is abstracting away the notion of host and working based on naming datagrams. However, one of the major challenges of NDN is supporting QoS-aware forwarding strategy so as to forward Interest packets intelligently over multiple paths based on the current network condition. In this paper, Neural Network (NN Based Traffic-aware Forwarding strategy (NNTF is introduced in order to determine an optimal path for Interest forwarding. NN is embedded in NDN routers to select next hop dynamically based on the path overload probability achieved from the NN. This solution is characterized by load balancing and QoS-awareness via monitoring the available path and forwarding data on the traffic-aware shortest path. The performance of NNTF is evaluated using ndnSIM which shows the efficiency of this scheme in terms of network QoS improvementof17.5% and 72% reduction in network delay and packet drop respectively.

Neuromuscular mechanisms and neural strategies in the control of time-varying muscle contractions.

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Erimaki, Sophia; Agapaki, Orsalia M; Christakos, Constantinos N

2013-09-01

The organization of the neural input to motoneurons that underlies time-varying muscle force is assumed to depend on muscle transfer characteristics and neural strategies or control modes utilizing sensory signals. We jointly addressed these interlinked, but previously studied individually and partially, issues for sinusoidal (range 0.5-5.0 Hz) force-tracking contractions of a human finger muscle. Using spectral and correlation analyses of target signal, force signal, and motor unit (MU) discharges, we studied 1) patterns of such discharges, allowing inferences on the motoneuronal input; 2) transformation of MU population activity (EMG) into quasi-sinusoidal force; and 3) relation of force oscillation to target, carrying information on the input's organization. A broad view of force control mechanisms and strategies emerged. Specifically, synchronized MU and EMG modulations, reflecting a frequency-modulated motoneuronal input, accompanied the force variations. Gain and delay drops between EMG modulation and force oscillation, critical for the appropriate organization of this input, occurred with increasing target frequency. According to our analyses, gain compensation was achieved primarily through rhythmical activation/deactivation of higher-threshold MUs and secondarily through the adaptation of the input's strength expected during tracking tasks. However, the input's timing was not adapted to delay behaviors and seemed to depend on the control modes employed. Thus, for low-frequency targets, the force oscillation was highly coherent with, but led, a target, this timing error being compatible with predictive feedforward control partly based on the target's derivatives. In contrast, the force oscillation was weakly coherent, but in phase, with high-frequency targets, suggesting control mainly based on a target's rhythm.

Mechanical ventilation strategies for the surgical patient

NARCIS (Netherlands)

Schultz, Marcus J.; Abreu, Marcelo Gama de; Pelosi, Paolo

2015-01-01

Purpose of review To summarize clinical evidence for intraoperative ventilation settings, which could protect against postoperative pulmonary complications (PPCs) in surgical patients with uninjured lungs. Recent findings There is convincing evidence for protection against PPCs by low tidal volumes:

Impact of the surgical strategy on the incidence of C5 nerve root palsy in decompressive cervical surgery.

Directory of Open Access Journals (Sweden)

Theresa Krätzig

Full Text Available Our aim was to identify the impact of different surgical strategies on the incidence of C5 palsy.Degenerative cervical spinal stenosis is a steadily increasing morbidity in the ageing population. Postoperative C5 nerve root palsy is a common complication with severe impact on the patients´ quality of life.We identified 1708 consecutive patients who underwent cervical decompression surgery due to degenerative changes. The incidence of C5 palsy and surgical parameters including type and level of surgery were recorded to identify predictors for C5 nerve palsy.The overall C5 palsy rate was 4.8%, with 18.3% of cases being bilateral. For ACDF alone the palsy rate was low (1.13%, compared to 14.0% of C5 palsy rate after corpectomy. The risk increased with extension of the procedures. Hybrid constructs with corpectomy plus ACDF at C3-6 showed significantly lower rates of C5 palsy (10.7% than corpectomy of two vertebrae (p = 0.005. Multiple regression analysis identified corpectomy of C4 or C5 as a significant predictor. We observed a lower overall incidence for ventral (4.3% compared to dorsal (10.9% approaches (p<0.001. When imaging detected a postoperative shift of the spinal cord at index segment C4/5, palsy rate increased significantly (33.3% vs. 12.5%, p = 0.034.Extended surgical strategies, such as dorsal laminectomies, multilevel corpectomies and procedures with extensive spinal cord shift were shown to display a high risk of C5 palsy. The use of extended procedures should therefore be employed cautiously. Switching to combined surgical methods like ACDF plus corpectomy can reduce the rate of C5 palsy.

Failed medial patellofemoral ligament reconstruction: Causes and surgical strategies

OpenAIRE

Sanchis-Alfonso, Vicente; Montesinos-Berry, Erik; Ramirez-Fuentes, Cristina; Leal Blanquet, Joan; Gelber, Pablo-Eduardo; Monllau García, Juan Carlos

2017-01-01

Patellar instability is a common clinical problem encountered by orthopedic surgeons specializing in the knee. For patients with chronic lateral patellar instability, the standard surgical approach is to stabilize the patella through a medial patellofemoral ligament (MPFL) reconstruction. Foreseeably, an increasing number of revision surgeries of the reconstructed MPFL will be seen in upcoming years. In this paper, the causes of failed MPFL reconstruction are analyzed: (1) incorrect surgical ...

Monitoring tool usage in surgery videos using boosted convolutional and recurrent neural networks.

Science.gov (United States)

Al Hajj, Hassan; Lamard, Mathieu; Conze, Pierre-Henri; Cochener, Béatrice; Quellec, Gwenolé

2018-05-09

This paper investigates the automatic monitoring of tool usage during a surgery, with potential applications in report generation, surgical training and real-time decision support. Two surgeries are considered: cataract surgery, the most common surgical procedure, and cholecystectomy, one of the most common digestive surgeries. Tool usage is monitored in videos recorded either through a microscope (cataract surgery) or an endoscope (cholecystectomy). Following state-of-the-art video analysis solutions, each frame of the video is analyzed by convolutional neural networks (CNNs) whose outputs are fed to recurrent neural networks (RNNs) in order to take temporal relationships between events into account. Novelty lies in the way those CNNs and RNNs are trained. Computational complexity prevents the end-to-end training of "CNN+RNN" systems. Therefore, CNNs are usually trained first, independently from the RNNs. This approach is clearly suboptimal for surgical tool analysis: many tools are very similar to one another, but they can generally be differentiated based on past events. CNNs should be trained to extract the most useful visual features in combination with the temporal context. A novel boosting strategy is proposed to achieve this goal: the CNN and RNN parts of the system are simultaneously enriched by progressively adding weak classifiers (either CNNs or RNNs) trained to improve the overall classification accuracy. Experiments were performed in a dataset of 50 cataract surgery videos, where the usage of 21 surgical tools was manually annotated, and a dataset of 80 cholecystectomy videos, where the usage of 7 tools was manually annotated. Very good classification performance are achieved in both datasets: tool usage could be labeled with an average area under the ROC curve of A z =0.9961 and A z =0.9939, respectively, in offline mode (using past, present and future information), and A z =0.9957 and A z =0.9936, respectively, in online mode (using past and present

Surgical treatment for central pain after stroke based on the neural mechanism

International Nuclear Information System (INIS)

Hirato, Masafumi; Takahashi, Akio; Watanabe, Katsushige; Kazama, Ken; Yoshimoto, Yuhei

2008-01-01

Previous neurophysiological and neuroimaging studies have suggested that functional changes might occur in the sensory thalamus, associated with reorganization of the thalamocortical system, in cases with central pain after stroke (thalamic pain). It might cause the misconduction of the sensory signal or a hyperactive response to peripheral natural stimulation on the thalamus, resulting in it playing an important roles in the genesis of central pain. Hyperactivity in the cerebral cortex adjacent to the central sulcus on the side ipsilateral to a cerebrovascular disease (CVD) lesion also might relate to central pain. We performed various kinds of surgical treatments in 29 cases with central pain after stroke based on the neural mechanism deserbed above. Epidural spinal cord stimulation was effective in 4 out of 7 cases with localized pain on the distal part of the leg and arm. We achieved pain control in these cases showing definite somatosensory evoked potential (SEP) originating in the sensory cortex before surgery. Stereotactic (Vim-Vcpc) thalamotomy with the aid of depth microrecording was effective in 4 out of 7 cases with diffuse pain. In good responders, we could find responses to natural peripheral stimulation and seldom encountered irregular burst discharges in the sensory thalamus during the operation. Preoperative positron emission tomography (PET) studies also revealed an increase of regional cerebral blood flow (rCBF) in the sensory cortex ipsilateral to the thalamic CVD lesion during contralateral thumb brushing. Gamma knife treatment was effective in 5 out of 7 cases after stereotactic thalamotomy. It became stable in 3 out of these 5 cases. Each case was treated with a maximum dose of 120-150 Gy using a 4 mm collimator. Precentral electrical cortical stimulation was performed in 8 cases. Sufficient pain relief was achieved in 3 out of 6 cases in which we could implant an importable pulse generator (IPG). In one of these cases, we found definite

Unlocking the “black box” of practice improvement strategies to implement surgical safety checklists: a process evaluation

Directory of Open Access Journals (Sweden)

Gillespie BM

2017-04-01

Full Text Available Brigid M Gillespie,1–3 Kyra Hamilton,4 Dianne Ball,5 Joanne Lavin,6 Therese Gardiner,6 Teresa K Withers,7 Andrea P Marshall1–3 1School of Nursing & Midwifery, Griffith University, Gold Coast, 2Gold Coast University Hospital and Health Service, Southport, 3Nursing & Midwifery Education & Research Unit (NMERU, National Centre of Research Excellence in Nursing, Menzies Health Institute of Queensland, Griffith University, Gold Coast, 4School of Applied Psychology, Griffith University, Mt Gravatt, 5Communio Pty Ltd, Sydney, 6Nursing & Midwifery Education & Research Unit, 7Surgical and Procedural Services, Gold Coast University Hospital and Health Service, Southport, Australia Background: Compliance with surgical safety checklists (SSCs has been associated with improvements in clinical processes such as antibiotic use, correct site marking, and overall safety processes. Yet, proper execution has been difficult to achieve.Objectives: The objective of this study was to undertake a process evaluation of four knowledge translation (KT strategies used to implement the Pass the Baton (PTB intervention which was designed to improve utilization of the SSC. Methods: As part of the process evaluation, a logic model was generated to explain which KT strategies worked well (or less well in the operating rooms of a tertiary referral hospital in Queensland, Australia. The KT strategies implemented included change champions/opinion leaders, education, audit and feedback, and reminders. In evaluating the implementation of these strategies, this study considered context, intervention and underpinning assumptions, implementation, and mechanism of impact. Observational and interview data were collected to assess implementation of the KT strategies relative to fidelity, feasibility, and acceptability. Results: Findings from 35 structured observations and 15 interviews with 96 intervention participants suggest that all of the KT strategies were consistently

The application of digital surgical diagnosis and treatment technology: a promising strategy for surgical reconstruction of craniomaxillofacial defect and deformity.

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Wang, Li-ya; Du, Hong-ming; Zhang, Gang; Tang, Wei; Liu, Lei; Jing, Wei; Long, Jie

2011-12-01

The craniomaxillofacial defect and deformity always leads to serious dysfunction in mastication and facial contour damage, significantly reducing patients' quality of life. However, surgical reconstruction of a craniomaxillofacial hard tissue defect or deformity is extremely complex and often does not result in desired facial morphology. Improving the result for patients with craniomaxillofacial defect and deformity remains a challenge for surgeons. Using digital technology for surgical diagnosis and treatment may help solve this problem. Computer-assisted surgical technology and surgical navigation technology are included in the accurate digital diagnosis and treatment system we propose. These technologies will increase the accuracy of the design of the operation plan. In addition, the intraoperative real-time navigating location system controlling the robotic arm or advanced intelligent robot will provide accurate, individualized surgical treatment for patients. Here we propose the hypothesis that a digital surgical diagnosis and treatment technology may provide a new approach for precise surgical reconstruction of complicated craniomaxillofacial defect and deformity. Our hypothesis involves modern digital surgery, a three-dimensional navigation surgery system and modern digital imaging technology, and our key aim is to establish a technological platform for customized digital surgical design and surgical navigation for craniomaxillofacial defect and deformity. If the hypothesis is proven practical, this novel therapeutic approach could improve the result of surgical reconstruction for craniomaxillofacial defect and deformity for many patients. Copyright © 2011 Elsevier Ltd. All rights reserved.

The introduction of an acute physiological support service for surgical patients is an effective error reduction strategy.

Science.gov (United States)

Clarke, D L; Kong, V Y; Naidoo, L C; Furlong, H; Aldous, C

2013-01-01

Acute surgical patients are particularly vulnerable to human error. The Acute Physiological Support Team (APST) was created with the twin objectives of identifying high-risk acute surgical patients in the general wards and reducing both the incidence of error and impact of error on these patients. A number of error taxonomies were used to understand the causes of human error and a simple risk stratification system was adopted to identify patients who are particularly at risk of error. During the period November 2012-January 2013 a total of 101 surgical patients were cared for by the APST at Edendale Hospital. The average age was forty years. There were 36 females and 65 males. There were 66 general surgical patients and 35 trauma patients. Fifty-six patients were referred on the day of their admission. The average length of stay in the APST was four days. Eleven patients were haemo-dynamically unstable on presentation and twelve were clinically septic. The reasons for referral were sepsis,(4) respiratory distress,(3) acute kidney injury AKI (38), post-operative monitoring (39), pancreatitis,(3) ICU down-referral,(7) hypoxia,(5) low GCS,(1) coagulopathy.(1) The mortality rate was 13%. A total of thirty-six patients experienced 56 errors. A total of 143 interventions were initiated by the APST. These included institution or adjustment of intravenous fluids (101), blood transfusion,(12) antibiotics,(9) the management of neutropenic sepsis,(1) central line insertion,(3) optimization of oxygen therapy,(7) correction of electrolyte abnormality,(8) correction of coagulopathy.(2) CONCLUSION: Our intervention combined current taxonomies of error with a simple risk stratification system and is a variant of the defence in depth strategy of error reduction. We effectively identified and corrected a significant number of human errors in high-risk acute surgical patients. This audit has helped understand the common sources of error in the general surgical wards and will inform

Surgical management of low grade isthmic spondylolisthesis; a randomized controlled study of the surgical fixation with and without reduction

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Bashaireh Khaldoon M

2011-07-01

Full Text Available Abstract Background spondylolisthesis is a condition in which a vertebra slips out of the proper position onto the bone below it as a result of pars interarticularis defect. The slipped segment produces abnormal positioning of the vertebrae in relation to each other along the spinal column and causes mechanical back pain and neural breach. Materials and methods A randomized and double blinded study consisted of 41 patients aged 36-69 years (18 females and 28 males treated for symptomatic spondylolisthesis between December,2006 and December, 2009. All patients were randomly distributed into two groups I and II. Twenty patients were in Group I; they underwent reduction of the slipped vertebrae by using Reduction-Screw Technique and posterior lumbar interbody fixation (PLIF. Group II consisted of twenty one patients who underwent only surgical fixation (PLIF without reduction. All patients in this study had same pre and post operative management. Results only one case had broken rod in group I that required revision. Superficial wound infection was experienced in two patients and one patient, from group II, developed wound hematoma. The outcome in both groups was variable on the short term but was almost the same on the long term follow up. Conclusion surgical management of symptomatic low grade spondylolisthesis should include neural decompression and surgical fixation. Reduction of slipped vertebral bodies is unnecessary as the ultimate outcome will be likely similar.

Neural substrates of male parochial altruism are modulated by testosterone and behavioral strategy.

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Reimers, Luise; Büchel, Christian; Diekhof, Esther K

2017-08-01

Parochial altruism refers to ingroup favoritism and outgroup hostility and has recently been linked to testosterone. Here, we investigated the neurobiological mechanism of parochial altruism in male soccer fans playing the ultimatum game (UG) against ingroup and outgroup members (i.e., fans of the favorite or of a rivalling team) using functional magnetic resonance imaging. Our results suggest that individual differences in altruistic tendency influence the tendency for parochialism. While altruistic subjects rejected unfair offers independent of team membership, the more self-oriented 'pro-selfs' displayed a stronger ingroup bias and rejected outgroup offers more often. However, during a second session that introduced a team competition the altruists adapted to this parochial pattern. Behavioral strategy was further characterized by dissociable and context-dependent correlations between endogenous testosterone and neural responses in the anterior insula and the ventromedial prefrontal cortex. In sum, the present findings indicate that parochial altruism is shaped by individual differences in testosterone and behavioral strategy. In that way the results are in line with evolutionary theories of both individual and group selection. Copyright © 2017 Elsevier Inc. All rights reserved.

Oculomotor nerve palsy by posterior communicating artery aneurysms: influence of surgical strategy on recovery.

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Güresir, Erdem; Schuss, Patrick; Seifert, Volker; Vatter, Hartmut

2012-11-01

Resolution of oculomotor nerve palsy (ONP) after clipping of posterior communicating artery (PCoA) aneurysms has been well documented. However, whether additional decompression of the oculomotor nerve via aneurysm sac dissection or resection is superior to pure aneurysm clipping is the subject of much debate. Therefore, the objective in the present investigation was to analyze the influence of surgical strategy--specifically, clipping with or without aneurysm dissection--on ONP resolution. Between June 1999 and December 2010, 18 consecutive patients with ruptured and unruptured PCoA aneurysms causing ONP were treated at the authors' institution. Oculomotor nerve palsy was evaluated on admission and at follow-up. The electronic database MEDLINE was searched for additional data in published studies of PCoA aneurysms causing ONP. Two reviewers independently extracted data. Overall, 8 studies from the literature review and 6 patients in the current series (121 PCoA aneurysms) met the study inclusion criteria. Ninety-four aneurysms were treated with simple aneurysm neck clipping and 27 with clipping plus aneurysm sac decompression. The surgical strategy, simple aneurysm neck clipping versus clipping plus oculomotor nerve decompression, had no effect on full ONP resolution on univariate (p = 0.5) and multivariate analyses. On multivariate analysis, patients with incomplete ONP at admission were more likely to have full resolution of the palsy than were those with complete ONP at admission (p = 0.03, OR = 4.2, 95% CI 1.1-16). Data in the present study indicated that ONP caused by PCoA aneurysms improves after clipping without and with oculomotor nerve decompression. The resolution of ONP is inversely associated with the initial severity of ONP.

Influence of Preoperative Chemoradiotherapy on the Surgical Strategy According to the Clinical T Stage of Patients With Rectal Cancer

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Park, In Ja; Lee, Jong Lyul; Yoon, Yong Sik; Kim, Chan Wook; Lim, Seok-Byung; Lee, Jong Seok; Park, Seong Ho; Park, Jin Hong; Kim, Jong Hoon; Yu, Chang Sik; Kim, Jin Cheon

2015-01-01

Abstract The aim of this study was to evaluate the pathologic responses and changes to surgical strategies following preoperative chemoradiotherapy (PCRT) in rectal cancer patients according to their clinical T stage (cT). The use of PCRT has recently been extended to less advanced disease. The authors enrolled 650 patients with cT2 to 4 mid and low rectal cancer who received both PCRT and surgical resection. The rate of total regression and the proportion of local excision were compared according to the cT category. The 3-year recurrence-free survival (RFS) rate was compared using the log-rank test according to patient cT category, pathologic stage, and type of surgical treatment. Patients with cT2 were older (P = 0.001), predominately female (P = 0.028), and had low-lying rectal cancer (P = 0.008). Pathologic total regression was achieved most frequently in cT2 patients (54% of cT2 versus 17.6% of cT3 versus 8.2% of cT4; P rectal cancer, optimal surgical treatment may be achieved with the tailored use of PCRT. PMID:26717384

Neural Interfaces for Intracortical Recording: Requirements, Fabrication Methods, and Characteristics.

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Szostak, Katarzyna M; Grand, Laszlo; Constandinou, Timothy G

2017-01-01

Implantable neural interfaces for central nervous system research have been designed with wire, polymer, or micromachining technologies over the past 70 years. Research on biocompatible materials, ideal probe shapes, and insertion methods has resulted in building more and more capable neural interfaces. Although the trend is promising, the long-term reliability of such devices has not yet met the required criteria for chronic human application. The performance of neural interfaces in chronic settings often degrades due to foreign body response to the implant that is initiated by the surgical procedure, and related to the probe structure, and material properties used in fabricating the neural interface. In this review, we identify the key requirements for neural interfaces for intracortical recording, describe the three different types of probes-microwire, micromachined, and polymer-based probes; their materials, fabrication methods, and discuss their characteristics and related challenges.

Surgical intervention in patients with necrotizing pancreatitis

NARCIS (Netherlands)

Besselink, MG; de Bruijn, MT; Rutten, JP; Boermeester, MA; Hofker, HS; Gooszen, HG

Background: This study evaluated the various surgical strategies for treatment of (suspected) infected necrotizing pancreatitis (INP) and patient referrals for this condition in the Netherlands. Methods: This retrospective study included all 106 consecutive patients who had surgical treatment for

Testicular neoplasia in undescended testes of cryptorchid boys-does surgical strategy have an impact on the risk of invasive testicular neoplasia?

DEFF Research Database (Denmark)

Cortes, Dina; Thorup, Jørgen Mogens; Petersen, Bodil Laub

2004-01-01

We investigated whether or not surgical strategy has an impact on the risk of invasive testicular neoplasia in cases of cryptorchidism. We made a database study of the incidence of testicular neoplasia at surgery for cryptorchidism in childhood, and evaluated if such abnormalities were found......, p placed...

Advanced surgical strategy for giant mediastinal germ cell tumor in children

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Shigehisa Fumino

2017-12-01

Conclusions: Resectability is the most important predictor of outcomes for MGCTs. Preoperative 3D-CT and CPS can enable complete resection and ensure surgical safety. Well-functioned surgical team is critical success factor in such advanced surgery.

Neural Interfaces for Intracortical Recording: Requirements, Fabrication Methods, and Characteristics

Directory of Open Access Journals (Sweden)

Katarzyna M. Szostak

2017-12-01

Full Text Available Implantable neural interfaces for central nervous system research have been designed with wire, polymer, or micromachining technologies over the past 70 years. Research on biocompatible materials, ideal probe shapes, and insertion methods has resulted in building more and more capable neural interfaces. Although the trend is promising, the long-term reliability of such devices has not yet met the required criteria for chronic human application. The performance of neural interfaces in chronic settings often degrades due to foreign body response to the implant that is initiated by the surgical procedure, and related to the probe structure, and material properties used in fabricating the neural interface. In this review, we identify the key requirements for neural interfaces for intracortical recording, describe the three different types of probes—microwire, micromachined, and polymer-based probes; their materials, fabrication methods, and discuss their characteristics and related challenges.

Aging differentially affects male and female neural stem cell neurogenic properties

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Jay Waldron

2010-09-01

Full Text Available Jay Waldron1, Althea McCourty1, Laurent Lecanu1,21The Research Institute of the McGill University Health Centre, Montreal, Canada; 2Department of Medicine, McGill University, Montreal, Quebec, CanadaPurpose: Neural stem cell transplantation as a brain repair strategy is a very promising technology. However, despite many attempts, the clinical success remains very deceiving. Despite clear evidence that sexual dimorphism rules many aspects of human biology, the occurrence of a sex difference in neural stem cell biology is largely understudied. Herein, we propose to determine whether gender is a dimension that drives the fate of neural stem cells through aging. Should it occur, we believe that neural stem cell sexual dimorphism and its variation during aging should be taken into account to refine clinical approaches of brain repair strategies.Methods: Neural stem cells were isolated from the subventricular zone of three- and 20-month-old male and female Long-Evans rats. Expression of the estrogen receptors, ERα and ERβ, progesterone receptor, androgen receptor, and glucocorticoid receptor was analyzed and quantified by Western blotting on undifferentiated neural stem cells. A second set of neural stem cells was treated with retinoic acid to trigger differentiation, and the expression of neuronal, astroglial, and oligodendroglial markers was determined using Western blotting.Conclusion: We provided in vitro evidence that the fate of neural stem cells is affected by sex and aging. Indeed, young male neural stem cells mainly expressed markers of neuronal and oligodendroglial fate, whereas young female neural stem cells underwent differentiation towards an astroglial phenotype. Aging resulted in a lessened capacity to express neuron and astrocyte markers. Undifferentiated neural stem cells displayed sexual dimorphism in the expression of steroid receptors, in particular ERα and ERβ, and the expression level of several steroid receptors increased

Interventional and surgical therapeutic strategies for pulmonary arterial hypertension: Beyond palliative treatments.

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Sandoval, Julio; Gomez-Arroyo, Jose; Gaspar, Jorge; Pulido-Zamudio, Tomas

2015-10-01

Despite significant advances in pharmacological treatments, pulmonary arterial hypertension remains an incurable disease with an unreasonably high morbidity and mortality. Although specific pharmacotherapies have shifted the survival curves of patients and improved exercise endurance as well as quality of life, it is also true that these pharmacological interventions are not always accessible (particularly in developing countries) and, perhaps most importantly, not all patients respond similarly to these drugs. Furthermore, many patients will continue to deteriorate and will eventually require an additional, non-pharmacological, intervention. In this review we analyze the role of atrial septostomy and Potts anastomosis in the management of patients with pulmonary arterial hypertension, we summarize the current worldwide clinical experience (case reports and case series), and discuss why these interventional/surgical strategies might have a therapeutic role beyond that of a "bridge" to transplantation. Copyright © 2015 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

Different surgical strategies for chronic pancreatitis significantly improve long-term outcome: a comparative single center study

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Hildebrand P

2010-08-01

Full Text Available Abstract Objective In general, chronic pancreatitis (CP primarily requires conservative treatment. The chronic pain syndrome and complications make patients seek surgical advice, frequently after years of progression. In the past, surgical procedures involving drainage as well as resection have been employed successfully. The present study compared the different surgical strategies. Patients and Methods From March 2000 until April 2005, a total of 51 patients underwent surgical treatment for CP at the Department of surgery, University of Schleswig-Holstein, Campus Lübeck. Out of those 51 patients, 39 (76.5% were operated according to the Frey procedure, and in 12 cases (23.5% the Whipple procedure was performed. Patient data were documented prospectively throughout the duration of the hospital stay. The evaluation of the postoperative pain score was carried out retrospectively with a validated questionnaire. Results Average operating time was 240 minutes for the Frey group and 411 minutes for the Whipple group. The medium number of blood transfusions was 1 in the Frey group and 4.5 in the Whipple group. Overall morbidity was 21% in the Frey group and 42% in the Whipple group. 30-day mortality was zero for all patients. During the median follow-up period of 50 months, an improvement in pain score was observed in 93% of the patients of the Frey group and 67% of the patients treated according to the Whipple procedure. Conclusion The results show that both the Frey procedure as well as partial pancreaticoduodenectomy are capable of improving chronic pain symptoms in CP. As far as later endocrine and exocrine pancreatic insufficiency is concerned, however, the extended drainage operation according to Frey proves to be advantageous compared to the traditional resection procedure by Whipple. Accordingly, the Frey procedure provides us with an organ-preserving surgical procedure which treats the complications of CP sufficiently, thus being an

ANT Advanced Neural Tool

Energy Technology Data Exchange (ETDEWEB)

Labrador, I.; Carrasco, R.; Martinez, L.

1996-07-01

This paper describes a practical introduction to the use of Artificial Neural Networks. Artificial Neural Nets are often used as an alternative to the traditional symbolic manipulation and first order logic used in Artificial Intelligence, due the high degree of difficulty to solve problems that can not be handled by programmers using algorithmic strategies. As a particular case of Neural Net a Multilayer Perception developed by programming in C language on OS9 real time operating system is presented. A detailed description about the program structure and practical use are included. Finally, several application examples that have been treated with the tool are presented, and some suggestions about hardware implementations. (Author) 15 refs.

ANT Advanced Neural Tool

International Nuclear Information System (INIS)

Labrador, I.; Carrasco, R.; Martinez, L.

1996-01-01

This paper describes a practical introduction to the use of Artificial Neural Networks. Artificial Neural Nets are often used as an alternative to the traditional symbolic manipulation and first order logic used in Artificial Intelligence, due the high degree of difficulty to solve problems that can not be handled by programmers using algorithmic strategies. As a particular case of Neural Net a Multilayer Perception developed by programming in C language on OS9 real time operating system is presented. A detailed description about the program structure and practical use are included. Finally, several application examples that have been treated with the tool are presented, and some suggestions about hardware implementations. (Author) 15 refs

Learning in Neural Networks: VLSI Implementation Strategies

Science.gov (United States)

Duong, Tuan Anh

1995-01-01

Fully-parallel hardware neural network implementations may be applied to high-speed recognition, classification, and mapping tasks in areas such as vision, or can be used as low-cost self-contained units for tasks such as error detection in mechanical systems (e.g. autos). Learning is required not only to satisfy application requirements, but also to overcome hardware-imposed limitations such as reduced dynamic range of connections.

Clinical and Surgical Strategies for Avoiding or Reducing Allogeneic Blood Transfusions.

Science.gov (United States)

Dos Santos, Antonio Alceu; Baumgratz, Jose Francisco; Vila, Jose Henrique Andrade; Castro, Rodrigo Moreira; Bezerra, Rodrigo Freire

2016-04-01

Blood transfusions have still been used as a standard therapy to treat severe anemia. Current evidences point to both excessive allogeneic blood consumption and decreased donations, which result in reduced stocks in blood banks. Several studies have increasingly suggested a more restrictive transfusion practice for blood products. Currently, a number of autologous blood conservation protocols in surgeries have been noted. We report a case of severe anemia with 2.9 g/dL hemoglobin, which was successfully handled without using the standard therapy to treat anemia with hemotransfusions. Such a case of severe anemia condition resulted after the patient was submitted to ascending aortic aneurism repair, valvar aortic replacement, reimplantation of right coronary ostium, followed by a coronary artery bypass grafting and several postoperative complications. The main clinical and surgical strategies used in this case to avoid blood transfusions were acute normovolemic hemodilution, intraoperative blood cell salvage, and meticulous hemostasis, beyond epsilon-aminocaproic acid, desmopressin, prothrombin complex concentrate, human fibrinogen concentrate, factor VIIa recombinant, erythropoietin and hyperoxic ventilation.

Implementing Signature Neural Networks with Spiking Neurons.

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Carrillo-Medina, José Luis; Latorre, Roberto

2016-01-01

Spiking Neural Networks constitute the most promising approach to develop realistic Artificial Neural Networks (ANNs). Unlike traditional firing rate-based paradigms, information coding in spiking models is based on the precise timing of individual spikes. It has been demonstrated that spiking ANNs can be successfully and efficiently applied to multiple realistic problems solvable with traditional strategies (e.g., data classification or pattern recognition). In recent years, major breakthroughs in neuroscience research have discovered new relevant computational principles in different living neural systems. Could ANNs benefit from some of these recent findings providing novel elements of inspiration? This is an intriguing question for the research community and the development of spiking ANNs including novel bio-inspired information coding and processing strategies is gaining attention. From this perspective, in this work, we adapt the core concepts of the recently proposed Signature Neural Network paradigm-i.e., neural signatures to identify each unit in the network, local information contextualization during the processing, and multicoding strategies for information propagation regarding the origin and the content of the data-to be employed in a spiking neural network. To the best of our knowledge, none of these mechanisms have been used yet in the context of ANNs of spiking neurons. This paper provides a proof-of-concept for their applicability in such networks. Computer simulations show that a simple network model like the discussed here exhibits complex self-organizing properties. The combination of multiple simultaneous encoding schemes allows the network to generate coexisting spatio-temporal patterns of activity encoding information in different spatio-temporal spaces. As a function of the network and/or intra-unit parameters shaping the corresponding encoding modality, different forms of competition among the evoked patterns can emerge even in the absence

Neural Signatures of Rational and Heuristic Choice Strategies: A Single Trial ERP Analysis

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Szymon Wichary

2017-08-01

Full Text Available In multi-attribute choice, people use heuristics to simplify decision problems. We studied the use of heuristic and rational strategies and their electrophysiological correlates. Since previous work linked the P3 ERP component to attention and decision making, we were interested whether the amplitude of this component is associated with decision strategy use. To this end, we recorded EEG when participants performed a two-alternative choice task, where they could acquire decision cues in a sequential manner and use them to make choices. We classified participants’ choices as consistent with a rational Weighted Additive rule (WADD or a simple heuristic Take The Best (TTB. Participants differed in their preference for WADD and TTB. Using a permutation-based single trial approach, we analyzed EEG responses to consecutive decision cues and their relation to the individual strategy preference. The preference for WADD over TTB was associated with overall higher signal amplitudes to decision cues in the P3 time window. Moreover, the preference for WADD was associated with similar P3 amplitudes to consecutive cues, whereas the preference for TTB was associated with substantial decreases in P3 amplitudes to consecutive cues. We also found that the preference for TTB was associated with enhanced N1 component to cues that discriminated decision alternatives, suggesting very early attention allocation to such cues by TTB users. Our results suggest that preference for either WADD or TTB has an early neural signature reflecting differences in attentional weighting of decision cues. In light of recent findings and hypotheses regarding P3, we interpret these results as indicating the involvement of catecholamine arousal systems in shaping predecisional information processing and strategy selection.

Neural Signatures of Rational and Heuristic Choice Strategies: A Single Trial ERP Analysis.

Science.gov (United States)

Wichary, Szymon; Magnuski, Mikołaj; Oleksy, Tomasz; Brzezicka, Aneta

2017-01-01

In multi-attribute choice, people use heuristics to simplify decision problems. We studied the use of heuristic and rational strategies and their electrophysiological correlates. Since previous work linked the P3 ERP component to attention and decision making, we were interested whether the amplitude of this component is associated with decision strategy use. To this end, we recorded EEG when participants performed a two-alternative choice task, where they could acquire decision cues in a sequential manner and use them to make choices. We classified participants' choices as consistent with a rational Weighted Additive rule (WADD) or a simple heuristic Take The Best (TTB). Participants differed in their preference for WADD and TTB. Using a permutation-based single trial approach, we analyzed EEG responses to consecutive decision cues and their relation to the individual strategy preference. The preference for WADD over TTB was associated with overall higher signal amplitudes to decision cues in the P3 time window. Moreover, the preference for WADD was associated with similar P3 amplitudes to consecutive cues, whereas the preference for TTB was associated with substantial decreases in P3 amplitudes to consecutive cues. We also found that the preference for TTB was associated with enhanced N1 component to cues that discriminated decision alternatives, suggesting very early attention allocation to such cues by TTB users. Our results suggest that preference for either WADD or TTB has an early neural signature reflecting differences in attentional weighting of decision cues. In light of recent findings and hypotheses regarding P3, we interpret these results as indicating the involvement of catecholamine arousal systems in shaping predecisional information processing and strategy selection.

Soft tissue deformation modelling through neural dynamics-based reaction-diffusion mechanics.

Science.gov (United States)

Zhang, Jinao; Zhong, Yongmin; Gu, Chengfan

2018-05-30

Soft tissue deformation modelling forms the basis of development of surgical simulation, surgical planning and robotic-assisted minimally invasive surgery. This paper presents a new methodology for modelling of soft tissue deformation based on reaction-diffusion mechanics via neural dynamics. The potential energy stored in soft tissues due to a mechanical load to deform tissues away from their rest state is treated as the equivalent transmembrane potential energy, and it is distributed in the tissue masses in the manner of reaction-diffusion propagation of nonlinear electrical waves. The reaction-diffusion propagation of mechanical potential energy and nonrigid mechanics of motion are combined to model soft tissue deformation and its dynamics, both of which are further formulated as the dynamics of cellular neural networks to achieve real-time computational performance. The proposed methodology is implemented with a haptic device for interactive soft tissue deformation with force feedback. Experimental results demonstrate that the proposed methodology exhibits nonlinear force-displacement relationship for nonlinear soft tissue deformation. Homogeneous, anisotropic and heterogeneous soft tissue material properties can be modelled through the inherent physical properties of mass points. Graphical abstract Soft tissue deformation modelling with haptic feedback via neural dynamics-based reaction-diffusion mechanics.

Characterization of the disruption of neural control strategies for dynamic fingertip forces from attractor reconstruction.

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Lorenzo Peppoloni

Full Text Available The Strength-Dexterity (SD test measures the ability of the pulps of the thumb and index finger to compress a compliant and slender spring prone to buckling at low forces (<3N. We know that factors such as aging and neurodegenerative conditions bring deteriorating physiological changes (e.g., at the level of motor cortex, cerebellum, and basal ganglia, which lead to an overall loss of dexterous ability. However, little is known about how these changes reflect upon the dynamics of the underlying biological system. The spring-hand system exhibits nonlinear dynamical behavior and here we characterize the dynamical behavior of the phase portraits using attractor reconstruction. Thirty participants performed the SD test: 10 young adults, 10 older adults, and 10 older adults with Parkinson's disease (PD. We used delayed embedding of the applied force to reconstruct its attractor. We characterized the distribution of points of the phase portraits by their density (number of distant points and interquartile range and geometric features (trajectory length and size. We find phase portraits from older adults exhibit more distant points (p = 0.028 than young adults and participants with PD have larger interquartile ranges (p = 0.001, trajectory lengths (p = 0.005, and size (p = 0.003 than their healthy counterparts. The increased size of the phase portraits with healthy aging suggests a change in the dynamical properties of the system, which may represent a weakening of the neural control strategy. In contrast, the distortion of the attractor in PD suggests a fundamental change in the underlying biological system, and disruption of the neural control strategy. This ability to detect differences in the biological mechanisms of dexterity in healthy and pathological aging provides a simple means to assess their disruption in neurodegenerative conditions and justifies further studies to understand the link with the physiological changes.

The effect of strategies, goals and stimulus material on the neural mechanisms of emotion regulation: A meta-analysis of fMRI studies.

Science.gov (United States)

Morawetz, Carmen; Bode, Stefan; Derntl, Birgit; Heekeren, Hauke R

2017-01-01

Emotion regulation comprises all extrinsic and intrinsic control processes whereby people monitor, evaluate and modify the occurrence, intensity and duration of emotional reactions. Here we sought to quantitatively summarize the existing neuroimaging literature to investigate a) whether different emotion regulation strategies are based on different or the same neural networks; b) which brain regions in particular support the up- and down-regulation of emotions, respectively; and c) to which degree the neural networks realising emotion regulation depend on the stimulus material used to elicit emotions. The left ventrolateral prefrontal cortex (VLPFC), the anterior insula and the supplementary motor area were consistently activated independent of the regulation strategy. VLPFC and posterior cingulate cortex were the main regions consistently found to be recruited during the up-regulation as well as the down-regulation of emotion. The down-regulation compared to the up-regulation of emotions was associated with more right-lateralized activity while up-regulating emotions more strongly modulated activity in the ventral striatum. Finally, the process of emotion regulation appeared to be unaffected by stimulus material. Copyright © 2016 Elsevier Ltd. All rights reserved.

Tissue engineering as a potential alternative or adjunct to surgical reconstruction in treating pelvic organ prolapse

DEFF Research Database (Denmark)

Boennelycke, M; Gräs, Søren; Lose, G

2013-01-01

Cell-based tissue engineering strategies could potentially provide attractive alternatives to surgical reconstruction of native tissue or the use of surgical implants in treating pelvic organ prolapse (POP).......Cell-based tissue engineering strategies could potentially provide attractive alternatives to surgical reconstruction of native tissue or the use of surgical implants in treating pelvic organ prolapse (POP)....

Surgical strategies in the treatment of chronic pancreatitis: An updated systematic review and meta-analysis of randomized controlled trials.

Science.gov (United States)

Zhao, Xin; Cui, Naiqiang; Wang, Ximo; Cui, Yunfeng

2017-03-01

Chronic pancreatitis (CP) is a common and frequently occurring disease. Pancreaticoduodenectomy (PD), pylorus-preserving pancreaticoduodenectomy (PPPD), and duodenum-preserving pancreatic head resection (DPPHR) are important treatment options for patients with chronic pancreatitis. The Beger and Frey procedures are 2 main duodenum-preserving techniques in duodenum-preserving pancreatic head resection (DPPHR) strategies. We conducted this systematic review and meta-analysis to compare the clinical efficacy of DPPHR versus PD, the Beger procedure versus PD, the Frey procedure versus PD, and the Beger procedure versus the Frey procedure in the treatment of pancreatitis. The optimal surgical option for chronic pancreatitis is still under debate. The aim of this systematic review and meta-analysis was to evaluate the clinical efficacy of different surgical strategies for chronic pancreatitis. Five databases (PubMed, Medline, SinoMed, Embase, and Cochrane Library) were searched with the limitations of human subjects and randomized controlled trials (RCTs) text. Data were extracted by 2 of the coauthors independently and analyzed using the RevMan statistical software, version 5.3. Weighted mean differences (WMDs), risk ratios (RRs), and 95% confidence intervals (CIs) were calculated. Cochrane Collaboration's Risk of Bias Tool was used to assess the risk of bias. Seven studies involving a total of 385 patients who underwent the surgical treatments were assessed. The methodological quality of the trials ranged from low to moderate and included PD (n = 134) and DPPHR (n = 251 [Beger procedure = 100; Frey procedure = 109; Beger or Frey procedure = 42]). There were no significant differences between DPPHR and PD in post-operation mortality (RR = 2.89, 95% CI = 0.31-26.87, P = 0.36), pain relief (RR = 1.09, 95% CI = 0.94-1.25, P = 0.26), exocrine insufficiency (follow-up time > 60 months: RR = 0.91, 95% CI = 0.72-1.15, P�

A fuzzy Hopfield neural network for medical image segmentation

International Nuclear Information System (INIS)

Lin, J.S.; Cheng, K.S.; Mao, C.W.

1996-01-01

In this paper, an unsupervised parallel segmentation approach using a fuzzy Hopfield neural network (FHNN) is proposed. The main purpose is to embed fuzzy clustering into neural networks so that on-line learning and parallel implementation for medical image segmentation are feasible. The idea is to cast a clustering problem as a minimization problem where the criteria for the optimum segmentation is chosen as the minimization of the Euclidean distance between samples to class centers. In order to generate feasible results, a fuzzy c-means clustering strategy is included in the Hopfield neural network to eliminate the need of finding weighting factors in the energy function, which is formulated and based on a basic concept commonly used in pattern classification, called the within-class scatter matrix principle. The suggested fuzzy c-means clustering strategy has also been proven to be convergent and to allow the network to learn more effectively than the conventional Hopfield neural network. The fuzzy Hopfield neural network based on the within-class scatter matrix shows the promising results in comparison with the hard c-means method

Idiopathic Intracranial Hypertension After Surgical Treatment of Cushing Disease: Case Report and Review of Management Strategies.

Science.gov (United States)

Wagner, Jeffrey; Fleseriu, Cara M; Ibrahim, Aly; Cetas, Justin S

2016-12-01

Idiopathic intracranial hypertension (IIH) in patients with Cushing disease (CD), after treatment, is rarely described, in adults. The cause is believed to be multifactorial, potentially related to a relative decrease in cortisol after surgical resection or medical treatment of a corticotroph pituitary adenoma. We investigate our center's CD database (140 surgically and 60 medically [primary or adjunct] treated patients) for cases of IIH, describe our center's experience with symptomatic IIH, and review treatment strategies in adults with CD after transsphenoidal resection. We present the case of a 22-year-old woman who presented with worsening headache, nausea, vomiting, blurry vision, diplopia, visual loss, and facial numbness 14 weeks after surgical resection of adrenocorticotropic hormone-positive pituitary adenoma. Her CD had been in remission since surgery, with subsequent adrenal insufficiency (AI), which was initially treated with supraphysiologic glucocorticoid replacement, tapered down to physiologic doses at the time the IIH symptoms developed. Symptomatic IIH is rare in adult patients but can be severe and result in permanent vision loss. A high index of suspicion should be maintained and a fundus examination is necessary to exclude papilledema, whenever there are suggestive symptoms that initially may overlap with AI. It is possible that some cases of mild IIH are misdiagnosed as GC withdrawal or AI; however, further studies are needed. Treatment consists of reinitiation of higher steroid doses together with acetazolamide with or without cerebrospinal fluid diversion and the priority is to preserve vision and reverse any visual loss. Published by Elsevier Inc.

The development of neural stimulators: a review of preclinical safety and efficacy studies.

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Shepherd, Robert K; Villalobos, Joel; Burns, Owen; Nayagam, David

2018-05-14

Given the rapid expansion of the field of neural stimulation and the rigorous regulatory approval requirements required before these devices can be applied clinically, it is important that there is clarity around conducting preclinical safety and efficacy studies required for the development of this technology. The present review examines basic design principles associated with the development of a safe neural stimulator and describes the suite of preclinical safety studies that need to be considered when taking a device to clinical trial. Neural stimulators are active implantable devices that provide therapeutic intervention, sensory feedback or improved motor control via electrical stimulation of neural or neuro-muscular tissue in response to trauma or disease. Because of their complexity, regulatory bodies classify these devices in the highest risk category (Class III), and they are therefore required to go through a rigorous regulatory approval process before progressing to market. The successful development of these devices is achieved through close collaboration across disciplines including engineers, scientists and a surgical/clinical team, and the adherence to clear design principles. Preclinical studies form one of several key components in the development pathway from concept to product release of neural stimulators. Importantly, these studies provide iterative feedback in order to optimise the final design of the device. Key components of any preclinical evaluation include: in vitro studies that are focussed on device reliability and include accelerated testing under highly controlled environments; in vivo studies using animal models of the disease or injury in order to assess safety and, given an appropriate animal model, the efficacy of the technology under both passive and electrically active conditions; and human cadaver and ex vivo studies designed to ensure the device's form factor conforms to human anatomy, to optimise the surgical approach and to

Multi-mode energy management strategy for fuel cell electric vehicles based on driving pattern identification using learning vector quantization neural network algorithm

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Song, Ke; Li, Feiqiang; Hu, Xiao; He, Lin; Niu, Wenxu; Lu, Sihao; Zhang, Tong

2018-06-01

The development of fuel cell electric vehicles can to a certain extent alleviate worldwide energy and environmental issues. While a single energy management strategy cannot meet the complex road conditions of an actual vehicle, this article proposes a multi-mode energy management strategy for electric vehicles with a fuel cell range extender based on driving condition recognition technology, which contains a patterns recognizer and a multi-mode energy management controller. This paper introduces a learning vector quantization (LVQ) neural network to design the driving patterns recognizer according to a vehicle's driving information. This multi-mode strategy can automatically switch to the genetic algorithm optimized thermostat strategy under specific driving conditions in the light of the differences in condition recognition results. Simulation experiments were carried out based on the model's validity verification using a dynamometer test bench. Simulation results show that the proposed strategy can obtain better economic performance than the single-mode thermostat strategy under dynamic driving conditions.

Two neural network based strategies for the detection of a total instantaneous blockage of a sodium-cooled fast reactor

International Nuclear Information System (INIS)

Martinez-Martinez, Sinuhe; Messai, Nadhir; Jeannot, Jean-Philippe; Nuzillard, Danielle

2015-01-01

The total instantaneous blockage (TIB) of an assembly in the core of a sodium-cooled fast reactor (SFR) is investigated. Such incident could appear as an abnormal rise in temperature on the assemblies neighbouring the blockage. Its detection relies on a dataset of temperature measurements of the assemblies making up the core of the French Phenix Nuclear Reactor. The data are provided by the French Commission of Atomic and Alternatives Energies (CEA). Here, two strategies are proposed depending on whether the sensor measurement of the suspected assembly is reliable or not. The proposed methodology implements a time-lagged feed-forward neural (TLFFN) Network in order to predict the one-step-ahead temperature of a given assembly. The incident is declared if the difference between the predicted process and the actual one exceeds a threshold. In these simulated conditions, the method is efficient to detect small gradients as expected in reality. - Highlights: • We study the total instantaneous blockage (TIB) of a sodium-cooled fast reactor. • The TIB symptom is simulated as an abrupt rise on temperature (0.1–1 °C/s). • The goal is to improve the early detection of the incident. • Two strategies laying on neural networks are proposed. • TIB is detected in 3 s for 1 °C/s and 18–21 s for 0.1 °C/s

Physics strategies for sparing neural stem cells during whole-brain radiation treatments

International Nuclear Information System (INIS)

Kirby, Neil; Chuang, Cynthia; Pouliot, Jean; Hwang, Andrew; Barani, Igor J.

2011-01-01

Purpose: Currently, there are no successful long-term treatments or preventive strategies for radiation-induced cognitive impairments, and only a few possibilities have been suggested. One such approach involves reducing the dose to neural stem cell compartments (within and outside of the hippocampus) during whole-brain radiation treatments for brain metastases. This study investigates the fundamental physics issues associated with the sparing of neural stem cells during photon radiotherapy for brain metastases. Methods: Several factors influence the stem cell dose: intracranial scattering, collimator leakage, beam energy, and total number of beams. The relative importance of these factors is investigated through a set of radiation therapy plans, which are all variations of an initial 6 MV intensity-modulated radiation therapy (IMRT) plan designed to simultaneously deliver a whole-brain dose of 30 Gy and maximally reduce stem cell compartment dose. Additionally, an in-house leaf segmentation algorithm was developed that utilizes jaw motion to minimize the collimator leakage. Results: The plans are all normalized such that 50% of the PTV receives 30 Gy. For the initial 6 MV IMRT plan, 50% of the stem cells receive a dose greater than 6.3 Gy. Calculations indicate that 3.6 Gy of this dose originates from intracranial scattering. The jaw-tracking segmentation algorithm, used in conjunction with direct machine parameter optimization, reduces the 50% stem cell dose to 4.3 and 3.7 Gy for 6 and 10 MV treatment beams, respectively. Conclusions: Intracranial scattering alone is responsible for a large dose contribution to the stem cell compartment. It is, therefore, important to minimize other contributing factors, particularly the collimator leakage, to maximally reduce dose to these critical structures. The use of collimator jaw tracking in conjunction with modern collimators can minimize this leakage.

Neutron spectrometry and dosimetry by means of Bonner spheres system and artificial neural networks applying robust design of artificial neural networks

Energy Technology Data Exchange (ETDEWEB)

Martinez B, M.R.; Ortiz R, J.M.; Vega C, H.R. [UAZ, Av. Ramon Lopez Velarde No. 801, 98000 Zacatecas (Mexico)

2006-07-01

An Artificial Neural Network has been designed, trained and tested to unfold neutron spectra and simultaneously to calculate equivalent doses. A set of 187 neutron spectra compiled by the International Atomic Energy Agency and 13 equivalent doses were used in the artificial neural network designed, trained and tested. In order to design the neural network was used the robust design of artificial neural networks methodology, which assures that the quality of the neural networks takes into account from the design stage. Unless previous works, here, for first time a group of neural networks were designed and trained to unfold 187 neutron spectra and at the same time to calculate 13 equivalent doses, starting from the count rates coming from the Bonner spheres system by using a systematic and experimental strategy. (Author)

Neutron spectrometry and dosimetry by means of Bonner spheres system and artificial neural networks applying robust design of artificial neural networks

International Nuclear Information System (INIS)

Martinez B, M.R.; Ortiz R, J.M.; Vega C, H.R.

2006-01-01

An Artificial Neural Network has been designed, trained and tested to unfold neutron spectra and simultaneously to calculate equivalent doses. A set of 187 neutron spectra compiled by the International Atomic Energy Agency and 13 equivalent doses were used in the artificial neural network designed, trained and tested. In order to design the neural network was used the robust design of artificial neural networks methodology, which assures that the quality of the neural networks takes into account from the design stage. Unless previous works, here, for first time a group of neural networks were designed and trained to unfold 187 neutron spectra and at the same time to calculate 13 equivalent doses, starting from the count rates coming from the Bonner spheres system by using a systematic and experimental strategy. (Author)

Neural networks for feedback feedforward nonlinear control systems.

Science.gov (United States)

Parisini, T; Zoppoli, R

1994-01-01

This paper deals with the problem of designing feedback feedforward control strategies to drive the state of a dynamic system (in general, nonlinear) so as to track any desired trajectory joining the points of given compact sets, while minimizing a certain cost function (in general, nonquadratic). Due to the generality of the problem, conventional methods are difficult to apply. Thus, an approximate solution is sought by constraining control strategies to take on the structure of multilayer feedforward neural networks. After discussing the approximation properties of neural control strategies, a particular neural architecture is presented, which is based on what has been called the "linear-structure preserving principle". The original functional problem is then reduced to a nonlinear programming one, and backpropagation is applied to derive the optimal values of the synaptic weights. Recursive equations to compute the gradient components are presented, which generalize the classical adjoint system equations of N-stage optimal control theory. Simulation results related to nonlinear nonquadratic problems show the effectiveness of the proposed method.

Surgical strategies in patients with gallbladder cancer: nihilism to optimism.

Science.gov (United States)

Sikora, Sadiq S; Singh, Rajneesh K

2006-06-15

Gallbladder cancer is an aggressive disease with dismal results of surgical treatment and a poor prognosis. However, over the last few decades selected groups have reported improved results with aggressive surgery for gallbladder cancer. Review of recent world literature was done to provide an update on the current concepts of surgical treatment of this disease. Long-term survival is possible in early stage gallbladder carcinoma. Tis and T1a gallbladder carcinoma can be treated with simple cholecystectomy only. However, in T1b and beyond cancers, aggressive surgery (extended cholecystectomy) is important in improving the long-term prognosis. Laparoscopic cholecystectomy should not be performed where there is a high index of suspicion of malignancy due to the frequent association with factors (such as gallbladder perforation and bile spill) which may lead to implantation of cancer cells and dissemination. Surgical resection for advanced carcinoma gallbladder is recommended only if a potentially curative R0 resection is possible. Aggressive surgery with vascular and multivisceral resection has been shown to be feasible albeit with an increase in mortality and morbidity. However, the true benefit of these radical resections is yet to be realized, as the actual number of long-term survivors of advanced gallbladder carcinoma is few. Surgery for gallbladder carcinoma, like other malignancies, has the potential to be curative only in local or regional disease. Pattern of loco-regional spread of disease dictates the surgical procedure. Radical surgery improves survival in early gallbladder carcinoma. The long-term benefit of aggressive surgery for advanced disease is unclear and may be offset by the high mortality and morbidity. Copyright 2006 Wiley-Liss, Inc.

Neural network-based nonlinear model predictive control vs. linear quadratic gaussian control

Science.gov (United States)

Cho, C.; Vance, R.; Mardi, N.; Qian, Z.; Prisbrey, K.

1997-01-01

One problem with the application of neural networks to the multivariable control of mineral and extractive processes is determining whether and how to use them. The objective of this investigation was to compare neural network control to more conventional strategies and to determine if there are any advantages in using neural network control in terms of set-point tracking, rise time, settling time, disturbance rejection and other criteria. The procedure involved developing neural network controllers using both historical plant data and simulation models. Various control patterns were tried, including both inverse and direct neural network plant models. These were compared to state space controllers that are, by nature, linear. For grinding and leaching circuits, a nonlinear neural network-based model predictive control strategy was superior to a state space-based linear quadratic gaussian controller. The investigation pointed out the importance of incorporating state space into neural networks by making them recurrent, i.e., feeding certain output state variables into input nodes in the neural network. It was concluded that neural network controllers can have better disturbance rejection, set-point tracking, rise time, settling time and lower set-point overshoot, and it was also concluded that neural network controllers can be more reliable and easy to implement in complex, multivariable plants.

A novel surgical strategy for secondary hyperparathyroidism: Purge parathyroidectomy.

Science.gov (United States)

Shan, Cheng-Xiang; Qiu, Nian-Cun; Zha, Si-Luo; Liu, Miao-E; Wang, Qiang; Zhu, Pei-Pei; Du, Zhi-Peng; Xia, Chun-Yan; Qiu, Ming; Zhang, Wei

2017-07-01

This study was intended to demonstrate the feasibility and efficacy of purge parathyroidectomy (PPTX) for patients with secondary hyperparathyroidism (SHPT). The "seed, environment, and soil" medical hypothesis was first raised, following review of the literatures, to demonstrate the possible causes of persistence or recurrence of SHPT after parathyroidectomy. Subsequently, the novel surgical strategy of PPTX was proposed, which involves comprehensive resection of the fibro-fatty tissues, including visible or invisible parathyroid, within the region surrounded by the thyroid cartilage, bilateral carotid artery sheath, and the brachiocephalic artery. The perioperative information and clinical outcomes of patients who underwent PPTX from June 2016 to December 2016 were analyzed. In total, PPTX was performed safely in nine patients with SHPT from June 2016 to December 2016. The operative time for PPTX ranged from 95 to 135 min, and blood loss ranged from 20 to 40 mL. No patients with perioperative death, bleeding, convulsions, or recurrent laryngeal nerve injury were reported. The preoperative concentration of PTH ranged from 1062 to 2879 pg/mL, and from 12.35 to 72.69 pg/mL on the first day after surgery. In total, 37 parathyroid glands were resected. The postoperative pathologic examination showed that supernumerary or ectopic parathyroid tissues were found within the "non-parathyroid" tissues in three patients. No cases encountered persistence or recurrence of SHPT, or severe hypocalcemia during the follow-up period. PPTX involves comprehensive resection of supernumerary and ectopic parathyroid tissues, which may provide a more permanent means of reducing PTH levels. Copyright © 2017. Published by Elsevier Ltd.

Neural Decoder for Topological Codes

Science.gov (United States)

Torlai, Giacomo; Melko, Roger G.

2017-07-01

We present an algorithm for error correction in topological codes that exploits modern machine learning techniques. Our decoder is constructed from a stochastic neural network called a Boltzmann machine, of the type extensively used in deep learning. We provide a general prescription for the training of the network and a decoding strategy that is applicable to a wide variety of stabilizer codes with very little specialization. We demonstrate the neural decoder numerically on the well-known two-dimensional toric code with phase-flip errors.

An overview of pre-surgical evaluation

Directory of Open Access Journals (Sweden)

Kurupath Radhakrishnan

2014-01-01

Full Text Available The success of an epilepsy surgery program depends upon the early identification of potential surgical candidates and selecting from them, ideal candidates for surgery, who are destined to have a post-operative seizure-free outcome without any unacceptable neurological deficits. Since epilepsy surgery centers in resource-poor countries will lack the full range of state-of-the-art technologies usually available in resource-rich countries to perform pre-surgical evaluation, cost-effectively utilization of the locally available investigative facilities to select the surgical candidates becomes challenging. In the present era of rapid electronic communications and telemedicine, it has become possible for epilepsy surgery centers to pool their technological and human resources and to partner with centers nationally and internationally in implementing pre-surgical evaluation strategies.

Toward automatic time-series forecasting using neural networks.

Science.gov (United States)

Yan, Weizhong

2012-07-01

Over the past few decades, application of artificial neural networks (ANN) to time-series forecasting (TSF) has been growing rapidly due to several unique features of ANN models. However, to date, a consistent ANN performance over different studies has not been achieved. Many factors contribute to the inconsistency in the performance of neural network models. One such factor is that ANN modeling involves determining a large number of design parameters, and the current design practice is essentially heuristic and ad hoc, this does not exploit the full potential of neural networks. Systematic ANN modeling processes and strategies for TSF are, therefore, greatly needed. Motivated by this need, this paper attempts to develop an automatic ANN modeling scheme. It is based on the generalized regression neural network (GRNN), a special type of neural network. By taking advantage of several GRNN properties (i.e., a single design parameter and fast learning) and by incorporating several design strategies (e.g., fusing multiple GRNNs), we have been able to make the proposed modeling scheme to be effective for modeling large-scale business time series. The initial model was entered into the NN3 time-series competition. It was awarded the best prediction on the reduced dataset among approximately 60 different models submitted by scholars worldwide.

Towards a magnetoresistive platform for neural signal recording

Science.gov (United States)

Sharma, P. P.; Gervasoni, G.; Albisetti, E.; D'Ercoli, F.; Monticelli, M.; Moretti, D.; Forte, N.; Rocchi, A.; Ferrari, G.; Baldelli, P.; Sampietro, M.; Benfenati, F.; Bertacco, R.; Petti, D.

2017-05-01

A promising strategy to get deeper insight on brain functionalities relies on the investigation of neural activities at the cellular and sub-cellular level. In this framework, methods for recording neuron electrical activity have gained interest over the years. Main technological challenges are associated to finding highly sensitive detection schemes, providing considerable spatial and temporal resolution. Moreover, the possibility to perform non-invasive assays would constitute a noteworthy benefit. In this work, we present a magnetoresistive platform for the detection of the action potential propagation in neural cells. Such platform allows, in perspective, the in vitro recording of neural signals arising from single neurons, neural networks and brain slices.

Barrier Function-Based Neural Adaptive Control With Locally Weighted Learning and Finite Neuron Self-Growing Strategy.

Science.gov (United States)

Jia, Zi-Jun; Song, Yong-Duan

2017-06-01

This paper presents a new approach to construct neural adaptive control for uncertain nonaffine systems. By integrating locally weighted learning with barrier Lyapunov function (BLF), a novel control design method is presented to systematically address the two critical issues in neural network (NN) control field: one is how to fulfill the compact set precondition for NN approximation, and the other is how to use varying rather than a fixed NN structure to improve the functionality of NN control. A BLF is exploited to ensure the NN inputs to remain bounded during the entire system operation. To account for system nonlinearities, a neuron self-growing strategy is proposed to guide the process for adding new neurons to the system, resulting in a self-adjustable NN structure for better learning capabilities. It is shown that the number of neurons needed to accomplish the control task is finite, and better performance can be obtained with less number of neurons as compared with traditional methods. The salient feature of the proposed method also lies in the continuity of the control action everywhere. Furthermore, the resulting control action is smooth almost everywhere except for a few time instants at which new neurons are added. Numerical example illustrates the effectiveness of the proposed approach.

Short-term synaptic plasticity and heterogeneity in neural systems

Science.gov (United States)

Mejias, J. F.; Kappen, H. J.; Longtin, A.; Torres, J. J.

2013-01-01

We review some recent results on neural dynamics and information processing which arise when considering several biophysical factors of interest, in particular, short-term synaptic plasticity and neural heterogeneity. The inclusion of short-term synaptic plasticity leads to enhanced long-term memory capacities, a higher robustness of memory to noise, and irregularity in the duration of the so-called up cortical states. On the other hand, considering some level of neural heterogeneity in neuron models allows neural systems to optimize information transmission in rate coding and temporal coding, two strategies commonly used by neurons to codify information in many brain areas. In all these studies, analytical approximations can be made to explain the underlying dynamics of these neural systems.

The impact of surgical strategies on outcomes for pediatric chronic pancreatitis.

Science.gov (United States)

Sacco Casamassima, Maria G; Goldstein, Seth D; Yang, Jingyan; Gause, Colin D; Abdullah, Fizan; Meoded, Avner; Makary, Martin A; Colombani, Paul M

2017-01-01

To review our institutional experience in the surgical treatment of pediatric chronic pancreatitis (CP) and evaluate predictors of long-term pain relief. Outcomes of patients ≤21 years surgically treated for CP in a single institution from 1995 to 2014 were evaluated. Twenty patients underwent surgery for CP at a median of 16.6 years (IQR 10.7-20.6 years). The most common etiology was pancreas divisum (n = 7; 35%). Therapeutic endoscopy was the first-line treatment in 17 cases (85%). Surgical procedures included: longitudinal pancreaticojejunostomy (n = 4, 20%), pancreatectomy (n = 9, 45%), total pancreatectomy with islet autotransplantation (n = 2; 10%), sphincteroplasty (n = 2, 10%) and pseudocyst drainage (n = 3, 15%). At a median follow-up of 5.3 years (IQR 4.2-5.3), twelve patients (63.2%) were pain free and five (26.3%) were insulin dependent. In univariate analysis, previous surgical procedure or >5 endoscopic treatments were associated with a lower likelihood of pain relief (OR 0.06; 95% CI 0.006-0.57; OR 0.07; 95%, CI 0.01-0.89). However, these associations were not present in multivariate analysis. In children with CP, the step-up practice including a limited trial of endoscopic interventions followed by surgery tailored to anatomical abnormalities and gene mutation status is effective in ensuring long-term pain relief and preserving pancreatic function.

An Evolutionary Perspective of the Relationship Between Corporate Strategy and Performance, Through the Use of Artificial Neural Networks and Genetic AlgorithmsHttp://Dx.Doi.Org/10.5585/Riae.V9i3.1689

Directory of Open Access Journals (Sweden)

Alexandre Teixeira Dias

2011-01-01

Full Text Available This study aims to contribute to the understanding of the relationship between Corporate Strategy and Performance, from the perspective of the Evolutionary Theory. As methods of data processing, obtained in secondary databases, we used artificial neural networks and genetic algorithms. The results of processing neural networks and genetic algorithms demonstrate the importance of corporate strategies in determining performance. The evolutionary perspective emphasizes the importance of investing in operations as a factor influencing the adequacy of the organization, in order to achieve an improved performance, in addition to establishing relationships with other organizations, through members of the board.

The surgical treatment strategy and results of parasellar meningiomas in the era of radiosurgery

International Nuclear Information System (INIS)

Iwai, Yoshiyasu; Yamanaka, Kazuhiro; Morikawa, Toshie; Ishiguro, Tomoya; Honda, Yuji; Matsuzaka, Yasuhiro; Komiyama, Masaki; Yasui, Toshihiro

2003-01-01

We evaluated the surgical treatment results of parasellar meningiomas in the era of radiosurgery. We treated 24 patients of parasellar meningiomas surgically. The median age was 60 yrs (ranging from 29 to 82 yrs). The most common tumor location was the sphenoid ridge in 12 patients and the tuberculum sellae in 7 patients. The pterional approach using fronto-temporal craniotomy was performed for all patients. The residual or recurrent tumors were treated by gamma knife radiosurgery (GKS). We are able to follow up these cases for a median of 3.8 yrs (ranging from 1 to 8 yrs) after the operations. The radicality of tumor resection was Simpson grade II in 13 patients (54%), grade III in 3 patients (13%) and grade IV in 7 patients (33%). Clinical improvement was achieved in 81% of the patients. Of the patients who had visual disturbance preoperatively, 8 patients (73%) showed improvement, but 3 patients suffered deterioration postoperatively. None of the patients died. One patient suffered transient memory disturbance and one patient suffered mild facial numbness postoperatively. Boost radiosurgery for the residual tumors was performed for six patients and tumor growth control was able to be achieved in all patients, with a median of 3.1 years follow-up period (ranging from 0.5 to 6 yrs). Five patients with tumor regrowth or recurrence were treated by GKS. We recommend fronto-temporal craniotomy with nonradical resection for parasellar meningiomas and radiosurgery for residual and recurrent tumors. This strategy will achieve good functional outcome with long-term tumor growth control. (author)

Self-regulated learning strategies used in surgical clerkship and the relationship with clinical achievement.

Science.gov (United States)

Turan, Sevgi; Konan, Ali

2012-01-01

Self-regulated learning indicates students' skills in controlling their own learning. Self-regulated learning, which a context-specific process, emphasizes autonomy and control. Students gain more autonomy with respect to learning in the clinical years. Examining the self-regulated learning skills of students in this period will provide important clues about the level at which students are ready to use these skills in real-life conditions. The self-regulated learning strategies used by medical students in surgical clerkship were investigated in this study and their relation with clinical achievement was analyzed. The study was conducted during the surgery clerkship of medical students. The participation rate was 94% (309 students). Motivated Strategies for Learning Questionnaire (MSLQ), a case-based examination, Objective Structured Clinical Examination (OSCE), and tutor evaluations for assessing achievement were used. The relationship between the Motivated Strategies for Learning Questionnaire scores of the students and clinical achievement was analyzed with multilinear regression analysis. The findings showed that students use self-regulated learning skills at medium levels during their surgery clerkship. A relationship between these skills and OSCE scores and tutor evaluations was determined. OSCE scores of the students were observed to increase in conjunction with increased self-efficacy levels. However, as students' beliefs regarding control over learning increased, OSCE scores decreased. No significant relationship was defined between self-regulated learning skills and case-based examination scores. We observed that a greater self-efficacy for learning resulted in higher OSCE scores. Conversely, students who believe that learning is a result of their own effort had lower OSCE scores. Copyright © 2012 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

NEURAL NETWORKS FOR STOCK MARKET OPTION PRICING

Directory of Open Access Journals (Sweden)

Sergey A. Sannikov

2017-03-01

Full Text Available Introduction: The use of neural networks for non-linear models helps to understand where linear model drawbacks, coused by their specification, reveal themselves. This paper attempts to find this out. The objective of research is to determine the meaning of “option prices calculation using neural networks”. Materials and Methods: We use two kinds of variables: endogenous (variables included in the model of neural network and variables affecting on the model (permanent disturbance. Results: All data are divided into 3 sets: learning, affirming and testing. All selected variables are normalised from 0 to 1. Extreme values of income were shortcut. Discussion and Conclusions: Using the 33-14-1 neural network with direct links we obtained two sets of forecasts. Optimal criteria of strategies in stock markets’ option pricing were developed.

Methodology for neural networks prototyping. Application to traffic control

Energy Technology Data Exchange (ETDEWEB)

Belegan, I.C.

1998-07-01

The work described in this report was carried out in the context of the European project ASTORIA (Advanced Simulation Toolbox for Real-World Industrial Application in Passenger Management and Adaptive Control), and concerns the development of an advanced toolbox for complex transportation systems. Our work was focused on the methodology for prototyping a set of neural networks corresponding to specific strategies for traffic control and congestion management. The tool used for prototyping is SNNS (Stuggart Neural Network Simulator), developed at the University of Stuggart, Institute for Parallel and Distributed High Performance Systems, and the real data from the field were provided by ZELT. This report is structured into six parts. The introduction gives some insights about traffic control and its approaches. The second chapter discusses the various control strategies existing. The third chapter is an introduction to the field of neural networks. The data analysis and pre-processing is described in the fourth chapter. In the fifth chapter, the methodology for prototyping the neural networks is presented. Finally, conclusions and further work are presented. (author) 14 refs.

Surgical Approaches to Chronic Pancreatitis: Indications and Techniques.

Science.gov (United States)

Dua, Monica M; Visser, Brendan C

2017-07-01

There are a number of surgical strategies for the treatment of chronic pancreatitis. The optimal intervention should provide effective pain relief, improve/maintain quality of life, preserve exocrine and endocrine function, and manage local complications. Pancreaticoduodenectomy was once the standard operation for patients with chronic pancreatitis; however, other procedures such as the duodenum-preserving pancreatic head resections and its variants have been introduced with good long-term results. Pancreatic duct drainage via a lateral pancreaticojejunostomy continues to be effective in ameliorating symptoms and expediting return to normal lifestyle in many patients. This review summarizes operative indications and gives an overview of the different surgical strategies in treating chronic pancreatitis.

Intraoperative biopsy of the major cranial nerves in the surgical strategy for adenoid cystic carcinoma close to the skull base.

Science.gov (United States)

Tarsitano, Achille; Pizzigallo, Angelo; Gessaroli, Manlio; Sturiale, Carmelo; Marchetti, Claudio

2012-02-01

Adenoid cystic carcinoma of the salivary glands has a propensity for perineural invasion, which could favor spread along the major cranial nerves, sometimes to the skull base and through the foramina to the brain parenchyma. This study evaluated the relationship between neural spread and relapse in the skull base. During surgery, we performed multiple biopsies with extemporaneous examination of the major nerves close to the tumor to guide the surgical resection. The percentage of actuarial local control at 5 years for patients with a positive named nerve and skull base infiltration was 12.5%, compared with 90.0% in patients who were named nerve-negative and without infiltration of the skull base (P = .001). Our study shows that local control of disease for patients who are named nerve-positive with skull base infiltration is significantly more complex compared with patients who are named nerve-negative without infiltration of the skull base. Copyright © 2012. Published by Mosby, Inc.

"Beating osteoARThritis": development of a stepped care strategy to optimize utilization and timing of non-surgical treatment modalities for patients with hip or knee osteoarthritis

NARCIS (Netherlands)

Smink, A.J.; Ende, C.H.; Vliet-Vlieland, Th.P.M.; Swierstra, B.A.; Kortland, J.H.; Bijlsma, J.W.; Voorn, T.B.; Schers, H.J.; Bierma-Zeinstra, S.M.; Dekker, J.

2011-01-01

Inadequacies in health care practices have been reported despite existing guidelines to manage hip or knee osteoarthritis. To facilitate guideline implementation and improve utilization of non-surgical treatment options a care strategy should be developed. This study describes the development of an

"Beating osteoARThritis": Development of a stepped care strategy to optimize utilization and timing of non-surgical treatment modalities for patients with hip or knee osteoarthritis

NARCIS (Netherlands)

Smink, A.J.; Ende, C.H.M. van den; Vliet Vlieland, T.P.M.; Swierstra, B.A.; Kortland, J.H.; Bijlsma, J.W.J.; Voorn, T.B.; Schers, H.J.; Bierma-Zeinstra, S.M.; Dekker, J.

2011-01-01

Inadequacies in health care practices have been reported despite existing guidelines to manage hip or knee osteoarthritis. To facilitate guideline implementation and improve utilization of non-surgical treatment options a care strategy should be developed. This study describes the development of an

New treatment strategies for canine intervertebral disc degeneration

NARCIS (Netherlands)

Smolders, L.A.

2013-01-01

Degeneration of the intervertebral disc (IVD) is a common problem in dogs and humans. IVD degeneration can lead to herniation of the IVD with subsequent compression of neural structures and various clinical signs, including back pain. Current treatment of IVD disease is conservative or surgical.

Neural stem cell sex dimorphism in aromatase (CYP19 expression: a basis for differential neural fate

Directory of Open Access Journals (Sweden)

Jay Waldron

2010-11-01

Full Text Available Jay Waldron1, Althea McCourty1, Laurent Lecanu1,21The Research Institute of the McGill University Health Centre, Montreal, Canada; 2Department of Medicine, McGill University, Quebec, CanadaPurpose: Neural stem cell (NSC transplantation and pharmacologic activation of endogenous neurogenesis are two approaches that trigger a great deal of interest as brain repair strategies. However, the success rate of clinical attempts using stem cells to restore neurologic functions altered either after traumatic brain injury or as a consequence of neurodegenerative disease remains rather disappointing. This suggests that factors affecting the fate of grafted NSCs are largely understudied and remain to be characterized. We recently reported that aging differentially affects the neurogenic properties of male and female NSCs. Although the sex steroids androgens and estrogens participate in the regulation of neurogenesis, to our knowledge, research on how gender-based differences affect the capacity of NSCs to differentiate and condition their neural fate is lacking. In the present study, we explored further the role of cell sex as a determining factor of the neural fate followed by differentiating NSCs and its relationship with a potential differential expression of aromatase (CYP19, the testosterone-metabolizing enzyme.Results: Using NSCs isolated from the subventricular zone of three-month-old male and female Long-Evans rats and maintained as neurospheres, we showed that differentiation triggered by retinoic acid resulted in a neural phenotype that depends on cell sex. Differentiated male NSCs mainly expressed markers of neuronal fate, including ßIII-tubulin, microtubule associated protein 2, growth-associated protein 43, and doublecortin. In contrast, female NSCs essentially expressed the astrocyte marker glial fibrillary acidic protein. Quantification of the expression of aromatase showed a very low level of expression in undifferentiated female NSCs

Sub-meninges implantation reduces immune response to neural implants.

Science.gov (United States)

Markwardt, Neil T; Stokol, Jodi; Rennaker, Robert L

2013-04-15

Glial scar formation around neural interfaces inhibits their ability to acquire usable signals from the surrounding neurons. To improve neural recording performance, the inflammatory response and glial scarring must be minimized. Previous work has indicated that meningeally derived cells participate in the immune response, and it is possible that the meninges may grow down around the shank of a neural implant, contributing to the formation of the glial scar. This study examines whether the glial scar can be reduced by placing a neural probe completely below the meninges. Rats were implanted with sets of loose microwire implants placed either completely below the meninges or implanted conventionally with the upper end penetrating the meninges, but not attached to the skull. Histological analysis was performed 4 weeks following surgical implantation to evaluate the glial scar. Our results found that sub-meninges implants showed an average reduction in reactive astrocyte activity of 63% compared to trans-meninges implants. Microglial activity was also reduced for sub-meninges implants. These results suggest that techniques that isolate implants from the meninges offer the potential to reduce the encapsulation response which should improve chronic recording quality and stability. Published by Elsevier B.V.

Behavioural and neural modulation of win-stay but not lose-shift strategies as a function of outcome value in Rock, Paper, Scissors.

Science.gov (United States)

Forder, Lewis; Dyson, Benjamin James

2016-09-23

Competitive environments in which individuals compete for mutually-exclusive outcomes require rational decision making in order to maximize gains but often result in poor quality heuristics. Reasons for the greater reliance on lose-shift relative to win-stay behaviour shown in previous studies were explored using the game of Rock, Paper, Scissors and by manipulating the value of winning and losing. Decision-making following a loss was characterized as relatively fast and relatively inflexible both in terms of the failure to modulate the magnitude of lose-shift strategy and the lack of significant neural modulation. In contrast, decision-making following a win was characterized as relatively slow and relatively flexible both in terms of a behavioural increase in the magnitude of win-stay strategy and a neural modulation of feedback-related negativity (FRN) and stimulus-preceding negativity (SPN) following outcome value modulation. The win-stay/lose-shift heuristic appears not to be a unified mechanism, with the former relying on System 2 processes and the latter relying on System 1 processes. Our ability to play rationally appears more likely when the outcome is positive and when the value of wins are low, highlighting how vulnerable we can be when trying to succeed during competition.

Surgical repair of idiopathic scrotal elephantiasis.

Science.gov (United States)

Zacharakis, Evangelos; Dudderidge, Tim; Zacharakis, Emmanouil; Ioannidis, Evangelos

2008-02-01

Scrotal lymphedema (scrotal elephantiasis) is uncommon outside of filariasis endemic regions. We present a case of a 65-year-old with idiopathic lymphedema of the scrotum and functional impairment of the penis. The patient underwent surgical excision of the edematous subcutaneous tissues and plastic reconstruction of his penis and scrotum. Three years later, the patient showed no signs of local recurrence, had complete restoration of urinary and sexual function and was extremely satisfied with the result. Surgical management was an effective strategy in the management of scrotal lymphedema in this case.

Quantized Synchronization of Chaotic Neural Networks With Scheduled Output Feedback Control.

Science.gov (United States)

Wan, Ying; Cao, Jinde; Wen, Guanghui

In this paper, the synchronization problem of master-slave chaotic neural networks with remote sensors, quantization process, and communication time delays is investigated. The information communication channel between the master chaotic neural network and slave chaotic neural network consists of several remote sensors, with each sensor able to access only partial knowledge of output information of the master neural network. At each sampling instants, each sensor updates its own measurement and only one sensor is scheduled to transmit its latest information to the controller's side in order to update the control inputs for the slave neural network. Thus, such communication process and control strategy are much more energy-saving comparing with the traditional point-to-point scheme. Sufficient conditions for output feedback control gain matrix, allowable length of sampling intervals, and upper bound of network-induced delays are derived to ensure the quantized synchronization of master-slave chaotic neural networks. Lastly, Chua's circuit system and 4-D Hopfield neural network are simulated to validate the effectiveness of the main results.In this paper, the synchronization problem of master-slave chaotic neural networks with remote sensors, quantization process, and communication time delays is investigated. The information communication channel between the master chaotic neural network and slave chaotic neural network consists of several remote sensors, with each sensor able to access only partial knowledge of output information of the master neural network. At each sampling instants, each sensor updates its own measurement and only one sensor is scheduled to transmit its latest information to the controller's side in order to update the control inputs for the slave neural network. Thus, such communication process and control strategy are much more energy-saving comparing with the traditional point-to-point scheme. Sufficient conditions for output feedback control

[Deep alkali burns: Evaluation of a two-step surgical strategy].

Science.gov (United States)

Devinck, F; Deveaux, C; Bennis, Y; Deken-Delannoy, V; Jeanne, M; Martinot-Duquennoy, V; Guerreschi, P; Pasquesoone, L

2018-04-10

Chemical burns are rare but often lead to deep cutaneous lesions. Alkali agents have a deep and long lasting penetrating power, causing burns that evolve over several days. The local treatment for these patients is excision of the wound and split thickness skin graft. Early excision and immediate skin grafting of alkali burns are more likely to be complicated by graft failure and delayed wound healing. We propose a two-step method that delays skin grafting until two-three days after burn wound excision. Our population included 25 controls and 16 cases. Men were predominant with a mean age of 41.9 years. In 78% of cases, burns were located on the lower limbs. The mean delay between the burn and excision was 16.5 days. In cases, the skin graft was performed at a mean of 11.3 days after the initial excision. We did not unveil any significant difference between both groups for the total skin surface affected, topography of the burns and the causal agent. Wound healing was significantly shorter in cases vs controls (37.5 days vs 50.3 days; P<0.025). Furthermore, we observed a decreased number of graft failures in cases vs controls (13.3% vs 46.7%; P=0.059). Our study shows the relevance of a two-step surgical strategy in patients with alkali chemical burns. Early excision followed by interval skin grafting is associated with quicker wound healing and decreased rate of graft failure. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Neural Network-Based State Estimation for a Closed-Loop Control Strategy Applied to a Fed-Batch Bioreactor

Directory of Open Access Journals (Sweden)

Santiago Rómoli

2017-01-01

Full Text Available The lack of online information on some bioprocess variables and the presence of model and parametric uncertainties pose significant challenges to the design of efficient closed-loop control strategies. To address this issue, this work proposes an online state estimator based on a Radial Basis Function (RBF neural network that operates in closed loop together with a control law derived on a linear algebra-based design strategy. The proposed methodology is applied to a class of nonlinear systems with three types of uncertainties: (i time-varying parameters, (ii uncertain nonlinearities, and (iii unmodeled dynamics. To reduce the effect of uncertainties on the bioreactor, some integrators of the tracking error are introduced, which in turn allow the derivation of the proper control actions. This new control scheme guarantees that all signals are uniformly and ultimately bounded, and the tracking error converges to small values. The effectiveness of the proposed approach is illustrated on the basis of simulated experiments on a fed-batch bioreactor, and its performance is compared with two controllers available in the literature.

Computational neuroanatomy: ontology-based representation of neural components and connectivity.

Science.gov (United States)

Rubin, Daniel L; Talos, Ion-Florin; Halle, Michael; Musen, Mark A; Kikinis, Ron

2009-02-05

A critical challenge in neuroscience is organizing, managing, and accessing the explosion in neuroscientific knowledge, particularly anatomic knowledge. We believe that explicit knowledge-based approaches to make neuroscientific knowledge computationally accessible will be helpful in tackling this challenge and will enable a variety of applications exploiting this knowledge, such as surgical planning. We developed ontology-based models of neuroanatomy to enable symbolic lookup, logical inference and mathematical modeling of neural systems. We built a prototype model of the motor system that integrates descriptive anatomic and qualitative functional neuroanatomical knowledge. In addition to modeling normal neuroanatomy, our approach provides an explicit representation of abnormal neural connectivity in disease states, such as common movement disorders. The ontology-based representation encodes both structural and functional aspects of neuroanatomy. The ontology-based models can be evaluated computationally, enabling development of automated computer reasoning applications. Neuroanatomical knowledge can be represented in machine-accessible format using ontologies. Computational neuroanatomical approaches such as described in this work could become a key tool in translational informatics, leading to decision support applications that inform and guide surgical planning and personalized care for neurological disease in the future.

The neural correlates of emotion regulation by implementation intentions.

Directory of Open Access Journals (Sweden)

Glyn P Hallam

Full Text Available Several studies have investigated the neural basis of effortful emotion regulation (ER but the neural basis of automatic ER has been less comprehensively explored. The present study investigated the neural basis of automatic ER supported by 'implementation intentions'. 40 healthy participants underwent fMRI while viewing emotion-eliciting images and used either a previously-taught effortful ER strategy, in the form of a goal intention (e.g., try to take a detached perspective, or a more automatic ER strategy, in the form of an implementation intention (e.g., "If I see something disgusting, then I will think these are just pixels on the screen!", to regulate their emotional response. Whereas goal intention ER strategies were associated with activation of brain areas previously reported to be involved in effortful ER (including dorsolateral prefrontal cortex, ER strategies based on an implementation intention strategy were associated with activation of right inferior frontal gyrus and ventro-parietal cortex, which may reflect the attentional control processes automatically captured by the cue for action contained within the implementation intention. Goal intentions were also associated with less effective modulation of left amygdala, supporting the increased efficacy of ER under implementation intention instructions, which showed coupling of orbitofrontal cortex and amygdala. The findings support previous behavioural studies in suggesting that forming an implementation intention enables people to enact goal-directed responses with less effort and more efficiency.

Context-dependent neural activation: internally and externally guided rhythmic lower limb movement in individuals with and without neurodegenerative disease

Directory of Open Access Journals (Sweden)

Madeleine Eve Hackney

2015-12-01

Full Text Available Parkinson’s Disease (PD is a neurodegenerative disorder that has received considerable attention in allopathic medicine over the past decades. However, it is clear that, to date, pharmacological and surgical interventions do not fully address symptoms of PD and patients’ quality of life. As both an alternative therapy and as an adjuvant to conventional approaches, several types of rhythmic movement (e.g., movement strategies, dance, tandem biking, tai chi have shown improvements to motor symptoms, lower limb control and postural stability in people with PD (Amano, Nocera, Vallabhajosula, Juncos, Gregor, Waddell et al., 2013; Earhart, 2009; M. E. Hackney & Earhart, 2008; Kadivar, Corcos, Foto, & Hondzinski, 2011; Morris, Iansek, & Kirkwood, 2009; Ridgel, Vitek, & Alberts, 2009. However, while these programs are increasing in number, still little is known about the neural mechanisms underlying motor improvements attained with such interventions. Studying limb motor control under task specific contexts can help determine the mechanisms of rehabilitation effectiveness. Both internally guided (IG and externally guided (EG movement strategies have evidence to support their use in rehabilitative programs. However, there appears to be a degree of differentiation in the neural substrates involved in IG versus EG designs. Because of the potential task specific benefits of rhythmic training within a rehabilitative context, this report will consider the use of IG and EG movement strategies, and observations produced by functional magnetic resonance imaging (fMRI and other imaging techniques. This review will present findings from lower limb imaging studies, under IG and EG conditions for populations with and without movement disorders. We will discuss how these studies might inform movement disorders rehabilitation (in the form of rhythmic, music-based movement training and highlight research gaps. We believe better understanding of lower limb neural

Training situational awareness to reduce surgical errors in the operating room

NARCIS (Netherlands)

Graafland, M.; Schraagen, J.M.C.; Boermeester, M.A.; Bemelman, W.A.; Schijven, M.P.

2015-01-01

Background: Surgical errors result from faulty decision-making, misperceptions and the application of suboptimal problem-solving strategies, just as often as they result from technical failure. To date, surgical training curricula have focused mainly on the acquisition of technical skills. The aim

Surgical treatment of chronic pancreatitis in young patients.

Science.gov (United States)

Zhou, Feng; Gou, Shan-Miao; Xiong, Jiong-Xin; Wu, He-Shui; Wang, Chun-You; Liu, Tao

2014-10-01

The main treatment strategies for chronic pancreatitis in young patients include therapeutic endoscopic retrograde cholangio-pancreatography (ERCP) intervention and surgical intervention. Therapeutic ERCP intervention is performed much more extensively for its minimally invasive nature, but a part of patients are referred to surgery at last. Historical and follow-up data of 21 young patients with chronic pancreatitis undergoing duodenum-preserving total pancreatic head resection were analyzed to evaluate the outcomes of therapeutic ERCP intervention and surgical intervention in this study. The surgical complications of repeated therapeutic ERCP intervention and surgical intervention were 38% and 19% respectively. During the first therapeutic ERCP intervention to surgical intervention, 2 patients developed diabetes, 5 patients developed steatorrhea, and 5 patients developed pancreatic type B pain. During the follow-up of surgical intervention, 1 new case of diabetes occurred, 1 case of steatorrhea recovered, and 4 cases of pancreatic type B pain were completely relieved. In a part of young patients with chronic pancreatitis, surgical intervention was more effective than therapeutic ERCP intervention on delaying the progression of the disease and relieving the symptoms.

Electrospun Nanofibrous Materials for Neural Tissue Engineering

Directory of Open Access Journals (Sweden)

Yee-Shuan Lee

2011-02-01

Full Text Available The use of biomaterials processed by the electrospinning technique has gained considerable interest for neural tissue engineering applications. The tissue engineering strategy is to facilitate the regrowth of nerves by combining an appropriate cell type with the electrospun scaffold. Electrospinning can generate fibrous meshes having fiber diameter dimensions at the nanoscale and these fibers can be nonwoven or oriented to facilitate neurite extension via contact guidance. This article reviews studies evaluating the effect of the scaffold’s architectural features such as fiber diameter and orientation on neural cell function and neurite extension. Electrospun meshes made of natural polymers, proteins and compositions having electrical activity in order to enhance neural cell function are also discussed.

Application of neural networks to seismic active control

International Nuclear Information System (INIS)

Tang, Yu.

1995-01-01

An exploratory study on seismic active control using an artificial neural network (ANN) is presented in which a singledegree-of-freedom (SDF) structural system is controlled by a trained neural network. A feed-forward neural network and the backpropagation training method are used in the study. In backpropagation training, the learning rate is determined by ensuring the decrease of the error function at each training cycle. The training patterns for the neural net are generated randomly. Then, the trained ANN is used to compute the control force according to the control algorithm. The control strategy proposed herein is to apply the control force at every time step to destroy the build-up of the system response. The ground motions considered in the simulations are the N21E and N69W components of the Lake Hughes No. 12 record that occurred in the San Fernando Valley in California on February 9, 1971. Significant reduction of the structural response by one order of magnitude is observed. Also, it is shown that the proposed control strategy has the ability to reduce the peak that occurs during the first few cycles of the time history. These promising results assert the potential of applying ANNs to active structural control under seismic loads

Feedforward Nonlinear Control Using Neural Gas Network

OpenAIRE

Machón-González, Iván; López-García, Hilario

2017-01-01

Nonlinear systems control is a main issue in control theory. Many developed applications suffer from a mathematical foundation not as general as the theory of linear systems. This paper proposes a control strategy of nonlinear systems with unknown dynamics by means of a set of local linear models obtained by a supervised neural gas network. The proposed approach takes advantage of the neural gas feature by which the algorithm yields a very robust clustering procedure. The direct model of the ...

The methodological quality of systematic reviews comparing temporomandibular joint disorder surgical and non-surgical treatment

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Vasconcelos Belmiro CE

2008-09-01

Full Text Available Abstract Background Temporomandibular joint disorders (TMJD are multifactor, complex clinical problems affecting approximately 60–70% of the general population, with considerable controversy about the most effective treatment. For example, reports claim success rates of 70% and 83% for non-surgical and surgical treatment, whereas other reports claim success rates of 40% to 70% for self-improvement without treatment. Therefore, the purpose of this study was to (1 identify systematic reviews comparing temporomandibular joint disorder surgical and non-surgical treatment, (2 evaluate their methodological quality, and (3 evaluate the evidence grade within the systematic reviews. Methods A search strategy was developed and implemented for MEDLINE, Cochrane Library, LILACS, and Brazilian Dentistry Bibliography databases. Inclusion criteria were: systematic reviews (± meta-analysis comparing surgical and non-surgical TMJD treatment, published in English, Spanish, Portuguese, Italian, or German between the years 1966 and 2007(up to July. Exclusion criteria were: in vitro or animal studies; narrative reviews or editorials or editorial letters; and articles published in other languages. Two investigators independently selected and evaluated systematic reviews. Three different instruments (AMSTAR, OQAQ and CASP were used to evaluate methodological quality, and the results averaged. The GRADE instrument was used to evaluate the evidence grade within the reviews. Results The search strategy identified 211 reports; of which 2 were systematic reviews meeting inclusion criteria. The first review met 23.5 ± 6.0% and the second met 77.5 ± 12.8% of the methodological quality criteria (mean ± sd. In these systematic reviews between 9 and 15% of the trials were graded as high quality, and 2 and 8% of the total number of patients were involved in these studies. Conclusion The results indicate that in spite of the widespread impact of TMJD, and the multitude of

Requirements for the design and implementation of checklists for surgical processes

NARCIS (Netherlands)

Verdaasdonk, E.G.G.; Stassen, L.P.S.; Widhiasmara, P.P.; Dankelman, J.

2008-01-01

Background- The use of checklists is a promising strategy for improving patient safety in all types of surgical processes inside and outside the operating room. This article aims to provide requirements and implementation of checklists for surgical processes. Methods- The literature on checklist use

Secondary and Tertiary Hyperparathyroidism, State of the Art Surgical Management

Science.gov (United States)

Pitt, Susan C.; Sippel, Rebecca S.

2010-01-01

Synopsis This article reviews the current surgical management of patients with secondary and tertiary hyperparathyroidism. The focus is on innovative surgical strategies that have improved the care of these patients over the past 10 to 15 years. Modalities such as intraoperative parathyroid hormone monitoring and radioguided probe utilization are discussed. PMID:19836494

Supervised Learning with Complex-valued Neural Networks

CERN Document Server

Suresh, Sundaram; Savitha, Ramasamy

2013-01-01

Recent advancements in the field of telecommunications, medical imaging and signal processing deal with signals that are inherently time varying, nonlinear and complex-valued. The time varying, nonlinear characteristics of these signals can be effectively analyzed using artificial neural networks.  Furthermore, to efficiently preserve the physical characteristics of these complex-valued signals, it is important to develop complex-valued neural networks and derive their learning algorithms to represent these signals at every step of the learning process. This monograph comprises a collection of new supervised learning algorithms along with novel architectures for complex-valued neural networks. The concepts of meta-cognition equipped with a self-regulated learning have been known to be the best human learning strategy. In this monograph, the principles of meta-cognition have been introduced for complex-valued neural networks in both the batch and sequential learning modes. For applications where the computati...

Neural responses to macronutrients: hedonic and homeostatic mechanisms.

Science.gov (United States)

Tulloch, Alastair J; Murray, Susan; Vaicekonyte, Regina; Avena, Nicole M

2015-05-01

The brain responds to macronutrients via intricate mechanisms. We review how the brain's neural systems implicated in homeostatic control of feeding and hedonic responses are influenced by the ingestion of specific types of food. We discuss how these neural systems are dysregulated in preclinical models of obesity. Findings from these studies can increase our understanding of overeating and, perhaps in some cases, the development of obesity. In addition, a greater understanding of the neural circuits affected by the consumption of specific macronutrients, and by obesity, might lead to new treatments and strategies for preventing unhealthy weight gain. Copyright © 2015 AGA Institute. Published by Elsevier Inc. All rights reserved.

Application of CMAC Neural Network Coupled with Active Disturbance Rejection Control Strategy on Three-motor Synchronization Control System

Directory of Open Access Journals (Sweden)

Hui Li

2014-04-01

Full Text Available Three-motor synchronous coordination system is a MI-MO nonlinear and complex control system. And it often works in poor working condition. Advanced control strategies are required to improve the control performance of the system and to achieve the decoupling between main motor speed and tension. Cerebellar Model Articulation Controller coupled with Active Disturbance Rejection Control (CMAC-ADRC control strategy is proposed. The speed of the main motor and tensions between two motors is decoupled by extended state observer (ESO in ADRC. ESO in ADRC is used to compensate internal and external disturbances of the system online. And the anti interference of the system is improved by ESO. And the same time the control model is optimized. Feedforward control is implemented by the adoption of CMAC neural network controller. And control precision of the system is improved in reason of CMAC. The overshoot of the system can be reduced without affecting the dynamic response of the system by the use of CMAC-ADRC. The simulation results show that: the CMAC- ADRC control strategy is better than the traditional PID control strategy. And CMAC-ADRC control strategy can achieve the decoupling between speed and tension. The control system using CMAC-ADRC have strong anti-interference ability and small regulate time and small overshoot. The magnitude of the system response incited by the interference using CMAC-ADRC is smaller than the system using conventional PID control 6.43 %. And the recovery time of the system with CMAC-ADRC is shorter than the system with traditional PID control 0.18 seconds. And the triangular wave tracking error of the system with CMAC-ADRC is smaller than the system with conventional PID control 0.24 rad/min. Thus the CMAC-ADRC control strategy is a good control strategy and is able to fit three-motor synchronous coordinated control.

Study on Maritime Logistics Warehousing Center Model and Precision Marketing Strategy Optimization Based on Fuzzy Method and Neural Network Model

Directory of Open Access Journals (Sweden)

Xiao Kefeng

2017-08-01

Full Text Available The bulk commodity, different with the retail goods, has a uniqueness in the location selection, the chosen of transportation program and the decision objectives. How to make optimal decisions in the facility location, requirement distribution, shipping methods and the route selection and establish an effective distribution system to reduce the cost has become a burning issue for the e-commerce logistics, which is worthy to be deeply and systematically solved. In this paper, Logistics warehousing center model and precision marketing strategy optimization based on fuzzy method and neural network model is proposed to solve this problem. In addition, we have designed principles of the fuzzy method and neural network model to solve the proposed model because of its complexity. Finally, we have solved numerous examples to compare the results of lingo and Matlab, we use Matlab and lingo just to check the result and to illustrate the numerical example, we can find from the result, the multi-objective model increases logistics costs and improves the efficiency of distribution time.

Periconceptional Folate Deficiency and Implications in Neural Tube Defects

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J. Safi

2012-01-01

Full Text Available Nutritional deficiencies are preventable etiological and epigenetic factors causing congenital abnormalities, first cause of infant mortality. Folate deficiency has a well-established teratogenic effect, leading to an increasing risk of neural tube defects. This paper highlights the most recent medical literature about folate deficiency, be it maternal or paternal. It then focuses on associated deficiencies as nutritional deficiencies are multiple and interrelated. Observational and interventional studies have all been consistent with a 50–70% protective effect of adequate women consumption of folates on neural tube defects. Since strategies to modify women’s dietary habits and vitamin use have achieved little progress, scientific as well as political effort is mandatory in order to implement global preventive public health strategies aimed at improving the alimentation of women in reproductive age, especially folic acid supplementation. Even with the recent breakthrough of fetal surgery for myelomeningocele, the emphasis should still be on prevention as the best practice rather than treatment of neural tube defects.

Random neural Q-learning for obstacle avoidance of a mobile robot in unknown environments

Directory of Open Access Journals (Sweden)

Jing Yang

2016-07-01

Full Text Available The article presents a random neural Q-learning strategy for the obstacle avoidance problem of an autonomous mobile robot in unknown environments. In the proposed strategy, two independent modules, namely, avoidance without considering the target and goal-seeking without considering obstacles, are first trained using the proposed random neural Q-learning algorithm to obtain their best control policies. Then, the two trained modules are combined based on a switching function to realize the obstacle avoidance in unknown environments. For the proposed random neural Q-learning algorithm, a single-hidden layer feedforward network is used to approximate the Q-function to estimate the Q-value. The parameters of the single-hidden layer feedforward network are modified using the recently proposed neural algorithm named the online sequential version of extreme learning machine, where the parameters of the hidden nodes are assigned randomly and the sample data can come one by one. However, different from the original online sequential version of extreme learning machine algorithm, the initial output weights are estimated subjected to quadratic inequality constraint to improve the convergence speed. Finally, the simulation results demonstrate that the proposed random neural Q-learning strategy can successfully solve the obstacle avoidance problem. Also, the higher learning efficiency and better generalization ability are achieved by the proposed random neural Q-learning algorithm compared with the Q-learning based on the back-propagation method.

An evaluation of Irish general surgical research publications from 2000 to 2009.

LENUS (Irish Health Repository)

Robertson, I J

2010-12-01

Maintaining a high standard of research, and being competitive in the funding application process requires a coordinated and focused research strategy. The first step in the formulation of such a strategy is the identification of those centres, and specifically those areas of study, in which Irish surgical research has previously performed strongly. The aim of this paper was to evaluate all surgical research produced in the Republic of Ireland in the first ten years of the new millennium.

Assessment of neural networks training strategies for histomorphometric analysis of synchrotron radiation medical images

International Nuclear Information System (INIS)

Alvarenga de Moura Meneses, Anderson; Gomes Pinheiro, Christiano Jorge; Rancoita, Paola; Schaul, Tom; Gambardella, Luca Maria; Schirru, Roberto; Barroso, Regina Cely; Oliveira, Luis Fernando de

2010-01-01

Micro-computed tomography (μCT) obtained by synchrotron radiation (SR) enables magnified images with a high space resolution that might be used as a non-invasive and non-destructive technique for the quantitative analysis of medical images, in particular the histomorphometry (HMM) of bony mass. In the preprocessing of such images, conventional operations such as binarization and morphological filtering are used before calculating the stereological parameters related, for example, to the trabecular bone microarchitecture. However, there is no standardization of methods for HMM based on μCT images, especially the ones obtained with SR X-ray. Notwithstanding the several uses of artificial neural networks (ANNs) in medical imaging, their application to the HMM of SR-μCT medical images is still incipient, despite the potential of both techniques. The contribution of this paper is the assessment and comparison of well-known training algorithms as well as the proposal of training strategies (combinations of training algorithms, sub-image kernel and symmetry information) for feed-forward ANNs in the task of bone pixels recognition in SR-μCT medical images. For a quantitative comparison, the results of a cross validation and a statistical analysis of the results for 36 training strategies are presented. The ANNs demonstrated both very low mean square errors in the validation, and good quality segmentation of the image of interest for application to HMM in SR-μCT medical images.

Assessment of neural networks training strategies for histomorphometric analysis of synchrotron radiation medical images

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Alvarenga de Moura Meneses, Anderson, E-mail: ameneses@lmp.ufrj.b [Federal University of Rio de Janeiro, COPPE, Nuclear Engineering Program, CP 68509, CEP 21.941-972, Rio de Janeiro, RJ (Brazil); IDSIA (Dalle Molle Institute for Artificial Intelligence), University of Lugano (Switzerland); Gomes Pinheiro, Christiano Jorge [State University of Rio de Janeiro, RJ (Brazil); Rancoita, Paola [IDSIA (Dalle Molle Institute for Artificial Intelligence), University of Lugano (Switzerland); Mathematics Department, Universita degli Studi di Milano (Italy); Schaul, Tom; Gambardella, Luca Maria [IDSIA (Dalle Molle Institute for Artificial Intelligence), University of Lugano (Switzerland); Schirru, Roberto [Federal University of Rio de Janeiro, COPPE, Nuclear Engineering Program, CP 68509, CEP 21.941-972, Rio de Janeiro, RJ (Brazil); Barroso, Regina Cely; Oliveira, Luis Fernando de [State University of Rio de Janeiro, RJ (Brazil)

2010-09-21

Micro-computed tomography ({mu}CT) obtained by synchrotron radiation (SR) enables magnified images with a high space resolution that might be used as a non-invasive and non-destructive technique for the quantitative analysis of medical images, in particular the histomorphometry (HMM) of bony mass. In the preprocessing of such images, conventional operations such as binarization and morphological filtering are used before calculating the stereological parameters related, for example, to the trabecular bone microarchitecture. However, there is no standardization of methods for HMM based on {mu}CT images, especially the ones obtained with SR X-ray. Notwithstanding the several uses of artificial neural networks (ANNs) in medical imaging, their application to the HMM of SR-{mu}CT medical images is still incipient, despite the potential of both techniques. The contribution of this paper is the assessment and comparison of well-known training algorithms as well as the proposal of training strategies (combinations of training algorithms, sub-image kernel and symmetry information) for feed-forward ANNs in the task of bone pixels recognition in SR-{mu}CT medical images. For a quantitative comparison, the results of a cross validation and a statistical analysis of the results for 36 training strategies are presented. The ANNs demonstrated both very low mean square errors in the validation, and good quality segmentation of the image of interest for application to HMM in SR-{mu}CT medical images.

Neural correlates of strategy use during auditory working memory in musicians and non-musicians.

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Schulze, K; Mueller, K; Koelsch, S

2011-01-01

Working memory (WM) performance in humans can be improved by structuring and organizing the material to be remembered. For visual and verbal information, this process of structuring has been associated with the involvement of a prefrontal-parietal network, but for non-verbal auditory material, the brain areas that facilitate WM for structured information have remained elusive. Using functional magnetic resonance imaging, this study compared neural correlates underlying encoding and rehearsal of auditory WM for structured and unstructured material. Musicians and non-musicians performed a WM task on five-tone sequences that were either tonally structured (with all tones belonging to one tonal key) or tonally unstructured (atonal) sequences. Functional differences were observed for musicians (who are experts in the music domain), but not for non-musicians - The right pars orbitalis was activated more strongly in musicians during the encoding of unstructured (atonal) vs. structured (tonal) sequences. In addition, data for musicians showed that a lateral (pre)frontal-parietal network (including the right premotor cortex, right inferior precentral sulcus and left intraparietal sulcus) was activated during WM rehearsal of structured, as compared with unstructured, sequences. Our findings indicate that this network plays a role in strategy-based WM for non-verbal auditory information, corroborating previous results showing a similar network for strategy-based WM for visual and verbal information. © 2010 The Authors. European Journal of Neuroscience © 2010 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

Time- and task-dependent non-neural effects of real and sham TMS.

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Felix Duecker

Full Text Available Transcranial magnetic stimulation (TMS is widely used in experimental brain research to manipulate brain activity in humans. Next to the intended neural effects, every TMS pulse produces a distinct clicking sound and sensation on the head which can also influence task performance. This necessitates careful consideration of control conditions in order to ensure that behavioral effects of interest can be attributed to the neural consequences of TMS and not to non-neural effects of a TMS pulse. Surprisingly, even though these non-neural effects of TMS are largely unknown, they are often assumed to be unspecific, i.e. not dependent on TMS parameters. This assumption is inherent to many control strategies in TMS research but has recently been challenged on empirical grounds. Here, we further develop the empirical basis of control strategies in TMS research. We investigated the time-dependence and task-dependence of the non-neural effects of TMS and compared real and sham TMS over vertex. Critically, we show that non-neural TMS effects depend on a complex interplay of these factors. Although TMS had no direct neural effects, both pre- and post-stimulus TMS time windows modulated task performance on both a sensory detection task and a cognitive angle judgment task. For the most part, these effects were quantitatively similar across tasks but effect sizes were clearly different. Moreover, the effects of real and sham TMS were almost identical with interesting exceptions that shed light on the relative contribution of auditory and somato-sensory aspects of a TMS pulse. Knowledge of such effects is of critical importance for the interpretation of TMS experiments and helps deciding what constitutes an appropriate control condition. Our results broaden the empirical basis of control strategies in TMS research and point at potential pitfalls that should be avoided.

Adaptive coordination in surgical teams: an interview study.

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Bogdanovic, Jasmina; Perry, Juliana; Guggenheim, Merlin; Manser, Tanja

2015-04-01

Effective teamwork has been recognised as a major contributor to safe patient care in surgery. Previous research has highlighted the importance of adaptive coordination for effective performance in acute care settings. Expanding this line of research this study explores the coordination behaviours and adaptive coordination strategies employed by surgical teams and identifies relevant situational characteristics influencing those coordination processes. We conducted a qualitative content analysis of semi-structured interviews with 33 surgical team members (nurses and physicians) from different specialties and hospitals. We identified coordination behaviours (i.e. task management, information management, teaching and leadership) and adaptive coordination strategies triggered by varying requirements due to non-routine events, intraoperative complications and differing level of experience among operating room staff. Interviewees highlighted the importance of effectively managing challenging moments and the supporting effect of positive climate on teamwork. This study complements previous research on the non-technical skills underpinning safe performance in surgical teams. It highlights the central role of coordination and points out the ways in which situational variability requires the team to behave adaptively.

Patients at High-Risk for Surgical Site Infection.

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Mueck, Krislynn M; Kao, Lillian S

Surgical site infections (SSIs) are a significant healthcare quality issue, resulting in increased morbidity, disability, length of stay, resource utilization, and costs. Identification of high-risk patients may improve pre-operative counseling, inform resource utilization, and allow modifications in peri-operative management to optimize outcomes. Review of the pertinent English-language literature. High-risk surgical patients may be identified on the basis of individual risk factors or combinations of factors. In particular, statistical models and risk calculators may be useful in predicting infectious risks, both in general and for SSIs. These models differ in the number of variables; inclusion of pre-operative, intra-operative, or post-operative variables; ease of calculation; and specificity for particular procedures. Furthermore, the models differ in their accuracy in stratifying risk. Biomarkers may be a promising way to identify patients at high risk of infectious complications. Although multiple strategies exist for identifying surgical patients at high risk for SSIs, no one strategy is superior for all patients. Further efforts are necessary to determine if risk stratification in combination with risk modification can reduce SSIs in these patient populations.

Surgical Treatment of Hepatocellular Carcinoma

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Zamora-Valdes, Daniel; Taner, Timucin; Nagorney, David M.

2017-01-01

Hepatocellular carcinoma (HCC) is a major cause of cancer-related death worldwide. In select patients, surgical treatment in the form of either resection or transplantation offers a curative option. The aims of this review are to (1) review the current American Association for the Study of Liver Diseases/European Association for the Study of the Liver guidelines on the surgical management of HCC and (2) review the proposed changes to these guidelines and analyze the strength of evidence underlying these proposals. Three authors identified the most relevant publications in the literature on liver resection and transplantation for HCC and analyzed the strength of evidence according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) classification. In the United States, the liver allocation system provides priority for liver transplantation to patients with HCC within the Milan criteria. Current evidence suggests that liver transplantation may also be indicated in certain patient groups beyond Milan criteria, such as pediatric patients with large tumor burden or adult patients who are successfully downstaged. Patients with no underlying liver disease may also benefit from liver transplantation if the HCC is unresectable. In patients with no or minimal (compensated) liver disease and solitary HCC ≥2 cm, liver resection is warranted. If liver transplantation is not available or contraindicated, liver resection can be offered to patients with multinodular HCC, provided that the underlying liver disease is not decompensated. Many patients may benefit from surgical strategies adapted to local resources and policies (hepatitis B prevalence, organ availability, etc). Although current low-quality evidence shows better overall survival with aggressive surgical strategies, this approach is limited to select patients. Larger and well-designed prospective studies are needed to better define the benefits and limits of such approach. PMID:28975836

Principles of neural information processing

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Seelen, Werner v

2016-01-01

In this fundamental book the authors devise a framework that describes the working of the brain as a whole. It presents a comprehensive introduction to the principles of Neural Information Processing as well as recent and authoritative research. The books´ guiding principles are the main purpose of neural activity, namely, to organize behavior to ensure survival, as well as the understanding of the evolutionary genesis of the brain. Among the developed principles and strategies belong self-organization of neural systems, flexibility, the active interpretation of the world by means of construction and prediction as well as their embedding into the world, all of which form the framework of the presented description. Since, in brains, their partial self-organization, the lifelong adaptation and their use of various methods of processing incoming information are all interconnected, the authors have chosen not only neurobiology and evolution theory as a basis for the elaboration of such a framework, but also syst...

Use of the 3D surgical modelling technique with open-source software for mandibular fibula free flap reconstruction and its surgical guides.

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Ganry, L; Hersant, B; Quilichini, J; Leyder, P; Meningaud, J P

2017-06-01

Tridimensional (3D) surgical modelling is a necessary step to create 3D-printed surgical tools, and expensive professional software is generally needed. Open-source software are functional, reliable, updated, may be downloaded for free and used to produce 3D models. Few surgical teams have used free solutions for mastering 3D surgical modelling for reconstructive surgery with osseous free flaps. We described an Open-source software 3D surgical modelling protocol to perform a fast and nearly free mandibular reconstruction with microvascular fibula free flap and its surgical guides, with no need for engineering support. Four successive specialised Open-source software were used to perform our 3D modelling: OsiriX ® , Meshlab ® , Netfabb ® and Blender ® . Digital Imaging and Communications in Medicine (DICOM) data on patient skull and fibula, obtained with a computerised tomography (CT) scan, were needed. The 3D modelling of the reconstructed mandible and its surgical guides were created. This new strategy may improve surgical management in Oral and Craniomaxillofacial surgery. Further clinical studies are needed to demonstrate the feasibility, reproducibility, transfer of know how and benefits of this technique. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

The Evolution of a Malignancy Risk Prediction Model for Thyroid Nodules Using the Artificial Neural Network

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Shahram Paydar

2016-01-01

Full Text Available Background: Clinically frank thyroid nodules are common and believed to be present in 4% to 10% of the adult population in the United States. In the current literature, fine needle aspiration biopsies are considered to be the milestone of a model which helps the physician decide whether a certain thyroid nodule needs a surgical approach or not. A considerable fact is that sensitivity and specificity of the fine needle aspiration varies significantly as it remains highly dependent on the operator as well as the cytologist’s skills. Practically, in the above group of patients, thyroid lobectomy/isthmusectomy becomes mandatory for attaining a definitive diagnosis where the majority (70%-80% have a benign surgical pathology. The scattered nature of clinically gathered data and analysis of their relevant variables need a compliant statistical method. The artificial neural network is a branch of artificial intelligence. We have hypothesized that conduction of an artificial neural network applied to certain clinical attributes could develop a malignancy risk assessment tool to help physicians interpret the fine needle aspiration biopsy results of thyroid nodules in a context composed of patient’s clinical variables, known as malignancy related risk factors. Methods: We designed and trained an artificial neural network on a prospectively formed cohort gathered over a four year period (2007-2011. The study population comprised 345 subjects who underwent thyroid resection at Nemazee and Rajaee hospitals, tertiary care centers of Shiraz University of Medical Sciences, and Rajaee Hospital as a level I trauma center in Shiraz, Iran after having undergone thyroid fine needle aspiration. Histopathological results of the fine needle aspirations and surgical specimens were analyzed and compared by experienced, board-certified pathologists who lacked knowledge of the fine needle aspiration results for thyroid malignancy. Results: We compared the preoperative

Optimizing patient flow in a large hospital surgical centre by means of discrete-event computer simulation models.

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Ferreira, Rodrigo B; Coelli, Fernando C; Pereira, Wagner C A; Almeida, Renan M V R

2008-12-01

This study used the discrete-events computer simulation methodology to model a large hospital surgical centre (SC), in order to analyse the impact of increases in the number of post-anaesthetic beds (PABs), of changes in surgical room scheduling strategies and of increases in surgery numbers. The used inputs were: number of surgeries per day, type of surgical room scheduling, anaesthesia and surgery duration, surgical teams' specialty and number of PABs, and the main outputs were: number of surgeries per day, surgical rooms' use rate and blocking rate, surgical teams' use rate, patients' blocking rate, surgery delays (minutes) and the occurrence of postponed surgeries. Two basic strategies were implemented: in the first strategy, the number of PABs was increased under two assumptions: (a) following the scheduling plan actually used by the hospital (the 'rigid' scheduling - surgical rooms were previously assigned and assignments could not be changed) and (b) following a 'flexible' scheduling (surgical rooms, when available, could be freely used by any surgical team). In the second, the same analysis was performed, increasing the number of patients (up to the system 'feasible maximum') but fixing the number of PABs, in order to evaluate the impact of the number of patients over surgery delays. It was observed that the introduction of a flexible scheduling/increase in PABs would lead to a significant improvement in the SC productivity.

Development of biomaterial scaffold for nerve tissue engineering: Biomaterial mediated neural regeneration

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2009-01-01

Neural tissue repair and regeneration strategies have received a great deal of attention because it directly affects the quality of the patient's life. There are many scientific challenges to regenerate nerve while using conventional autologous nerve grafts and from the newly developed therapeutic strategies for the reconstruction of damaged nerves. Recent advancements in nerve regeneration have involved the application of tissue engineering principles and this has evolved a new perspective to neural therapy. The success of neural tissue engineering is mainly based on the regulation of cell behavior and tissue progression through the development of a synthetic scaffold that is analogous to the natural extracellular matrix and can support three-dimensional cell cultures. As the natural extracellular matrix provides an ideal environment for topographical, electrical and chemical cues to the adhesion and proliferation of neural cells, there exists a need to develop a synthetic scaffold that would be biocompatible, immunologically inert, conducting, biodegradable, and infection-resistant biomaterial to support neurite outgrowth. This review outlines the rationale for effective neural tissue engineering through the use of suitable biomaterials and scaffolding techniques for fabrication of a construct that would allow the neurons to adhere, proliferate and eventually form nerves. PMID:19939265

Therapeutic physical exercise in neural injury: friend or foe?

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Park, Kanghui; Lee, Seunghoon; Hong, Yunkyung; Park, Sookyoung; Choi, Jeonghyun; Chang, Kyu-Tae; Kim, Joo-Heon; Hong, Yonggeun

2015-12-01

[Purpose] The intensity of therapeutic physical exercise is complex and sometimes controversial in patients with neural injuries. This review assessed whether therapeutic physical exercise is beneficial according to the intensity of the physical exercise. [Methods] The authors identified clinically or scientifically relevant articles from PubMed that met the inclusion criteria. [Results] Exercise training can improve body strength and lead to the physiological adaptation of skeletal muscles and the nervous system after neural injuries. Furthermore, neurophysiological and neuropathological studies show differences in the beneficial effects of forced therapeutic exercise in patients with severe or mild neural injuries. Forced exercise alters the distribution of muscle fiber types in patients with neural injuries. Based on several animal studies, forced exercise may promote functional recovery following cerebral ischemia via signaling molecules in ischemic brain regions. [Conclusions] This review describes several types of therapeutic forced exercise and the controversy regarding the therapeutic effects in experimental animals versus humans with neural injuries. This review also provides a therapeutic strategy for physical therapists that grades the intensity of forced exercise according to the level of neural injury.

[Surgery for pancreatic cancer: Evidence-based surgical strategies].

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Sánchez Cabús, Santiago; Fernández-Cruz, Laureano

2015-01-01

Pancreatic cancer surgery represents a challenge for surgeons due to its technical complexity, the potential complications that may appear, and ultimately because of its poor survival. The aim of this article is to summarize the scientific evidence regarding the surgical treatment of pancreatic cancer in order to help surgeons in the decision making process in the management of these patients .Here we will review such fundamental issues as the need for a biopsy before surgery, the type of pancreatic anastomosis leading to better results, and the need for placement of drains after pancreatic surgery will be discussed. Copyright © 2014 AEC. Publicado por Elsevier España, S.L.U. All rights reserved.

Surgical strategy for intra- and extra-vertebral dumbbell-shaped tumors

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SUN Li-yong

2013-12-01

Full Text Available Objective To investigate the clinical features and surgical strategy of intra- and extra-vertebral dumbbell-shaped tumors. Methods Clinical data of 39 patients with intra- and extra-vertebral tumor were retrospectively studied. The tumors were removed via posterior midline approach in 33 patients, and via posterior combined with anterior approach in 6 patients. Thirty patients underwent tumor resection and internal fixation. Lateral mass screw fixation was performed in the level of C3-7, while the pedicular screw fixation was performed in the level of C2 and thoracic and lumbar segment. Results Tumors were totally excised in all the cases. The patients were followed-up for 6 months to 5 years with an average of 18.67 months. Pain relief occured in 29 cases, of whom the average Visual Analogue Scale (VAS score decreased from (7.51 ± 1.05 before surgery to (3.17 ± 1.17 24 h after surgery (P < 0.05. The numbness area emerged or enlarged in 12 cases and was unchanged in 3 cases. The average American Spinal Injury Association (ASIA sensation score decreased from (218.67 ± 2.80 before surgery to (213.33 ± 2.16 24 h after surgery (P < 0.05, but it increased to (216.78 ± 1.47 6 months after operation (P < 0.05. The motor function improved in 18 cases, and ASIA motor function score improved from (92.33 ± 1.63 before surgery to (95.05 ± 1.41 6 months after operation (P < 0.05. No tumor recurrence and secondary spinal deformity were found. Conclusion Most cases of dumbbell-shaped intra- and extra-vertebral tumor can be totally removed with one-session microsurgery. In the cases with bony erosion caused by tumor and facetectomy, concurrent internal fixation and fusion were recommended in order to maintain spinal stability.

[Changing surgical therapy because of clinical studies?].

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Schwenk, W; Haase, O; Müller, J M

2002-04-01

The randomised controlled clinical trial (RCT) is a powerful instrument to evaluate different therapeutic regimens. In a survey among 115 physicians visiting the 25th annual meeting of the Surgical Society of Berlin and Brandenburg, the RCT was judged to be very important when changes of therapeutic strategies are discussed. 90 % of all participants claimed to use data from RCTs in the clinical routine and 89 % would participate in such a trial. In official (e. g. discussions during coffee breaks at scientific meetings) or non-medical (e. g. non-scientific press or media) sources of information were assessed as irrelevant for decisions regarding therapeutic strategies. However, in contrast to this view laparoscopic cholecystectomy was introduced into clinical practice rapidly because patients informed by external (non-medical) sources preferred to be operated on with the "modern" technique. Clinical trials with a high level of evidence had no relevant influence on the rapid distribution of laparoscopic cholecystectomy. Controversial discussions concerning the extent of lymphadenectomy with gastric resection for carcinoma demonstrate that the value of excellent clinical RCTs is low if their results challenge a stable paradigma of the surgical scientific society. To allow a rational judgement, new surgical technologies should undergo a scientific gradual evaluation in agreement with the principles of evidence based medicine.

Perioperative feedback in surgical training: A systematic review.

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McKendy, Katherine M; Watanabe, Yusuke; Lee, Lawrence; Bilgic, Elif; Enani, Ghada; Feldman, Liane S; Fried, Gerald M; Vassiliou, Melina C

2017-07-01

Changes in surgical training have raised concerns about residents' operative exposure and preparedness for independent practice. One way of addressing this concern is by optimizing teaching and feedback in the operating room (OR). The objective of this study was to perform a systematic review on perioperative teaching and feedback. A systematic literature search identified articles from 1994 to 2014 that addressed teaching, feedback, guidance, or debriefing in the perioperative period. Data was extracted according to ENTREQ guidelines, and a qualitative analysis was performed. Thematic analysis of the 26 included studies identified four major topics. Observation of teaching behaviors in the OR described current teaching practices. Identification of effective teaching strategies analyzed teaching behaviors, differentiating positive and negative teaching strategies. Perceptions of teaching behaviors described resident and attending satisfaction with teaching in the OR. Finally models for delivering structured feedback cited examples of feedback strategies and measured their effectiveness. This study provides an overview of perioperative teaching and feedback for surgical trainees and identifies a need for improved quality and quantity of structured feedback. Copyright © 2016 Elsevier Inc. All rights reserved.

Applying Fuzzy Artificial Neural Network OSPF to develop Smart ...

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pc

2018-03-05

Mar 5, 2018 ... Fuzzy Artificial Neural Network to create Smart Routing. Protocol Algorithm. ... manufactured mental aptitude strategy. The capacity to study .... Based Energy Efficiency in Wireless Sensor Networks: A Survey",. International ...

Surgical waste audit of 5 total knee arthroplasties.

Science.gov (United States)

Stall, Nathan M; Kagoma, Yoan M; Bondy, Jennifer N; Naudie, Douglas

2013-04-01

Operating rooms (ORs) are estimated to generate up to one-third of hospital waste. At the London Health Sciences Centre, prosthetics and implants represent 17% of the institution's ecological footprint. To investigate waste production associated with total knee arthroplasties (TKAs), we performed a surgical waste audit to gauge the environmental impact of this procedure and generate strategies to improve waste management. We conducted a waste audit of 5 primary TKAs performed by a single surgeon in February 2010. Waste was categorized into 6 streams: regular solid waste, recyclable plastics, biohazard waste, laundered linens, sharps and blue sterile wrap. Volume and weight of each stream was quantified. We used Canadian Joint Replacement Registry data (2008-2009) to estimate annual weight and volume totals of waste from all TKAs performed in Canada. The average surgical waste (excluding laundered linens) per TKA was 13.3 kg, of which 8.6 kg (64.5%) was normal solid waste, 2.5 kg (19.2%) was biohazard waste, 1.6 kg (12.1%) was blue sterile wrap, 0.3 kg (2.2%) was recyclables and 0.3 kg (2.2%) was sharps. Plastic wrappers, disposable surgical linens and personal protective equipment contributed considerably to total waste. We estimated that landfill waste from all 47 429 TKAs performed in Canada in 2008-2009 was 407 889 kg by weight and 15 272 m3 by volume. Total knee arthroplasties produce substantial amounts of surgical waste. Environmentally friendly surgical products and waste management strategies may allow ORs to reduce the negative impacts of waste production without compromising patient care. Level IV, case series.

Decorrelated Jet Substructure Tagging using Adversarial Neural Networks

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CERN. Geneva

2017-01-01

We describe a strategy for constructing a neural network jet substructure tagger which powerfully discriminates boosted decay signals while remaining largely uncorrelated with the jet mass. This reduces the impact of systematic uncertainties in background modeling while enhancing signal purity, resulting in improved discovery significance relative to existing taggers. The network is trained using an adversarial strategy, resulting in a tagger that learns to balance classification accuracy with decorrelation. As a benchmark scenario, we consider the case where large-radius jets originating from a boosted Z' decay are discriminated from a background of nonresonant quark and gluon jets. We show that in the presence of systematic uncertainties on the background rate, our adversarially-trained, decorrelated tagger considerably outperforms a conventionally trained neural network, despite having a slightly worse signal-background separation power. We generalize the adversarial training technique to include a paramet...

Separate neural mechanisms underlie choices and strategic preferences in risky decision making.

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Venkatraman, Vinod; Payne, John W; Bettman, James R; Luce, Mary Frances; Huettel, Scott A

2009-05-28

Adaptive decision making in real-world contexts often relies on strategic simplifications of decision problems. Yet, the neural mechanisms that shape these strategies and their implementation remain largely unknown. Using an economic decision-making task, we dissociate brain regions that predict specific choices from those predicting an individual's preferred strategy. Choices that maximized gains or minimized losses were predicted by functional magnetic resonance imaging activation in ventromedial prefrontal cortex or anterior insula, respectively. However, choices that followed a simplifying strategy (i.e., attending to overall probability of winning) were associated with activation in parietal and lateral prefrontal cortices. Dorsomedial prefrontal cortex, through differential functional connectivity with parietal and insular cortex, predicted individual variability in strategic preferences. Finally, we demonstrate that robust decision strategies follow from neural sensitivity to rewards. We conclude that decision making reflects more than compensatory interaction of choice-related regions; in addition, specific brain systems potentiate choices depending on strategies, traits, and context.

Enhancing neural activity to drive respiratory plasticity following cervical spinal cord injury

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Hormigo, Kristiina M.; Zholudeva, Lyandysha V.; Spruance, Victoria M.; Marchenko, Vitaliy; Cote, Marie-Pascale; Vinit, Stephane; Giszter, Simon; Bezdudnaya, Tatiana; Lane, Michael A.

2016-01-01

Cervical spinal cord injury (SCI) results in permanent life-altering sensorimotor deficits, among which impaired breathing is one of the most devastating and life-threatening. While clinical and experimental research has revealed that some spontaneous respiratory improvement (functional plasticity) can occur post-SCI, the extent of the recovery is limited and significant deficits persist. Thus, increasing effort is being made to develop therapies that harness and enhance this neuroplastic potential to optimize long-term recovery of breathing in injured individuals. One strategy with demonstrated therapeutic potential is the use of treatments that increase neural and muscular activity (e.g. locomotor training, neural and muscular stimulation) and promote plasticity. With a focus on respiratory function post-SCI, this review will discuss advances in the use of neural interfacing strategies and activity-based treatments, and highlights some recent results from our own research. PMID:27582085

The neural basis of financial risk taking.

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Kuhnen, Camelia M; Knutson, Brian

2005-09-01

Investors systematically deviate from rationality when making financial decisions, yet the mechanisms responsible for these deviations have not been identified. Using event-related fMRI, we examined whether anticipatory neural activity would predict optimal and suboptimal choices in a financial decision-making task. We characterized two types of deviations from the optimal investment strategy of a rational risk-neutral agent as risk-seeking mistakes and risk-aversion mistakes. Nucleus accumbens activation preceded risky choices as well as risk-seeking mistakes, while anterior insula activation preceded riskless choices as well as risk-aversion mistakes. These findings suggest that distinct neural circuits linked to anticipatory affect promote different types of financial choices and indicate that excessive activation of these circuits may lead to investing mistakes. Thus, consideration of anticipatory neural mechanisms may add predictive power to the rational actor model of economic decision making.

Neural-fuzzy control of adept one SCARA

International Nuclear Information System (INIS)

Er, M.J.; Toh, B.H.; Toh, B.Y.

1998-01-01

This paper presents an Intelligent Control Strategy for the Adept One SCARA (Selective Compliance Assembly Robot Arm). It covers the design and simulation study of a Neural-Fuzzy Controller (NFC) for the SCARA with a view of tracking a predetermined trajectory of motion in the joint space. The SCARA was simulated as a three-axis manipulator with the dynamics of the tool (fourth link) neglected and the mass of the load incorporated into the mass of the third link. The overall performance of the control system under different conditions, namely variation in playload, variations in coefficients of static, dynamic and viscous friction and different trajectories were studied and comparison made with an existing Neural Network Controller and two Computed Torque Controllers. The NFC was shown to be robust and is able to overcome the drawback of the existing Neural Network Controller

[Surgical assessment of complications after thyroid gland operations].

Science.gov (United States)

Dralle, H

2015-01-01

The extent, magnitude and technical equipment used for thyroid surgery has changed considerably in Germany during the last decade. The number of thyroidectomies due to benign goiter have decreased while the extent of thyroidectomy, nowadays preferentially total thyroidectomy, has increased. Due to an increased awareness of surgical complications the number of malpractice claims is increasing. In contrast to surgical databases the frequency of complications in malpractice claims reflects the individual impact of complications on the quality of life. In contrast to surgical databases unilateral and bilateral vocal fold palsy are therefore at the forefront of malpractice claims. As guidelines are often not applicable for the individual surgical expert review, the question arises which are the relevant criteria for the professional expert witness assessing the severity of the individual complication. While in surgical databases major complications after thyroidectomy, such as vocal fold palsy, hypoparathyroidism, hemorrhage and infections are equally frequent (1-3 %), in malpractice claims vocal fold palsy is significantly more frequent (50 %) compared to hypoparathyroidism (15 %), hemorrhage and infections (about 5 % each). To avoid bilateral nerve palsy intraoperative nerve monitoring has become of utmost importance for surgical strategy and malpractice suits alike. For surgical expert review documentation of individual risk-oriented indications, the surgical approach and postoperative management are highly important. Guidelines only define the treatment corridors of good clinical practice. Surgical expert reviews in malpractice suits concerning quality of care and causality between surgical management, complications and sequelae of complications are therefore highly dependent on the grounds and documentation of risk-oriented indications for thyroidectomy, intraoperative and postoperative surgical management.

Feedforward Nonlinear Control Using Neural Gas Network

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Iván Machón-González

2017-01-01

Full Text Available Nonlinear systems control is a main issue in control theory. Many developed applications suffer from a mathematical foundation not as general as the theory of linear systems. This paper proposes a control strategy of nonlinear systems with unknown dynamics by means of a set of local linear models obtained by a supervised neural gas network. The proposed approach takes advantage of the neural gas feature by which the algorithm yields a very robust clustering procedure. The direct model of the plant constitutes a piece-wise linear approximation of the nonlinear system and each neuron represents a local linear model for which a linear controller is designed. The neural gas model works as an observer and a controller at the same time. A state feedback control is implemented by estimation of the state variables based on the local transfer function that was provided by the local linear model. The gradient vectors obtained by the supervised neural gas algorithm provide a robust procedure for feedforward nonlinear control, that is, supposing the inexistence of disturbances.

CT of lumbar spine disk herniation: correlation with surgical findings

International Nuclear Information System (INIS)

Firooznia, H.; Benjamin, V.; Kricheff, I.I.; Rafii, M.; Golimbu, C.

1984-01-01

Computed tomography (CT) of the lumbar spine was performed with selectively positioned 5-mm-thick axial cross sections to examine each disk level from the top of the neural foramen to the pedicle of the next caudad vertebra. One hundred consecutive patients with 116 surgical disk explorations were reviewed. There was agreement between the CT and surgical findings in 89 patients (104 explorations) in determination of presence or absence of a herniated nucleus pulposus (HNP). Discrepancy occurred in 12 instances (11 patients): two because of incorrect interpretations, five in previously operated patients, three in spondylolisthesis, and two in spinal stenosis. There were 97 true-positives, eight false-negatives, seven true-negatives, and four false-positives. If nine previously operated patients are excluded from the study, then CT was accurate in detection of presence or absence of an HNP in 93% of the disk explorations

Deep Neural Network-Based Chinese Semantic Role Labeling

Institute of Scientific and Technical Information of China (English)

ZHENG Xiaoqing; CHEN Jun; SHANG Guoqiang

2017-01-01

A recent trend in machine learning is to use deep architec-tures to discover multiple levels of features from data, which has achieved impressive results on various natural language processing (NLP) tasks. We propose a deep neural network-based solution to Chinese semantic role labeling (SRL) with its application on message analysis. The solution adopts a six-step strategy: text normalization, named entity recognition (NER), Chinese word segmentation and part-of-speech (POS) tagging, theme classification, SRL, and slot filling. For each step, a novel deep neural network - based model is designed and optimized, particularly for smart phone applications. Ex-periment results on all the NLP sub - tasks of the solution show that the proposed neural networks achieve state-of-the-art performance with the minimal computational cost. The speed advantage of deep neural networks makes them more competitive for large-scale applications or applications requir-ing real-time response, highlighting the potential of the pro-posed solution for practical NLP systems.

ELeaRNT: Evolutionary Learning of Rich Neural Network Topologies

National Research Council Canada - National Science Library

Matteucci, Matteo

2006-01-01

In this paper we present ELeaRNT an evolutionary strategy which evolves rich neural network topologies in order to find an optimal domain specific non linear function approximator with a good generalization performance...

Surgical treatment of pancreatic endocrine tumors in multiple endocrine neoplasia type 1

Directory of Open Access Journals (Sweden)

Marcel Cerqueira Cesar Machado

Full Text Available Surgical approaches to pancreatic endocrine tumors associated with multiple endocrine neoplasia type 1 may differ greatly from those applied to sporadic pancreatic endocrine tumors. Presurgical diagnosis of multiple endocrine neoplasia type 1 is therefore crucial to plan a proper intervention. Of note, hyperparathyroidism/multiple endocrine neoplasia type 1 should be surgically treated before pancreatic endocrine tumors/multiple endocrine neoplasia type 1 resection, apart from insulinoma. Non-functioning pancreatic endocrine tumors/multiple endocrine neoplasia type 1 >1 cm have a high risk of malignancy and should be treated by a pancreatic resection associated with lymphadenectomy. The vast majority of patients with gastrinoma/multiple endocrine neoplasia type 1 present with tumor lesions at the duodenum, so the surgery of choice is subtotal or total pancreatoduodenectomy followed by regional lymphadenectomy. The usual surgical treatment for insulinoma/multiple endocrine neoplasia type 1 is distal pancreatectomy up to the mesenteric vein with or without spleen preservation, associated with enucleation of tumor lesions in the pancreatic head. Surgical procedures for glucagonomas, somatostatinomas, and vipomas/ multiple endocrine neoplasia type 1 are similar to those applied to sporadic pancreatic endocrine tumors. Some of these surgical strategies for pancreatic endocrine tumors/multiple endocrine neoplasia type 1 still remain controversial as to their proper extension and timing. Furthermore, surgical resection of single hepatic metastasis secondary to pancreatic endocrine tumors/multiple endocrine neoplasia type 1 may be curative and even in multiple liver metastases surgical resection is possible. Hepatic trans-arterial chemo-embolization is usually associated with surgical resection. Liver transplantation may be needed for select cases. Finally, pre-surgical clinical and genetic diagnosis of multiple endocrine neoplasia type 1 syndrome and

Neural substrate expansion for the restoration of brain function

Directory of Open Access Journals (Sweden)

Han-Chiao Isaac Chen

2016-01-01

Full Text Available Restoring neurological and cognitive function in individuals who have suffered brain damage is one of the principal objectives of modern translational neuroscience. Electrical stimulation approaches, such as deep-brain stimulation, have achieved the most clinical success, but they ultimately may be limited by the computational capacity of the residual cerebral circuitry. An alternative strategy is brain substrate expansion, in which the computational capacity of the brain is augmented through the addition of new processing units and the reconstitution of network connectivity. This latter approach has been explored to some degree using both biological and electronic means but thus far has not demonstrated the ability to reestablish the function of large-scale neuronal networks. In this review, we contend that fulfilling the potential of brain substrate expansion will require a significant shift from current methods that emphasize direct manipulations of the brain (e.g., injections of cellular suspensions and the implantation of multi-electrode arrays to the generation of more sophisticated neural tissues and neural-electric hybrids in vitro that are subsequently transplanted into the brain. Drawing from neural tissue engineering, stem cell biology, and neural interface technologies, this strategy makes greater use of the manifold techniques available in the laboratory to create biocompatible constructs that recapitulate brain architecture and thus are more easily recognized and utilized by brain networks.

Neural networks for genetic epidemiology: past, present, and future

Directory of Open Access Journals (Sweden)

Motsinger-Reif Alison A

2008-07-01

Full Text Available Abstract During the past two decades, the field of human genetics has experienced an information explosion. The completion of the human genome project and the development of high throughput SNP technologies have created a wealth of data; however, the analysis and interpretation of these data have created a research bottleneck. While technology facilitates the measurement of hundreds or thousands of genes, statistical and computational methodologies are lacking for the analysis of these data. New statistical methods and variable selection strategies must be explored for identifying disease susceptibility genes for common, complex diseases. Neural networks (NN are a class of pattern recognition methods that have been successfully implemented for data mining and prediction in a variety of fields. The application of NN for statistical genetics studies is an active area of research. Neural networks have been applied in both linkage and association analysis for the identification of disease susceptibility genes. In the current review, we consider how NN have been used for both linkage and association analyses in genetic epidemiology. We discuss both the successes of these initial NN applications, and the questions that arose during the previous studies. Finally, we introduce evolutionary computing strategies, Genetic Programming Neural Networks (GPNN and Grammatical Evolution Neural Networks (GENN, for using NN in association studies of complex human diseases that address some of the caveats illuminated by previous work.

Video content analysis of surgical procedures.

Science.gov (United States)

Loukas, Constantinos

2018-02-01

In addition to its therapeutic benefits, minimally invasive surgery offers the potential for video recording of the operation. The videos may be archived and used later for reasons such as cognitive training, skills assessment, and workflow analysis. Methods from the major field of video content analysis and representation are increasingly applied in the surgical domain. In this paper, we review recent developments and analyze future directions in the field of content-based video analysis of surgical operations. The review was obtained from PubMed and Google Scholar search on combinations of the following keywords: 'surgery', 'video', 'phase', 'task', 'skills', 'event', 'shot', 'analysis', 'retrieval', 'detection', 'classification', and 'recognition'. The collected articles were categorized and reviewed based on the technical goal sought, type of surgery performed, and structure of the operation. A total of 81 articles were included. The publication activity is constantly increasing; more than 50% of these articles were published in the last 3 years. Significant research has been performed for video task detection and retrieval in eye surgery. In endoscopic surgery, the research activity is more diverse: gesture/task classification, skills assessment, tool type recognition, shot/event detection and retrieval. Recent works employ deep neural networks for phase and tool recognition as well as shot detection. Content-based video analysis of surgical operations is a rapidly expanding field. Several future prospects for research exist including, inter alia, shot boundary detection, keyframe extraction, video summarization, pattern discovery, and video annotation. The development of publicly available benchmark datasets to evaluate and compare task-specific algorithms is essential.

Neural networkbased semi-active control strategy for structural vibration mitigation with magnetorheological damper

DEFF Research Database (Denmark)

Bhowmik, Subrata

2011-01-01

This paper presents a neural network based semi-active control method for a rotary type magnetorheological (MR) damper. The characteristics of the MR damper are described by the classic Bouc-Wen model, and the performance of the proposed control method is evaluated in terms of a base exited shear...... to determine the damper current based on the derived optimal damper force. For that reason an inverse MR damper model is also designed based on the neural network identification of the particular rotary MR damper. The performance of the proposed controller is compared to that of an optimal pure viscous damper...

Development of biomaterial scaffold for nerve tissue engineering: Biomaterial mediated neural regeneration

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Sethuraman Swaminathan

2009-11-01

Full Text Available Abstract Neural tissue repair and regeneration strategies have received a great deal of attention because it directly affects the quality of the patient's life. There are many scientific challenges to regenerate nerve while using conventional autologous nerve grafts and from the newly developed therapeutic strategies for the reconstruction of damaged nerves. Recent advancements in nerve regeneration have involved the application of tissue engineering principles and this has evolved a new perspective to neural therapy. The success of neural tissue engineering is mainly based on the regulation of cell behavior and tissue progression through the development of a synthetic scaffold that is analogous to the natural extracellular matrix and can support three-dimensional cell cultures. As the natural extracellular matrix provides an ideal environment for topographical, electrical and chemical cues to the adhesion and proliferation of neural cells, there exists a need to develop a synthetic scaffold that would be biocompatible, immunologically inert, conducting, biodegradable, and infection-resistant biomaterial to support neurite outgrowth. This review outlines the rationale for effective neural tissue engineering through the use of suitable biomaterials and scaffolding techniques for fabrication of a construct that would allow the neurons to adhere, proliferate and eventually form nerves.

Novel paths towards neural cellular products for neurological disorders.

Science.gov (United States)

Daadi, Marcel M

2011-11-01

The prospect of using neural cells derived from stem cells or from reprogrammed adult somatic cells provides a unique opportunity in cell therapy and drug discovery for developing novel strategies for brain repair. Cell-based therapeutic approaches for treating CNS afflictions caused by disease or injury aim to promote structural repair of the injured or diseased neural tissue, an outcome currently not achieved by drug therapy. Preclinical research in animal models of various diseases or injuries report that grafts of neural cells enhance endogenous repair, provide neurotrophic support to neurons undergoing degeneration and replace lost neural cells. In recent years, the sources of neural cells for treating neurological disorders have been rapidly expanding and in addition to offering therapeutic potential, neural cell products hold promise for disease modeling and drug discovery use. Specific neural cell types have been derived from adult or fetal brain, from human embryonic stem cells, from induced pluripotent stem cells and directly transdifferentiated from adult somatic cells, such as skin cells. It is yet to be determined if the latter approach will evolve into a paradigm shift in the fields of stem cell research and regenerative medicine. These multiple sources of neural cells cover a wide spectrum of safety that needs to be balanced with efficacy to determine the viability of the cellular product. In this article, we will review novel sources of neural cells and discuss current obstacles to developing them into viable cellular products for treating neurological disorders.

Replicable Expansion and Differentiation of Neural Precursors from Adult Canine Skin

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Thomas Duncan

2017-08-01

Full Text Available Repopulation of brain circuits by neural precursors is a potential therapeutic strategy for neurodegenerative disorders; however, choice of cell is critical. Previously, we introduced a two-step culture system that generates a high yield of neural precursors from small samples of adult canine skin. Here, we probe their gene and protein expression profiles in comparison with dermal fibroblasts and brain-derived neural stem cells and characterize their neuronal potential. To date, we have produced >50 skin-derived neural precursor (SKN lines. SKNs can be cultured in a highly replicable fashion and uniformly express a panel of identifying markers. Upon differentiation, they self-upregulate neural specification genes, generating neurons with basic electrophysiological functionality. This unique population of neural precursors, derived from mature skin, overcomes many of the practical issues that have limited clinical translation of alternative cell types. Easily accessible, neuronally committed, and patient specific, SKNs may have potential for the treatment of brain disorders.

Efficiency turns the table on neural encoding, decoding and noise.

Science.gov (United States)

Deneve, Sophie; Chalk, Matthew

2016-04-01

Sensory neurons are usually described with an encoding model, for example, a function that predicts their response from the sensory stimulus using a receptive field (RF) or a tuning curve. However, central to theories of sensory processing is the notion of 'efficient coding'. We argue here that efficient coding implies a completely different neural coding strategy. Instead of a fixed encoding model, neural populations would be described by a fixed decoding model (i.e. a model reconstructing the stimulus from the neural responses). Because the population solves a global optimization problem, individual neurons are variable, but not noisy, and have no truly invariant tuning curve or receptive field. We review recent experimental evidence and implications for neural noise correlations, robustness and adaptation. Copyright © 2016. Published by Elsevier Ltd.

Efficacy of Surgical Therapy for Carotid Body Tumors

Institute of Scientific and Technical Information of China (English)

Li-shan Lian; Chang-wei Liu; Heng Guan; Yue-hong Zheng; Xing-ming Chen; Yong-jun Li

2011-01-01

Objective To evaluate the efficacy of surgical therapy for carotid body tumors.Methods A retrospective analysis was conducted,covering the diagnosis,surgical procedure,post-operative complications,and prognosis of 120 cases of carotid body tumors in Peking Union Medical College Hospital from 1949 to May,2011.Results Surgical excision was successfully performed in 111 cases with 117 tumors.In all those cases,50 underwent simple tumor resection,42 underwent resection of tumors and ligation of the external carotid arteries,7 underwent co-resection of tumors and common carotid arteries,internal carotid arteries,as well as external arteries without vascular reconstruction,and the other 12 cases experienced tumor resection and vascular reconstruction as internal carotid arteries were involved.After operation,3 cases developed cerebral infarction,30 cases showed cranial nerve palsy,including 15 cases of hypoglossal nerve damage,10 cases of vagus paralysis,and 5 cases of Horner's syndrome.Conclusion It is essential to make a proper surgical strategy,which can reduce postoperative complications.

Data Mining on Romanian Stock Market Using Neural Networks for Price Prediction

Directory of Open Access Journals (Sweden)

Magdalena Daniela NEMES

2013-01-01

Full Text Available Predicting future prices by using time series forecasting models has become a relevant trading strategy for most stock market players. Intuition and speculation are no longer reliable as many new trading strategies based on artificial intelligence emerge. Data mining represents a good source of information, as it ensures data processing in a convenient manner. Neural networks are considered useful prediction models when designing forecasting strategies. In this paper we present a series of neural networks designed for stock exchange rates forecasting applied on three Romanian stocks traded on the Bucharest Stock Exchange (BSE. A multistep ahead strategy was used in order to predict short-time price fluctuations. Later, the findings of our study can be integrated with an intelligent multi-agent system model which uses data mining and data stream processing techniques for helping users in the decision making process of buying or selling stocks.

Clinical results of a new strategy (modified CHIVA) for surgical treatment of anterior accessory great saphenous varicose veins.

Science.gov (United States)

Maldonado-Fernández, Nicolás; Linares-Palomino, Jose Patricio; López-Espada, Cristina; Martínez-Gámez, Francisco Javier; Ros-Díe, Eduardo

2016-03-01

Traditionally, anterior accessory great saphenous vein insufficiency was managed by crossectomy and resection of varicose veins. The aim of this paper is to show the safety and efficacy of a new therapeutic strategy for anterior accessory great saphenous varicose veins. This non-randomised prospective study included 65 patients with varicose veins from the anterior accessory great saphenous vein. The novelty of the technique is to avoid the great saphenous vein crossectomy and perform just flebectomy of the visible veins. Venous duplex studies were performed preoperatively, a month and a year postoperatively. The clinical assessment was done by the Fligelstone scale. The baseline CEAP clinical classification was: 58% C2, 26% C3 and 15% C4-6. The new strategy was applied to all cases. 3 haematomas, 7 cases of asymptomatic partial anterior saphenous thrombosis. Reduction of the initial average diameter was from 6.4 mm anterior saphenous to 3.4 mm by one year (p <0.001). At twelve months a forward flow is maintained in 82% of cases. Recurrence of varicose veins was 8%. All patients improved their clinical status based on the Fligelstone scale. Cases with saphenous diameter bigger than 7.5 mm and obesity were identified as predictors of worse clinical and hemodynamic outcome. This modified surgical strategy for anterior saphenous varicose veins results in better clinical outcomes at one year postoperatively. Copyright © 2015 AEC. Publicado por Elsevier España, S.L.U. All rights reserved.

Implementation of surgical quality improvement: auditing tool for surgical site infection prevention practices.

Science.gov (United States)

Hechenbleikner, Elizabeth M; Hobson, Deborah B; Bennett, Jennifer L; Wick, Elizabeth C

2015-01-01

Surgical site infections are a potentially preventable patient harm. Emerging evidence suggests that the implementation of evidence-based process measures for infection reduction is highly variable. The purpose of this work was to develop an auditing tool to assess compliance with infection-related process measures and establish a system for identifying and addressing defects in measure implementation. This was a retrospective cohort study using electronic medical records. We used the auditing tool to assess compliance with 10 process measures in a sample of colorectal surgery patients with and without postoperative infections at an academic medical center (January 2012 to March 2013). We investigated 59 patients with surgical site infections and 49 patients without surgical site infections. First, overall compliance rates for the 10 process measures were compared between patients with infection vs patients without infection to assess if compliance was lower among patients with surgical site infections. Then, because of the burden of data collection, the tool was used exclusively to evaluate quarterly compliance rates among patients with infection. The results were reviewed, and the key factors contributing to noncompliance were identified and addressed. Ninety percent of process measures had lower compliance rates among patients with infection. Detailed review of infection cases identified many defects that improved following the implementation of system-level changes: correct cefotetan redosing (education of anesthesia personnel), temperature at surgical incision >36.0°C (flags used to identify patients for preoperative warming), and the use of preoperative mechanical bowel preparation with oral antibiotics (laxative solutions and antibiotics distributed in clinic before surgery). Quarterly compliance improved for 80% of process measures by the end of the study period. This study was conducted on a small surgical cohort within a select subspecialty. The

A deep convolutional neural network-based automatic delineation strategy for multiple brain metastases stereotactic radiosurgery.

Directory of Open Access Journals (Sweden)

Yan Liu

Full Text Available Accurate and automatic brain metastases target delineation is a key step for efficient and effective stereotactic radiosurgery (SRS treatment planning. In this work, we developed a deep learning convolutional neural network (CNN algorithm for segmenting brain metastases on contrast-enhanced T1-weighted magnetic resonance imaging (MRI datasets. We integrated the CNN-based algorithm into an automatic brain metastases segmentation workflow and validated on both Multimodal Brain Tumor Image Segmentation challenge (BRATS data and clinical patients' data. Validation on BRATS data yielded average DICE coefficients (DCs of 0.75±0.07 in the tumor core and 0.81±0.04 in the enhancing tumor, which outperformed most techniques in the 2015 BRATS challenge. Segmentation results of patient cases showed an average of DCs 0.67±0.03 and achieved an area under the receiver operating characteristic curve of 0.98±0.01. The developed automatic segmentation strategy surpasses current benchmark levels and offers a promising tool for SRS treatment planning for multiple brain metastases.

Strategy of Surgical Management of Peripheral Neuropathy Form of Diabetic Foot Syndrome in Ghana

Directory of Open Access Journals (Sweden)

W. M. Rdeini

2014-01-01

Full Text Available Introduction. Foot disorders such as ulceration, infection, and gangrene which are often due to diabetes mellitus are some major causes of morbidity and high amputation. Aim. This study aims to use a group of methods for the management of diabetic foot ulcers (DFU in order to salvage the lower limb so as to reduce the rate of high amputations of the lower extremity. Materials and Methods. A group of different advanced methods for the management of DFU such as sharp debridement of ulcers, application of vacuum therapy, and other forms of reconstructive plastic surgical procedures were used. Data collection was done at 3 different hospitals where the treatments were given. Results. Fifty-four patients with type 2 diabetes mellitus were enrolled in the current study: females n=37 (68.51% and males n=17 (31.49% with different stages of PEDIS classification. They underwent different methods of surgical management: debridement, vacuum therapy (some constructed from locally used materials, and skin grafting giving good and fast results. Only 4 had below knee amputations. Conclusion. Using advanced surgical wound management including reconstructive plastic surgical procedures, it was possible to reduce the rate of high amputations of the lower limb.

Robust Adaptive Neural Control of Morphing Aircraft with Prescribed Performance

Directory of Open Access Journals (Sweden)

Zhonghua Wu

2017-01-01

Full Text Available This study proposes a low-computational composite adaptive neural control scheme for the longitudinal dynamics of a swept-back wing aircraft subject to parameter uncertainties. To efficiently release the constraint often existing in conventional neural designs, whose closed-loop stability analysis always necessitates that neural networks (NNs be confined in the active regions, a smooth switching function is presented to conquer this issue. By integrating minimal learning parameter (MLP technique, prescribed performance control, and a kind of smooth switching strategy into back-stepping design, a new composite switching adaptive neural prescribed performance control scheme is proposed and a new type of adaptive laws is constructed for the altitude subsystem. Compared with previous neural control scheme for flight vehicle, the remarkable feature is that the proposed controller not only achieves the prescribed performance including transient and steady property but also addresses the constraint on NN. Two comparative simulations are presented to verify the effectiveness of the proposed controller.

Neural Basis of Empathy and Its Dysfunction in Autism Spectrum Disorders (ASD)

Science.gov (United States)

2014-10-01

our work tests the idea that empathy derives from the activation of neural circuits that process primary emotions or feelings , such as reward or...ticipated. For all monkeys, a sterile surgery was performed to implant a head- restraint prosthesis (Crist Instruments) using standard techniques11...participated in the study. All animals underwent standard surgical procedures for implanting a head-restraint prosthesis at least 6 mo before the present study

A qualitative study on perceptions of surgical careers in Rwanda: A gender-based approach.

Science.gov (United States)

Yi, Sojung; Lin, Yihan; Kansayisa, Grace; Costas-Chavarri, Ainhoa

2018-01-01

Access to surgical care in low- and middle-income countries (LMICs) remains deficient without an adequate workforce. There is limited understanding of the gender gap in surgical trainees in LMICs. In Rwanda, females fill only one of 20 positions available. Understanding surgeons' experiences and perceptions of surgical careers may help facilitate support for females to contribute to the global surgical workforce. We performed qualitative analysis on perceptions of surgical careers through semi-structured interviews of all female surgeons (n = 6) and corresponding male surgeons (n = 6) who are training or have trained at University of Rwanda. Transcripts were analyzed with code structure formed through an integrated approach. Question categories formed the deductive framework, while theoretical saturation was reached through inductive grounded theory. Themes were organized within two key points of the career timeline. First, for developing interest in surgery, three main themes were identified: role models, patient case encounters, and exposure to surgery. Second, for selecting and sustaining surgical careers, four main themes emerged: social expectations about roles within the family, physical and mental challenges, professional and personal support, and finances. All female surgeons emphasized gender assumptions and surgical working culture as obstacles, with a corresponding strong sense of self-confidence and internal motivation that drew them to select and maintain careers in surgery. Family, time, and physical endurance were cited as persistent challenges for female participants. Our study reveals concepts for further exploration about gendered perceptions of surgical careers. Efforts to improve support for female surgical careers as a strategy for shaping surgical work culture and professional development in Rwanda should be considered. Such strategies may be beneficial for improving the global surgical workforce.

Top tagging with deep neural networks [Vidyo

CERN Multimedia

CERN. Geneva

2017-01-01

Recent literature on deep neural networks for top tagging has focussed on image based techniques or multivariate approaches using high level jet substructure variables. Here, we take a sequential approach to this task by using anordered sequence of energy deposits as training inputs. Unlike previous approaches, this strategy does not result in a loss of information during pixelization or the calculation of high level features. We also propose new preprocessing methods that do not alter key physical quantities such as jet mass. We compare the performance of this approach to standard tagging techniques and present results evaluating the robustness of the neural network to pileup.

Spiking Neural P Systems with Communication on Request.

Science.gov (United States)

Pan, Linqiang; Păun, Gheorghe; Zhang, Gexiang; Neri, Ferrante

2017-12-01

Spiking Neural [Formula: see text] Systems are Neural System models characterized by the fact that each neuron mimics a biological cell and the communication between neurons is based on spikes. In the Spiking Neural [Formula: see text] systems investigated so far, the application of evolution rules depends on the contents of a neuron (checked by means of a regular expression). In these [Formula: see text] systems, a specified number of spikes are consumed and a specified number of spikes are produced, and then sent to each of the neurons linked by a synapse to the evolving neuron. [Formula: see text]In the present work, a novel communication strategy among neurons of Spiking Neural [Formula: see text] Systems is proposed. In the resulting models, called Spiking Neural [Formula: see text] Systems with Communication on Request, the spikes are requested from neighboring neurons, depending on the contents of the neuron (still checked by means of a regular expression). Unlike the traditional Spiking Neural [Formula: see text] systems, no spikes are consumed or created: the spikes are only moved along synapses and replicated (when two or more neurons request the contents of the same neuron). [Formula: see text]The Spiking Neural [Formula: see text] Systems with Communication on Request are proved to be computationally universal, that is, equivalent with Turing machines as long as two types of spikes are used. Following this work, further research questions are listed to be open problems.

Surgical management of U-shaped sacral fractures: a systematic review of current treatment strategies.

Science.gov (United States)

König, M A; Jehan, S; Boszczyk, A A; Boszczyk, B M

2012-05-01

U-shaped sacral fractures usually result from axial loading of the spine with simultaneous sacral pivoting due to a horizontal fracture which leads to a highly unstable spino-pelvic dissociation. Due to the rarity of these fractures, there is lack of an agreed treatment strategy. A thorough literature search was carried out to identify current treatment concepts. The studies were analysed for mechanism of injury, diagnostic imaging, associated injuries, type of surgery, follow-up times, complications, neurological, clinical and radiological outcome. Sixty-three cases were found in 12 articles. No Class I, II or III evidence was found in the literature. The most common mechanism of injury was a fall or jump from height. Pre-operative neurological deficit was noted in 50 (94.3%) out of 53 cases (not available in 10 patients). The most used surgical options were spino-pelvic fixation with or without decompression and ilio-sacral screws. Post-operative complications occurred in 24 (38.1%) patients. Average follow-up time was 18.6 months (range 2-34 months). Full neurological recovery was noted in 20 cases, partial recovery in 14 and 9 patients had no neurological recovery (5 patients were lost in follow-up). Fracture healing was mentioned in 7 articles with only 1 case of fracture reduction loss. From the current available data, an evidence based treatment strategy regarding outcome, neurological recovery or fracture healing could not be identified. Limited access and minimal-invasive surgery focussing on sacral reduction and restoration seems to offer comparable results to large spino-pelvic constructs with fewer complications and should be considered as the method of choice. If the fracture is highly unstable and displaced, spino-pelvic fixation might offer better stability.

Identifying optimal postmarket surveillance strategies for medical and surgical devices: implications for policy, practice and research.

Science.gov (United States)

Gagliardi, Anna R; Umoquit, Muriah; Lehoux, Pascale; Ross, Sue; Ducey, Ariel; Urbach, David R

2013-03-01

Non-drug technologies offer many benefits, but have been associated with adverse events, prompting calls for improved postmarket surveillance. There is little empirical research to guide the development of such a system. The purpose of this study was to identify optimal postmarket surveillance strategies for medical and surgical devices. Qualitative methods were used for sampling, data collection and analysis. Stakeholders from Canada and the USA representing different roles and perspectives were first interviewed to identify examples and characteristics of different surveillance strategies. These stakeholders and others they recommended were then assembled at a 1-day nominal group meeting to discuss and prioritise the components of a postmarket device surveillance system, and research needed to achieve such a system. Consultations were held with 37 participants, and 47 participants attended the 1-day meeting. They recommended a multicomponent system including reporting by facilities, clinicians and patients, supported with some external surveillance for validation and real-time trials for high-risk devices. Many considerations were identified that constitute desirable characteristics of, and means by which to implement such a system. An overarching network was envisioned to broker linkages, establish a shared minimum dataset, and support communication and decision making. Numerous research questions were identified, which could be pursued in tandem with phased implementation of the system. These findings provide unique guidance for establishing a device safety network that is based on existing initiatives, and could be expanded and evaluated in a prospective, phased fashion as it was developed.

Strategy of Surgical Resection for Glioma Based on Intraoperative Functional Mapping and Monitoring

Science.gov (United States)

TAMURA, Manabu; MURAGAKI, Yoshihiro; SAITO, Taiichi; MARUYAMA, Takashi; NITTA, Masayuki; TSUZUKI, Shunsuke; ISEKI, Hiroshi; OKADA, Yoshikazu

2015-01-01

A growing number of papers have pointed out the relationship between aggressive resection of gliomas and survival prognosis. For maximum resection, the current concept of surgical decision-making is in “information-guided surgery” using multimodal intraoperative information. With this, anatomical information from intraoperative magnetic resonance imaging (MRI) and navigation, functional information from brain mapping and monitoring, and histopathological information must all be taken into account in the new perspective for innovative minimally invasive surgical treatment of glioma. Intraoperative neurofunctional information such as neurophysiological functional monitoring takes the most important part in the process to acquire objective visual data during tumor removal and to integrate these findings as digitized data for intraoperative surgical decision-making. Moreover, the analysis of qualitative data and threshold-setting for quantitative data raise difficult issues in the interpretation and processing of each data type, such as determination of motor evoked potential (MEP) decline, underestimation in tractography, and judgments of patient response for neurofunctional mapping and monitoring during awake craniotomy. Neurofunctional diagnosis of false-positives in these situations may affect the extent of resection, while false-negatives influence intra- and postoperative complication rates. Additionally, even though the various intraoperative visualized data from multiple sources contribute significantly to the reliability of surgical decisions when the information is integrated and provided, it is not uncommon for individual pieces of information to convey opposing suggestions. Such conflicting pieces of information facilitate higher-order decision-making that is dependent on the policies of the facility and the priorities of the patient, as well as the availability of the histopathological characteristics from resected tissue. PMID:26185825

Surgical management of the newborn with congenital diaphragmatic hernia.

Science.gov (United States)

Tsao, Kuojen; Lally, Kevin P

2011-01-01

Despite advances in the surgical treatment and medical management over the last 20 years, neonates with congenital diaphragmatic hernia (CDH) remain one of the most challenging patient groups for all clinicians. Treatment strategies have shifted from emergent surgical repair and maximum ventilatory support to delayed repair and preoperative hemodynamic stabilization with lung-sparing ventilation strategies and extracorporeal membrane oxygenation. Subsequently, overall survival has improved to as high as 80% in some centers. However, specific treatment criteria are vague and highly variable amongst centers. This lack of consensus of these treatment modalities remains elusive due to the heterogeneity in disease severity as well as heterogeneity in patient care amongst centers. As a result of the rare incidence of disease and limited experience of individual centers, the evidence for CDH is typically reported as a homogenous disease largely supported by case series and networked-based studies. To better evaluate the data and compare treatment strategies, a classification and stratification of disease and centers is needed. Copyright © 2010 S. Karger AG, Basel.

Incidental regulation of attraction: The neural basis of the derogation of attractive alternatives in romantic relationships

NARCIS (Netherlands)

Meyer, M.L.; Berkman, E.T.; Karremans, J.C.T.M.; Lieberman, M.D.

2011-01-01

Although a great deal of research addresses the neural basis of deliberate and intentional emotion-regulation strategies, less attention has been paid to the neural mechanisms involved in implicit forms of emotion regulation. Behavioural research suggests that romantically involved participants

Kontrol Kecepatan Motor Induksi menggunakan Algoritma Backpropagation Neural Network

Directory of Open Access Journals (Sweden)

MUHAMMAD RUSWANDI DJALAL

2017-07-01

Full Text Available ABSTRAKBanyak strategi kontrol berbasis kecerdasan buatan telah diusulkan dalam penelitian seperti Fuzzy Logic dan Artificial Neural Network (ANN. Tujuan dari penelitian ini adalah untuk mendesain sebuah kontrol agar kecepatan motor induksi dapat diatur sesuai kebutuhan serta membandingkan kinerja motor induksi tanpa kontrol dan dengan kontrol. Dalam penelitian ini diusulkan sebuah metode artificial neural network untuk mengontrol kecepatan motor induksi tiga fasa. Kecepatan referensi motor diatur pada kecepatan 140 rad/s, 150 rad/s, dan 130 rad/s. Perubahan kecepatan diatur pada setiap interval 0.3 detik dan waktu simulasi maksimum adalah 0,9 detik. Kasus 1 tanpa kontrol, menunjukkan respon torka dan kecepatan dari motor induksi tiga fasa tanpa kontrol. Meskipun kecepatan motor induksi tiga fasa diatur berubah pada setiap 0,3 detik tidak akan mempengaruhi torka. Selain itu, motor induksi tiga fasa tanpa kontrol memiliki kinerja yang buruk dikarenakan kecepatan motor induksi tidak dapat diatur sesuai dengan kebutuhan. Kasus 2 dengan control backpropagation neural network, meskipun kecepatan motor induksi tiga fasa berubah pada setiap 0.3 detik tidak akan mempengaruhi torsi. Selain itu, kontrol backpropagation neural network memiliki kinerja yang baik dikarenakan kecepatan motor induksi dapat diatur sesuai dengan kebutuhan.Kata kunci: Backpropagation Neural Network (BPNN, NN Training, NN Testing, Motor.ABSTRACTMany artificial intelligence-based control strategies have been proposed in research such as Fuzzy Logic and Artificial Neural Network (ANN. The purpose of this research was design a control for the induction motor speed that could be adjusted as needed and compare the performance of induction motor without control and with control. In this research, it was proposed an artificial neural network method to control the speed of three-phase induction motors. The reference speed of motor was set at the rate of 140 rad / s, 150 rad / s, and 130

Pulsed DC Electric Field-Induced Differentiation of Cortical Neural Precursor Cells.

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Hui-Fang Chang

Full Text Available We report the differentiation of neural stem and progenitor cells solely induced by direct current (DC pulses stimulation. Neural stem and progenitor cells in the adult mammalian brain are promising candidates for the development of therapeutic neuroregeneration strategies. The differentiation of neural stem and progenitor cells depends on various in vivo environmental factors, such as nerve growth factor and endogenous EF. In this study, we demonstrated that the morphologic and phenotypic changes of mouse neural stem and progenitor cells (mNPCs could be induced solely by exposure to square-wave DC pulses (magnitude 300 mV/mm at frequency of 100-Hz. The DC pulse stimulation was conducted for 48 h, and the morphologic changes of mNPCs were monitored continuously. The length of primary processes and the amount of branching significantly increased after stimulation by DC pulses for 48 h. After DC pulse treatment, the mNPCs differentiated into neurons, astrocytes, and oligodendrocytes simultaneously in stem cell maintenance medium. Our results suggest that simple DC pulse treatment could control the fate of NPCs. With further studies, DC pulses may be applied to manipulate NPC differentiation and may be used for the development of therapeutic strategies that employ NPCs to treat nervous system disorders.

Pulsed DC Electric Field-Induced Differentiation of Cortical Neural Precursor Cells.

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Chang, Hui-Fang; Lee, Ying-Shan; Tang, Tang K; Cheng, Ji-Yen

2016-01-01

We report the differentiation of neural stem and progenitor cells solely induced by direct current (DC) pulses stimulation. Neural stem and progenitor cells in the adult mammalian brain are promising candidates for the development of therapeutic neuroregeneration strategies. The differentiation of neural stem and progenitor cells depends on various in vivo environmental factors, such as nerve growth factor and endogenous EF. In this study, we demonstrated that the morphologic and phenotypic changes of mouse neural stem and progenitor cells (mNPCs) could be induced solely by exposure to square-wave DC pulses (magnitude 300 mV/mm at frequency of 100-Hz). The DC pulse stimulation was conducted for 48 h, and the morphologic changes of mNPCs were monitored continuously. The length of primary processes and the amount of branching significantly increased after stimulation by DC pulses for 48 h. After DC pulse treatment, the mNPCs differentiated into neurons, astrocytes, and oligodendrocytes simultaneously in stem cell maintenance medium. Our results suggest that simple DC pulse treatment could control the fate of NPCs. With further studies, DC pulses may be applied to manipulate NPC differentiation and may be used for the development of therapeutic strategies that employ NPCs to treat nervous system disorders.

The influence of stress responses on surgical performance and outcomes: Literature review and the development of the surgical stress effects (SSE) framework.

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Chrouser, Kristin L; Xu, Jie; Hallbeck, Susan; Weinger, Matthew B; Partin, Melissa R

2018-02-22

Surgical adverse events persist despite several decades of system-based quality improvement efforts, suggesting the need for alternative strategies. Qualitative studies suggest stress-induced negative intraoperative interpersonal dynamics might contribute to performance errors and undesirable patient outcomes. Understanding the impact of intraoperative stressors may be critical to reducing adverse events and improving outcomes. We searched MEDLINE, psycINFO, EMBASE, Business Source Premier, and CINAHL databases (1996-2016) to assess the relationship between negative (emotional and behavioral) responses to acute intraoperative stressors and provider performance or patient surgical outcomes. Drawing on theory and evidence from reviewed studies, we present the Surgical Stress Effects (SSE) framework. This illustrates how emotional and behavioral responses to stressors can influence individual surgical provider (e.g. surgeon, nurse) performance, team performance, and patient outcomes. It also demonstrates how uncompensated intraoperative threats and errors can lead to adverse events, highlighting evidence gaps for future research efforts. Published by Elsevier Inc.

Neural Alterations in Acquired Age-Related Hearing Loss

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Raksha Anand Mudar

2016-06-01

Full Text Available Hearing loss is one of the most prevalent chronic health conditions in older adults. Growing evidence suggests that hearing loss is associated with reduced cognitive functioning and incident dementia. In this mini-review, we briefly examine literature on anatomical and functional alterations in the brains of adults with acquired age-associated hearing loss, which may underlie the cognitive consequences observed in this population, focusing on studies that have used structural and functional magnetic resonance imaging, diffusion tensor imaging, and event-related electroencephalography. We discuss structural and functional alterations observed in the temporal and frontal cortices and the limbic system. These neural alterations are discussed in the context of common cause, information-degradation, and sensory-deprivation hypotheses, and we suggest possible rehabilitation strategies. Although we are beginning to learn more about changes in neural architecture and functionality related to age-associated hearing loss, much work remains to be done. Understanding the neural alterations will provide objective markers for early identification of neural consequences of age-associated hearing loss and for evaluating benefits of intervention approaches.

In Vivo Recording of Neural and Behavioral Correlates of Anesthesia Induction, Reversal, and Euthanasia in Cephalopod Molluscs

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Hanna M. Butler-Struben

2018-02-01

demonstrate that a standard euthanasia protocol—immersion in isotonic magnesium chloride followed by surgical decerebration—produced no behavioral response and no neural activity during surgical euthanasia. Based on these data, we conclude that both magnesium chloride and ethanol can function as general anesthetic agents, and lidocaine and magnesium chloride can function as local anesthetic agents for cephalopod molluscs.

In Vivo Recording of Neural and Behavioral Correlates of Anesthesia Induction, Reversal, and Euthanasia in Cephalopod Molluscs.

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Butler-Struben, Hanna M; Brophy, Samantha M; Johnson, Nasira A; Crook, Robyn J

2018-01-01

standard euthanasia protocol-immersion in isotonic magnesium chloride followed by surgical decerebration-produced no behavioral response and no neural activity during surgical euthanasia. Based on these data, we conclude that both magnesium chloride and ethanol can function as general anesthetic agents, and lidocaine and magnesium chloride can function as local anesthetic agents for cephalopod molluscs.

Solving differential equations with unknown constitutive relations as recurrent neural networks

Energy Technology Data Exchange (ETDEWEB)

Hagge, Tobias J.; Stinis, Panagiotis; Yeung, Enoch H.; Tartakovsky, Alexandre M.

2017-12-08

We solve a system of ordinary differential equations with an unknown functional form of a sink (reaction rate) term. We assume that the measurements (time series) of state variables are partially available, and use a recurrent neural network to “learn” the reaction rate from this data. This is achieved by including discretized ordinary differential equations as part of a recurrent neural network training problem. We extend TensorFlow’s recurrent neural network architecture to create a simple but scalable and effective solver for the unknown functions, and apply it to a fedbatch bioreactor simulation problem. Use of techniques from recent deep learning literature enables training of functions with behavior manifesting over thousands of time steps. Our networks are structurally similar to recurrent neural networks, but differ in purpose, and require modified training strategies.

The development of search filters for adverse effects of surgical interventions in medline and Embase.

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Golder, Su; Wright, Kath; Loke, Yoon Kong

2018-03-31

Search filter development for adverse effects has tended to focus on retrieving studies of drug interventions. However, a different approach is required for surgical interventions. To develop and validate search filters for medline and Embase for the adverse effects of surgical interventions. Systematic reviews of surgical interventions where the primary focus was to evaluate adverse effect(s) were sought. The included studies within these reviews were divided randomly into a development set, evaluation set and validation set. Using word frequency analysis we constructed a sensitivity maximising search strategy and this was tested in the evaluation and validation set. Three hundred and fifty eight papers were included from 19 surgical intervention reviews. Three hundred and fifty two papers were available on medline and 348 were available on Embase. Generic adverse effects search strategies in medline and Embase could achieve approximately 90% relative recall. Recall could be further improved with the addition of specific adverse effects terms to the search strategies. We have derived and validated a novel search filter that has reasonable performance for identifying adverse effects of surgical interventions in medline and Embase. However, we appreciate the limitations of our methods, and recommend further research on larger sample sizes and prospective systematic reviews. © 2018 The Authors Health Information and Libraries Journal published by John Wiley & Sons Ltd on behalf of Health Libraries Group.

Novel perspectives of neural stem cell differentiation: from neurotransmitters to therapeutics.

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Trujillo, Cleber A; Schwindt, Telma T; Martins, Antonio H; Alves, Janaína M; Mello, Luiz Eugênio; Ulrich, Henning

2009-01-01

In the past years, many reports have described the existence of neural progenitor and stem cells in the adult central nervous system capable of generating new neurons, astrocytes, and oligodendrocytes. This discovery has overturned the central assumption in the neuroscience field, of no new neurons being originated in the brain after birth and provided the fundaments to understand the molecular basis of neural differentiation and to develop new therapies for neural tissue repair. Although the mechanisms underlying cell fate during neural development are not yet understood, the importance of intrinsic and extrinsic factors and of an appropriate microenvironment is well known. In this context, emerging evidence strongly suggests that glial cells play a key role in controlling multiple steps of neurogenesis. Those cells, of particular radial glia, are important for migration, cell specification, and integration of neurons into a functional neural network. This review aims to present an update in the neurogenesis area and highlight the modulation of neural stem cell differentiation by neurotransmitters, growth factors, and their receptors, with possible applications for cell therapy strategies of neurological disorders.

Abortion - surgical

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Suction curettage; Surgical abortion; Elective abortion - surgical; Therapeutic abortion - surgical ... Surgical abortion involves dilating the opening to the uterus (cervix) and placing a small suction tube into the uterus. ...

Evaluation of the Influential Factors in Cancelling Surgical Operations and Developing Management Strategies to Reduce these Factors in Shahid Kamyab Hospital of Mashhad, Iran during 2012-2013

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Amir Ashkan Nasiripour

2017-04-01

Conclusion: According to the results, most of the causes of surgery cancellation were patient-related. Therefore, it is suggested that patient evaluation be performed by surgeons and anesthesiologists prior to the surgical operation in order to prevent clinical problems during the surgery, offer insurance strategies, and solve the problems relating to the healthcare costs for the less privileged patients, especially those requiring surgery after accidents.

Vascular mapping of the retroauricular skin - proposal for a posterior superior surgical incision for transcutaneous bone-conduction hearing implants.

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Perenyi, Adam; Bere, Zsofia; Jarabin, Janos; Sztano, Balazs; Kukla, Edit; Bikhazi, Ziad; Tiszlavicz, Laszlo; Toth, Ferenc; Kiss, Jozsef Geza; Rovo, Laszlo

2017-01-17

Passive transcutaneous osseointegrated hearing implant systems have become increasingly popular more recently. The area over the implant is vulnerable due to vibration and pressure from the externally worn sound processor. Good perfusion and neural integrity has the potential to reduce complications. The authors' objective was to determine the ideal surgical exposure to maintain perfusion and neural integrity and decrease surgical time as a result of reduced bleeding. The vascular anatomy of the temporal-parietal soft tissue was examined in a total of 50 subjects. Imaging diagnostics included magnetic resonance angiography in 12 and Doppler ultrasound in 25 healthy subjects to reveal the arterial network. Cadaver dissection of 13 subjects formed the control group. The prevalence of the arteries were statistically analyzed with sector analysis in the surgically relevant area. The main arterial branches of this region could be well identified with each method. Statistical analysis showed that the arterial pattern was similar in all subjects. The prevalence of major arteries is low in the upper posterior area though large in proximity to the auricle region. Diverse methods indicate the advantages of a posterior superior incision because the major arteries and nerves are at less risk of damage and best preserved. Although injury to these structures is rare, when it occurs, the distal flow is compromised and the peri-implant area is left intact. Hand-held Doppler is efficient and cost-effective in finding the best position for incision, if necessary, in subjects with a history of surgical stress to the retroauricular skin. This was a non-interventional study.

Post surgical complications from students' large animal surgical ...

African Journals Online (AJOL)

A retrospective study of post surgical complications was conducted on records of students' Large Animal Surgical Laboratories in the Faculty of Veterinary Medicine (F.V.M.), Ahmadu Bello University (A.B.U), Zaria from 1989 to 1993. Three hundred and eleven surgical complications were recorded from five surgical ...

Echocardiographic definition and surgical decision-making in unbalanced atrioventricular septal defect: a Congenital Heart Surgeons' Society multiinstitutional study.

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Jegatheeswaran, Anusha; Pizarro, Christian; Caldarone, Christopher A; Cohen, Meryl S; Baffa, Jeanne M; Gremmels, David B; Mertens, Luc; Morell, Victor O; Williams, William G; Blackstone, Eugene H; McCrindle, Brian W; Overman, David M

2010-09-14

Although identification of unbalanced atrioventricular septal defect (AVSD) is obvious when extreme, exact criteria to define the limits of unbalanced are not available. We sought to validate an atrioventricular valve index (AVVI) (left atrioventricular valve area/total atrioventricular valve area, centimeters squared) as a discriminator of balanced and unbalanced forms of complete AVSD and to characterize the association of AVVI with surgical strategies and outcomes. Diagnostic echocardiograms and hospital records of 356 infants with complete AVSD at 4 Congenital Heart Surgeons' Society (CHSS) institutions (2000-2006) were reviewed and AVVI measured (n=315). Patients were classified as unbalanced if AVVI≤0.4 (right dominant) or ≥0.6 (left dominant). Surgical strategy and outcomes were examined across the range of AVVI. Competing risks analysis until the time of commitment to a surgical strategy examined 4 end states: biventricular repair (BVR), univentricular repair (UVR), pulmonary artery banding (PAB), and death before surgery. A prediction nomogram for surgical strategy based on AVVI was developed. The majority of patients had balanced AVSD (0.4strategies were found when 0.19≤AVVI≤0.39 (UVR and BVR), with a disproportionate number of deaths in this range. AVVI≥0.6 (left dominant) was less common. The proportion of subjects predicted for the end states at 12 months after diagnosis are: BVR, 86%; UVR, 7%; PAB, 1%; death without surgery, 1%; alive without surgery, 5%. AVVI effectively characterizes the transition between balanced and unbalanced AVSD with important correlation to anatomic substrate and selected surgical strategy.

A Case Study on Neural Inspired Dynamic Memory Management Strategies for High Performance Computing.

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Vineyard, Craig Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Verzi, Stephen Joseph [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-09-01

As high performance computing architectures pursue more computational power there is a need for increased memory capacity and bandwidth as well. A multi-level memory (MLM) architecture addresses this need by combining multiple memory types with different characteristics as varying levels of the same architecture. How to efficiently utilize this memory infrastructure is an unknown challenge, and in this research we sought to investigate whether neural inspired approaches can meaningfully help with memory management. In particular we explored neurogenesis inspired re- source allocation, and were able to show a neural inspired mixed controller policy can beneficially impact how MLM architectures utilize memory.

Cognitive deficits caused by prefrontal cortical and hippocampal neural disinhibition.

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Bast, Tobias; Pezze, Marie; McGarrity, Stephanie

2017-10-01

contributes to clinically relevant cognitive deficits, and we consider pharmacological strategies for ameliorating cognitive deficits by rebalancing disinhibition-induced aberrant neural activity. Linked Articles This article is part of a themed section on Pharmacology of Cognition: a Panacea for Neuropsychiatric Disease? To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.19/issuetoc. © 2017 The British Pharmacological Society.

Surgical management for displaced pediatric proximal humeral fractures: a cost analysis

OpenAIRE

Shore, Benjamin J.; Hedequist, Daniel J.; Miller, Patricia E.; Waters, Peter M.; Bae, Donald S.

2015-01-01

Purpose The purpose of this investigation was to determine which of the following methods of fixation, percutaneous pinning (PP) or intramedullary nailing (IMN), was more cost-effective in the treatment of displaced pediatric proximal humeral fractures (PPHF). Methods: A retrospective cohort of surgically treated PPHF over a 12-year period at a single institution was performed. A decision analysis model was constructed to compare three surgical strategies: IMN versus percutaneous pinning leav...

Prediction of Bladder Cancer Recurrences Using Artificial Neural Networks

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Zulueta Guerrero, Ekaitz; Garay, Naiara Telleria; Lopez-Guede, Jose Manuel; Vilches, Borja Ayerdi; Iragorri, Eider Egilegor; Castaños, David Lecumberri; de La Hoz Rastrollo, Ana Belén; Peña, Carlos Pertusa

Even if considerable advances have been made in the field of early diagnosis, there is no simple, cheap and non-invasive method that can be applied to the clinical monitorisation of bladder cancer patients. Moreover, bladder cancer recurrences or the reappearance of the tumour after its surgical resection cannot be predicted in the current clinical setting. In this study, Artificial Neural Networks (ANN) were used to assess how different combinations of classical clinical parameters (stage-grade and age) and two urinary markers (growth factor and pro-inflammatory mediator) could predict post surgical recurrences in bladder cancer patients. Different ANN methods, input parameter combinations and recurrence related output variables were used and the resulting positive and negative prediction rates compared. MultiLayer Perceptron (MLP) was selected as the most predictive model and urinary markers showed the highest sensitivity, predicting correctly 50% of the patients that would recur in a 2 year follow-up period.

Neural decoding of collective wisdom with multi-brain computing.

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Eckstein, Miguel P; Das, Koel; Pham, Binh T; Peterson, Matthew F; Abbey, Craig K; Sy, Jocelyn L; Giesbrecht, Barry

2012-01-02

Group decisions and even aggregation of multiple opinions lead to greater decision accuracy, a phenomenon known as collective wisdom. Little is known about the neural basis of collective wisdom and whether its benefits arise in late decision stages or in early sensory coding. Here, we use electroencephalography and multi-brain computing with twenty humans making perceptual decisions to show that combining neural activity across brains increases decision accuracy paralleling the improvements shown by aggregating the observers' opinions. Although the largest gains result from an optimal linear combination of neural decision variables across brains, a simpler neural majority decision rule, ubiquitous in human behavior, results in substantial benefits. In contrast, an extreme neural response rule, akin to a group following the most extreme opinion, results in the least improvement with group size. Analyses controlling for number of electrodes and time-points while increasing number of brains demonstrate unique benefits arising from integrating neural activity across different brains. The benefits of multi-brain integration are present in neural activity as early as 200 ms after stimulus presentation in lateral occipital sites and no additional benefits arise in decision related neural activity. Sensory-related neural activity can predict collective choices reached by aggregating individual opinions, voting results, and decision confidence as accurately as neural activity related to decision components. Estimation of the potential for the collective to execute fast decisions by combining information across numerous brains, a strategy prevalent in many animals, shows large time-savings. Together, the findings suggest that for perceptual decisions the neural activity supporting collective wisdom and decisions arises in early sensory stages and that many properties of collective cognition are explainable by the neural coding of information across multiple brains. Finally

Strategies in the Surgical Management of Atrial Fibrillation

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Leanne Harling

2011-01-01

Full Text Available Atrial fibrillation (AF is associated with substantial morbidity, mortality, and economic burden and confers a lifetime risk of up to 25%. Current medical management involves thromboembolism prevention, rate, and rhythm control. An increased understanding of AF pathophysiology has led to enhanced pharmacological and medical therapies; however this is often limited by toxicity, variable symptom control, and inability to modulate the atrial substrate. Surgical AF ablation has been available since the original description of the Cox Maze procedure, either as a standalone or concomitant intervention. Advances in novel energy delivery systems have allowed the development of less technically demanding procedures potentially eliminating the need for median sternotomy and cardiopulmonary bypass. Variations in the definition, duration, and reporting of AF have produced methodological limitations impacting on the validity of interstudy comparisons. Standardization of these parameters may, in future, allow us to further evaluate clinical endpoints and establish the efficacy of these techniques.

Sequential and parallel image restoration: neural network implementations.

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Figueiredo, M T; Leitao, J N

1994-01-01

Sequential and parallel image restoration algorithms and their implementations on neural networks are proposed. For images degraded by linear blur and contaminated by additive white Gaussian noise, maximum a posteriori (MAP) estimation and regularization theory lead to the same high dimension convex optimization problem. The commonly adopted strategy (in using neural networks for image restoration) is to map the objective function of the optimization problem into the energy of a predefined network, taking advantage of its energy minimization properties. Departing from this approach, we propose neural implementations of iterative minimization algorithms which are first proved to converge. The developed schemes are based on modified Hopfield (1985) networks of graded elements, with both sequential and parallel updating schedules. An algorithm supported on a fully standard Hopfield network (binary elements and zero autoconnections) is also considered. Robustness with respect to finite numerical precision is studied, and examples with real images are presented.

Influence of neural adaptation on dynamics and equilibrium state of neural activities in a ring neural network

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Takiyama, Ken

2017-12-01

How neural adaptation affects neural information processing (i.e. the dynamics and equilibrium state of neural activities) is a central question in computational neuroscience. In my previous works, I analytically clarified the dynamics and equilibrium state of neural activities in a ring-type neural network model that is widely used to model the visual cortex, motor cortex, and several other brain regions. The neural dynamics and the equilibrium state in the neural network model corresponded to a Bayesian computation and statistically optimal multiple information integration, respectively, under a biologically inspired condition. These results were revealed in an analytically tractable manner; however, adaptation effects were not considered. Here, I analytically reveal how the dynamics and equilibrium state of neural activities in a ring neural network are influenced by spike-frequency adaptation (SFA). SFA is an adaptation that causes gradual inhibition of neural activity when a sustained stimulus is applied, and the strength of this inhibition depends on neural activities. I reveal that SFA plays three roles: (1) SFA amplifies the influence of external input in neural dynamics; (2) SFA allows the history of the external input to affect neural dynamics; and (3) the equilibrium state corresponds to the statistically optimal multiple information integration independent of the existence of SFA. In addition, the equilibrium state in a ring neural network model corresponds to the statistically optimal integration of multiple information sources under biologically inspired conditions, independent of the existence of SFA.

Neural bases of different cognitive strategies for facial affect processing in schizophrenia.

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Fakra, Eric; Salgado-Pineda, Pilar; Delaveau, Pauline; Hariri, Ahmad R; Blin, Olivier

2008-03-01

To examine the neural basis and dynamics of facial affect processing in schizophrenic patients as compared to healthy controls. Fourteen schizophrenic patients and fourteen matched controls performed a facial affect identification task during fMRI acquisition. The emotional task included an intuitive emotional condition (matching emotional faces) and a more cognitively demanding condition (labeling emotional faces). Individual analysis for each emotional condition, and second-level t-tests examining both within-, and between-group differences, were carried out using a random effects approach. Psychophysiological interactions (PPI) were tested for variations in functional connectivity between amygdala and other brain regions as a function of changes in experimental conditions (labeling versus matching). During the labeling condition, both groups engaged similar networks. During the matching condition, schizophrenics failed to activate regions of the limbic system implicated in the automatic processing of emotions. PPI revealed an inverse functional connectivity between prefrontal regions and the left amygdala in healthy volunteers but there was no such change in patients. Furthermore, during the matching condition, and compared to controls, patients showed decreased activation of regions involved in holistic face processing (fusiform gyrus) and increased activation of regions associated with feature analysis (inferior parietal cortex, left middle temporal lobe, right precuneus). Our findings suggest that schizophrenic patients invariably adopt a cognitive approach when identifying facial affect. The distributed neocortical network observed during the intuitive condition indicates that patients may resort to feature-based, rather than configuration-based, processing and may constitute a compensatory strategy for limbic dysfunction.

Evaluating the effects of increasing surgical volume on emergency department patient access.

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Levin, S; Dittus, R; Aronsky, D; Weinger, M; France, D

2011-02-01

To determine how increases in surgical patient volume will affect emergency department (ED) access to inpatient cardiac services. To compare how strategies to increase cardiology inpatient throughput can either accommodate increases in surgical volume or improve ED patient access. A stochastic discrete event simulation was created to model patient flow through a cardiology inpatient system within a US, urban, academic hospital. The simulation used survival analysis to examine the relationship between anticipated increases in surgical volume and ED patient boarding time (ie, time interval from cardiology admission request to inpatient bed placement). ED patients boarded for a telemetry and cardiovascular intensive care unit (CVICU) bed had a mean boarding time of 5.3 (median 3.1, interquartile range 1.5-6.9) h and 2.7 (median 1.7, interquartile range 0.8-3.0) h, respectively. Each 10% incremental increase in surgical volume resulted in a 37 and 33 min increase in mean boarding time to the telemetry unit and CVICU, respectively. Strategies to increase cardiology inpatient throughput by increasing capacity and decreasing length of stay for specific inpatients was compared. Increasing cardiology capacity by one telemetry and CVICU bed or decreasing length of stay by 1 h resulted in a 7-9 min decrease in average boarding time or an 11-19% increase in surgical patient volume accommodation. Simulating competition dynamics for hospital admissions provides prospective planning (ie, decision making) information and demonstrates how interventions to increase inpatient throughput will have a much greater effect on higher priority surgical admissions compared with ED admissions.

A theory of how active behavior stabilises neural activity: Neural gain modulation by closed-loop environmental feedback.

Directory of Open Access Journals (Sweden)

Christopher L Buckley

2018-01-01

Full Text Available During active behaviours like running, swimming, whisking or sniffing, motor actions shape sensory input and sensory percepts guide future motor commands. Ongoing cycles of sensory and motor processing constitute a closed-loop feedback system which is central to motor control and, it has been argued, for perceptual processes. This closed-loop feedback is mediated by brainwide neural circuits but how the presence of feedback signals impacts on the dynamics and function of neurons is not well understood. Here we present a simple theory suggesting that closed-loop feedback between the brain/body/environment can modulate neural gain and, consequently, change endogenous neural fluctuations and responses to sensory input. We support this theory with modeling and data analysis in two vertebrate systems. First, in a model of rodent whisking we show that negative feedback mediated by whisking vibrissa can suppress coherent neural fluctuations and neural responses to sensory input in the barrel cortex. We argue this suppression provides an appealing account of a brain state transition (a marked change in global brain activity coincident with the onset of whisking in rodents. Moreover, this mechanism suggests a novel signal detection mechanism that selectively accentuates active, rather than passive, whisker touch signals. This mechanism is consistent with a predictive coding strategy that is sensitive to the consequences of motor actions rather than the difference between the predicted and actual sensory input. We further support the theory by re-analysing previously published two-photon data recorded in zebrafish larvae performing closed-loop optomotor behaviour in a virtual swim simulator. We show, as predicted by this theory, that the degree to which each cell contributes in linking sensory and motor signals well explains how much its neural fluctuations are suppressed by closed-loop optomotor behaviour. More generally we argue that our results

A theory of how active behavior stabilises neural activity: Neural gain modulation by closed-loop environmental feedback.

Science.gov (United States)

Buckley, Christopher L; Toyoizumi, Taro

2018-01-01

During active behaviours like running, swimming, whisking or sniffing, motor actions shape sensory input and sensory percepts guide future motor commands. Ongoing cycles of sensory and motor processing constitute a closed-loop feedback system which is central to motor control and, it has been argued, for perceptual processes. This closed-loop feedback is mediated by brainwide neural circuits but how the presence of feedback signals impacts on the dynamics and function of neurons is not well understood. Here we present a simple theory suggesting that closed-loop feedback between the brain/body/environment can modulate neural gain and, consequently, change endogenous neural fluctuations and responses to sensory input. We support this theory with modeling and data analysis in two vertebrate systems. First, in a model of rodent whisking we show that negative feedback mediated by whisking vibrissa can suppress coherent neural fluctuations and neural responses to sensory input in the barrel cortex. We argue this suppression provides an appealing account of a brain state transition (a marked change in global brain activity) coincident with the onset of whisking in rodents. Moreover, this mechanism suggests a novel signal detection mechanism that selectively accentuates active, rather than passive, whisker touch signals. This mechanism is consistent with a predictive coding strategy that is sensitive to the consequences of motor actions rather than the difference between the predicted and actual sensory input. We further support the theory by re-analysing previously published two-photon data recorded in zebrafish larvae performing closed-loop optomotor behaviour in a virtual swim simulator. We show, as predicted by this theory, that the degree to which each cell contributes in linking sensory and motor signals well explains how much its neural fluctuations are suppressed by closed-loop optomotor behaviour. More generally we argue that our results demonstrate the dependence

Surgical lighting

NARCIS (Netherlands)

Knulst, A.J.

2017-01-01

The surgical light is an important tool for surgeons to create and maintain good visibility on the surgical task. Chapter 1 gives background to the field of (surgical) lighting and related terminology. Although the surgical light has been developed strongly since its introduction a long time ago,

Weather forecasting based on hybrid neural model

Science.gov (United States)

Saba, Tanzila; Rehman, Amjad; AlGhamdi, Jarallah S.

2017-11-01

Making deductions and expectations about climate has been a challenge all through mankind's history. Challenges with exact meteorological directions assist to foresee and handle problems well in time. Different strategies have been investigated using various machine learning techniques in reported forecasting systems. Current research investigates climate as a major challenge for machine information mining and deduction. Accordingly, this paper presents a hybrid neural model (MLP and RBF) to enhance the accuracy of weather forecasting. Proposed hybrid model ensure precise forecasting due to the specialty of climate anticipating frameworks. The study concentrates on the data representing Saudi Arabia weather forecasting. The main input features employed to train individual and hybrid neural networks that include average dew point, minimum temperature, maximum temperature, mean temperature, average relative moistness, precipitation, normal wind speed, high wind speed and average cloudiness. The output layer composed of two neurons to represent rainy and dry weathers. Moreover, trial and error approach is adopted to select an appropriate number of inputs to the hybrid neural network. Correlation coefficient, RMSE and scatter index are the standard yard sticks adopted for forecast accuracy measurement. On individual standing MLP forecasting results are better than RBF, however, the proposed simplified hybrid neural model comes out with better forecasting accuracy as compared to both individual networks. Additionally, results are better than reported in the state of art, using a simple neural structure that reduces training time and complexity.

Gelatin methacrylamide hydrogel with graphene nanoplatelets for neural cell-laden 3D bioprinting.

Science.gov (United States)

Wei Zhu; Harris, Brent T; Zhang, Lijie Grace

2016-08-01

Nervous system is extremely complex which leads to rare regrowth of nerves once injury or disease occurs. Advanced 3D bioprinting strategy, which could simultaneously deposit biocompatible materials, cells and supporting components in a layer-by-layer manner, may be a promising solution to address neural damages. Here we presented a printable nano-bioink composed of gelatin methacrylamide (GelMA), neural stem cells, and bioactive graphene nanoplatelets to target nerve tissue regeneration in the assist of stereolithography based 3D bioprinting technique. We found the resultant GelMA hydrogel has a higher compressive modulus with an increase of GelMA concentration. The porous GelMA hydrogel can provide a biocompatible microenvironment for the survival and growth of neural stem cells. The cells encapsulated in the hydrogel presented good cell viability at the low GelMA concentration. Printed neural construct exhibited well-defined architecture and homogenous cell distribution. In addition, neural stem cells showed neuron differentiation and neurites elongation within the printed construct after two weeks of culture. These findings indicate the 3D bioprinted neural construct has great potential for neural tissue regeneration.

Surgical smoke.

Science.gov (United States)

Fan, Joe King-Man; Chan, Fion Siu-Yin; Chu, Kent-Man

2009-10-01

Surgical smoke is the gaseous by-product formed during surgical procedures. Most surgeons, operating theatre staff and administrators are unaware of its potential health risks. Surgical smoke is produced by various surgical instruments including those used in electrocautery, lasers, ultrasonic scalpels, high speed drills, burrs and saws. The potential risks include carbon monoxide toxicity to the patient undergoing a laparoscopic operation, pulmonary fibrosis induced by non-viable particles, and transmission of infectious diseases like human papilloma virus. Cytotoxicity and mutagenicity are other concerns. Minimisation of the production of surgical smoke and modification of any evacuation systems are possible solutions. In general, a surgical mask can provide more than 90% protection to exposure to surgical smoke; however, in most circumstances it cannot provide air-tight protection to the user. An at least N95 grade or equivalent respirator offers the best protection against surgical smoke, but whether such protection is necessary is currently unknown.

Surgical Scales: Primary Closure versus Gastric Resection for ...

African Journals Online (AJOL)

Perforated gastric ulcer is one of the most life‑threatening complications of peptic ulcer disease with high morbidity and mortality rates. The surgical strategy for gastric perforation in contrast with duodenal perforations often requires consilium and intraoperative debates. The subject of the debate is a 59‑year‑old male patient ...

Radial basis function (RBF) neural network control for mechanical systems design, analysis and Matlab simulation

CERN Document Server

Liu, Jinkun

2013-01-01

Radial Basis Function (RBF) Neural Network Control for Mechanical Systems is motivated by the need for systematic design approaches to stable adaptive control system design using neural network approximation-based techniques. The main objectives of the book are to introduce the concrete design methods and MATLAB simulation of stable adaptive RBF neural control strategies. In this book, a broad range of implementable neural network control design methods for mechanical systems are presented, such as robot manipulators, inverted pendulums, single link flexible joint robots, motors, etc. Advanced neural network controller design methods and their stability analysis are explored. The book provides readers with the fundamentals of neural network control system design.   This book is intended for the researchers in the fields of neural adaptive control, mechanical systems, Matlab simulation, engineering design, robotics and automation. Jinkun Liu is a professor at Beijing University of Aeronautics and Astronauti...

Surgical approach in patients with hyperparathyroidism in multiple endocrine neoplasia type 1: total versus partial parathyroidectomy

Directory of Open Access Journals (Sweden)

Francesco Tonelli

2012-01-01

Full Text Available Usually, primary hyperparathyroidism is the first endocrinopathy to be diagnosed in patients with multiple endocrine neoplasia type 1, and is also the most common one. The timing of the surgery and strategy in multiple endocrine neoplasia type 1/hyperparathyroidism are still under debate. The aims of surgery are to: 1 correct hypercalcemia, thus preventing persistent or recurrent hyperparathyroidism; 2 avoid persistent hypoparathyroidism; and 3 facilitate the surgical treatment of possible recurrences. Currently, two types of surgical approach are indicated: 1 subtotal parathyroidectomy with removal of at least 3-3 K glands; and 2 total parathyroidectomy with grafting of autologous parathyroid tissue. Transcervical thymectomy must be performed with both of these procedures. Unsuccessful surgical treatment of hyperparathyroidism is more frequently observed in multiple endocrine neoplasia type 1 than in sporadic hyperparathyroidism. The recurrence rate is strongly influenced by: 1 the lack of a pre-operative multiple endocrine neoplasia type 1 diagnosis; 2 the surgeon's experience; 3 the timing of surgery; 4 the possibility of performing intra-operative confirmation (histologic examination, rapid parathyroid hormone assay of the curative potential of the surgical procedure; and, 5 the surgical strategy. Persistent hyperparathyroidism seems to be more frequent after subtotal parathyroidectomy than after total parathyroidectomy with autologous graft of parathyroid tissue. Conversely, recurrent hyperparathyroidism has a similar frequency in the two surgical strategies. To plan further operations, it is very helpful to know all the available data about previous surgery and to undertake accurate identification of the site of recurrence.

Virtual Reality Simulator Systems in Robotic Surgical Training.

Science.gov (United States)

Mangano, Alberto; Gheza, Federico; Giulianotti, Pier Cristoforo

2018-06-01

The number of robotic surgical procedures has been increasing worldwide. It is important to maximize the cost-effectiveness of robotic surgical training and safely reduce the time needed for trainees to reach proficiency. The use of preliminary lab training in robotic skills is a good strategy for the rapid acquisition of further, standardized robotic skills. Such training can be done either by using a simulator or by exercises in a dry or wet lab. While the use of an actual robotic surgical system for training may be problematic (high cost, lack of availability), virtual reality (VR) simulators can overcome many of these obstacles. However, there is still a lack of standardization. Although VR training systems have improved, they cannot yet replace experience in a wet lab. In particular, simulated scenarios are not yet close enough to a real operative experience. Indeed, there is a difference between technical skills (i.e., mechanical ability to perform a simulated task) and surgical competence (i.e., ability to perform a real surgical operation). Thus, while a VR simulator can replace a dry lab, it cannot yet replace training in a wet lab or operative training in actual patients. However, in the near future, it is expected that VR surgical simulators will be able to provide total reality simulation and replace training in a wet lab. More research is needed to produce more wide-ranging, trans-specialty robotic curricula.

Surgical Management of the Giant Pannus: Indications, Strategies, and Outcomes.

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Michaels, Joseph; Coon, Devin; Calotta, Nicholas A; Peter Rubin, J

2018-04-01

The obesity pandemic continues to produce an inexorable increase in the number of patients requiring surgical treatment of obesity and obesity-related complications. Along with this growing number of patients, there is a concomitant increase in the complexity of management. One particular example is the treatment of patients with an exceptionally large and morbid pannus. In this report, we detail the management of seven patients suffering from a giant pannus. Medical and surgical variables were assessed. A quality of life questionnaire was administered pre- and postoperatively. All seven patients suffered some obesity-related medical morbidity and six of seven (86%) had local complications of the giant pannus. Each patient underwent giant panniculectomy [resection weight > 13. 6 kg (30 lb)]. The mean resection weight was 20.0 kg. Four of seven (57%) patients experienced postoperative complications, with two (29%) requiring re-operation and blood transfusion. Six patients were available for long-term follow-up; 100% of participants indicated an increased quality of life while five (83%) reported additional postoperative weight loss, increase in exercise frequency and walking ability, and improved ability to work. Our results indicate that giant panniculectomy is a challenging and risky procedure, but careful patient selection and intraoperative scrutiny can ameliorate these risks and afford patients a dramatically improved quality of life. Level of Evidence IV This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Ca(2+) coding and decoding strategies for the specification of neural and renal precursor cells during development.

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Moreau, Marc; Néant, Isabelle; Webb, Sarah E; Miller, Andrew L; Riou, Jean-François; Leclerc, Catherine

2016-03-01

During embryogenesis, a rise in intracellular Ca(2+) is known to be a widespread trigger for directing stem cells towards a specific tissue fate, but the precise Ca(2+) signalling mechanisms involved in achieving these pleiotropic effects are still poorly understood. In this review, we compare the Ca(2+) signalling events that appear to be one of the first steps in initiating and regulating both neural determination (neural induction) and kidney development (nephrogenesis). We have highlighted the necessary and sufficient role played by Ca(2+) influx and by Ca(2+) transients in the determination and differentiation of pools of neural or renal precursors. We have identified new Ca(2+) target genes involved in neural induction and we showed that the same Ca(2+) early target genes studied are not restricted to neural tissue but are also present in other tissues, principally in the pronephros. In this review, we also described a mechanism whereby the transcriptional control of gene expression during neurogenesis and nephrogenesis might be directly controlled by Ca(2+) signalling. This mechanism involves members of the Kcnip family such that a change in their binding properties to specific DNA sites is a result of Ca(2+) binding to EF-hand motifs. The different functions of Ca(2+) signalling during these two events illustrate the versatility of Ca(2+) as a second messenger. Copyright © 2015 Elsevier Ltd. All rights reserved.

Handwritten Digits Recognition Using Neural Computing

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Călin Enăchescu

2009-12-01

Full Text Available In this paper we present a method for the recognition of handwritten digits and a practical implementation of this method for real-time recognition. A theoretical framework for the neural networks used to classify the handwritten digits is also presented.The classification task is performed using a Convolutional Neural Network (CNN. CNN is a special type of multy-layer neural network, being trained with an optimized version of the back-propagation learning algorithm.CNN is designed to recognize visual patterns directly from pixel images with minimal preprocessing, being capable to recognize patterns with extreme variability (such as handwritten characters, and with robustness to distortions and simple geometric transformations.The main contributions of this paper are related to theoriginal methods for increasing the efficiency of the learning algorithm by preprocessing the images before the learning process and a method for increasing the precision and performance for real-time applications, by removing the non useful information from the background.By combining these strategies we have obtained an accuracy of 96.76%, using as training set the NIST (National Institute of Standards and Technology database.

Surgical Assisting

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... instruction, including: Microbiology Pathophysiology Pharmacology Anatomy and physiology Medical terminology Curriculum . Course content includes: Advanced surgical anatomy Surgical microbiology Surgical pharmacology Anesthesia methods and agents Bioscience Ethical ...

Paediatric Abdominal Surgical Emergencies in a General Surgical ...

African Journals Online (AJOL)

... organized for general surgeons undertaking paediatric surgical emergencies. More paediatric surgeons should be trained and more paediatric surgical units should established in the country. Key Words: Paediatric Abdominal Surgical Emergencies; Paediatric Surgeons, General Surgeons. Journal of College of Medicine ...

Automated sleep stage detection with a classical and a neural learning algorithm--methodological aspects.

Science.gov (United States)

Schwaibold, M; Schöchlin, J; Bolz, A

2002-01-01

For classification tasks in biosignal processing, several strategies and algorithms can be used. Knowledge-based systems allow prior knowledge about the decision process to be integrated, both by the developer and by self-learning capabilities. For the classification stages in a sleep stage detection framework, three inference strategies were compared regarding their specific strengths: a classical signal processing approach, artificial neural networks and neuro-fuzzy systems. Methodological aspects were assessed to attain optimum performance and maximum transparency for the user. Due to their effective and robust learning behavior, artificial neural networks could be recommended for pattern recognition, while neuro-fuzzy systems performed best for the processing of contextual information.

Neural correlate of human reciprocity in social interactions.

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Sakaiya, Shiro; Shiraito, Yuki; Kato, Junko; Ide, Hiroko; Okada, Kensuke; Takano, Kouji; Kansaku, Kenji

2013-01-01

Reciprocity plays a key role maintaining cooperation in society. However, little is known about the neural process that underpins human reciprocity during social interactions. Our neuroimaging study manipulated partner identity (computer, human) and strategy (random, tit-for-tat) in repeated prisoner's dilemma games and investigated the neural correlate of reciprocal interaction with humans. Reciprocal cooperation with humans but exploitation of computers by defection was associated with activation in the left amygdala. Amygdala activation was also positively and negatively correlated with a preference change for human partners following tit-for-tat and random strategies, respectively. The correlated activation represented the intensity of positive feeling toward reciprocal and negative feeling toward non-reciprocal partners, and so reflected reciprocity in social interaction. Reciprocity in social interaction, however, might plausibly be misinterpreted and so we also examined the neural coding of insight into the reciprocity of partners. Those with and without insight revealed differential brain activation across the reward-related circuitry (i.e., the right middle dorsolateral prefrontal cortex and dorsal caudate) and theory of mind (ToM) regions [i.e., ventromedial prefrontal cortex (VMPFC) and precuneus]. Among differential activations, activation in the precuneus, which accompanied deactivation of the VMPFC, was specific to those without insight into human partners who were engaged in a tit-for-tat strategy. This asymmetric (de)activation might involve specific contributions of ToM regions to the human search for reciprocity. Consequently, the intensity of emotion attached to human reciprocity was represented in the amygdala, whereas insight into the reciprocity of others was reflected in activation across the reward-related and ToM regions. This suggests the critical role of mentalizing, which was not equated with reward expectation during social interactions.

Neural correlate of human reciprocity in social interactions

Directory of Open Access Journals (Sweden)

Shiro eSakaiya

2013-12-01

Full Text Available Reciprocity plays a key role maintaining cooperation in society. However, little is known about the neural process that underpins human reciprocity during social interactions. Our neuroimaging study manipulated partner identity (computer, human and strategy (random, tit-for-tat in repeated prisoner’s dilemma games and investigated the neural correlate of reciprocal interaction with humans. Reciprocal cooperation with humans but exploitation of computers by defection was associated with activation in the left amygdala. Amygdala activation was also positively and negatively correlated with a preference change for human partners following tit-for-tat and random strategies, respectively. The correlated activation represented the intensity of positive feeling toward reciprocal and negative feeling toward non-reciprocal partners, and so reflected reciprocity in social interaction. Reciprocity in social interaction, however, might plausibly be misinterpreted and so we also examined the neural coding of insight into the reciprocity of partners. Those with and without insight revealed differential brain activation across the reward-related circuitry (i.e., the right middle dorsolateral prefrontal cortex and dorsal caudate and theory of mind (ToM regions (i.e., ventromedial prefrontal cortex [VMPFC] and precuneus. Among differential activations, activation in the precuneus, which accompanied deactivation of the VMPFC, was specific to those without insight into human partners who were engaged in a tit-for-tat strategy. This asymmetric (deactivation might involve specific contributions of ToM regions to the human search for reciprocity. Consequently, the intensity of emotion attached to human reciprocity was represented in the amygdala, whereas insight into the reciprocity of others was reflected in activation across the reward-related and ToM regions. This suggests the critical role of mentalizing, which was not equated with reward expectation during

Neural network-based sensor signal accelerator.

Energy Technology Data Exchange (ETDEWEB)

Vogt, M. C.

2000-10-16

A strategy has been developed to computationally accelerate the response time of a generic electronic sensor. The strategy can be deployed as an algorithm in a control system or as a physical interface (on an embedded microcontroller) between a slower responding external sensor and a higher-speed control system. Optional code implementations are available to adjust algorithm performance when computational capability is limited. In one option, the actual sensor signal can be sampled at the slower rate with adaptive linear neural networks predicting the sensor's future output and interpolating intermediate synthetic output values. In another option, a synchronized collection of predictors sequentially controls the corresponding synthetic output voltage. Error is adaptively corrected in both options. The core strategy has been demonstrated with automotive oxygen sensor data. A prototype interface device is under construction. The response speed increase afforded by this strategy could greatly offset the cost of developing a replacement sensor with a faster physical response time.

SELECTING NEURAL NETWORK ARCHITECTURE FOR INVESTMENT PROFITABILITY PREDICTIONS

Directory of Open Access Journals (Sweden)

Marijana Zekić-Sušac

2012-07-01

Full Text Available After production and operations, finance and investments are one of the mostfrequent areas of neural network applications in business. The lack of standardizedparadigms that can determine the efficiency of certain NN architectures in a particularproblem domain is still present. The selection of NN architecture needs to take intoconsideration the type of the problem, the nature of the data in the model, as well as somestrategies based on result comparison. The paper describes previous research in that areaand suggests a forward strategy for selecting best NN algorithm and structure. Since thestrategy includes both parameter-based and variable-based testings, it can be used forselecting NN architectures as well as for extracting models. The backpropagation, radialbasis,modular, LVQ and probabilistic neural network algorithms were used on twoindependent sets: stock market and credit scoring data. The results show that neuralnetworks give better accuracy comparing to multiple regression and logistic regressionmodels. Since it is model-independant, the strategy can be used by researchers andprofessionals in other areas of application.

Differential neural network configuration during human path integration

Science.gov (United States)

Arnold, Aiden E. G. F; Burles, Ford; Bray, Signe; Levy, Richard M.; Iaria, Giuseppe

2014-01-01

Path integration is a fundamental skill for navigation in both humans and animals. Despite recent advances in unraveling the neural basis of path integration in animal models, relatively little is known about how path integration operates at a neural level in humans. Previous attempts to characterize the neural mechanisms used by humans to visually path integrate have suggested a central role of the hippocampus in allowing accurate performance, broadly resembling results from animal data. However, in recent years both the central role of the hippocampus and the perspective that animals and humans share similar neural mechanisms for path integration has come into question. The present study uses a data driven analysis to investigate the neural systems engaged during visual path integration in humans, allowing for an unbiased estimate of neural activity across the entire brain. Our results suggest that humans employ common task control, attention and spatial working memory systems across a frontoparietal network during path integration. However, individuals differed in how these systems are configured into functional networks. High performing individuals were found to more broadly express spatial working memory systems in prefrontal cortex, while low performing individuals engaged an allocentric memory system based primarily in the medial occipito-temporal region. These findings suggest that visual path integration in humans over short distances can operate through a spatial working memory system engaging primarily the prefrontal cortex and that the differential configuration of memory systems recruited by task control networks may help explain individual biases in spatial learning strategies. PMID:24808849

Application of an artificial neural network and morphing techniques in the redesign of dysplastic trochlea.

Science.gov (United States)

Cho, Kyung Jin; Müller, Jacobus H; Erasmus, Pieter J; DeJour, David; Scheffer, Cornie

2014-01-01

Segmentation and computer assisted design tools have the potential to test the validity of simulated surgical procedures, e.g., trochleoplasty. A repeatable measurement method for three dimensional femur models that enables quantification of knee parameters of the distal femur is presented. Fifteen healthy knees are analysed using the method to provide a training set for an artificial neural network. The aim is to use this artificial neural network for the prediction of parameter values that describe the shape of a normal trochlear groove geometry. This is achieved by feeding the artificial neural network with the unaffected parameters of a dysplastic knee. Four dysplastic knees (Type A through D) are virtually redesigned by way of morphing the groove geometries based on the suggested shape from the artificial neural network. Each of the four resulting shapes is analysed and compared to its initial dysplastic shape in terms of three anteroposterior dimensions: lateral, central and medial. For the four knees the trochlear depth is increased, the ventral trochlear prominence reduced and the sulcus angle corrected to within published normal ranges. The results show a lateral facet elevation inadequate, with a sulcus deepening or a depression trochleoplasty more beneficial to correct trochlear dysplasia.

The role of student surgical interest groups and surgical Olympiads in anatomical and surgical undergraduate training in Russia.

Science.gov (United States)

Dydykin, Sergey; Kapitonova, Marina

2015-01-01

Traditional department-based surgical interest groups in Russian medical schools are useful tools for student-based selection of specialty training. They also form a nucleus for initiating research activities among undergraduate students. In Russia, the Departments of Topographical Anatomy and Operative Surgery play an important role in initiating student-led research and providing learners with advanced, practical surgical skills. In tandem with department-led activities, student surgical interest groups prepare learners through surgical competitions, known as "Surgical Olympiads," which have been conducted in many Russian centers on a regular basis since 1988. Surgical Olympiads stimulate student interest in the development of surgical skills before graduation and encourage students to choose surgery as their postgraduate specialty. Many of the participants in these surgical Olympiads have become highly qualified specialists in general surgery, orthopedic surgery, neurosurgery, urology, gynecology, and emergency medicine. The present article emphasizes the role of student interest groups and surgical Olympiads in clinical anatomical and surgical undergraduate training in Russia. © 2015 American Association of Anatomists.

Thorascopic resection of an apical paraspinal schwannoma using the da Vinci surgical system.

Science.gov (United States)

Finley, David; Sherman, Jonathan H; Avila, Edward; Bilsky, Mark

2014-01-01

Posterior mediastinal neurogenic tumors have traditionally been resected via an open posterolateral thoracotomy. Video-assisted thorascopic surgery has emerged as an alternative technique allowing for improved morbidity with decreased blood loss, less postoperative pain, and a shorter recovery period, among others. The da Vinci surgical system, as first described for urologic procedures, has recently been reported for lung lobectomy. This technique provides the advantages of instrumentation with 6 degrees of freedom, stable operating arms, and improved visualization with the three-dimensional high-definition camera. We describe the technique for thorascopic resection of an apical paraspinal schwannoma of the T1 nerve root with the da Vinci surgical system. This technique used a specialized intraoperative neuromonitoring probe for free-running electromyography (EMG) and triggered EMG. We demonstrate successful resection of a posterior paraspinal schwannoma with the da Vinci surgical system while preserving neurologic function. The patient displayed stable intraoperative monitoring of the T1 nerve root and full intrinsic hand strength postoperatively. The technique described in this article introduces robotic system accuracy and precludes the need for an open thoracotomy. In addition, this approach demonstrates the ability of the da Vinci surgical system to safely dissect tumors from their neural attachments and is applicable to other such lesions of similar size and location. Georg Thieme Verlag KG Stuttgart · New York.

Finite-Time Stabilization and Adaptive Control of Memristor-Based Delayed Neural Networks.

Science.gov (United States)

Wang, Leimin; Shen, Yi; Zhang, Guodong

Finite-time stability problem has been a hot topic in control and system engineering. This paper deals with the finite-time stabilization issue of memristor-based delayed neural networks (MDNNs) via two control approaches. First, in order to realize the stabilization of MDNNs in finite time, a delayed state feedback controller is proposed. Then, a novel adaptive strategy is applied to the delayed controller, and finite-time stabilization of MDNNs can also be achieved by using the adaptive control law. Some easily verified algebraic criteria are derived to ensure the stabilization of MDNNs in finite time, and the estimation of the settling time functional is given. Moreover, several finite-time stability results as our special cases for both memristor-based neural networks (MNNs) without delays and neural networks are given. Finally, three examples are provided for the illustration of the theoretical results.Finite-time stability problem has been a hot topic in control and system engineering. This paper deals with the finite-time stabilization issue of memristor-based delayed neural networks (MDNNs) via two control approaches. First, in order to realize the stabilization of MDNNs in finite time, a delayed state feedback controller is proposed. Then, a novel adaptive strategy is applied to the delayed controller, and finite-time stabilization of MDNNs can also be achieved by using the adaptive control law. Some easily verified algebraic criteria are derived to ensure the stabilization of MDNNs in finite time, and the estimation of the settling time functional is given. Moreover, several finite-time stability results as our special cases for both memristor-based neural networks (MNNs) without delays and neural networks are given. Finally, three examples are provided for the illustration of the theoretical results.

In vitro differentiation of neural cells from human adipose tissue derived stromal cells.

Science.gov (United States)

Dave, Shruti D; Patel, Chetan N; Vanikar, Aruna V; Trivedi, Hargovind L

2018-01-01

Stem cells, including neural stem cells (NSCs), are endowed with self-renewal capability and hence hold great opportunity for the institution of replacement/protective therapy. We propose a method for in vitro generation of stromal cells from human adipose tissue and their differentiation into neural cells. Ten grams of donor adipose tissue was surgically resected from the abdominal wall of the human donor after the participants' informed consents. The resected adipose tissue was minced and incubated for 1 hour in the presence of an enzyme (collagenase-type I) at 37 0 C followed by its centrifugation. After centrifugation, the supernatant and pellets were separated and cultured in a medium for proliferation at 37 0 C with 5% CO2 for 9-10 days in separate tissue culture dishes for generation of mesenchymal stromal cells (MSC). At the end of the culture, MSC were harvested and analyzed. The harvested MSC were subjected for further culture for their differentiation into neural cells for 5-7 days using differentiation medium mainly comprising of neurobasal medium. At the end of the procedure, culture cells were isolated and studied for expression of transcriptional factor proteins: orthodenticle homolog-2 (OTX-2), beta-III-tubulin (β3-Tubulin), glial-fibrillary acid protein (GFAP) and synaptophysin-β2. In total, 50 neural cells-lines were generated. In vitro generated MSC differentiated neural cells' mean quantum was 5.4 ± 6.9 ml with the mean cell count being, 5.27 ± 2.65 × 10 3/ μl. All of them showed the presence of OTX-2, β3-Tubulin, GFAP, synaptophysin-β2. Neural cells can be differentiated in vitro from MSC safely and effectively. In vitro generated neural cells represent a potential therapy for recovery from spinal cord injuries and neurodegenerative disease.

Can SPECT change the surgical strategy in patients with primary hyperparathyroidism?

Energy Technology Data Exchange (ETDEWEB)

Iervolino, Leticia; Scalisse, Nilza Maria; Maeda, Sergio Setsuo, E-mail: leiervolino@hotmail.com [Discipline of Endocrinology, Department of Medicine, Faculdade de Medicina da Santa Casa de Sao Paulo (FMSCSP), Sao Paulo, SP (Brazil)

2012-06-15

Primary hyperparathyroidism (PHPT) is the most common cause of hypercalcaemia in outpatients. It is more common in females, after menopause, and the prevalence is 1 to 4:1000 in the general population. Patients with PHPT have abnormal regulation of PTH secretion, resulting in elevated serum calcium and inappropriately high or normal PTH in relation to the calcium value. Sporadic PTH-secreting adenoma alone accounts for 90% of cases of PHPT, while multiglandular hyperplasia is more common in familial hyperparathyroidism syndromes (5%) and parathyroid carcinomas represent less than 1% of cases. Only after making sure there is functional autonomy of one or more parathyroid glands, localization imaging tests should be performed to guide a possible surgical procedure. It is important to highlight that these tests have limitations and can yield false-positive and false-negative results. There are cases in which the parathyroid gland is difficult to be located, requiring a combination of imaging methods for pre-operative localization, such as {sup 99m}Tc-pertechnetate, SPECT, SPECT/CT, and US. We describe the case of a 50-year-old female patient diagnosed with PHPT, who underwent a surgical procedure without success, with maintenance of hypercalcaemia and hyperparathyroidism. In this case, the hyper functioning parathyroid was located in the retrotracheal region only after scintigraphy combined with SPECT/CT were used. (author)

Can SPECT change the surgical strategy in patients with primary hyperparathyroidism?

International Nuclear Information System (INIS)

Iervolino, Leticia; Scalisse, Nilza Maria; Maeda, Sergio Setsuo

2012-01-01

Primary hyperparathyroidism (PHPT) is the most common cause of hypercalcaemia in outpatients. It is more common in females, after menopause, and the prevalence is 1 to 4:1000 in the general population. Patients with PHPT have abnormal regulation of PTH secretion, resulting in elevated serum calcium and inappropriately high or normal PTH in relation to the calcium value. Sporadic PTH-secreting adenoma alone accounts for 90% of cases of PHPT, while multiglandular hyperplasia is more common in familial hyperparathyroidism syndromes (5%) and parathyroid carcinomas represent less than 1% of cases. Only after making sure there is functional autonomy of one or more parathyroid glands, localization imaging tests should be performed to guide a possible surgical procedure. It is important to highlight that these tests have limitations and can yield false-positive and false-negative results. There are cases in which the parathyroid gland is difficult to be located, requiring a combination of imaging methods for pre-operative localization, such as 99m Tc-pertechnetate, SPECT, SPECT/CT, and US. We describe the case of a 50-year-old female patient diagnosed with PHPT, who underwent a surgical procedure without success, with maintenance of hypercalcaemia and hyperparathyroidism. In this case, the hyper functioning parathyroid was located in the retrotracheal region only after scintigraphy combined with SPECT/CT were used. (author)

Controlled invasive mechanical ventilation strategies in obese patients undergoing surgery.

Science.gov (United States)

Maia, Lígia de Albuquerque; Silva, Pedro Leme; Pelosi, Paolo; Rocco, Patricia Rieken Macedo

2017-06-01

The obesity prevalence is increasing in surgical population. As the number of obese surgical patients increases, so does the demand for mechanical ventilation. Nevertheless, ventilatory strategies in this population are challenging, since obesity results in pathophysiological changes in respiratory function. Areas covered: We reviewed the impact of obesity on respiratory system and the effects of controlled invasive mechanical ventilation strategies in obese patients undergoing surgery. To date, there is no consensus regarding the optimal invasive mechanical ventilation strategy for obese surgical patients, and no evidence that possible intraoperative beneficial effects on oxygenation and mechanics translate into better postoperative pulmonary function or improved outcomes. Expert commentary: Before determining the ideal intraoperative ventilation strategy, it is important to analyze the pathophysiology and comorbidities of each obese patient. Protective ventilation with low tidal volume, driving pressure, energy, and mechanical power should be employed during surgery; however, further studies are required to clarify the most effective ventilation strategies, such as the optimal positive end-expiratory pressure and whether recruitment maneuvers minimize lung injury. In this context, an ongoing trial of intraoperative ventilation in obese patients (PROBESE) should help determine the mechanical ventilation strategy that best improves clinical outcome in patients with body mass index≥35kg/m 2 .

Surgical treatment of cavernous malformations involving medulla oblongata.

Science.gov (United States)

Zhang, Si; Lin, Sen; Hui, Xuhui; Li, Hao; You, Chao

2017-03-01

Surgical treatment of cavernous malformations (CMs) involving medulla oblongata is more difficult than the CMs in other sites because of the surrounding vital structures. However, the distinctive features and treatment strategies have not been well illustrated. Therefore, we enrolled a total of 19 patients underwent surgical treatment of CMs involving medulla oblongata in our hospital from August 2008 to August 2014. The clinical features, surgical management and clinical outcome of these patients were retrospectively analyzed, while our institutional surgical indications, approaches and microsurgical techniques were discussed. In our study, gross total resection was achieved in 17 patients and subtotal resection in 2. Two patients underwent emergency surgeries due to severe and progressive neurological deficits. The postoperative new-onset or worsened neurological deficits occurred in 6 patients. After a mean follow-up of 45.8±22.2months, the neurological status was improved in 10 patients and remained stable in 7. The mean modified Rankin Scale (mRS) was 2.58±1.26 preoperatively, 3.11±0.99 postoperatively and 1.84±1.42 at the recent follow-up, respectively. During the follow-up period, no rehemorrhage and recurrence occurred, and the residual lesions remained stable. We recommended surgical resection of symptomatic CMs involving medulla oblongata via optimal approaches, feasible entry zones and meticulous microsurgical techniques in attempting to achieve safe resection and favorable outcome. The clinical features, surgical indications, timing and microsurgical techniques of this special entity should be distinctive from the brainstem cavernous malformations in other sites. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evolvable synthetic neural system

Science.gov (United States)

Curtis, Steven A. (Inventor)

2009-01-01

An evolvable synthetic neural system includes an evolvable neural interface operably coupled to at least one neural basis function. Each neural basis function includes an evolvable neural interface operably coupled to a heuristic neural system to perform high-level functions and an autonomic neural system to perform low-level functions. In some embodiments, the evolvable synthetic neural system is operably coupled to one or more evolvable synthetic neural systems in a hierarchy.

Neural electrical activity and neural network growth.

Science.gov (United States)

Gafarov, F M

2018-05-01

The development of central and peripheral neural system depends in part on the emergence of the correct functional connectivity in its input and output pathways. Now it is generally accepted that molecular factors guide neurons to establish a primary scaffold that undergoes activity-dependent refinement for building a fully functional circuit. However, a number of experimental results obtained recently shows that the neuronal electrical activity plays an important role in the establishing of initial interneuronal connections. Nevertheless, these processes are rather difficult to study experimentally, due to the absence of theoretical description and quantitative parameters for estimation of the neuronal activity influence on growth in neural networks. In this work we propose a general framework for a theoretical description of the activity-dependent neural network growth. The theoretical description incorporates a closed-loop growth model in which the neural activity can affect neurite outgrowth, which in turn can affect neural activity. We carried out the detailed quantitative analysis of spatiotemporal activity patterns and studied the relationship between individual cells and the network as a whole to explore the relationship between developing connectivity and activity patterns. The model, developed in this work will allow us to develop new experimental techniques for studying and quantifying the influence of the neuronal activity on growth processes in neural networks and may lead to a novel techniques for constructing large-scale neural networks by self-organization. Copyright © 2018 Elsevier Ltd. All rights reserved.

Adaptive Control of Nonlinear Discrete-Time Systems by Using OS-ELM Neural Networks

Directory of Open Access Journals (Sweden)

Xiao-Li Li

2014-01-01

Full Text Available As a kind of novel feedforward neural network with single hidden layer, ELM (extreme learning machine neural networks are studied for the identification and control of nonlinear dynamic systems. The property of simple structure and fast convergence of ELM can be shown clearly. In this paper, we are interested in adaptive control of nonlinear dynamic plants by using OS-ELM (online sequential extreme learning machine neural networks. Based on data scope division, the problem that training process of ELM neural network is sensitive to the initial training data is also solved. According to the output range of the controlled plant, the data corresponding to this range will be used to initialize ELM. Furthermore, due to the drawback of conventional adaptive control, when the OS-ELM neural network is used for adaptive control of the system with jumping parameters, the topological structure of the neural network can be adjusted dynamically by using multiple model switching strategy, and an MMAC (multiple model adaptive control will be used to improve the control performance. Simulation results are included to complement the theoretical results.

Toward multi-area distributed network of implanted neural interrogators

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Powell, Marc P.; Hou, Xiaoxiao; Galligan, Craig; Ashe, Jeffrey; Borton, David A.

2017-08-01

As we aim to improve our understanding of the brain, it is critical that researchers have simultaneous multi-area, large-scale access to the brain. Information processing in the brain occurs through close and distant coupling of functional sub-domains, as opposed to within isolated single neurons. However, commercially available neural interfaces capable of sensing electrophysiology of single neurons, currently allow access to only a small, mm3 volume of cortical cells, are not scalable to recording from orders of magnitude more neurons, and leverage bulky, skull mounted hardware and cabling sensitive to relative movements of the skull and brain. In this work, we propose a system capable of recording from many individual distributed neural interrogator nodes, untethered from any external electronics. Using an array of epidural inductive coils to wirelessly power the implanted electronics, the system is intended to be agnostic to the surgical placement of any individual node. Here, we demonstrate the ability to transmit nearly 15mW of power with greater than 50% power transfer efficiency, benchtop testing of individual subcircuit system components showing successful digitization of neural signals, and wireless transmission currently supporting a data rate of 3.84Mbps. We leverage a software defined radio based RF receiver to demodulate the data which can be stored in memory for later retrieval. Finally, we introduce a packaging technology capable of isolating active electronics from the surrounding tissue while providing capability for electrical feed-through assemblies for external neural interfacing. We expect, based on the presented preliminary findings, that the system can be integrated into a platform technology for the study of the intricate interactions between cortical domains.

Two-phase strategy of neural control for planar reaching movements: II--relation to spatiotemporal characteristics of movement trajectory.

Science.gov (United States)

Rand, Miya K; Shimansky, Yury P

2013-09-01

In the companion paper utilizing a quantitative model of optimal motor coordination (Part I, Rand and Shimansky, in Exp Brain Res 225:55-73, 2013), we examined coordination between X and Y movement directions (XYC) during reaching movements performed under three prescribed speeds, two movement amplitudes, and two target sizes. The obtained results indicated that the central nervous system (CNS) utilizes a two-phase strategy, where the initial and the final phases correspond to lower and higher precision of information processing, respectively, for controlling goal-directed reach-type movements to optimize the total cost of task performance including the cost of neural computations. The present study investigates how two different well-known concepts used for describing movement performance relate to the concepts of optimal XYC and two-phase control strategy. First, it is examined to what extent XYC is equivalent to movement trajectory straightness. The data analysis results show that the variability, the movement trajectory's deviation from the straight line, increases with an increase in prescribed movement speed. In contrast, the dependence of XYC strength on movement speed is opposite (in total agreement with an assumption of task performance optimality), suggesting that XYC is a feature of much higher level of generality than trajectory straightness. Second, it is tested how well the ballistic and the corrective components described in the traditional concept of two-component model of movement performance match with the initial and the final phase of the two-phase control strategy, respectively. In fast reaching movements, the percentage of trials with secondary corrective submovement was smaller under larger-target shorter-distance conditions. In slower reaching movements, meaningful parsing was impossible due to massive fluctuations in the kinematic profile throughout the movement. Thus, the parsing points determined by the conventional submovement analysis

Advanced biomaterial strategies to transplant preformed micro-tissue engineered neural networks into the brain

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Harris, J. P.; Struzyna, L. A.; Murphy, P. L.; Adewole, D. O.; Kuo, E.; Cullen, D. K.

2016-02-01

Objective. Connectome disruption is a hallmark of many neurological diseases and trauma with no current strategies to restore lost long-distance axonal pathways in the brain. We are creating transplantable micro-tissue engineered neural networks (micro-TENNs), which are preformed constructs consisting of embedded neurons and long axonal tracts to integrate with the nervous system to physically reconstitute lost axonal pathways. Approach. We advanced micro-tissue engineering techniques to generate micro-TENNs consisting of discrete populations of mature primary cerebral cortical neurons spanned by long axonal fascicles encased in miniature hydrogel micro-columns. Further, we improved the biomaterial encasement scheme by adding a thin layer of low viscosity carboxymethylcellulose (CMC) to enable needle-less insertion and rapid softening for mechanical similarity with brain tissue. Main results. The engineered architecture of cortical micro-TENNs facilitated robust neuronal viability and axonal cytoarchitecture to at least 22 days in vitro. Micro-TENNs displayed discrete neuronal populations spanned by long axonal fasciculation throughout the core, thus mimicking the general systems-level anatomy of gray matter—white matter in the brain. Additionally, micro-columns with thin CMC-coating upon mild dehydration were able to withstand a force of 893 ± 457 mN before buckling, whereas a solid agarose cylinder of similar dimensions was predicted to withstand less than 150 μN of force. This thin CMC coating increased the stiffness by three orders of magnitude, enabling needle-less insertion into brain while significantly reducing the footprint of previous needle-based delivery methods to minimize insertion trauma. Significance. Our novel micro-TENNs are the first strategy designed for minimally invasive implantation to facilitate nervous system repair by simultaneously providing neuronal replacement and physical reconstruction of long-distance axon pathways in the brain

Surgical management of venous malformations.

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Loose, D A

2007-01-01

Among vascular malformations, the predominantly venous malformations represent the majority of cases. They form a clinical entity and therefore need clear concepts concerning diagnosis and treatment. This paper presents an overview of contemporary classification as well as tactics and techniques of treatment. According to the Hamburg Classification, predominantly venous malformations are categorized into truncular and extratruncular forms, with truncular forms distinguished as obstructions and dilations, and extratruncular forms as limited or infiltrating. The tactics of treatment represent surgical and non-surgical methods or combined techniques. Surgical approaches utilize different tactics and techniques that are adopted based on the pathologic form and type of the malformation: (I) operation to reduce the haemodynamic activity of the malformation; (II) operation to eliminate the malformation; and (III) reconstructive operation. As for (I), a type of a tactic is the operation to derive the venous flow. In (II), the total or partial removal of the venous malformation is demonstrated subdivided into three different techniques. In this way, the infiltrating as well as the limited forms can be treated. An additional technique is dedicated to the treatment of a marginal vein. Approach (III) involves the treatment of venous aneurysms, where a variety of techniques have been successful. Long-term follow-up demonstrates positive results in 91% of the cases. Congenital predominantly venous malformations should be treated according to the principles developed during the past decades in vascular surgery, interventional treatment and multidisciplinary treatment. The days of predominantly conservative treatment should be relegated to the past. Special skills and experiences are necessary to carry out appropriate surgical strategy, and the required operative techniques should be dictated by the location and type of malformation and associated findings.

Impact of Open Reduction on Surgical Strategies for Missed Monteggia Fracture in Children.

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Park, Hoon; Park, Kwang Won; Park, Kun Bo; Kim, Hyun Woo; Eom, Nam Kyu; Lee, Dong Hoon

2017-07-01

The aims of this study were to review our cases of missed Monteggia fracture treated by open reduction of the radial head with or without ulnar osteotomy and to investigate the indications for open reduction alone in surgical treatment of missed Monteggia fracture. We retrospectively reviewed 22 patients who presented with missed Monteggia fracture. The patients' mean age at the time of surgery was 7.6 years. The mean interval from injury to surgery was 16.1 months. The surgical procedure consisted of open reduction of the radiocapitellar joint followed by ulnar osteotomy without reconstruction of the annular ligament. The mean period of follow-up was 3.8 years. Radiographic assessment was performed for the maximum ulnar bow (MUB) and the location of the MUB. Clinical results were evaluated with the Mayo Elbow Performance Index and Kim's scores. Five patients underwent open reduction alone, and 17 patients underwent open reduction and ulnar osteotomy. When the MUB was less than 4 mm and the location of the MUB was in the distal 40% of the ulna, we could achieve reduction of the radial head without ulnar osteotomy. The radial head was maintained in a completely reduced position in 21 patients and was dislocated in one patient at final follow-up. Open reduction alone can be an attractive surgical option in select patients with missed Monteggia fracture with minimal bowing of the distal ulna. However, ulnar osteotomy should be considered in patients with a definite ulnar deformity. © Copyright: Yonsei University College of Medicine 2017

Isolation, characterization, and differentiation of multipotent neural progenitor cells from human cerebrospinal fluid in fetal cystic myelomeningocele

Directory of Open Access Journals (Sweden)

Mario Marotta

2017-07-01

Full Text Available Despite benefits of prenatal in utero repair of myelomeningocele, a severe type of spina bifida aperta, many of these patients will still suffer mild to severe impairment. One potential source of stem cells for new regenerative medicine-based therapeutic approaches for spinal cord injury repair is neural progenitor cells (NPCs in cerebrospinal fluid (CSF. To this aim, we extracted CSF from the cyst surrounding the exposed neural placode during the surgical repair of myelomeningocele in 6 fetuses (20 to 26 weeks of gestation. In primary cultured CSF-derived cells, neurogenic properties were confirmed by in vitro differentiation into various neural lineage cell types, and NPC markers expression (TBR2, CD15, SOX2 were detected by immunofluorescence and RT-PCR analysis. Differentiation into three neural lineages was corroborated by arbitrary differentiation (depletion of growths factors or explicit differentiation as neuronal, astrocyte, or oligodendrocyte cell types using specific induction mediums. Differentiated cells showed the specific expression of neural differentiation markers (βIII-tubulin, GFAP, CNPase, oligo-O1. In myelomeningocele patients, CSF-derived cells could become a potential source of NPCs with neurogenic capacity. Our findings support the development of innovative stem-cell-based therapeutics by autologous transplantation of CSF-derived NPCs in damaged spinal cords, such as myelomeningocele, thus promoting neural tissue regeneration in fetuses.

Wrong-Site Surgery, Retained Surgical Items, and Surgical Fires : A Systematic Review of Surgical Never Events.

Science.gov (United States)

Hempel, Susanne; Maggard-Gibbons, Melinda; Nguyen, David K; Dawes, Aaron J; Miake-Lye, Isomi; Beroes, Jessica M; Booth, Marika J; Miles, Jeremy N V; Shanman, Roberta; Shekelle, Paul G

2015-08-01

Serious, preventable surgical events, termed never events, continue to occur despite considerable patient safety efforts. To examine the incidence and root causes of and interventions to prevent wrong-site surgery, retained surgical items, and surgical fires in the era after the implementation of the Universal Protocol in 2004. We searched 9 electronic databases for entries from 2004 through June 30, 2014, screened references, and consulted experts. Two independent reviewers identified relevant publications in June 2014. One reviewer used a standardized form to extract data and a second reviewer checked the data. Strength of evidence was established by the review team. Data extraction was completed in January 2015. Incidence of wrong-site surgery, retained surgical items, and surgical fires. We found 138 empirical studies that met our inclusion criteria. Incidence estimates for wrong-site surgery in US settings varied by data source and procedure (median estimate, 0.09 events per 10,000 surgical procedures). The median estimate for retained surgical items was 1.32 events per 10,000 procedures, but estimates varied by item and procedure. The per-procedure surgical fire incidence is unknown. A frequently reported root cause was inadequate communication. Methodologic challenges associated with investigating changes in rare events limit the conclusions of 78 intervention evaluations. Limited evidence supported the Universal Protocol (5 studies), education (4 studies), and team training (4 studies) interventions to prevent wrong-site surgery. Limited evidence exists to prevent retained surgical items by using data-matrix-coded sponge-counting systems (5 pertinent studies). Evidence for preventing surgical fires was insufficient, and intervention effects were not estimable. Current estimates for wrong-site surgery and retained surgical items are 1 event per 100,000 and 1 event per 10,000 procedures, respectively, but the precision is uncertain, and the per

Fronto-orbital feminization technique. A surgical strategy using fronto-orbital burring with or without eggshell technique to optimize the risk/benefit ratio.

Science.gov (United States)

Villepelet, A; Jafari, A; Baujat, B

2018-05-04

The demand for facial feminization is increasing in transsexual patients. Masculine foreheads present extensive supraorbital bossing with a more acute glabellar angle, whereas female foreheads show softer features. The aim of this article is to describe our surgical technique for fronto-orbital feminization. The mask-lift technique is an upper face-lift. It provides rejuvenation by correcting collapsed features, and fronto-orbital feminization through burring of orbital rims and lateral canthopexies. Depending on the size of the frontal sinus and the thickness of its anterior wall, frontal remodeling is achieved using simple burring or by means of the eggshell technique. Orbital remodeling comprises a superolateral orbital opening, a reduction of ridges and a trough at the lateral orbital rim to support the lateral canthopexy. Frontal, corrugator and procerus myectomies, plus minimal scalp excision, complete the surgery. Our technique results in significant, natural-looking feminization. No complications were observed in our series of patients. The eggshell technique is an alternative to bone flap on over-pneumatized sinus. Fronto-orbital feminization fits into a wider surgical strategy. It can be associated to rhinoplasty, genioplasty, mandibular angle remodeling, face lift and laryngoplasty. Achieving facial feminization in 2 or 3 stages improves psychological and physiological tolerance. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

3D multi-view convolutional neural networks for lung nodule classification

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Kang, Guixia; Hou, Beibei; Zhang, Ningbo

2017-01-01

The 3D convolutional neural network (CNN) is able to make full use of the spatial 3D context information of lung nodules, and the multi-view strategy has been shown to be useful for improving the performance of 2D CNN in classifying lung nodules. In this paper, we explore the classification of lung nodules using the 3D multi-view convolutional neural networks (MV-CNN) with both chain architecture and directed acyclic graph architecture, including 3D Inception and 3D Inception-ResNet. All networks employ the multi-view-one-network strategy. We conduct a binary classification (benign and malignant) and a ternary classification (benign, primary malignant and metastatic malignant) on Computed Tomography (CT) images from Lung Image Database Consortium and Image Database Resource Initiative database (LIDC-IDRI). All results are obtained via 10-fold cross validation. As regards the MV-CNN with chain architecture, results show that the performance of 3D MV-CNN surpasses that of 2D MV-CNN by a significant margin. Finally, a 3D Inception network achieved an error rate of 4.59% for the binary classification and 7.70% for the ternary classification, both of which represent superior results for the corresponding task. We compare the multi-view-one-network strategy with the one-view-one-network strategy. The results reveal that the multi-view-one-network strategy can achieve a lower error rate than the one-view-one-network strategy. PMID:29145492

Two-phase strategy of neural control for planar reaching movements: I. XY coordination variability and its relation to end-point variability.

Science.gov (United States)

Rand, Miya K; Shimansky, Yury P

2013-03-01

A quantitative model of optimal transport-aperture coordination (TAC) during reach-to-grasp movements has been developed in our previous studies. The utilization of that model for data analysis allowed, for the first time, to examine the phase dependence of the precision demand specified by the CNS for neurocomputational information processing during an ongoing movement. It was shown that the CNS utilizes a two-phase strategy for movement control. That strategy consists of reducing the precision demand for neural computations during the initial phase, which decreases the cost of information processing at the expense of lower extent of control optimality. To successfully grasp the target object, the CNS increases precision demand during the final phase, resulting in higher extent of control optimality. In the present study, we generalized the model of optimal TAC to a model of optimal coordination between X and Y components of point-to-point planar movements (XYC). We investigated whether the CNS uses the two-phase control strategy for controlling those movements, and how the strategy parameters depend on the prescribed movement speed, movement amplitude and the size of the target area. The results indeed revealed a substantial similarity between the CNS's regulation of TAC and XYC. First, the variability of XYC within individual trials was minimal, meaning that execution noise during the movement was insignificant. Second, the inter-trial variability of XYC was considerable during the majority of the movement time, meaning that the precision demand for information processing was lowered, which is characteristic for the initial phase. That variability significantly decreased, indicating higher extent of control optimality, during the shorter final movement phase. The final phase was the longest (shortest) under the most (least) challenging combination of speed and accuracy requirements, fully consistent with the concept of the two-phase control strategy. This paper

SuperSpike: Supervised Learning in Multilayer Spiking Neural Networks.

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Zenke, Friedemann; Ganguli, Surya

2018-04-13

A vast majority of computation in the brain is performed by spiking neural networks. Despite the ubiquity of such spiking, we currently lack an understanding of how biological spiking neural circuits learn and compute in vivo, as well as how we can instantiate such capabilities in artificial spiking circuits in silico. Here we revisit the problem of supervised learning in temporally coding multilayer spiking neural networks. First, by using a surrogate gradient approach, we derive SuperSpike, a nonlinear voltage-based three-factor learning rule capable of training multilayer networks of deterministic integrate-and-fire neurons to perform nonlinear computations on spatiotemporal spike patterns. Second, inspired by recent results on feedback alignment, we compare the performance of our learning rule under different credit assignment strategies for propagating output errors to hidden units. Specifically, we test uniform, symmetric, and random feedback, finding that simpler tasks can be solved with any type of feedback, while more complex tasks require symmetric feedback. In summary, our results open the door to obtaining a better scientific understanding of learning and computation in spiking neural networks by advancing our ability to train them to solve nonlinear problems involving transformations between different spatiotemporal spike time patterns.

Surgical Instrument Sets for Special Operations Expeditionary Surgical Teams.

Science.gov (United States)

Hale, Diane F; Sexton, Justin C; Benavides, Linda C; Benavides, Jerry M; Lundy, Jonathan B

The deployment of surgical assets has been driven by mission demands throughout years of military operations in Iraq and Afghanistan. The transition to the highly expeditious Golden Hour Offset Surgical Transport Team (GHOST- T) now offers highly mobile surgical assets in nontraditional operating rooms; the content of the surgical instrument sets has also transformed to accommodate this change. The 102nd Forward Surgical Team (FST) was attached to Special Operations assigned to southern Afghanistan from June 2015 to March 2016. The focus was to decrease overall size and weight of FST instrument sets without decreasing surgical capability of the GHOST-T. Each instrument set was evaluated and modified to include essential instruments to perform damage control surgery. The overall number of main instrument sets was decreased from eight to four; simplified augmentation sets have been added, which expand the capabilities of any main set. The overall size was decreased by 40% and overall weight decreased by 58%. The cardiothoracic, thoracotomy, and emergency thoracotomy trays were condensed to thoracic set. The orthopedic and amputation sets were replaced with an augmentation set of a prepackaged orthopedic external fixator set). An augmentation set to the major or minor basic sets, specifically for vascular injuries, was created. Through the reorganization of conventional FST surgical instrument sets to maintain damage control capabilities and mobility, the 102nd GHOST-T reduced surgical equipment volume and weight, providing a lesson learned for future surgical teams operating in austere environments. 2017.

High Performance Implementation of 3D Convolutional Neural Networks on a GPU

Science.gov (United States)

Wang, Zelong; Wen, Mei; Zhang, Chunyuan; Wang, Yijie

2017-01-01

Convolutional neural networks have proven to be highly successful in applications such as image classification, object tracking, and many other tasks based on 2D inputs. Recently, researchers have started to apply convolutional neural networks to video classification, which constitutes a 3D input and requires far larger amounts of memory and much more computation. FFT based methods can reduce the amount of computation, but this generally comes at the cost of an increased memory requirement. On the other hand, the Winograd Minimal Filtering Algorithm (WMFA) can reduce the number of operations required and thus can speed up the computation, without increasing the required memory. This strategy was shown to be successful for 2D neural networks. We implement the algorithm for 3D convolutional neural networks and apply it to a popular 3D convolutional neural network which is used to classify videos and compare it to cuDNN. For our highly optimized implementation of the algorithm, we observe a twofold speedup for most of the 3D convolution layers of our test network compared to the cuDNN version. PMID:29250109

High Performance Implementation of 3D Convolutional Neural Networks on a GPU.

Science.gov (United States)

Lan, Qiang; Wang, Zelong; Wen, Mei; Zhang, Chunyuan; Wang, Yijie

2017-01-01

Convolutional neural networks have proven to be highly successful in applications such as image classification, object tracking, and many other tasks based on 2D inputs. Recently, researchers have started to apply convolutional neural networks to video classification, which constitutes a 3D input and requires far larger amounts of memory and much more computation. FFT based methods can reduce the amount of computation, but this generally comes at the cost of an increased memory requirement. On the other hand, the Winograd Minimal Filtering Algorithm (WMFA) can reduce the number of operations required and thus can speed up the computation, without increasing the required memory. This strategy was shown to be successful for 2D neural networks. We implement the algorithm for 3D convolutional neural networks and apply it to a popular 3D convolutional neural network which is used to classify videos and compare it to cuDNN. For our highly optimized implementation of the algorithm, we observe a twofold speedup for most of the 3D convolution layers of our test network compared to the cuDNN version.

[Principles of direct surgical procedures on the pancreas in surgical treatment of chronic pancreatitis].

Science.gov (United States)

Kopchak, V M; Khomiak, I V; Cheverdiuk, D A; Kopchak, K V; Duvalko, A V; Serdiuk, V P

2012-01-01

An analysis of treatment of 584 patients with complicated forms of chronic pancreatitis operated during 2000-2100 years was carried out. Quality of life of postoperative patients was estimated according to a technique of calculations of modules EORTC QLQ-C30 and EORTC QLQ-PAN26. The indicators of quality of life have improved by 19.7% in performance of saving duodenal outflow of operations of pancreatic juice. Change of the surgical strategy has led to decreased number of postoperative complications by 4.6% and to satisfactory long-term results in 92.6% of the patients.

Pediatric surgical diseases. A radiological surgical case study approach

International Nuclear Information System (INIS)

Esposito, Ciro; Esposito, Giovanni

2009-01-01

Radiologic evaluation of an infant or child suspected of having a surgical disease can be a complex problem. With this volume, the editors have created a book focused on pediatric imaging written by pediatricians, pediatric surgeons and pediatric radiologists. This book is a collection of over 200 case reports. The concept is a case study approach: The reader is given radiologic images (plain radiography, computed tomography, magnetic resonance imaging, ultrasonography, etc.) and the clinical history of the patient. On the basis of this information, the reader is asked to identify a diagnostic and therapeutic strategy. Each case is complemented by information on the disease affecting the patient and the management of the case shown, including therapy and follow-up. This educational text is targeted at all medical professionals faced with a variety of diagnostic and therapeutic problems affecting infants and children. (orig.)

Pediatric surgical diseases. A radiological surgical case study approach

Energy Technology Data Exchange (ETDEWEB)

Esposito, Ciro [Federico II Univ. of Naples (Italy). Chair of Pediatric Surgery; Esposito, Giovanni (eds.) [Federico II Univ. of Naples (Italy). School of Medicine

2009-07-01

Radiologic evaluation of an infant or child suspected of having a surgical disease can be a complex problem. With this volume, the editors have created a book focused on pediatric imaging written by pediatricians, pediatric surgeons and pediatric radiologists. This book is a collection of over 200 case reports. The concept is a case study approach: The reader is given radiologic images (plain radiography, computed tomography, magnetic resonance imaging, ultrasonography, etc.) and the clinical history of the patient. On the basis of this information, the reader is asked to identify a diagnostic and therapeutic strategy. Each case is complemented by information on the disease affecting the patient and the management of the case shown, including therapy and follow-up. This educational text is targeted at all medical professionals faced with a variety of diagnostic and therapeutic problems affecting infants and children. (orig.)

Bioelectrochemical control of neural cell development on conducting polymers.

Science.gov (United States)

Collazos-Castro, Jorge E; Polo, José L; Hernández-Labrado, Gabriel R; Padial-Cañete, Vanesa; García-Rama, Concepción

2010-12-01

Electrically conducting polymers hold promise for developing advanced neuroprostheses, bionic systems and neural repair devices. Among them, poly(3, 4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS) exhibits superior physicochemical properties but biocompatibility issues have limited its use. We describe combinations of electrochemical and molecule self-assembling methods to consistently control neural cell development on PEDOT:PSS while maintaining very low interfacial impedance. Electro-adsorbed polylysine enabled long-term neuronal survival and growth on the nanostructured polymer. Neurite extension was strongly inhibited by an additional layer of PSS or heparin, which in turn could be either removed electrically or further coated with spermine to activate cell growth. Binding basic fibroblast growth factor (bFGF) to the heparin layer inhibited neurons but promoted proliferation and migration of precursor cells. This methodology may orchestrate neural cell behavior on electroactive polymers, thus improving cell/electrode communication in prosthetic devices and providing a platform for tissue repair strategies. Copyright © 2010 Elsevier Ltd. All rights reserved.

Stephen L. Gans Distinguished Overseas Lecture. The neural crest in pediatric surgery.

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Tovar, Juan A

2007-06-01

This review highlights the relevance of the neural crest (NC) as a developmental control mechanism involved in several pediatric surgical conditions and the investigative interest of following some of its known signaling pathways. The participation of the NC in facial clefts, ear defects, branchial fistulae and cysts, heart outflow tract and aortic arch anomalies, pigmentary disorders, abnormal enteric innervation, neural tumors, hemangiomas, and vascular anomalies is briefly reviewed. Then, the literature on clinical and experimental esophageal atresia-tracheoesophageal fistula (EA-TEF) and congenital diaphragmatic hernia (CDH) is reviewed for the presence of associated NC defects. Finally, some of the molecular signaling pathways involved in both conditions (sonic hedgehog, Hox genes, and retinoids) are summarized. The association of facial, cardiovascular, thymic, parathyroid, and C-cell defects together with anomalies of extrinsic and intrinsic esophageal innervation in babies and/or animals with both EA-TEF and CDH strongly supports the hypothesis that NC is involved in the pathogenesis of these malformative clusters. On the other hand, both EA-TEF and CDH are observed in mice mutant for genes involved in the previously mentioned signaling pathways. The investigation of NC-related molecular pathogenic pathways involved in malformative associations like EA-TEF and CDH that are induced by chromosomal anomalies, chemical teratogens, and engineered mutations is a promising way of clarifying why and how some pediatric surgical conditions occur. Pediatric surgeons should be actively involved in these investigations.

Non-surgical care in patients with hip or knee osteoarthritis is modestly consistent with a stepped care strategy after its implementation.

Science.gov (United States)

Smink, Agnes J; Bierma-Zeinstra, Sita M A; Schers, Henk J; Swierstra, Bart A; Kortland, Joke H; Bijlsma, Johannes W J; Teerenstra, Steven; Voorn, Theo B; Dekker, Joost; Vliet Vlieland, Thea P M; van den Ende, Cornelia H M

2014-08-01

To improve the management of hip or knee osteoarthritis (OA), a stepped care strategy (SCS) has been developed that presents the optimal sequence for care in three steps. This study evaluates the extent to which clinical practice is consistent with the strategy after implementation and identifies determinants of SCS-consistent care. A 2-year observational prospective cohort study. General practices in the region of Nijmegen in the Netherlands. Three hundred and thirteen patients with hip or knee OA and their general practitioner (GP). Multifaceted interventions were developed to implement the strategy. Consistency between clinical practice and the strategy was examined regarding three aspects of care: (i) timing of radiological assessment, (ii) sequence of non-surgical treatment options and (iii) making follow-up appointments. Out of the 212 patients who reported to have had an X-ray, 92 (44%) received it in line with the SCS. The sequence of treatment was inconsistent with the SCS in 58% of the patients, which was mainly caused by the underuse of lifestyle advice and dietary therapy. In 57% of the consultations, the patient reported to have been advised to make a follow-up appointment. No determinants that influenced all three aspects of care were identified. Consistency with the SCS was found in about half of the patients for each of the three aspects of care. Health care can be further optimized by encouraging GP s to use X-rays more appropriately and to make more use of lifestyle advice, dietary therapy and follow-up appointments. © The Author 2014. Published by Oxford University Press in association with the International Society for Quality in Health Care; all rights reserved.

Modeling and Control of CSTR using Model based Neural Network Predictive Control

OpenAIRE

Shrivastava, Piyush

2012-01-01

This paper presents a predictive control strategy based on neural network model of the plant is applied to Continuous Stirred Tank Reactor (CSTR). This system is a highly nonlinear process; therefore, a nonlinear predictive method, e.g., neural network predictive control, can be a better match to govern the system dynamics. In the paper, the NN model and the way in which it can be used to predict the behavior of the CSTR process over a certain prediction horizon are described, and some commen...

[Surgical treatment of Marfan syndrome; analysis of the patients required multiple surgical interventions].

Science.gov (United States)

Yamazaki, F; Shimamoto, M; Fujita, S; Nakai, M; Aoyama, A; Chen, F; Nakata, T; Yamada, T

2002-07-01

Without treatment, the life expectancy of patients with Marfan syndrome is reduced by the associated cardiovascular abnormalities. In this study, we reviewed our experience of the patients with Marfan syndrome who required multiple surgical interventions to identify the optimal treatment for these patients. Between January 1986 and December 2000, 44 patients with Marfan syndrome were operated on at Shizuoka City Hospital (SCH). Among them, 10 patients (22.7%) underwent multiple surgical interventions. There were 5 male and 5 female patients with a mean age of 40.6 +/- 16.1 years at the initial surgery. Only one patient was operated on at another hospital for his first, second, and third operations. His fourth operation was carried out at SCH. The remaining 9 patients underwent a total of 14 additional surgical procedures at SCH. Computed tomography (CT) scans were taken every 6 months postoperatively, and aortic diameter greater than 60 mm was considered as the indication for the additional surgery. There were no early death and one late death. The causes of additional surgery were enlargement of true aneurysm in 6, enlargement of residual dissection in 4, new dissection in 4, false aneurysm at the coronary anastomosis of Bentall procedure in 1. In 9 patients, both ascending and descending aorta were replaced. Among these 9 patients, only 3 patients underwent total arch replacement, and remaining 6 patients had their arch left in place with or without dissection. Our current strategy of the treatment of Marfan patients with acute type A dissection is total arch replacement with an elephant trunk at the initial emergent surgery.

Surgeons' and surgical trainees' acute stress in real operations or simulation: A systematic review.

Science.gov (United States)

Georgiou, Konstantinos; Larentzakis, Andreas; Papavassiliou, Athanasios G

2017-12-01

Acute stress in surgery is ubiquitous and has an immediate impact on surgical performance and patient safety. Surgeons react with several coping strategies; however, they recognise the necessity of formal stress management training. Thus, stress assessment is a direct need. Surgical simulation is a validated standardised training milieu designed to replicate real-life situations. It replicates stress, prevents biases, and provides objective metrics. The complexity of stress mechanisms makes stress measurement difficult to quantify and interpret. This systematic review aims to identify studies that have used acute stress estimation measurements in surgeons or surgical trainees during real operations or surgical simulation, and to collectively present the rationale of these tools, with special emphasis in salivary markers. A search strategy was implemented to retrieve relevant articles from MEDLINE and SCOPUS databases. The 738 articles retrieved were reviewed for further evaluation according to the predetermined inclusion/exclusion criteria. Thirty-three studies were included in this systematic review. The methods for acute stress assessment varied greatly among studies with the non-invasive techniques being the most commonly used. Subjective and objective tests for surgeons' acute stress assessment are being presented. There is a broad spectrum of acute mental stress assessment tools in the surgical field and simulation and salivary biomarkers have recently gained popularity. There is a need to maintain a consistent methodology in future research, towards a deeper understanding of acute stress in the surgical field. Copyright © 2017 Royal College of Surgeons of Edinburgh (Scottish charity number SC005317) and Royal College of Surgeons in Ireland. Published by Elsevier Ltd. All rights reserved.

Identifying the nontechnical skills required of nurses in general surgical wards.

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Marshall, Dianne C; Finlayson, Mary P

2018-04-01

To identify the nontechnical skills (NTS) required of nurses in general surgical wards for safe and effective care. As the largest occupational group, nurses are in an ideal position to block the vulnerabilities of patient adverse events in a surgical ward. Previous studies in the surgical environment have identified the NTS required of nurses for safe care in operating rooms; however, these skills have not been identified for nurses in general surgical wards. A nonparticipant observational descriptive design was used. A purposive sample of 15 registered nurses was recruited from four surgical wards and observed for a full shift on a morning, afternoon or night shift. Nonparticipant observations were conducted using field notes to collect data. A coding frame was developed, and an inductive process was used to analyse the data. A taxonomy comprising seven NTS required of nurses in their roles in surgical ward teams emerged from the data analysis. They are communication, leadership and management, planning, decision-making, situation awareness, teamwork and patient advocacy. Patient care provided by general surgical nurses involved the seven identified key NTS. These particular NTS are an important component of safe nursing practice as they underpin the provision of safe and effective care for general surgical patients. Nurses block the trajectory of error by using NTS to address the vulnerabilities in the system that can lead to adverse patient events. Identifying general surgical nurses' NTS enables the development of teaching strategies that target the learning of those skills to achieve successful work outcomes and improve patient safety. © 2018 John Wiley & Sons Ltd.

Treatment Strategies in Childhood Craniopharyngioma

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Stephanie ePuget

2012-06-01

Full Text Available The surgical management of craniopharyngioma in children has been one of the most controversial topics in pediatric neurosurgery. In theory, based on its benign histology total surgical excision could provide a cure. However, the therapeutic goals for pediatric craniopharyngioma are not only the cure of the disease but also the preservation of function. It has been widely established that in some particular cases total excision could leads to inacceptable damages, especially those linked to hypothalamic functions. During the last 15 years, we observed worldwide a growing advocacy for less-invasive pediatric craniopharyngioma resection supported by international consensus conferences. The state-of-the-art in the surgical management of some craniopharyngioma is now turning to multi-modality treatment strategies (combination surgery and radiotherapy aiming to limit morbidiy. Recent literature and our own experience helped to develop risk-adapted treatment strategies at initial diagnosis, respecting hypothalamic structures to provide optimal quality of life for these children. Following new algorithms of treatment, preliminary results with intention to spare the hypothalamus seem to be encouraging but the long-term clinical outcome in terms of post irradiation complications and relapse management is currently unknown.

Morphological neural networks

Energy Technology Data Exchange (ETDEWEB)

Ritter, G.X.; Sussner, P. [Univ. of Florida, Gainesville, FL (United States)

1996-12-31

The theory of artificial neural networks has been successfully applied to a wide variety of pattern recognition problems. In this theory, the first step in computing the next state of a neuron or in performing the next layer neural network computation involves the linear operation of multiplying neural values by their synaptic strengths and adding the results. Thresholding usually follows the linear operation in order to provide for nonlinearity of the network. In this paper we introduce a novel class of neural networks, called morphological neural networks, in which the operations of multiplication and addition are replaced by addition and maximum (or minimum), respectively. By taking the maximum (or minimum) of sums instead of the sum of products, morphological network computation is nonlinear before thresholding. As a consequence, the properties of morphological neural networks are drastically different than those of traditional neural network models. In this paper we consider some of these differences and provide some particular examples of morphological neural network.

Surgical Site Infections and Associated Operative Characteristics.

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Waltz, Paul K; Zuckerbraun, Brian S

Surgical site infection (SSI) contributes significantly to surgical morbidity. Patient factors and operative factors contribute to the risk of development of SSI. This review focuses on understanding operative characteristics that are associated with an increased risk of SSI. Much attention has been given to protocol care to reduce SSI, such as hair removal, skin preparation, and pre-operative antibiotic agents. Even with this, the appropriate antibiotic and re-dosing regimens often remain a challenge. Other operative factors such as blood loss/transfusion, emergency/urgent cases, duration of the operation, type of anesthesia, and resident involvement are also potentially modifiable to reduce the risk of SSI. Data are reviewed to highlight the increased risk associated with such factors. Strategies to reduce risk, such as operative care bundles, have significant promise to reduce the incidence of SSI for any given procedure.

Non-Viral Generation of Neural Precursor-like Cells from Adult Human Fibroblasts

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Maucksch C

2012-01-01

Full Text Available Recent studies have reported direct reprogramming of human fibroblasts to mature neurons by the introduction of defined neural genes. This technology has potential use in the areas of neurological disease modeling and drug development. However, use of induced neurons for large-scale drug screening and cell-based replacement strategies is limited due to their inability to expand once reprogrammed. We propose it would be more desirable to induce expandable neural precursor cells directly from human fibroblasts. To date several pluripotent and neural transcription factors have been shown to be capable of converting mouse fibroblasts to neural stem/precursor-like cells when delivered by viral vectors. Here we extend these findings and demonstrate that transient ectopic insertion of the transcription factors SOX2 and PAX6 to adult human fibroblasts through use of non-viral plasmid transfection or protein transduction allows the generation of induced neural precursor (iNP colonies expressing a range of neural stem and pro-neural genes. Upon differentiation, iNP cells give rise to neurons exhibiting typical neuronal morphologies and expressing multiple neuronal markers including tyrosine hydroxylase and GAD65/67. Importantly, iNP-derived neurons demonstrate electrophysiological properties of functionally mature neurons with the capacity to generate action potentials. In addition, iNP cells are capable of differentiating into glial fibrillary acidic protein (GFAP-expressing astrocytes. This study represents a novel virus-free approach for direct reprogramming of human fibroblasts to a neural precursor fate.

RM-SORN: a reward-modulated self-organizing recurrent neural network.

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Aswolinskiy, Witali; Pipa, Gordon

2015-01-01

Neural plasticity plays an important role in learning and memory. Reward-modulation of plasticity offers an explanation for the ability of the brain to adapt its neural activity to achieve a rewarded goal. Here, we define a neural network model that learns through the interaction of Intrinsic Plasticity (IP) and reward-modulated Spike-Timing-Dependent Plasticity (STDP). IP enables the network to explore possible output sequences and STDP, modulated by reward, reinforces the creation of the rewarded output sequences. The model is tested on tasks for prediction, recall, non-linear computation, pattern recognition, and sequence generation. It achieves performance comparable to networks trained with supervised learning, while using simple, biologically motivated plasticity rules, and rewarding strategies. The results confirm the importance of investigating the interaction of several plasticity rules in the context of reward-modulated learning and whether reward-modulated self-organization can explain the amazing capabilities of the brain.

A cross-sectional survey of essential surgical capacity in Somalia.

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Elkheir, Natalie; Sharma, Akshay; Cherian, Meena; Saleh, Omar Abdelrahman; Everard, Marthe; Popal, Ghulam Rabani; Ibrahim, Abdi Awad

2014-05-07

To assess life-saving and disability-preventing surgical services (including emergency, trauma, obstetrics, anaesthesia) of health facilities in Somalia and to assist in the planning of strategies for strengthening surgical care systems. Cross-sectional survey. Health facilities in all 3 administrative zones of Somalia; northwest Somalia (NWS), known as Somaliland; northeast Somalia (NES), known as Puntland; and south/central Somalia (SCS). 14 health facilities. The WHO Tool for Situational Analysis to Assess Emergency and Essential Surgical Care was employed to capture a health facility's capacity to deliver surgical and anaesthesia services by investigating four categories of data: infrastructure, human resources, interventions available and equipment. The 14 facilities surveyed in Somalia represent 10 of the 18 districts throughout the country. The facilities serve an average patient population of 331 250 people, and 12 of the 14 identify as hospitals. While major surgical procedures were provided at many facilities (caesarean section, laparotomy, appendicectomy, etc), only 22% had fully available oxygen access, 50% fully available electricity and less than 30% had any management guidelines for emergency and surgical care. Furthermore, only 36% were able to provide general anaesthesia inhalation due to lack of skills, supplies and equipment. Basic supplies for airway management and the prevention of infection transmission were severely lacking in most facilities. According to the results of the WHO Tool for Situational Analysis to Assess Emergency and Essential Surgical Care survey, there exist significant gaps in the capacity of emergency and essential surgical services in Somalia including inadequacies in essential equipment, service provision and infrastructure. The information provided by the WHO tool can serve as a basis for evidence-based decisions on country-level policy regarding the allocation of resources and provision of emergency and essential

Neural Networks

International Nuclear Information System (INIS)

Smith, Patrick I.

2003-01-01

Physicists use large detectors to measure particles created in high-energy collisions at particle accelerators. These detectors typically produce signals indicating either where ionization occurs along the path of the particle, or where energy is deposited by the particle. The data produced by these signals is fed into pattern recognition programs to try to identify what particles were produced, and to measure the energy and direction of these particles. Ideally, there are many techniques used in this pattern recognition software. One technique, neural networks, is particularly suitable for identifying what type of particle caused by a set of energy deposits. Neural networks can derive meaning from complicated or imprecise data, extract patterns, and detect trends that are too complex to be noticed by either humans or other computer related processes. To assist in the advancement of this technology, Physicists use a tool kit to experiment with several neural network techniques. The goal of this research is interface a neural network tool kit into Java Analysis Studio (JAS3), an application that allows data to be analyzed from any experiment. As the final result, a physicist will have the ability to train, test, and implement a neural network with the desired output while using JAS3 to analyze the results or output. Before an implementation of a neural network can take place, a firm understanding of what a neural network is and how it works is beneficial. A neural network is an artificial representation of the human brain that tries to simulate the learning process [5]. It is also important to think of the word artificial in that definition as computer programs that use calculations during the learning process. In short, a neural network learns by representative examples. Perhaps the easiest way to describe the way neural networks learn is to explain how the human brain functions. The human brain contains billions of neural cells that are responsible for processing

[Gastrointestinal bleeding--concepts of surgical therapy in the upper gastrointestinal tract].

Science.gov (United States)

Knoefel, W T; Rehders, A

2006-02-01

Bleeding of the upper gastrointestinal tract is the main symptom of a variety of possible conditions and still results in considerable mortality. Endoscopy is the first diagnostic modality, enabling rapid therapeutic intervention. In case of intractable or relapsing bleeding, surgery is often inevitable. However, emergency operations result in significantly higher mortality rates. Therefore the option of early elective surgical intervention should be considered for patients at increased risk of relapsing bleeding. If bleeding is symptomatic due to a complex underlying condition such as hemosuccus pancreaticus or hemobilia, angiography is now recognized as the definitive investigation. Angiographic hemostasis can be achieved in most cases. Due to the underlying condition, surgical management still remains the mainstay in treating these patients. This paper reviews surgical strategy in handling upper gastrointestinal bleeding.

Adaptive control using a hybrid-neural model: application to a polymerisation reactor

Directory of Open Access Journals (Sweden)

Cubillos F.

2001-01-01

Full Text Available This work presents the use of a hybrid-neural model for predictive control of a plug flow polymerisation reactor. The hybrid-neural model (HNM is based on fundamental conservation laws associated with a neural network (NN used to model the uncertain parameters. By simulations, the performance of this approach was studied for a peroxide-initiated styrene tubular reactor. The HNM was synthesised for a CSTR reactor with a radial basis function neural net (RBFN used to estimate the reaction rates recursively. The adaptive HNM was incorporated in two model predictive control strategies, a direct synthesis scheme and an optimum steady state scheme. Tests for servo and regulator control showed excellent behaviour following different setpoint variations, and rejecting perturbations. The good generalisation and training capacities of hybrid models, associated with the simplicity and robustness characteristics of the MPC formulations, make an attractive combination for the control of a polymerisation reactor.

Upper Limb Immobilisation: A Neural Plasticity Model with Relevance to Poststroke Motor Rehabilitation

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Leonardo Furlan

2016-01-01

Full Text Available Advances in our understanding of the neural plasticity that occurs after hemiparetic stroke have contributed to the formulation of theories of poststroke motor recovery. These theories, in turn, have underpinned contemporary motor rehabilitation strategies for treating motor deficits after stroke, such as upper limb hemiparesis. However, a relative drawback has been that, in general, these strategies are most compatible with the recovery profiles of relatively high-functioning stroke survivors and therefore do not easily translate into benefit to those individuals sustaining low-functioning upper limb hemiparesis, who otherwise have poorer residual function. For these individuals, alternative motor rehabilitation strategies are currently needed. In this paper, we will review upper limb immobilisation studies that have been conducted with healthy adult humans and animals. Then, we will discuss how the findings from these studies could inspire the creation of a neural plasticity model that is likely to be of particular relevance to the context of motor rehabilitation after stroke. For instance, as will be elaborated, such model could contribute to the development of alternative motor rehabilitation strategies for treating poststroke upper limb hemiparesis. The implications of the findings from those immobilisation studies for contemporary motor rehabilitation strategies will also be discussed and perspectives for future research in this arena will be provided as well.

Neural Based Orthogonal Data Fitting The EXIN Neural Networks

CERN Document Server

Cirrincione, Giansalvo

2008-01-01

Written by three leaders in the field of neural based algorithms, Neural Based Orthogonal Data Fitting proposes several neural networks, all endowed with a complete theory which not only explains their behavior, but also compares them with the existing neural and traditional algorithms. The algorithms are studied from different points of view, including: as a differential geometry problem, as a dynamic problem, as a stochastic problem, and as a numerical problem. All algorithms have also been analyzed on real time problems (large dimensional data matrices) and have shown accurate solutions. Wh

Artificial neural network approach to predict surgical site infection after free-flap reconstruction in patients receiving surgery for head and neck cancer.

Science.gov (United States)

Kuo, Pao-Jen; Wu, Shao-Chun; Chien, Peng-Chen; Chang, Shu-Shya; Rau, Cheng-Shyuan; Tai, Hsueh-Ling; Peng, Shu-Hui; Lin, Yi-Chun; Chen, Yi-Chun; Hsieh, Hsiao-Yun; Hsieh, Ching-Hua

2018-03-02

The aim of this study was to develop an effective surgical site infection (SSI) prediction model in patients receiving free-flap reconstruction after surgery for head and neck cancer using artificial neural network (ANN), and to compare its predictive power with that of conventional logistic regression (LR). There were 1,836 patients with 1,854 free-flap reconstructions and 438 postoperative SSIs in the dataset for analysis. They were randomly assigned tin ratio of 7:3 into a training set and a test set. Based on comprehensive characteristics of patients and diseases in the absence or presence of operative data, prediction of SSI was performed at two time points (pre-operatively and post-operatively) with a feed-forward ANN and the LR models. In addition to the calculated accuracy, sensitivity, and specificity, the predictive performance of ANN and LR were assessed based on area under the curve (AUC) measures of receiver operator characteristic curves and Brier score. ANN had a significantly higher AUC (0.892) of post-operative prediction and AUC (0.808) of pre-operative prediction than LR (both P <0.0001). In addition, there was significant higher AUC of post-operative prediction than pre-operative prediction by ANN (p<0.0001). With the highest AUC and the lowest Brier score (0.090), the post-operative prediction by ANN had the highest overall predictive performance. The post-operative prediction by ANN had the highest overall performance in predicting SSI after free-flap reconstruction in patients receiving surgery for head and neck cancer.

Comparing Pre- and Post-Operative Fontan Hemodynamic Simulations: Implications for the Reliability of Surgical Planning

Science.gov (United States)

Haggerty, Christopher M.; de Zélicourt, Diane A.; Restrepo, Maria; Rossignac, Jarek; Spray, Thomas L.; Kanter, Kirk R.; Fogel, Mark A.; Yoganathan, Ajit P.

2012-01-01

Background Virtual modeling of cardiothoracic surgery is a new paradigm that allows for systematic exploration of various operative strategies and uses engineering principles to predict the optimal patient-specific plan. This study investigates the predictive accuracy of such methods for the surgical palliation of single ventricle heart defects. Methods Computational fluid dynamics (CFD)-based surgical planning was used to model the Fontan procedure for four patients prior to surgery. The objective for each was to identify the operative strategy that best distributed hepatic blood flow to the pulmonary arteries. Post-operative magnetic resonance data were acquired to compare (via CFD) the post-operative hemodynamics with predictions. Results Despite variations in physiologic boundary conditions (e.g., cardiac output, venous flows) and the exact geometry of the surgical baffle, sufficient agreement was observed with respect to hepatic flow distribution (90% confidence interval-14 ± 4.3% difference). There was also good agreement of flow-normalized energetic efficiency predictions (19 ± 4.8% error). Conclusions The hemodynamic outcomes of prospective patient-specific surgical planning of the Fontan procedure are described for the first time with good quantitative comparisons between preoperatively predicted and postoperative simulations. These results demonstrate that surgical planning can be a useful tool for single ventricle cardiothoracic surgery with the ability to deliver significant clinical impact. PMID:22777126

Artificial neural networks for control of a grid-connected rectifier/inverter under disturbance, dynamic and power converter switching conditions.

Science.gov (United States)

Li, Shuhui; Fairbank, Michael; Johnson, Cameron; Wunsch, Donald C; Alonso, Eduardo; Proaño, Julio L

2014-04-01

Three-phase grid-connected converters are widely used in renewable and electric power system applications. Traditionally, grid-connected converters are controlled with standard decoupled d-q vector control mechanisms. However, recent studies indicate that such mechanisms show limitations in their applicability to dynamic systems. This paper investigates how to mitigate such restrictions using a neural network to control a grid-connected rectifier/inverter. The neural network implements a dynamic programming algorithm and is trained by using back-propagation through time. To enhance performance and stability under disturbance, additional strategies are adopted, including the use of integrals of error signals to the network inputs and the introduction of grid disturbance voltage to the outputs of a well-trained network. The performance of the neural-network controller is studied under typical vector control conditions and compared against conventional vector control methods, which demonstrates that the neural vector control strategy proposed in this paper is effective. Even in dynamic and power converter switching environments, the neural vector controller shows strong ability to trace rapidly changing reference commands, tolerate system disturbances, and satisfy control requirements for a faulted power system.

Expression of neuronal antigens and related ventral and dorsal proteins in the normal spinal cord and a surgically induced open neural tube defect of the spine in chick embryos: an immunohistochemical study.

Science.gov (United States)

Lee, Do-Hun; Phi, Ji Hoon; Chung, You-Nam; Lee, Yun-Jin; Kim, Seung-Ki; Cho, Byung-Kyu; Kim, Dong Won; Park, Moon-Sik; Wang, Kyu-Chang

2010-05-01

The aims of this study were to elucidate the processes of neuronal differentiation and ventrodorsal patterning in the spinal cord of the chick embryo from embryonic day (E) 3 to E17 and to study the effect of a prenatal spinal open neural tube defect (ONTD) on these processes. Expression patterns of neuronal antigens (neuronal nuclear antigen, neurofilament-associated protein (NAP), and synaptophysin) and related ventral markers [sonic hedgehog, paired box gene (PAX)6, and islet-1], and dorsal markers (bone morphogenetic protein, Notch homolog 1, and PAX7) were investigated in the normal spinal cord and in a surgically induced spinal ONTD in chick embryos. Four normal and ONTD chick embryos were used for each antigen group. There were no differences in the expression of neuronal and ventrodorsal markers between the control and ONTD groups. NAP and synaptophysin were useful for identifying dorsal structures in the distorted anatomy of the ONTD chicks.

Micro-surgical endodontics.

Science.gov (United States)

Eliyas, S; Vere, J; Ali, Z; Harris, I

2014-02-01

Non-surgical endodontic retreatment is the treatment of choice for endodontically treated teeth with recurrent or residual disease in the majority of cases. In some cases, surgical endodontic treatment is indicated. Successful micro-surgical endodontic treatment depends on the accuracy of diagnosis, appropriate case selection, the quality of the surgical skills, and the application of the most appropriate haemostatic agents and biomaterials. This article describes the armamentarium and technical procedures involved in performing micro-surgical endodontics to a high standard.

Adult-Brain-Derived Neural Stem Cells Grafting into a Vein Bridge Increases Postlesional Recovery and Regeneration in a Peripheral Nerve of Adult Pig

Directory of Open Access Journals (Sweden)

Olivier Liard

2012-01-01

Full Text Available We attempted transplantation of adult neural stem cells (ANSCs inside an autologous venous graft following surgical transsection of nervis cruralis with 30 mm long gap in adult pig. The transplanted cell suspension was a primary culture of neurospheres from adult pig subventricular zone (SVZ which had been labeled in vitro with BrdU or lentivirally transferred fluorescent protein. Lesion-induced loss of leg extension on the thigh became definitive in controls but was reversed by 45–90 days after neurosphere-filled vein grafting. Electromyography showed stimulodetection recovery in neurosphere-transplanted pigs but not in controls. Postmortem immunohistochemistry revealed neurosphere-derived cells that survived inside the venous graft from 10 to 240 post-lesion days and all displayed a neuronal phenotype. Newly formed neurons were distributed inside the venous graft along the severed nerve longitudinal axis. Moreover, ANSC transplantation increased CNPase expression, indicating activation of intrinsic Schwann cells. Thus ANSC transplantation inside an autologous venous graft provides an efficient repair strategy.

Artificial neural net system for interactive tissue classification with MR imaging and image segmentation

International Nuclear Information System (INIS)

Clarke, L.P.; Silbiger, M.; Naylor, C.; Brown, K.

1990-01-01

This paper reports on the development of interactive methods for MR tissue classification that permit mathematically rigorous methods for three-dimensional image segmentation and automatic organ/tumor contouring, as required for surgical and RTP planning. The authors investigate a number of image-intensity based tissue- classification methods that make no implicit assumptions on the MR parameters and hence are not limited by image data set. Similarly, we have trained artificial neural net (ANN) systems for both supervised and unsupervised tissue classification

Improvisation versus guideline concordance in surgical antibiotic prophylaxis: a qualitative study.

Science.gov (United States)

Broom, Jennifer; Broom, Alex; Kirby, Emma; Post, Jeffrey J

2018-05-28

Surgical antibiotic prophylaxis (SAP) is a common area of antimicrobial misuse. The aim of this study was to explore the social dynamics that influence the use of SAP. 20 surgeons and anaesthetists from a tertiary referral hospital in Australia participated in semi-structured interviews focusing on experiences and perspectives on SAP prescribing. Interview data were analysed using the framework approach. Systematic analysis of the participants' account of the social factors influencing SAP revealed four themes. First, antibiotic prophylaxis is treated as a low priority with the competing demands of the operating theatre environment. Second, whilst guidelines have increased in prominence in recent years, there exists a lack of confidence in their ability to protect the surgeon from responsibility for infectious complications (thus driving SAP over-prescribing). Third, non-concordance prolonged duration of SAP is perceived to be driven by benevolence for the individual patient. Finally, improvisation with novel SAP strategies is reported as ubiquitous, and acknowledged to confer a sense of reassurance to the surgeon despite potential non-concordance with guidelines or clinical efficacy. Surgical-specific concerns have thus far not been meaningfully integrated into antimicrobial stewardship (AMS) programmes, including important dynamics of confidence, trust and mitigating fear of adverse infective events. Surgeons require specific forms of AMS support to enact optimisation, including support for strong collaborative ownership of the surgical risk of infection, and intra-specialty (within surgical specialties) and inter-specialty (between surgery, anaesthetics and infectious diseases) intervention strategies to establish endorsement of and address barriers to guideline implementation.

Surgical management for early-stage bilateral breast cancer patients in China.

Directory of Open Access Journals (Sweden)

Jia-jian Chen

Full Text Available The aim of this study was to investigate the current surgical management strategy for bilateral breast cancer (BBC patients and to assess the changes in this strategy in China.This is a retrospective review of all patients with early-stage BBC who underwent surgical treatment at the Fudan University Shanghai Cancer Center between June 2007 and June 2014.A total of 15,337 patients with primary breast cancer were identified. Of these patients, 218 (1.5% suffered from synchronous bilateral breast cancer (sBBC, and 296 (2.0% suffered from metachronous bilateral breast cancer (mBBC. Patients with a lobular carcinoma component, those with estrogen receptor-positive cancer, and those with an accompanying sclerosing adenosis in the affected breast tended to develop BBC. The rates of bilateral mastectomy, breast conserving therapy, reconstruction, and combined surgeries were 86.2%, 6.4%, 3.7%, and 3.7%, respectively, for patients with sBBC and 81.1%, 4.4%, 3.0%, and 11.5%, respectively, for patients with mBBC. The interval between bilateral cancers, age at first diagnosis of breast cancer, histopathological type, and stage have significant impacts on the choice of surgery for patients with BBC.Bilateral mastectomy was the dominant surgical management for patients with BBC in China, despite the increased application of breast reconstruction surgery observed in recent years. Bilateral prosthetic breast reconstruction was the ideal choice for patients with sBBC. Chinese surgeons should take responsibility for patient education and inform their patients about their surgical options.

The differentiation of embryonic stem cells seeded on electrospun nanofibers into neural lineages.

Science.gov (United States)

Xie, Jingwei; Willerth, Stephanie M; Li, Xiaoran; Macewan, Matthew R; Rader, Allison; Sakiyama-Elbert, Shelly E; Xia, Younan

2009-01-01

Due to advances in stem cell biology, embryonic stem (ES) cells can be induced to differentiate into a particular mature cell lineage when cultured as embryoid bodies. Although transplantation of ES cells-derived neural progenitor cells has been demonstrated with some success for either spinal cord injury repair in small animal model, control of ES cell differentiation into complex, viable, higher ordered tissues is still challenging. Mouse ES cells have been induced to become neural progenitors by adding retinoic acid to embryoid body cultures for 4 days. In this study, we examine the use of electrospun biodegradable polymers as scaffolds not only for enhancing the differentiation of mouse ES cells into neural lineages but also for promoting and guiding the neurite outgrowth. A combination of electrospun fiber scaffolds and ES cells-derived neural progenitor cells could lead to the development of a better strategy for nerve injury repair.

Quasi-projective synchronization of fractional-order complex-valued recurrent neural networks.

Science.gov (United States)

Yang, Shuai; Yu, Juan; Hu, Cheng; Jiang, Haijun

2018-08-01

In this paper, without separating the complex-valued neural networks into two real-valued systems, the quasi-projective synchronization of fractional-order complex-valued neural networks is investigated. First, two new fractional-order inequalities are established by using the theory of complex functions, Laplace transform and Mittag-Leffler functions, which generalize traditional inequalities with the first-order derivative in the real domain. Additionally, different from hybrid control schemes given in the previous work concerning the projective synchronization, a simple and linear control strategy is designed in this paper and several criteria are derived to ensure quasi-projective synchronization of the complex-valued neural networks with fractional-order based on the established fractional-order inequalities and the theory of complex functions. Moreover, the error bounds of quasi-projective synchronization are estimated. Especially, some conditions are also presented for the Mittag-Leffler synchronization of the addressed neural networks. Finally, some numerical examples with simulations are provided to show the effectiveness of the derived theoretical results. Copyright © 2018 Elsevier Ltd. All rights reserved.

Peroral endoscopic myotomy is a viable option for failed surgical esophagocardiomyotomy instead of redo surgical Heller myotomy: a single center prospective study.

Science.gov (United States)

Onimaru, Manabu; Inoue, Haruhiro; Ikeda, Haruo; Yoshida, Akira; Santi, Esperanza Grace; Sato, Hiroki; Ito, Hiroaki; Maselli, Roberta; Kudo, Shin-ei

2013-10-01

Surgical Heller myotomy has high rates of successful long-term results, but failed cases still remain. Moreover, the treatment strategy in patients with surgical myotomy failure is controversial. Recently, peroral endscopic myotomy (POEM) was reported to be efficient and safe in primary treatment of achalasia. In this study, we aimed to evaluate the efficacy and safety of POEM for surgical myotomy failure as a rescue second-line treatment, and we discuss the treatment options adapted in achalasia recurrence. A total of 315 consecutive achalasia patients received POEM from September 2008 to December 2012 in our hospital. Eleven (3.5%) patients who had persistent or recurrent achalasia and had received surgical myotomy as a first-line treatment from other hospitals were included in this study. Patient background, barium swallow studies, esophagogastroduodenoscopy (EGD), manometry, and symptom scores were prospectively evaluated. In principle, all patients in whom surgical myotomy failed received pneumatic balloon dilatation (PBD) as the first line "rescue" treatment, and only if PBD failed were patients considered for rescue POEM. The PBD alone was effective in 1 patient, and in the remaining 10 patients, rescue POEM was performed successfully without complications. Three months after rescue POEM, significant reduction in lower esophageal sphincter (LES) resting pressures (22.1 ± 6.6 mmHg vs 10.9 ± 4.5 mmHg, p myotomy were excellent. Long-term results are awaited. Copyright © 2013 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

Ship Benchmark Shaft and Engine Gain FDI Using Neural Network

DEFF Research Database (Denmark)

Bendtsen, Jan Dimon; Izadi-Zamanabadi, Roozbeh

2002-01-01

threshold value. In the paper a method for determining this threshold based on the neural network model is proposed, which can be used for a design strategy to handle residual sensitivity to input variations. The proposed method is used for successful FDI of a diesel engine gain fault in a ship propulsion...

VEIL Surgical Steps.

Science.gov (United States)

Raghunath, S K; Nagaraja, H; Srivatsa, N

2017-03-01

Inguinal lymphadenectomy remains the standard of care for metastatic nodal disease in cases of penile, urethral, vulval and vaginal cancers. Outcomes, including cure rates and overall and progression-free survivals, have progressively improved in these diseases with extending criteria to offer inguinal lymph node dissection for patients 'at-risk' for metastasis or loco-regional recurrence. Hence, despite declining incidence of advanced stages of these cancers, many patients will still need to undergo lymphadenectomy for optimal oncological outcomes. Inguinal node dissection is a morbid procedure with operative morbidity noted in almost two third of the patients. Video endoscopic inguinal lymphadenectomy (VEIL) was described and currently practiced with proven equivalent oncological outcomes. We describe our technique of VEIL using laparoscopic and robotic access as well as various new surgical strategies.

Selection for Surgical Training: An Evidence-Based Review.

Science.gov (United States)

Schaverien, Mark V

2016-01-01

The predictive relationship between candidate selection criteria for surgical training programs and future performance during and at the completion of training has been investigated for several surgical specialties, however there is no interspecialty agreement regarding which selection criteria should be used. Better understanding the predictive reliability between factors at selection and future performance may help to optimize the process and lead to greater standardization of the surgical selection process. PubMed and Ovid MEDLINE databases were searched. Over 560 potentially relevant publications were identified using the search strategy and screened using the Cochrane Collaboration Data Extraction and Assessment Template. 57 studies met the inclusion criteria. Several selection criteria used in the traditional selection demonstrated inconsistent correlation with subsequent performance during and at the end of surgical training. The following selection criteria, however, demonstrated good predictive relationships with subsequent resident performance: USMLE examination scores, Letters of Recommendation (LOR) including the Medical Student Performance Evaluation (MSPE), academic performance during clinical clerkships, the interview process, displaying excellence in extracurricular activities, and the use of unadjusted rank lists. This systematic review supports that the current selection process needs to be further evaluated and improved. Multicenter studies using standardized outcome measures of success are now required to improve the reliability of the selection process to select the best trainees. Published by Elsevier Inc.

Development and Validation of a Deep Neural Network Model for Prediction of Postoperative In-hospital Mortality.

Science.gov (United States)

Lee, Christine K; Hofer, Ira; Gabel, Eilon; Baldi, Pierre; Cannesson, Maxime

2018-04-17

The authors tested the hypothesis that deep neural networks trained on intraoperative features can predict postoperative in-hospital mortality. The data used to train and validate the algorithm consists of 59,985 patients with 87 features extracted at the end of surgery. Feed-forward networks with a logistic output were trained using stochastic gradient descent with momentum. The deep neural networks were trained on 80% of the data, with 20% reserved for testing. The authors assessed improvement of the deep neural network by adding American Society of Anesthesiologists (ASA) Physical Status Classification and robustness of the deep neural network to a reduced feature set. The networks were then compared to ASA Physical Status, logistic regression, and other published clinical scores including the Surgical Apgar, Preoperative Score to Predict Postoperative Mortality, Risk Quantification Index, and the Risk Stratification Index. In-hospital mortality in the training and test sets were 0.81% and 0.73%. The deep neural network with a reduced feature set and ASA Physical Status classification had the highest area under the receiver operating characteristics curve, 0.91 (95% CI, 0.88 to 0.93). The highest logistic regression area under the curve was found with a reduced feature set and ASA Physical Status (0.90, 95% CI, 0.87 to 0.93). The Risk Stratification Index had the highest area under the receiver operating characteristics curve, at 0.97 (95% CI, 0.94 to 0.99). Deep neural networks can predict in-hospital mortality based on automatically extractable intraoperative data, but are not (yet) superior to existing methods.

Energy efficiency optimisation for distillation column using artificial neural network models

International Nuclear Information System (INIS)

Osuolale, Funmilayo N.; Zhang, Jie

2016-01-01

This paper presents a neural network based strategy for the modelling and optimisation of energy efficiency in distillation columns incorporating the second law of thermodynamics. Real-time optimisation of distillation columns based on mechanistic models is often infeasible due to the effort in model development and the large computation effort associated with mechanistic model computation. This issue can be addressed by using neural network models which can be quickly developed from process operation data. The computation time in neural network model evaluation is very short making them ideal for real-time optimisation. Bootstrap aggregated neural networks are used in this study for enhanced model accuracy and reliability. Aspen HYSYS is used for the simulation of the distillation systems. Neural network models for exergy efficiency and product compositions are developed from simulated process operation data and are used to maximise exergy efficiency while satisfying products qualities constraints. Applications to binary systems of methanol-water and benzene-toluene separations culminate in a reduction of utility consumption of 8.2% and 28.2% respectively. Application to multi-component separation columns also demonstrate the effectiveness of the proposed method with a 32.4% improvement in the exergy efficiency. - Highlights: • Neural networks can accurately model exergy efficiency in distillation columns. • Bootstrap aggregated neural network offers improved model prediction accuracy. • Improved exergy efficiency is obtained through model based optimisation. • Reductions of utility consumption by 8.2% and 28.2% were achieved for binary systems. • The exergy efficiency for multi-component distillation is increased by 32.4%.

Experiments in Neural-Network Control of a Free-Flying Space Robot

Science.gov (United States)

Wilson, Edward

1995-01-01

Four important generic issues are identified and addressed in some depth in this thesis as part of the development of an adaptive neural network based control system for an experimental free flying space robot prototype. The first issue concerns the importance of true system level design of the control system. A new hybrid strategy is developed here, in depth, for the beneficial integration of neural networks into the total control system. A second important issue in neural network control concerns incorporating a priori knowledge into the neural network. In many applications, it is possible to get a reasonably accurate controller using conventional means. If this prior information is used purposefully to provide a starting point for the optimizing capabilities of the neural network, it can provide much faster initial learning. In a step towards addressing this issue, a new generic Fully Connected Architecture (FCA) is developed for use with backpropagation. A third issue is that neural networks are commonly trained using a gradient based optimization method such as backpropagation; but many real world systems have Discrete Valued Functions (DVFs) that do not permit gradient based optimization. One example is the on-off thrusters that are common on spacecraft. A new technique is developed here that now extends backpropagation learning for use with DVFs. The fourth issue is that the speed of adaptation is often a limiting factor in the implementation of a neural network control system. This issue has been strongly resolved in the research by drawing on the above new contributions.

Neural crest stem cell population in craniomaxillofacial development and tissue repair

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M La Noce

2014-10-01

Full Text Available Neural crest cells, delaminating from the neural tube during migration, undergo an epithelial-mesenchymal transition and differentiate into several cell types strongly reinforcing the mesoderm of the craniofacial body area – giving rise to bone, cartilage and other tissues and cells of this human body area. Recent studies on craniomaxillofacial neural crest-derived cells have provided evidence for the tremendous plasticity of these cells. Actually, neural crest cells can respond and adapt to the environment in which they migrate and the cranial mesoderm plays an important role toward patterning the identity of the migrating neural crest cells. In our experience, neural crest-derived stem cells, such as dental pulp stem cells, can actively proliferate, repair bone and give rise to other tissues and cytotypes, including blood vessels, smooth muscle, adipocytes and melanocytes, highlighting that their use in tissue engineering is successful. In this review, we provide an overview of the main pathways involved in neural crest formation, delamination, migration and differentiation; and, in particular, we concentrate our attention on the translatability of the latest scientific progress. Here we try to suggest new ideas and strategies that are needed to fully develop the clinical use of these cells. This effort should involve both researchers/clinicians and improvements in good manufacturing practice procedures. It is important to address studies towards clinical application or take into consideration that studies must have an effective therapeutic prospect for humans. New approaches and ideas must be concentrated also toward stem cell recruitment and activation within the human body, overcoming the classical grafting.

Surgical treatment analysis of idiopathic esophageal achalasia.

Science.gov (United States)

Aquino, José Luis Braga de; Said, Marcelo Manzano; Pereira, Douglas Rizzanti; Amaral, Paula Casals do; Lima, Juliana Carolina Alves; Leandro-Merhi, Vânia Aparecida

2015-01-01

strategy proposed for the surgical treatment of idiopathic esophageal achalasia according to the stages of the disease was of great value, due to post-surgical low morbidity complications and proper recovery of swallowing.

Generation and properties of a new human ventral mesencephalic neural stem cell line

DEFF Research Database (Denmark)

Villa, Ana; Liste, Isabel; Courtois, Elise T

2009-01-01

. Here we report the generation of a new stable cell line of human neural stem cells derived from ventral mesencephalon (hVM1) based on v-myc immortalization. The cells expressed neural stem cell and radial glia markers like nestin, vimentin and 3CB2 under proliferation conditions. After withdrawal......Neural stem cells (NSCs) are powerful research tools for the design and discovery of new approaches to cell therapy in neurodegenerative diseases like Parkinson's disease. Several epigenetic and genetic strategies have been tested for long-term maintenance and expansion of these cells in vitro...... derivatives may constitute good candidates for the study of development and physiology of human dopaminergic neurons in vitro, and to develop tools for Parkinson's disease cell replacement preclinical research and drug testing....

Neural networks

International Nuclear Information System (INIS)

Denby, Bruce; Lindsey, Clark; Lyons, Louis

1992-01-01

The 1980s saw a tremendous renewal of interest in 'neural' information processing systems, or 'artificial neural networks', among computer scientists and computational biologists studying cognition. Since then, the growth of interest in neural networks in high energy physics, fueled by the need for new information processing technologies for the next generation of high energy proton colliders, can only be described as explosive

Mobile surgical skills education unit: a new concept in surgical training.

Science.gov (United States)

Shaikh, Faisal M; Hseino, Hazem; Hill, Arnold D K; Kavanagh, Eamon; Traynor, Oscar

2011-08-01

Basic surgical skills are an integral part of surgical training. Simulation-based surgical training offers an opportunity both to trainees and trainers to learn and teach surgical skills outside the operating room in a nonpatient, nonstressed environment. However, widespread adoption of simulation technology especially in medical education is prohibited by its inherent higher cost, limited space, and interruptions to clinical duties. Mobile skills laboratory has been proposed as a means to address some of these limitations. A new program is designed by the Royal College of Surgeons in Ireland (RCSI), in an approach to teach its postgraduate basic surgical trainees the necessary surgical skills, by making the use of mobile innovative simulation technology in their own hospital settings. In this article, authors describe the program and students response to the mobile surgical skills being delivered in the region of their training hospitals and by their own regional consultant trainers.

Capacity of Human Dental Follicle Cells to Differentiate into Neural Cells In Vitro

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Shingo Kanao

2017-01-01

Full Text Available The dental follicle is an ectomesenchymal tissue surrounding the developing tooth germ. Human dental follicle cells (hDFCs have the capacity to commit to differentiation into multiple cell types. Here we investigated the capacity of hDFCs to differentiate into neural cells and the efficiency of a two-step strategy involving floating neurosphere-like bodies for neural differentiation. Undifferentiated hDFCs showed a spindle-like morphology and were positive for neural markers such as nestin, β-III-tubulin, and S100β. The cellular morphology of several cells was neuronal-like including branched dendrite-like processes and neurites. Next, hDFCs were used for neurosphere formation in serum-free medium containing basic fibroblast growth factor, epidermal growth factor, and B27 supplement. The number of cells with neuronal-like morphology and that were strongly positive for neural markers increased with sphere formation. Gene expression of neural markers also increased in hDFCs with sphere formation. Next, gene expression of neural markers was examined in hDFCs during neuronal differentiation after sphere formation. Expression of Musashi-1 and Musashi-2, MAP2, GFAP, MBP, and SOX10 was upregulated in hDFCs undergoing neuronal differentiation via neurospheres, whereas expression of nestin and β-III-tubulin was downregulated. In conclusion, hDFCs may be another optimal source of neural/glial cells for cell-based therapies to treat neurological diseases.

Age-Related Differences in Neural Recruitment During the Use of Cognitive Reappraisal and Selective Attention as Emotion Regulation Strategies

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Eric S Allard

2014-04-01

Full Text Available The present study examined age differences in the timing and neural recruitment within lateral and medial PFC while younger and older adults hedonically regulated their responses to unpleasant film clips. When analyses focused on activity during the emotional peak of the film clip (the most emotionally salient portion of the film, several age differences emerged. When comparing regulation to passive viewing (combined effects of selective attention and reappraisal younger adults showed greater regulation related activity in lateral PFC (DLPFC, VLPFC, OFC and medial PFC (ACC while older adults showed greater activation within a region DLPFC. When assessing distinct effects of the regulation conditions, an ANOVA revealed a significant Age X Regulation Condition interaction within bilateral DLPFC and ACC; older adults but not young adults showed greater recruitment within these regions for reappraisal than selective attention. When examining activity at the onset of the film clip and at its emotional peak, the timing of reappraisal-related activity within VLPFC differed between age groups: Younger adults showed greater activity at film onset while older adults showed heightened activity during the peak. Our results suggest that older adults rely more heavily on PFC recruitment when engaging cognitively demanding reappraisal strategies while PFC-mediated regulation might not be as task-specific for younger adults. Older adults’ greater reliance on cognitive control processing during emotion regulation may also be reflected in the time needed to implement these strategies.

An artificial neural network for modeling reliability, availability and maintainability of a repairable system

International Nuclear Information System (INIS)

Rajpal, P.S.; Shishodia, K.S.; Sekhon, G.S.

2006-01-01

The paper explores the application of artificial neural networks to model the behaviour of a complex, repairable system. A composite measure of reliability, availability and maintainability parameters has been proposed for measuring the system performance. The artificial neural network has been trained using past data of a helicopter transportation facility. It is used to simulate behaviour of the facility under various constraints. The insights obtained from results of simulation are useful in formulating strategies for optimal operation of the system

Flexible, Penetrating Brain Probes Enabled by Advances in Polymer Microfabrication

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Ahuva Weltman

2016-10-01

Full Text Available The acquisition of high-fidelity, long-term neural recordings in vivo is critically important to advance neuroscience and brain–machine interfaces. For decades, rigid materials such as metal microwires and micromachined silicon shanks were used as invasive electrophysiological interfaces to neurons, providing either single or multiple electrode recording sites. Extensive research has revealed that such rigid interfaces suffer from gradual recording quality degradation, in part stemming from tissue damage and the ensuing immune response arising from mechanical mismatch between the probe and brain. The development of “soft” neural probes constructed from polymer shanks has been enabled by advancements in microfabrication; this alternative has the potential to mitigate mismatch-related side effects and thus improve the quality of recordings. This review examines soft neural probe materials and their associated microfabrication techniques, the resulting soft neural probes, and their implementation including custom implantation and electrical packaging strategies. The use of soft materials necessitates careful consideration of surgical placement, often requiring the use of additional surgical shuttles or biodegradable coatings that impart temporary stiffness. Investigation of surgical implantation mechanics and histological evidence to support the use of soft probes will be presented. The review concludes with a critical discussion of the remaining technical challenges and future outlook.

Novel experimental surgical strategy to prevent traumatic neuroma formation by combining a 3D-printed Y-tube with an autograft.

Science.gov (United States)

Bolleboom, Anne; de Ruiter, Godard C W; Coert, J Henk; Tuk, Bastiaan; Holstege, Jan C; van Neck, Johan W

2018-02-09

OBJECTIVE Traumatic neuromas may develop after nerve injury at the proximal nerve stump, which can lead to neuropathic pain. These neuromas are often resistant to therapy, and excision of the neuroma frequently leads to recurrence. In this study, the authors present a novel surgical strategy to prevent neuroma formation based on the principle of centro-central anastomosis (CCA), but rather than directly connecting the nerve ends to an autograft, they created a loop using a 3D-printed polyethylene Y-shaped conduit with an autograft in the distal outlets. METHODS The 3D-printed Y-tube with autograft was investigated in a model of rat sciatic nerve transection in which the Y-tube was placed on the proximal sciatic nerve stump and a peroneal graft was placed between the distal outlets of the Y-tube to form a closed loop. This model was compared with a CCA model, in which a loop was created between the proximal tibial and peroneal nerves with a peroneal autograft. Additional control groups consisted of the closed Y-tube and the extended-arm Y-tube. Results were analyzed at 12 weeks of survival using nerve morphometry for the occurrence of neuroma formation and axonal regeneration in plastic semi-thin sections. RESULTS Among the different surgical groups, the Y-tube with interposed autograft was the only model that did not result in neuroma formation at 12 weeks of survival. In addition, a 13% reduction in the number of myelinated axons regenerating through the interposed autograft was observed in the Y-tube with autograft model. In the CCA model, the authors also observed a decrease of 17% in the number of myelinated axons, but neuroma formation was present in this model. The closed Y-tube resulted in minimal nerve regeneration inside the tube together with extensive neuroma formation before the entrance of the tube. The extended-arm Y-tube model clearly showed that the majority of the regenerating axons merged into the Y-tube arm, which was connected to the autograft

Modeling of methane emissions using artificial neural network approach

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Stamenković Lidija J.

2015-01-01

Full Text Available The aim of this study was to develop a model for forecasting CH4 emissions at the national level, using Artificial Neural Networks (ANN with broadly available sustainability, economical and industrial indicators as their inputs. ANN modeling was performed using two different types of architecture; a Backpropagation Neural Network (BPNN and a General Regression Neural Network (GRNN. A conventional multiple linear regression (MLR model was also developed in order to compare model performance and assess which model provides the best results. ANN and MLR models were developed and tested using the same annual data for 20 European countries. The ANN model demonstrated very good performance, significantly better than the MLR model. It was shown that a forecast of CH4 emissions at the national level using the ANN model can be made successfully and accurately for a future period of up to two years, thereby opening the possibility to apply such a modeling technique which can be used to support the implementation of sustainable development strategies and environmental management policies. [Projekat Ministarstva nauke Republike Srbije, br. 172007

Fault Diagnosis Method of Polymerization Kettle Equipment Based on Rough Sets and BP Neural Network

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Shu-zhi Gao

2013-01-01

Full Text Available Polyvinyl chloride (PVC polymerizing production process is a typical complex controlled object, with complexity features, such as nonlinear, multivariable, strong coupling, and large time-delay. Aiming at the real-time fault diagnosis and optimized monitoring requirements of the large-scale key polymerization equipment of PVC production process, a real-time fault diagnosis strategy is proposed based on rough sets theory with the improved discernibility matrix and BP neural networks. The improved discernibility matrix is adopted to reduct the attributes of rough sets in order to decrease the input dimensionality of fault characteristics effectively. Levenberg-Marquardt BP neural network is trained to diagnose the polymerize faults according to the reducted decision table, which realizes the nonlinear mapping from fault symptom set to polymerize fault set. Simulation experiments are carried out combining with the industry history datum to show the effectiveness of the proposed rough set neural networks fault diagnosis method. The proposed strategy greatly increased the accuracy rate and efficiency of the polymerization fault diagnosis system.

Output control of da Vinci surgical system's surgical graspers.

Science.gov (United States)

Johnson, Paul J; Schmidt, David E; Duvvuri, Umamaheswar

2014-01-01

The number of robot-assisted surgeries performed with the da Vinci surgical system has increased significantly over the past decade. The articulating movements of the robotic surgical grasper are controlled by grip controls at the master console. The user interface has been implicated as one contributing factor in surgical grasping errors. The goal of our study was to characterize and evaluate the user interface of the da Vinci surgical system in controlling surgical graspers. An angular manipulator with force sensors was used to increment the grip control angle as grasper output angles were measured. Input force at the grip control was simultaneously measured throughout the range of motion. Pressure film was used to assess the maximum grasping force achievable with the endoscopic grasping tool. The da Vinci robot's grip control angular input has a nonproportional relationship with the grasper instrument output. The grip control mechanism presents an intrinsic resistant force to the surgeon's fingertips and provides no haptic feedback. The da Vinci Maryland graspers are capable of applying up to 5.1 MPa of local pressure. The angular and force input at the grip control of the da Vinci robot's surgical graspers is nonproportional to the grasper instrument's output. Understanding the true relationship of the grip control input to grasper instrument output may help surgeons understand how to better control the surgical graspers and promote fewer grasping errors. Copyright © 2014 Elsevier Inc. All rights reserved.

Matrix regulators in neural stem cell functions.

Science.gov (United States)

Wade, Anna; McKinney, Andrew; Phillips, Joanna J

2014-08-01

Neural stem/progenitor cells (NSPCs) reside within a complex and dynamic extracellular microenvironment, or niche. This niche regulates fundamental aspects of their behavior during normal neural development and repair. Precise yet dynamic regulation of NSPC self-renewal, migration, and differentiation is critical and must persist over the life of an organism. In this review, we summarize some of the major components of the NSPC niche and provide examples of how cues from the extracellular matrix regulate NSPC behaviors. We use proteoglycans to illustrate the many diverse roles of the niche in providing temporal and spatial regulation of cellular behavior. The NSPC niche is comprised of multiple components that include; soluble ligands, such as growth factors, morphogens, chemokines, and neurotransmitters, the extracellular matrix, and cellular components. As illustrated by proteoglycans, a major component of the extracellular matrix, the NSPC, niche provides temporal and spatial regulation of NSPC behaviors. The factors that control NSPC behavior are vital to understand as we attempt to modulate normal neural development and repair. Furthermore, an improved understanding of how these factors regulate cell proliferation, migration, and differentiation, crucial for malignancy, may reveal novel anti-tumor strategies. This article is part of a Special Issue entitled Matrix-mediated cell behaviour and properties. Copyright © 2014 Elsevier B.V. All rights reserved.

Surgical strategies for treatment of malignant pancreatic tumors: extended, standard or local surgery?

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Jacob Dietmar

2008-11-01

Full Text Available Abstract Tumor related pancreatic surgery has progressed significantly during recent years. Pancreatoduodenectomy (PD with lymphadenectomy, including vascular resection, still presents the optimal surgical procedure for carcinomas in the head of pancreas. For patients with small or low-grade malignant neoplasms, as well as small pancreatic metastases located in the mid-portion of pancreas, central pancreatectomy (CP is emerging as a safe and effective option with a low risk of developing de-novo exocrine and/or endocrine insufficiency. Total pancreatectomy (TP is not as risky as it was years ago and can nowadays safely be performed, but its indication is limited to locally extended tumors that cannot be removed by PD or distal pancreatectomy (DP with tumor free surgical margins. Consequently, TP has not been adopted as a routine procedure by most surgeons. On the other hand, an aggressive attitude is required in case of advanced distal pancreatic tumors, provided that safe and experienced surgery is available. Due to the development of modern instruments, laparoscopic operations became more and more successful, even in malignant pancreatic diseases. This review summarizes the recent literature on the abovementioned topics.

Standardization of surgical techniques used in facial bone contouring.

Science.gov (United States)

Lee, Tae Sung

2015-12-01

Since the introduction of facial bone contouring surgery for cosmetic purposes, various surgical methods have been used to improve the aesthetics of facial contours. In general, by standardizing the surgical techniques, it is possible to decrease complication rates and achieve more predictable surgical outcomes, thereby increasing patient satisfaction. The technical strategies used by the author to standardize facial bone contouring procedures are introduced here. The author uses various pre-manufactured surgical tools and hardware for facial bone contouring. During a reduction malarplasty or genioplasty procedure, double-bladed reciprocating saws and pre-bent titanium plates customized for the zygomatic body, arch and chin are used. Various guarded oscillating saws are used for mandibular angloplasty. The use of double-bladed saws and pre-bent plates to perform reduction malarplasty reduces the chances of post-operative asymmetry or under- or overcorrection of the zygoma contours due to technical faults. Inferior alveolar nerve injury and post-operative jawline asymmetry or irregularity can be reduced by using a guarded saw during mandibular angloplasty. For genioplasty, final placement of the chin in accordance with preoperative quantitative analysis can be easily performed with pre-bent plates, and a double-bladed saw allows more procedural accuracy during osteotomies. Efforts by the surgeon to avoid unintentional faults are key to achieving satisfactory results and reducing the incidence of complications. The surgical techniques described in this study in conjunction with various in-house surgical tools and modified hardware can be used to standardize techniques to achieve aesthetically gratifying outcomes. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Upper Limb Immobilisation: A Neural Plasticity Model with Relevance to Poststroke Motor Rehabilitation

OpenAIRE

Furlan, Leonardo; Conforto, Adriana Bastos; Cohen, Leonardo G.; Sterr, Annette

2016-01-01

Advances in our understanding of the neural plasticity that occurs after hemiparetic stroke have contributed to the formulation of theories of poststroke motor recovery. These theories, in turn, have underpinned contemporary motor rehabilitation strategies for treating motor deficits after stroke, such as upper limb hemiparesis. However, a relative drawback has been that, in general, these strategies are most compatible with the recovery profiles of relatively high-functioning stroke survivor...

Robot-Assisted Laparoscopic Radical Prostatectomy for Patients with Prostatic Cancer and Factors Promoting Installation of the Robotic Surgical Equipment-Questionnaire Survey

OpenAIRE

塚本, 泰司; 田中, 滋

2015-01-01

We conducted a questionnaire survey of hospitals with robot-assisted surgical equipment to study changes of the surgical case loads after its installation and the managerial strategies for its purchase. The study included 154 hospitals (as of April 2014) that were queried about their radical prostatectomy case loads from January 2009 to December 2013, strategies for installation of the equipment in their hospitals, and other topics related to the study purpose. The overall response rate of ho...

Direction-of-change forecasting using a volatility-based recurrent neural network

NARCIS (Netherlands)

Bekiros, S.D.; Georgoutsos, D.A.

2008-01-01

This paper investigates the profitability of a trading strategy, based on recurrent neural networks, that attempts to predict the direction-of-change of the market in the case of the NASDAQ composite index. The sample extends over the period 8 February 1971 to 7 April 1998, while the sub-period 8

Disc degeneration: current surgical options

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C Schizas

2010-10-01

Full Text Available Chronic low back pain attributed to lumbar disc degeneration poses a serious challenge to physicians. Surgery may be indicated in selected cases following failure of appropriate conservative treatment. For decades, the only surgical option has been spinal fusion, but its results have been inconsistent. Some prospective trials show superiority over usual conservative measures while others fail to demonstrate its advantages. In an effort to improve results of fusion and to decrease the incidence of adjacent segment degeneration, total disc replacement techniques have been introduced and studied extensively. Short-term results have shown superiority over some fusion techniques. Mid-term results however tend to show that this approach yields results equivalent to those of spinal fusion. Nucleus replacement has gained some popularity initially, but evidence on its efficacy is scarce. Dynamic stabilisation, a technique involving less rigid implants than in spinal fusion and performed without the need for bone grafting, represents another surgical option. Evidence again is lacking on its superiority over other surgical strategies and conservative measures. Insertion of interspinous devices posteriorly, aiming at redistributing loads and relieving pain, has been used as an adjunct to disc removal surgery for disc herniation. To date however, there is no clear evidence on their efficacy. Minimally invasive intradiscal thermocoagulation techniques have also been tried, but evidence of their effectiveness is questioned. Surgery using novel biological solutions may be the future of discogenic pain treatment. Collaboration between clinicians and basic scientists in this multidisciplinary field will undoubtedly shape the future of treating symptomatic disc degeneration.

Hepatocellular Carcinoma: Current Management and Future Development—Improved Outcomes with Surgical Resection

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Yoji Kishi

2011-01-01

Full Text Available Currently, surgical resection is the treatment strategy offering the best long-term outcomes in patients with hepatocellular carcinoma (HCC. Especially for advanced HCC, surgical resection is the only strategy that is potentially curative, and the indications for surgical resection have expanded concomitantly with the technical advances in hepatectomy. A major problem is the high recurrence rate even after curative resection, especially in the remnant liver. Although repeat hepatectomy may prolong survival, the suitability may be limited due to multiple tumor recurrence or background liver cirrhosis. Multimodality approaches combining other local ablation or systemic therapy may help improve the prognosis. On the other hand, minimally invasive, or laparoscopic, hepatectomy has become popular over the last decade. Although the short-term safety and feasibility has been established, the long-term outcomes have not yet been adequately evaluated. Liver transplantation for HCC is also a possible option. Given the current situation of donor shortage, however, other local treatments should be considered as the first choice as long as liver function is maintained. Non-transplant treatment as a bridge to transplantation also helps in decreasing the risk of tumor progression or death during the waiting period. The optimal timing for transplantation after HCC recurrence remains to be investigated.

A Novel Fractional-Order PID Controller for Integrated Pressurized Water Reactor Based on Wavelet Kernel Neural Network Algorithm

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Yu-xin Zhao

2014-01-01

Full Text Available This paper presents a novel wavelet kernel neural network (WKNN with wavelet kernel function. It is applicable in online learning with adaptive parameters and is applied on parameters tuning of fractional-order PID (FOPID controller, which could handle time delay problem of the complex control system. Combining the wavelet function and the kernel function, the wavelet kernel function is adopted and validated the availability for neural network. Compared to the conservative wavelet neural network, the most innovative character of the WKNN is its rapid convergence and high precision in parameters updating process. Furthermore, the integrated pressurized water reactor (IPWR system is established by RELAP5, and a novel control strategy combining WKNN and fuzzy logic rule is proposed for shortening controlling time and utilizing the experiential knowledge sufficiently. Finally, experiment results verify that the control strategy and controller proposed have the practicability and reliability in actual complicated system.

Quantitative Analysis of Human Pluripotency and Neural Specification by In-Depth (PhosphoProteomic Profiling

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Ilyas Singec

2016-09-01

Full Text Available Controlled differentiation of human embryonic stem cells (hESCs can be utilized for precise analysis of cell type identities during early development. We established a highly efficient neural induction strategy and an improved analytical platform, and determined proteomic and phosphoproteomic profiles of hESCs and their specified multipotent neural stem cell derivatives (hNSCs. This quantitative dataset (nearly 13,000 proteins and 60,000 phosphorylation sites provides unique molecular insights into pluripotency and neural lineage entry. Systems-level comparative analysis of proteins (e.g., transcription factors, epigenetic regulators, kinase families, phosphorylation sites, and numerous biological pathways allowed the identification of distinct signatures in pluripotent and multipotent cells. Furthermore, as predicted by the dataset, we functionally validated an autocrine/paracrine mechanism by demonstrating that the secreted protein midkine is a regulator of neural specification. This resource is freely available to the scientific community, including a searchable website, PluriProt.

Cascade Optimization for Aircraft Engines With Regression and Neural Network Analysis - Approximators

Science.gov (United States)

Patnaik, Surya N.; Guptill, James D.; Hopkins, Dale A.; Lavelle, Thomas M.

2000-01-01

The NASA Engine Performance Program (NEPP) can configure and analyze almost any type of gas turbine engine that can be generated through the interconnection of a set of standard physical components. In addition, the code can optimize engine performance by changing adjustable variables under a set of constraints. However, for engine cycle problems at certain operating points, the NEPP code can encounter difficulties: nonconvergence in the currently implemented Powell's optimization algorithm and deficiencies in the Newton-Raphson solver during engine balancing. A project was undertaken to correct these deficiencies. Nonconvergence was avoided through a cascade optimization strategy, and deficiencies associated with engine balancing were eliminated through neural network and linear regression methods. An approximation-interspersed cascade strategy was used to optimize the engine's operation over its flight envelope. Replacement of Powell's algorithm by the cascade strategy improved the optimization segment of the NEPP code. The performance of the linear regression and neural network methods as alternative engine analyzers was found to be satisfactory. This report considers two examples-a supersonic mixed-flow turbofan engine and a subsonic waverotor-topped engine-to illustrate the results, and it discusses insights gained from the improved version of the NEPP code.

Back to basics: hand hygiene and surgical hand antisepsis.

Science.gov (United States)

Spruce, Lisa

2013-11-01

Health care-associated infections (HAIs) are a significant issue in the United States and throughout the world, but following proper hand hygiene practices is the most effective and least expensive way to prevent HAIs. Hand hygiene is inexpensive and protects patients and health care personnel alike. The four general types of hand hygiene that should be performed in the perioperative environment are washing hands that are visibly soiled, hand hygiene using alcohol-based products, surgical hand scrubs, and surgical hand scrubs using an alcohol-based surgical hand rub product. Barriers to proper hand hygiene may include not thinking about it, forgetting, skin irritation, a lack of role models, or a lack of a safety culture. One strategy for improving hand hygiene practices is monitoring hand hygiene as part of a quality improvement project, but the most important aspect for perioperative team members is to set an example for other team members by following proper hand hygiene practices and reminding each other to perform hand hygiene. Copyright © 2013 AORN, Inc. Published by Elsevier Inc. All rights reserved.

Current strategies in surgical myocardial revascularization: Indian perspective

Directory of Open Access Journals (Sweden)

Sameer Kumar

2013-01-01

A retrospective analysis was carried out of 172 patients who underwent CABG at INHS Asvini between 01 Jan 2008 and 31 May 2013.39% had Left Main Coronary artery disease, 85% patient had triple vessel disease, 56% were diabetics, 12% had undergone stenting in recent past. Beating heart strategy was used in 10%, average no of grafts per patient was 2.3 with LIMA and Radial artery being used as a conduit in 84% and 4% respectively. 4.6% patients succumbed in post-operative period.

Surgical Treatment of Severe Traumatic Brain Injury in Switzerland: Results from a Multicenter Study.

Science.gov (United States)

Rossi-Mossuti, Frédéric; Fisch, Urs; Schoettker, Patrick; Gugliotta, Marinella; Morard, Marc; Schucht, Philippe; Schatlo, Bawarjan; Levivier, Marc; Walder, Bernhard; Fandino, Javier

2016-01-01

Since the introduction of modern surgical techniques and monitoring tools for the treatment of severe traumatic brain injury (TBI) in Switzerland, standardized nationwide operative procedures are still lacking. This study aimed to assess surgical management and monitoring strategies in patients admitted throughout Switzerland with severe TBI. Demographic, clinical, and radiologic data from a prospective national cohort study on severe brain-injured patients (Patient-relevant Endpoints after Brain Injury from Traumatic Accidents [PEBITA]) were collected during a 3-year period. This study evaluated patients admitted to 7 of the 11 trauma centers included in PEBITA. We retrospectively analyzed surgery-related computed tomography (CT) findings prior to and after treatment, intracranial pressure (ICP) monitoring, size and technical features of craniotomy, as well as surgical complications. ResULTS: This study included 353 of the 921 patients enrolled in PEBITA who underwent surgical treatment for severe TBI. At admission, acute subdural hematoma was the most frequent focal lesion diagnosed (n = 154 [44%]), followed by epidural hematoma (n = 96 [27%]) and intracerebral hematoma (n = 84 [24%]). A total of 198 patients (61%) presented with midline shift. Clinical deterioration in terms of Glasgow Coma Scale scores or intractable ICP values as an indication for surgical evacuation or decompression were documented in 20% and 6%, respectively. A total of 97 (27.5%) only received a catheter/probe for ICP monitoring. Surgical procedures to treat a focal lesion or decompress the cerebrum were performed in 256 patients (72.5%). Of the 290 surgical procedures (excluding ICP probe implantation), craniotomy (137 [47.2%]) or decompressive craniectomy (133 [45.9%]) were performed most frequently. The mean size of craniectomy in terms of maximal linear width on the CT axial slice was 8.4 ± 2.9 cm. Intraoperative ICP monitoring was reported in 61% of the interventions. Significant

Surgical Management of the Thick-Skinned Nose.

Science.gov (United States)

Davis, Richard E; Hrisomalos, Emily N

2018-02-01

When executed properly, open structure rhinoplasty can dramatically improve the consistency, durability, and quality of the cosmetic surgical outcome. Moreover, in expert hands, dramatic transformations in skeletal architecture can be accomplished with minimal risk and unparalleled control, all while preserving nasal airway function. While skeletal enhancements have become increasingly more controlled and precise, the outer skin-soft tissue envelope (SSTE) often presents a formidable obstacle to a satisfactory cosmetic result. In noses with unusually thick skin, excessive skin volume and characteristically hostile healing responses frequently combine to obscure or sometimes even negate cosmetic skeletal modifications and taint the surgical outcome. For this challenging patient subgroup, care must be taken to optimize the SSTE using a graduated treatment strategy directed at minimizing skin thickness and controlling unfavorable healing responses. When appropriate efforts are implemented to manage thick nasal skin, cosmetic outcomes are often substantially improved, sometimes even negating the ill-effects of thick skin altogether. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

The potential of neural transplantation for brain repair and regeneration following traumatic brain injury

Institute of Scientific and Technical Information of China (English)

Dong Sun

2016-01-01

Traumatic brain injury is a major health problem worldwide. Currently, there is no effective treatment to improve neural structural repair and functional recovery of patients in the clinic. Cell transplantation is a potential strategy to repair and regenerate the injured brain. This review article summarized recent de-velopment in cell transplantation studies for post-traumatic brain injury brain repair with varying types of cell sources. It also discussed the potential of neural transplantation to repair/promote recovery of the injured brain following traumatic brain injury.

Construction of implantable optical fibers for long-term optogenetic manipulation of neural circuits.

Science.gov (United States)

Sparta, Dennis R; Stamatakis, Alice M; Phillips, Jana L; Hovelsø, Nanna; van Zessen, Ruud; Stuber, Garret D

2011-12-08

In vivo optogenetic strategies have redefined our ability to assay how neural circuits govern behavior. Although acutely implanted optical fibers have previously been used in such studies, long-term control over neuronal activity has been largely unachievable. Here we describe a method to construct implantable optical fibers to readily manipulate neural circuit elements with minimal tissue damage or change in light output over time (weeks to months). Implanted optical fibers readily interface with in vivo electrophysiological arrays or electrochemical detection electrodes. The procedure described here, from implant construction to the start of behavioral experimentation, can be completed in approximately 2-6 weeks. Successful use of implantable optical fibers will allow for long-term control of mammalian neural circuits in vivo, which is integral to the study of the neurobiology of behavior.

Evolvable Neural Software System

Science.gov (United States)

Curtis, Steven A.

2009-01-01

The Evolvable Neural Software System (ENSS) is composed of sets of Neural Basis Functions (NBFs), which can be totally autonomously created and removed according to the changing needs and requirements of the software system. The resulting structure is both hierarchical and self-similar in that a given set of NBFs may have a ruler NBF, which in turn communicates with other sets of NBFs. These sets of NBFs may function as nodes to a ruler node, which are also NBF constructs. In this manner, the synthetic neural system can exhibit the complexity, three-dimensional connectivity, and adaptability of biological neural systems. An added advantage of ENSS over a natural neural system is its ability to modify its core genetic code in response to environmental changes as reflected in needs and requirements. The neural system is fully adaptive and evolvable and is trainable before release. It continues to rewire itself while on the job. The NBF is a unique, bilevel intelligence neural system composed of a higher-level heuristic neural system (HNS) and a lower-level, autonomic neural system (ANS). Taken together, the HNS and the ANS give each NBF the complete capabilities of a biological neural system to match sensory inputs to actions. Another feature of the NBF is the Evolvable Neural Interface (ENI), which links the HNS and ANS. The ENI solves the interface problem between these two systems by actively adapting and evolving from a primitive initial state (a Neural Thread) to a complicated, operational ENI and successfully adapting to a training sequence of sensory input. This simulates the adaptation of a biological neural system in a developmental phase. Within the greater multi-NBF and multi-node ENSS, self-similar ENI s provide the basis for inter-NBF and inter-node connectivity.

Multi-step-prediction of chaotic time series based on co-evolutionary recurrent neural network

International Nuclear Information System (INIS)

Ma Qianli; Zheng Qilun; Peng Hong; Qin Jiangwei; Zhong Tanwei

2008-01-01

This paper proposes a co-evolutionary recurrent neural network (CERNN) for the multi-step-prediction of chaotic time series, it estimates the proper parameters of phase space reconstruction and optimizes the structure of recurrent neural networks by co-evolutionary strategy. The searching space was separated into two subspaces and the individuals are trained in a parallel computational procedure. It can dynamically combine the embedding method with the capability of recurrent neural network to incorporate past experience due to internal recurrence. The effectiveness of CERNN is evaluated by using three benchmark chaotic time series data sets: the Lorenz series, Mackey-Glass series and real-world sun spot series. The simulation results show that CERNN improves the performances of multi-step-prediction of chaotic time series

Using Appreciative Inquiry to Discover and Deliver Change for Surgical Technology Students

Science.gov (United States)

Cabai, Katherine A.

2012-01-01

The purpose of this study was to examine efficacious teaching-learning strategies that community college stakeholders employ that enhance surgical technology student outcomes. Knowles's adult learning theory, constructivist theory, and appreciative inquiry served as the theoretical foundation for this study. Discovering effective aspects and…

A concept paper: using the outcomes of common surgical conditions as quality metrics to benchmark district surgical services in South Africa as part of a systematic quality improvement programme.

Science.gov (United States)

Clarke, Damian L; Kong, Victor Y; Handley, Jonathan; Aldous, Colleen

2013-07-31

The fourth, fifth and sixth Millennium Development Goals relate directly to improving global healthcare and health outcomes. The focus is to improve global health outcomes by reducing maternal and childhood mortality and the burden of infectious diseases such as HIV/AIDS, tuberculosis and malaria. Specific targets and time frames have been set for these diseases. There is, however, no specific mention of surgically treated diseases in these goals, reflecting a bias that is slowly changing with emerging consensus that surgical care is an integral part of primary healthcare systems in the developing world. The disparities between the developed and developing world in terms of wealth and social indicators are reflected in disparities in access to surgical care. Health administrators must develop plans and strategies to reduce these disparities. However, any strategic plan that addresses deficits in healthcare must have a system of metrics, which benchmark the current quality of care so that specific improvement targets may be set.This concept paper outlines the role of surgical services in a primary healthcare system, highlights the ongoing disparities in access to surgical care and outcomes of surgical care, discusses the importance of a systems-based approach to healthcare and quality improvement, and reviews the current state of surgical care at district hospitals in South Africa. Finally, it proposes that the results from a recently published study on acute appendicitis, as well as data from a number of other common surgical conditions, can provide measurable outcomes across a healthcare system and so act as an indicator for judging improvements in surgical care. This would provide a framework for the introduction of collection of these outcomes as a routine epidemiological health policy tool.

Brain substrates of implicit and explicit memory: the importance of concurrently acquired neural signals of both memory types.

Science.gov (United States)

Voss, Joel L; Paller, Ken A

2008-11-01

A comprehensive understanding of human memory requires cognitive and neural descriptions of memory processes along with a conception of how memory processing drives behavioral responses and subjective experiences. One serious challenge to this endeavor is that an individual memory process is typically operative within a mix of other contemporaneous memory processes. This challenge is particularly disquieting in the context of implicit memory, which, unlike explicit memory, transpires without the subject necessarily being aware of memory retrieval. Neural correlates of implicit memory and neural correlates of explicit memory are often investigated in different experiments using very different memory tests and procedures. This strategy poses difficulties for elucidating the interactions between the two types of memory process that may result in explicit remembering, and for determining the extent to which certain neural processing events uniquely contribute to only one type of memory. We review recent studies that have succeeded in separately assessing neural correlates of both implicit memory and explicit memory within the same paradigm using event-related brain potentials (ERPs) and functional magnetic resonance imaging (fMRI), with an emphasis on studies from our laboratory. The strategies we describe provide a methodological framework for achieving valid assessments of memory processing, and the findings support an emerging conceptualization of the distinct neurocognitive events responsible for implicit and explicit memory.

Chaotic diagonal recurrent neural network

International Nuclear Information System (INIS)

Wang Xing-Yuan; Zhang Yi

2012-01-01

We propose a novel neural network based on a diagonal recurrent neural network and chaos, and its structure and learning algorithm are designed. The multilayer feedforward neural network, diagonal recurrent neural network, and chaotic diagonal recurrent neural network are used to approach the cubic symmetry map. The simulation results show that the approximation capability of the chaotic diagonal recurrent neural network is better than the other two neural networks. (interdisciplinary physics and related areas of science and technology)

Application of hierarchical dissociated neural network in closed-loop hybrid system integrating biological and mechanical intelligence.

Directory of Open Access Journals (Sweden)

Yongcheng Li

Full Text Available Neural networks are considered the origin of intelligence in organisms. In this paper, a new design of an intelligent system merging biological intelligence with artificial intelligence was created. It was based on a neural controller bidirectionally connected to an actual mobile robot to implement a novel vehicle. Two types of experimental preparations were utilized as the neural controller including 'random' and '4Q' (cultured neurons artificially divided into four interconnected parts neural network. Compared to the random cultures, the '4Q' cultures presented absolutely different activities, and the robot controlled by the '4Q' network presented better capabilities in search tasks. Our results showed that neural cultures could be successfully employed to control an artificial agent; the robot performed better and better with the stimulus because of the short-term plasticity. A new framework is provided to investigate the bidirectional biological-artificial interface and develop new strategies for a future intelligent system using these simplified model systems.

Application of Hierarchical Dissociated Neural Network in Closed-Loop Hybrid System Integrating Biological and Mechanical Intelligence

Science.gov (United States)

Zhang, Bin; Wang, Yuechao; Li, Hongyi

2015-01-01

Neural networks are considered the origin of intelligence in organisms. In this paper, a new design of an intelligent system merging biological intelligence with artificial intelligence was created. It was based on a neural controller bidirectionally connected to an actual mobile robot to implement a novel vehicle. Two types of experimental preparations were utilized as the neural controller including ‘random’ and ‘4Q’ (cultured neurons artificially divided into four interconnected parts) neural network. Compared to the random cultures, the ‘4Q’ cultures presented absolutely different activities, and the robot controlled by the ‘4Q’ network presented better capabilities in search tasks. Our results showed that neural cultures could be successfully employed to control an artificial agent; the robot performed better and better with the stimulus because of the short-term plasticity. A new framework is provided to investigate the bidirectional biological-artificial interface and develop new strategies for a future intelligent system using these simplified model systems. PMID:25992579

Application of hierarchical dissociated neural network in closed-loop hybrid system integrating biological and mechanical intelligence.

Science.gov (United States)

Li, Yongcheng; Sun, Rong; Zhang, Bin; Wang, Yuechao; Li, Hongyi

2015-01-01

Neural networks are considered the origin of intelligence in organisms. In this paper, a new design of an intelligent system merging biological intelligence with artificial intelligence was created. It was based on a neural controller bidirectionally connected to an actual mobile robot to implement a novel vehicle. Two types of experimental preparations were utilized as the neural controller including 'random' and '4Q' (cultured neurons artificially divided into four interconnected parts) neural network. Compared to the random cultures, the '4Q' cultures presented absolutely different activities, and the robot controlled by the '4Q' network presented better capabilities in search tasks. Our results showed that neural cultures could be successfully employed to control an artificial agent; the robot performed better and better with the stimulus because of the short-term plasticity. A new framework is provided to investigate the bidirectional biological-artificial interface and develop new strategies for a future intelligent system using these simplified model systems.

Computational modeling of neural plasticity for self-organization of neural networks.

Science.gov (United States)

Chrol-Cannon, Joseph; Jin, Yaochu

2014-11-01

Self-organization in biological nervous systems during the lifetime is known to largely occur through a process of plasticity that is dependent upon the spike-timing activity in connected neurons. In the field of computational neuroscience, much effort has been dedicated to building up computational models of neural plasticity to replicate experimental data. Most recently, increasing attention has been paid to understanding the role of neural plasticity in functional and structural neural self-organization, as well as its influence on the learning performance of neural networks for accomplishing machine learning tasks such as classification and regression. Although many ideas and hypothesis have been suggested, the relationship between the structure, dynamics and learning performance of neural networks remains elusive. The purpose of this article is to review the most important computational models for neural plasticity and discuss various ideas about neural plasticity's role. Finally, we suggest a few promising research directions, in particular those along the line that combines findings in computational neuroscience and systems biology, and their synergetic roles in understanding learning, memory and cognition, thereby bridging the gap between computational neuroscience, systems biology and computational intelligence. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Open surgical simulation--a review.

Science.gov (United States)

Davies, Jennifer; Khatib, Manaf; Bello, Fernando

2013-01-01

Surgical simulation has benefited from a surge in interest over the last decade as a result of the increasing need for a change in the traditional apprentice model of teaching surgery. However, despite the recent interest in surgical simulation as an adjunct to surgical training, most of the literature focuses on laparoscopic, endovascular, and endoscopic surgical simulation with very few studies scrutinizing open surgical simulation and its benefit to surgical trainees. The aim of this review is to summarize the current standard of available open surgical simulators and to review the literature on the benefits of open surgical simulation. Open surgical simulators currently used include live animals, cadavers, bench models, virtual reality, and software-based computer simulators. In the current literature, there are 18 different studies (including 6 randomized controlled trials and 12 cohort studies) investigating the efficacy of open surgical simulation using live animal, bench, and cadaveric models in many surgical specialties including general, cardiac, trauma, vascular, urologic, and gynecologic surgery. The current open surgical simulation studies show, in general, a significant benefit of open surgical simulation in developing the surgical skills of surgical trainees. However, these studies have their limitations including a low number of participants, variable assessment standards, and a focus on short-term results often with no follow-up assessment. The skills needed for open surgical procedures are the essential basis that a surgical trainee needs to grasp before attempting more technical procedures such as laparoscopic procedures. In this current climate of medical practice with reduced hours of surgical exposure for trainees and where the patient's safety and outcome is key, open surgical simulation is a promising adjunct to modern surgical training, filling the void between surgeons being trained in a technique and a surgeon achieving fluency in that

MicroRNA let-7b regulates neural stem cell proliferation and differentiation by targeting nuclear receptor TLX signaling.

Science.gov (United States)

Zhao, Chunnian; Sun, GuoQiang; Li, Shengxiu; Lang, Ming-Fei; Yang, Su; Li, Wendong; Shi, Yanhong

2010-02-02

Neural stem cell self-renewal and differentiation is orchestrated by precise control of gene expression involving nuclear receptor TLX. Let-7b, a member of the let-7 microRNA family, is expressed in mammalian brains and exhibits increased expression during neural differentiation. However, the role of let-7b in neural stem cell proliferation and differentiation remains unknown. Here we show that let-7b regulates neural stem cell proliferation and differentiation by targeting the stem cell regulator TLX and the cell cycle regulator cyclin D1. Overexpression of let-7b led to reduced neural stem cell proliferation and increased neural differentiation, whereas antisense knockdown of let-7b resulted in enhanced proliferation of neural stem cells. Moreover, in utero electroporation of let-7b to embryonic mouse brains led to reduced cell cycle progression in neural stem cells. Introducing an expression vector of Tlx or cyclin D1 that lacks the let-7b recognition site rescued let-7b-induced proliferation deficiency, suggesting that both TLX and cyclin D1 are important targets for let-7b-mediated regulation of neural stem cell proliferation. Let-7b, by targeting TLX and cyclin D1, establishes an efficient strategy to control neural stem cell proliferation and differentiation.

Anxiety in veterinary surgical students

DEFF Research Database (Denmark)

Langebæk, Rikke; Eika, Berit; Jensen, Asger Lundorff

2012-01-01

The surgical educational environment is potentially stressful and this can negatively affect students' learning. The aim of this study was to investigate whether veterinary students' level of anxiety is higher in a surgical course than in a non-surgical course and if pre-surgical training...... in a Surgical Skills Lab (SSL) has an anxiety reducing effect. Investigations were carried out as a comparative study and a parallel group study. Potential participants were fourth-year veterinary students who attended a surgical course (Basic Surgical Skills) and a non-surgical course (Clinical Examination...... and 28 students from 2010). Our results show that anxiety levels in veterinary students are significantly higher in a surgical course than in a non-surgical course (p...

Neural activation associated with the cognitive emotion regulation of sadness in healthy children

Directory of Open Access Journals (Sweden)

Andy C. Belden

2014-07-01

Full Text Available When used effectively, cognitive reappraisal of distressing events is a highly adaptive cognitive emotion regulation (CER strategy, with impairments in cognitive reappraisal associated with greater risk for psychopathology. Despite extensive literature examining the neural correlates of cognitive reappraisal in healthy and psychiatrically ill adults, there is a dearth of data to inform the neural bases of CER in children, a key gap in the literature necessary to map the developmental trajectory of cognitive reappraisal. In this fMRI study, psychiatrically healthy schoolchildren were instructed to use cognitive reappraisal to modulate their emotional reactions and responses of negative affect after viewing sad photos. Consistent with the adult literature, when actively engaged in reappraisal compared to passively viewing sad photos, children showed increased activation in the vlPFC, dlPFC, and dmPFC as well as in parietal and temporal lobe regions. When children used cognitive reappraisal to minimize their experience of negative affect after viewing sad stimuli they exhibited dampened amygdala responses. Results are discussed in relation to the importance of identifying and characterizing neural processes underlying adaptive CER strategies in typically developing children in order to understand how these systems go awry and relate to the risk and occurrence of affective disorders.

Surgical management and perioperative morbidity of patients with primary borderline ovarian tumor (BOT).

Science.gov (United States)

Trillsch, Fabian; Ruetzel, Jan David; Herwig, Uwe; Doerste, Ulrike; Woelber, Linn; Grimm, Donata; Choschzick, Matthias; Jaenicke, Fritz; Mahner, Sven

2013-07-09

Surgery is the cornerstone for clinical management of patients with borderline ovarian tumors (BOT). As these patients have an excellent overall prognosis, perioperative morbidity is the critical point for decision making when the treatment strategy is developed and the primary surgical approach is defined. Clinical and surgical parameters of patients undergoing surgery for primary BOT at our institutions between 1993 and 2008 were analyzed with regard to perioperative morbidity depending on the surgical approach (laparotomy vs. laparoscopy). A total of 105 patients were analyzed (44 with primary laparoscopy [42%], 61 with primary laparotomy [58%]). Complete surgical staging was achieved in 33 patients at primary surgical approach (31.4%) frequently leading to formal indication of re-staging procedures. Tumor rupture was significantly more frequent during laparoscopy compared to laparotomy (29.5% vs. 13.1%, p = 0.038) but no other intraoperative complications were seen in laparoscopic surgery in contrast to 7 of 61 laparotomies (0% vs. 11.5%, p = 0.020). Postoperative complication rates were similar in both groups (19.7% vs. 18.2%, p = 0.848). Irrespective of the surgical approach, surgical management of BOT has acceptable rates of perioperative complications and morbidity. Choice of initial surgical approach can therefore be made independent of complication-concerns. As the recently published large retrospective AGO ROBOT study observed similar oncologic outcome for both approaches, laparoscopy can be considered for staging of patients with BOT if this appears feasible. An algorithm for the surgical management of BOT patients has been developed.

Three-Dimensional-Bioprinted Dopamine-Based Matrix for Promoting Neural Regeneration.

Science.gov (United States)

Zhou, Xuan; Cui, Haitao; Nowicki, Margaret; Miao, Shida; Lee, Se-Jun; Masood, Fahed; Harris, Brent T; Zhang, Lijie Grace

2018-03-14

Central nerve repair and regeneration remain challenging problems worldwide, largely because of the extremely weak inherent regenerative capacity and accompanying fibrosis of native nerves. Inadequate solutions to the unmet needs for clinical therapeutics encourage the development of novel strategies to promote nerve regeneration. Recently, 3D bioprinting techniques, as one of a set of valuable tissue engineering technologies, have shown great promise toward fabricating complex and customizable artificial tissue scaffolds. Gelatin methacrylate (GelMA) possesses excellent biocompatible and biodegradable properties because it contains many arginine-glycine-aspartic acids (RGD) and matrix metalloproteinase sequences. Dopamine (DA), as an essential neurotransmitter, has proven effective in regulating neuronal development and enhancing neurite outgrowth. In this study, GelMA-DA neural scaffolds with hierarchical structures were 3D-fabricated using our custom-designed stereolithography-based printer. DA was functionalized on GelMA to synthesize a biocompatible printable ink (GelMA-DA) for improving neural differentiation. Additionally, neural stem cells (NSCs) were employed as the primary cell source for these scaffolds because of their ability to terminally differentiate into a variety of cell types including neurons, astrocytes, and oligodendrocytes. The resultant GelMA-DA scaffolds exhibited a highly porous and interconnected 3D environment, which is favorable for supporting NSC growth. Confocal microscopy analysis of neural differentiation demonstrated that a distinct neural network was formed on the GelMA-DA scaffolds. In particular, the most significant improvements were the enhanced neuron gene expression of TUJ1 and MAP2. Overall, our results demonstrated that 3D-printed customizable GelMA-DA scaffolds have a positive role in promoting neural differentiation, which is promising for advancing nerve repair and regeneration in the future.

Developing Process Maps as a Tool for a Surgical Infection Prevention Quality Improvement Initiative in Resource-Constrained Settings.

Science.gov (United States)

Forrester, Jared A; Koritsanszky, Luca A; Amenu, Demisew; Haynes, Alex B; Berry, William R; Alemu, Seifu; Jiru, Fekadu; Weiser, Thomas G

2018-06-01

Surgical infections cause substantial morbidity and mortality in low-and middle-income countries (LMICs). To improve adherence to critical perioperative infection prevention standards, we developed Clean Cut, a checklist-based quality improvement program to improve compliance with best practices. We hypothesized that process mapping infection prevention activities can help clinicians identify strategies for improving surgical safety. We introduced Clean Cut at a tertiary hospital in Ethiopia. Infection prevention standards included skin antisepsis, ensuring a sterile field, instrument decontamination/sterilization, prophylactic antibiotic administration, routine swab/gauze counting, and use of a surgical safety checklist. Processes were mapped by a visiting surgical fellow and local operating theater staff to facilitate the development of contextually relevant solutions; processes were reassessed for improvements. Process mapping helped identify barriers to using alcohol-based hand solution due to skin irritation, inconsistent administration of prophylactic antibiotics due to variable delivery outside of the operating theater, inefficiencies in assuring sterility of surgical instruments through lack of confirmatory measures, and occurrences of retained surgical items through inappropriate guidelines, staffing, and training in proper routine gauze counting. Compliance with most processes improved significantly following organizational changes to align tasks with specific process goals. Enumerating the steps involved in surgical infection prevention using a process mapping technique helped identify opportunities for improving adherence and plotting contextually relevant solutions, resulting in superior compliance with antiseptic standards. Simplifying these process maps into an adaptable tool could be a powerful strategy for improving safe surgery delivery in LMICs. Copyright © 2018 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

The Virtual Surgical Pelvis : Anatomy Visualization for Education and Surgical Planning

NARCIS (Netherlands)

Smit, N.N.

2016-01-01

This thesis deals with visualizing anatomical data for medical education and surgical planning purposes. To this end, we have developed a detailed virtual atlas, the Virtual Surgical Pelvis (VSP),which unifies surgically relevant knowledge on pelvic anatomy. We provide methods to share the knowledge

A novel application of artificial neural network for wind speed estimation

Science.gov (United States)

Fang, Da; Wang, Jianzhou

2017-05-01

Providing accurate multi-steps wind speed estimation models has increasing significance, because of the important technical and economic impacts of wind speed on power grid security and environment benefits. In this study, the combined strategies for wind speed forecasting are proposed based on an intelligent data processing system using artificial neural network (ANN). Generalized regression neural network and Elman neural network are employed to form two hybrid models. The approach employs one of ANN to model the samples achieving data denoising and assimilation and apply the other to predict wind speed using the pre-processed samples. The proposed method is demonstrated in terms of the predicting improvements of the hybrid models compared with single ANN and the typical forecasting method. To give sufficient cases for the study, four observation sites with monthly average wind speed of four given years in Western China were used to test the models. Multiple evaluation methods demonstrated that the proposed method provides a promising alternative technique in monthly average wind speed estimation.

Deriving DICOM surgical extensions from surgical workflows

Science.gov (United States)

Burgert, O.; Neumuth, T.; Gessat, M.; Jacobs, S.; Lemke, H. U.

2007-03-01

The generation, storage, transfer, and representation of image data in radiology are standardized by DICOM. To cover the needs of image guided surgery or computer assisted surgery in general one needs to handle patient information besides image data. A large number of objects must be defined in DICOM to address the needs of surgery. We propose an analysis process based on Surgical Workflows that helps to identify these objects together with use cases and requirements motivating for their specification. As the first result we confirmed the need for the specification of representation and transfer of geometric models. The analysis of Surgical Workflows has shown that geometric models are widely used to represent planned procedure steps, surgical tools, anatomical structures, or prosthesis in the context of surgical planning, image guided surgery, augmented reality, and simulation. By now, the models are stored and transferred in several file formats bare of contextual information. The standardization of data types including contextual information and specifications for handling of geometric models allows a broader usage of such models. This paper explains the specification process leading to Geometry Mesh Service Object Pair classes. This process can be a template for the definition of further DICOM classes.

Robust adaptive backstepping neural networks control for spacecraft rendezvous and docking with input saturation.

Science.gov (United States)

Xia, Kewei; Huo, Wei

2016-05-01

This paper presents a robust adaptive neural networks control strategy for spacecraft rendezvous and docking with the coupled position and attitude dynamics under input saturation. Backstepping technique is applied to design a relative attitude controller and a relative position controller, respectively. The dynamics uncertainties are approximated by radial basis function neural networks (RBFNNs). A novel switching controller consists of an adaptive neural networks controller dominating in its active region combined with an extra robust controller to avoid invalidation of the RBFNNs destroying stability of the system outside the neural active region. An auxiliary signal is introduced to compensate the input saturation with anti-windup technique, and a command filter is employed to approximate derivative of the virtual control in the backstepping procedure. Globally uniformly ultimately bounded of the relative states is proved via Lyapunov theory. Simulation example demonstrates effectiveness of the proposed control scheme. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

STRATEGIES OF COMPLETE ORAL REHABILITATION IN PATIENTS WITH DISFUNCTIONAL SYNDROM OF THE STOMATOGNATE SYSTEM

Directory of Open Access Journals (Sweden)

Vasile BURLUI

2015-12-01

Full Text Available The complete oral and dental rehabilitation (ROC or (CODR requires an advanced understanding level, based on the capacity to prepare and successfully fix the complete strategy for the complex oral rehabilitation had in view.The method applied was to subject a representative group of patients to the algorithm of diagnosis and clinical solution. The strategies of complete oral rehabilitation applied included surgical-periodontal, implanto-surgical, implanto-prosthetic rehabilitation techniques.

Cellular Neural Networks: A genetic algorithm for parameters optimization in artificial vision applications

International Nuclear Information System (INIS)

Taraglio, S.; Zanela, A.

1997-03-01

An optimization method for some of the CNN's (Cellular Neural Network) parameters, based on evolutionary strategies, is proposed. The new class of feedback template found is more effective in extracting features from the images that an autonomous vehicle acquires, than in the previous CNN's literature

Transcriptional profiling of adult neural stem-like cells from the human brain.

Directory of Open Access Journals (Sweden)

Cecilie Jonsgar Sandberg

Full Text Available There is a great potential for the development of new cell replacement strategies based on adult human neural stem-like cells. However, little is known about the hierarchy of cells and the unique molecular properties of stem- and progenitor cells of the nervous system. Stem cells from the adult human brain can be propagated and expanded in vitro as free floating neurospheres that are capable of self-renewal and differentiation into all three cell types of the central nervous system. Here we report the first global gene expression study of adult human neural stem-like cells originating from five human subventricular zone biopsies (mean age 42, range 33-60. Compared to adult human brain tissue, we identified 1,189 genes that were significantly up- and down-regulated in adult human neural stem-like cells (1% false discovery rate. We found that adult human neural stem-like cells express stem cell markers and have reduced levels of markers that are typical of the mature cells in the nervous system. We report that the genes being highly expressed in adult human neural stem-like cells are associated with developmental processes and the extracellular region of the cell. The calcium signaling pathway and neuroactive ligand-receptor interactions are enriched among the most differentially regulated genes between adult human neural stem-like cells and adult human brain tissue. We confirmed the expression of 10 of the most up-regulated genes in adult human neural stem-like cells in an additional sample set that included adult human neural stem-like cells (n = 6, foetal human neural stem cells (n = 1 and human brain tissues (n = 12. The NGFR, SLITRK6 and KCNS3 receptors were further investigated by immunofluorescence and shown to be heterogeneously expressed in spheres. These receptors could potentially serve as new markers for the identification and characterisation of neural stem- and progenitor cells or as targets for manipulation of cellular

Neural Parallel Engine: A toolbox for massively parallel neural signal processing.

Science.gov (United States)

Tam, Wing-Kin; Yang, Zhi

2018-05-01

Large-scale neural recordings provide detailed information on neuronal activities and can help elicit the underlying neural mechanisms of the brain. However, the computational burden is also formidable when we try to process the huge data stream generated by such recordings. In this study, we report the development of Neural Parallel Engine (NPE), a toolbox for massively parallel neural signal processing on graphical processing units (GPUs). It offers a selection of the most commonly used routines in neural signal processing such as spike detection and spike sorting, including advanced algorithms such as exponential-component-power-component (EC-PC) spike detection and binary pursuit spike sorting. We also propose a new method for detecting peaks in parallel through a parallel compact operation. Our toolbox is able to offer a 5× to 110× speedup compared with its CPU counterparts depending on the algorithms. A user-friendly MATLAB interface is provided to allow easy integration of the toolbox into existing workflows. Previous efforts on GPU neural signal processing only focus on a few rudimentary algorithms, are not well-optimized and often do not provide a user-friendly programming interface to fit into existing workflows. There is a strong need for a comprehensive toolbox for massively parallel neural signal processing. A new toolbox for massively parallel neural signal processing has been created. It can offer significant speedup in processing signals from large-scale recordings up to thousands of channels. Copyright © 2018 Elsevier B.V. All rights reserved.

Disposable surgical face masks for preventing surgical wound infection in clean surgery

Directory of Open Access Journals (Sweden)

Allyson Lipp

Full Text Available BACKGROUND: Surgical face masks were originally developed to contain and filter droplets containing microorganisms expelled from the mouth and nasopharynx of healthcare workers during surgery, thereby providing protection for the patient. However, there are several ways in which surgical face masks could potentially contribute to contamination of the surgical wound, e.g. by incorrect wear or by leaking air from the side of the mask due to poor string tension. OBJECTIVES: To determine whether disposable surgical face masks worn by the surgical team during clean surgery prevent postoperative surgical wound infection. SEARCH METHODS: We searched The Cochrane Wounds Group Specialised Register (searched 14 September 2011; The Cochrane Central Register of Controlled Trials (CENTRAL (The Cochrane Library 2011, Issue 3; Ovid MEDLINE (2008 to August Week 5 2011; Ovid MEDLINE (In-Process &Other Non-Indexed Citations September 13, 2011; Ovid EMBASE (2008 to 2011 Week 35; and EBSCO CINAHL (2008 to 9 September 2011. SELECTION CRITERIA: Randomized controlled trials (RCTs and quasi-randomized controlled trials comparing the use of disposable surgical masks with the use of no mask. DATA COLLECTION AND ANALYSIS: Two review authors extracted data independently. MAIN RESULTS: Three trials were included, involving a total of 2113 participants. There was no statistically significant difference in infection rates between the masked and unmasked group in any of the trials. AUTHORS' CONCLUSIONS: From the limited results it is unclear whether the wearing of surgical face masks by members of the surgical team has any impact on surgical wound infection rates for patients undergoing clean surgery.

Neural chips, neural computers and application in high and superhigh energy physics experiments

International Nuclear Information System (INIS)

Nikityuk, N.M.; )

2001-01-01

Architecture peculiarity and characteristics of series of neural chips and neural computes used in scientific instruments are considered. Tendency of development and use of them in high energy and superhigh energy physics experiments are described. Comparative data which characterize the efficient use of neural chips for useful event selection, classification elementary particles, reconstruction of tracks of charged particles and for search of hypothesis Higgs particles are given. The characteristics of native neural chips and accelerated neural boards are considered [ru

Differentiation of insulin-producing cells from human neural progenitor cells.

Directory of Open Access Journals (Sweden)

Yuichi Hori

2005-04-01

Full Text Available BACKGROUND: Success in islet-transplantation-based therapies for type 1 diabetes, coupled with a worldwide shortage of transplant-ready islets, has motivated efforts to develop renewable sources of islet-replacement tissue. Islets and neurons share features, including common developmental programs, and in some species brain neurons are the principal source of systemic insulin. METHODS AND FINDINGS: Here we show that brain-derived human neural progenitor cells, exposed to a series of signals that regulate in vivo pancreatic islet development, form clusters of glucose-responsive insulin-producing cells (IPCs. During in vitro differentiation of neural progenitor cells with this novel method, genes encoding essential known in vivo regulators of pancreatic islet development were expressed. Following transplantation into immunocompromised mice, IPCs released insulin C-peptide upon glucose challenge, remained differentiated, and did not form detectable tumors. CONCLUSION: Production of IPCs solely through extracellular factor modulation in the absence of genetic manipulations may promote strategies to derive transplantable islet-replacement tissues from human neural progenitor cells and other types of multipotent human stem cells.

Neural networks for tracking of unknown SISO discrete-time nonlinear dynamic systems.

Science.gov (United States)

Aftab, Muhammad Saleheen; Shafiq, Muhammad

2015-11-01

This article presents a Lyapunov function based neural network tracking (LNT) strategy for single-input, single-output (SISO) discrete-time nonlinear dynamic systems. The proposed LNT architecture is composed of two feedforward neural networks operating as controller and estimator. A Lyapunov function based back propagation learning algorithm is used for online adjustment of the controller and estimator parameters. The controller and estimator error convergence and closed-loop system stability analysis is performed by Lyapunov stability theory. Moreover, two simulation examples and one real-time experiment are investigated as case studies. The achieved results successfully validate the controller performance. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

A review on mechanical considerations for chronically-implanted neural probes

Science.gov (United States)

Lecomte, Aziliz; Descamps, Emeline; Bergaud, Christian

2018-06-01

This review intends to present a comprehensive analysis of the mechanical considerations for chronically-implanted neural probes. Failure of neural electrical recordings or stimulation over time has shown to arise from foreign body reaction and device material stability. It seems that devices that match most closely with the mechanical properties of the brain would be more likely to reduce the mechanical stress at the probe/tissue interface, thus improving body acceptance. The use of low Young’s modulus polymers instead of hard substrates is one way to enhance this mechanical mimetism, though compliance can be achieved through a variety of means. The reduction of probe width and thickness in comparison to a designated length, the use of soft hydrogel coatings and the release in device tethering to the skull, can also improve device compliance. Paradoxically, the more compliant the device, the more likely it will fail during the insertion process in the brain. Strategies have multiplied this past decade to offer partial or temporary stiffness to the device to overcome this buckling effect. A detailed description of the probe insertion mechanisms is provided to analyze potential sources of implantation failure and the need for a mechanically-enhancing structure. This leads us to present an overview of the strategies that have been put in place over the last ten years to overcome buckling issues. Particularly, great emphasis is put on bioresorbable polymers and their assessment for neural applications. Finally, a discussion is provided on some of the key features for the design of mechanically-reliable, polymer-based next generation of chronic neuroprosthetic devices.

Neural tissue-spheres

DEFF Research Database (Denmark)

Andersen, Rikke K; Johansen, Mathias; Blaabjerg, Morten

2007-01-01

By combining new and established protocols we have developed a procedure for isolation and propagation of neural precursor cells from the forebrain subventricular zone (SVZ) of newborn rats. Small tissue blocks of the SVZ were dissected and propagated en bloc as free-floating neural tissue...... content, thus allowing experimental studies of neural precursor cells and their niche...

Pre-Exposure to Context Affects Learning Strategy Selection in Mice

Science.gov (United States)

Tunur, Tumay; Dohanich, Gary P.; Schrader, Laura A.

2010-01-01

The multiple memory systems hypothesis proposes that different types of learning strategies are mediated by distinct neural systems in the brain. Male and female mice were tested on a water plus-maze task that could be solved by either a place or response strategy. One group of mice was pre-exposed to the same context as training and testing (PTC)…

Pooled Open Blocks Shorten Wait Times for Nonelective Surgical Cases.

Science.gov (United States)

Zenteno, Ana C; Carnes, Tim; Levi, Retsef; Daily, Bethany J; Price, Devon; Moss, Susan C; Dunn, Peter F

2015-07-01

Assess the impact of the implementation of a data-driven scheduling strategy that aimed to improve the access to care of nonelective surgical patients at Massachusetts General Hospital (MGH). Between July 2009 and June 2010, MGH experienced increasing throughput challenges in its perioperative environment: approximately 30% of the nonelective patients were waiting more than the prescribed amount of time to get to surgery, hampering access to care and aggravating the lack of inpatient beds. This work describes the design and implementation of an "open block" strategy: operating room (OR) blocks were reserved for nonelective patients during regular working hours (prime time) and their management centralized. Discrete event simulation showed that 5 rooms would decrease the percentage of delayed patients from 30% to 2%, assuming that OR availability was the only reason for preoperative delay. Implementation began in January 2012. We compare metrics for June through December of 2012 against the same months of 2011. The average preoperative wait time of all nonelective surgical patients decreased by 25.5% (P reason for delay. Rigorous metrics were developed to evaluate its performance. Strong managerial leadership was crucial to enact the new practices and turn them into organizational change.

Dissociated neural processing for decisions in managers and non-managers.

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Caspers, Svenja; Heim, Stefan; Lucas, Marc G; Stephan, Egon; Fischer, Lorenz; Amunts, Katrin; Zilles, Karl

2012-01-01

Functional neuroimaging studies of decision-making so far mainly focused on decisions under uncertainty or negotiation with other persons. Dual process theory assumes that, in such situations, decision making relies on either a rapid intuitive, automated or a slower rational processing system. However, it still remains elusive how personality factors or professional requirements might modulate the decision process and the underlying neural mechanisms. Since decision making is a key task of managers, we hypothesized that managers, facing higher pressure for frequent and rapid decisions than non-managers, prefer the heuristic, automated decision strategy in contrast to non-managers. Such different strategies may, in turn, rely on different neural systems. We tested managers and non-managers in a functional magnetic resonance imaging study using a forced-choice paradigm on word-pairs. Managers showed subcortical activation in the head of the caudate nucleus, and reduced hemodynamic response within the cortex. In contrast, non-managers revealed the opposite pattern. With the head of the caudate nucleus being an initiating component for process automation, these results supported the initial hypothesis, hinting at automation during decisions in managers. More generally, the findings reveal how different professional requirements might modulate cognitive decision processing.

Surgical management for displaced pediatric proximal humeral fractures: a cost analysis.

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Shore, Benjamin J; Hedequist, Daniel J; Miller, Patricia E; Waters, Peter M; Bae, Donald S

2015-02-01

The purpose of this investigation was to determine which of the following methods of fixation, percutaneous pinning (PP) or intramedullary nailing (IMN), was more cost-effective in the treatment of displaced pediatric proximal humeral fractures (PPHF). A retrospective cohort of surgically treated PPHF over a 12-year period at a single institution was performed. A decision analysis model was constructed to compare three surgical strategies: IMN versus percutaneous pinning leaving the pins exposed (PPE) versus leaving the pins buried (PPB). Finally, sensitivity analyses were performed, assessing the cost-effectiveness of each technique when infection rates and cost of deep infections were varied. A total of 84 patients with displaced PPHF underwent surgical stabilization. A total of 35 cases were treated with IMN, 32 with PPE, and 17 with PPB. The age, sex, and preoperative fracture angulation were similar across all groups. A greater percentage of open reduction was seen in the IMN and PPB groups (p = 0.03), while a higher proportion of physeal injury was seen in the PPE group (p = 0.02). Surgical time and estimated blood loss was higher in the IMN group (p exposed implants approached 55 %. Leaving pins exposed after surgical fixation of PPHF is more cost-effective than either burying pins or using intramedullary fixation.

Convolutional Neural Network for Histopathological Analysis of Osteosarcoma.

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Mishra, Rashika; Daescu, Ovidiu; Leavey, Patrick; Rakheja, Dinesh; Sengupta, Anita

2018-03-01

Pathologists often deal with high complexity and sometimes disagreement over osteosarcoma tumor classification due to cellular heterogeneity in the dataset. Segmentation and classification of histology tissue in H&E stained tumor image datasets is a challenging task because of intra-class variations, inter-class similarity, crowded context, and noisy data. In recent years, deep learning approaches have led to encouraging results in breast cancer and prostate cancer analysis. In this article, we propose convolutional neural network (CNN) as a tool to improve efficiency and accuracy of osteosarcoma tumor classification into tumor classes (viable tumor, necrosis) versus nontumor. The proposed CNN architecture contains eight learned layers: three sets of stacked two convolutional layers interspersed with max pooling layers for feature extraction and two fully connected layers with data augmentation strategies to boost performance. The use of a neural network results in higher accuracy of average 92% for the classification. We compare the proposed architecture with three existing and proven CNN architectures for image classification: AlexNet, LeNet, and VGGNet. We also provide a pipeline to calculate percentage necrosis in a given whole slide image. We conclude that the use of neural networks can assure both high accuracy and efficiency in osteosarcoma classification.

Non-pharmacological strategies for blood conservation in cardiac surgery.

Science.gov (United States)

Ruel, M A; Rubens, F D

2001-04-01

Of all surgical specialties, cardiac operations are most often associated with coagulopathy, blood loss, and the need for transfusions. This not only represents a major burden on blood procurement and banking organizations at all levels, but also constitutes a risk for each patient receiving allogeneic blood products. This paper reviews current non-pharmacological strategies aimed at decreasing blood use in patients undergoing cardiac surgery. The literature pertaining to each blood conservation strategy was searched, reviewed, and appraised. Meta- analyses were also consulted and their results complemented with subsequent reports when available. Preoperative autologous donation programs are effective in decreasing allogeneic transfusions, but are costly and applicable to elective patients only. Off-pump revascularization strategies also appear to decrease transfusion requirements in suitable patients. The effectiveness of acute normovolemic hemodilution, retrograde autologous priming, small volume cardiopulmonary bypass circuits, platelet-rich plasmapheresis, alternative heparin strategies, and postoperative cell salvage are more difficult to appraise as a high proportion of available studies suffer from lack of transfusion guidelines or the absence of blinding. Biological glues, surgical adhesives, and postoperative increases in positive end-expiratory pressure (PEEP) have no demonstrated efficacy. The applicability or effectiveness of many of these modalities remains controversial and more studies are needed before they may be employed routinely in cardiac surgical patients. The judicious use of rational transfusion guidelines may still be the simplest and most cost-effective means of blood conservation today.

Electricity price forecast using Combinatorial Neural Network trained by a new stochastic search method

International Nuclear Information System (INIS)

Abedinia, O.; Amjady, N.; Shafie-khah, M.; Catalão, J.P.S.

2015-01-01

Highlights: • Presenting a Combinatorial Neural Network. • Suggesting a new stochastic search method. • Adapting the suggested method as a training mechanism. • Proposing a new forecast strategy. • Testing the proposed strategy on real-world electricity markets. - Abstract: Electricity price forecast is key information for successful operation of electricity market participants. However, the time series of electricity price has nonlinear, non-stationary and volatile behaviour and so its forecast method should have high learning capability to extract the complex input/output mapping function of electricity price. In this paper, a Combinatorial Neural Network (CNN) based forecasting engine is proposed to predict the future values of price data. The CNN-based forecasting engine is equipped with a new training mechanism for optimizing the weights of the CNN. This training mechanism is based on an efficient stochastic search method, which is a modified version of chemical reaction optimization algorithm, giving high learning ability to the CNN. The proposed price forecast strategy is tested on the real-world electricity markets of Pennsylvania–New Jersey–Maryland (PJM) and mainland Spain and its obtained results are extensively compared with the results obtained from several other forecast methods. These comparisons illustrate effectiveness of the proposed strategy.

Sound Localization Strategies in Three Predators

DEFF Research Database (Denmark)

Carr, Catherine E; Christensen-Dalsgaard, Jakob

2015-01-01

. Despite the similar organization of their auditory systems, archosaurs and lizards use different strategies for encoding the ITDs that underlie localization of sound in azimuth. Barn owls encode ITD information using a place map, which is composed of neurons serving as labeled lines tuned for preferred......In this paper, we compare some of the neural strategies for sound localization and encoding interaural time differences (ITDs) in three predatory species of Reptilia, alligators, barn owls and geckos. Birds and crocodilians are sister groups among the extant archosaurs, while geckos are lepidosaurs...... spatial locations, while geckos may use a meter strategy or population code composed of broadly sensitive neurons that represent ITD via changes in the firing rate....

Cellular Neural Networks: A genetic algorithm for parameters optimization in artificial vision applications

Energy Technology Data Exchange (ETDEWEB)

Taraglio, S. [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dipt. Innovazione; Zanela, A. [Rome Univ. `La Sapienza` (Italy). Dipt. di Fisica

1997-03-01

An optimization method for some of the CNN`s (Cellular Neural Network) parameters, based on evolutionary strategies, is proposed. The new class of feedback template found is more effective in extracting features from the images that an autonomous vehicle acquires, than in the previous CNN`s literature.

Endogenous retinal neural stem cell reprogramming for neuronal regeneration

Directory of Open Access Journals (Sweden)

Romain Madelaine

2017-01-01

Full Text Available In humans, optic nerve injuries and associated neurodegenerative diseases are often followed by permanent vision loss. Consequently, an important challenge is to develop safe and effective methods to replace retinal neurons and thereby restore neuronal functions and vision. Identifying cellular and molecular mechanisms allowing to replace damaged neurons is a major goal for basic and translational research in regenerative medicine. Contrary to mammals, the zebrafish has the capacity to fully regenerate entire parts of the nervous system, including retina. This regenerative process depends on endogenous retinal neural stem cells, the Müller glial cells. Following injury, zebrafish Müller cells go back into cell cycle to proliferate and generate new neurons, while mammalian Müller cells undergo reactive gliosis. Recently, transcription factors and microRNAs have been identified to control the formation of new neurons derived from zebrafish and mammalian Müller cells, indicating that cellular reprogramming can be an efficient strategy to regenerate human retinal neurons. Here we discuss recent insights into the use of endogenous neural stem cell reprogramming for neuronal regeneration, differences between zebrafish and mammalian Müller cells, and the need to pursue the identification and characterization of new molecular factors with an instructive and potent function in order to develop theurapeutic strategies for eye diseases.

Same task, different strategies: How brain networks can be influenced by memory strategy

OpenAIRE

Sanfratello, Lori; Caprihan, Arvind; Stephen, Julia M.; Knoefel, Janice E.; Adair, John C.; Qualls, Clifford; Lundy, S. Laura; Aine, Cheryl J.

2014-01-01

Previous functional neuroimaging studies demonstrated that different neural networks underlie different types of cognitive processing by engaging participants in particular tasks, such as verbal or spatial working memory (WM) tasks. However, we report here that even when a working memory task is defined as verbal or spatial, different types of memory strategies may be employed to complete it, with concomitant variations in brain activity. We developed a questionnaire to characterize the type ...

The evolution of the surgical treatment of chronic pancreatitis.

Science.gov (United States)

Andersen, Dana K; Frey, Charles F

2010-01-01

To establish the current status of surgical therapy for chronic pancreatitis, recent published reports are examined in the context of the historical advances in the field. The basis for decompression (drainage), denervation, and resection strategies for the treatment of pain caused by chronic pancreatitis is reviewed. These divergent approaches have finally coalesced as the head of the pancreas has become apparent as the nidus of chronic inflammation. The recent developments in surgical methods to treat the complications of chronic pancreatitis and the results of recent prospective randomized trials of operative approaches were reviewed to establish the current best practices. Local resection of the pancreatic head, with or without duct drainage, and duodenum-preserving pancreatic head resection offer outcomes as effective as pancreaticoduodenectomy, with lowered morbidity and mortality. Local resection or excavation of the pancreatic head offers the advantage of lowest cost and morbidity and early prevention of postoperative diabetes. The late incidences of recurrent pain, diabetes, and exocrine insufficiency are equivalent for all 3 surgical approaches. Local resection of the pancreatic head appears to offer best outcomes and lowest risk for the management of the pain of chronic pancreatitis.

Contemporary surgical management of synchronous colorectal liver metastases [version 1; referees: 2 approved

Directory of Open Access Journals (Sweden)

Danielle Collins

2017-04-01

Full Text Available Historically, the 5-year survival rates for patients with stage 4 (metastatic colorectal cancer were extremely poor (5%; however, with advances in systemic chemotherapy combined with an ability to push the boundaries of surgical resection, survival rates in the range of 25–40% can be achieved. This multimodal approach of combining neo-adjuvant strategies with surgical resection has raised a number of questions regarding the optimal management and timing of surgery. For the purpose of this review, we will focus on the treatment of stage 4 colorectal cancer with synchronous liver metastases.

Improving Pattern Recognition and Neural Network Algorithms with Applications to Solar Panel Energy Optimization

Science.gov (United States)

Zamora Ramos, Ernesto

, multilayer percepterons and convolutional neural networks. Our research with neural networks has encountered a great deal of difficulties regarding hyperparameter estimation for good training convergence rate and accuracy. Most hyperparameters, including architecture, learning rate, regularization, trainable parameters (or weights) initialization, and so on, are chosen via a trial and error process with some educated guesses. However, we developed the first quantitative method to compare weight initialization strategies, a critical hyperparameter choice during training, to estimate among a group of candidate strategies which would make the network converge to the highest classification accuracy faster with high probability. Our method provides a quick, objective measure to compare initialization strategies to select the best possible among them beforehand without having to complete multiple training sessions for each candidate strategy to compare final results.

Backstepping fuzzy-neural-network control design for hybrid maglev transportation system.

Science.gov (United States)

Wai, Rong-Jong; Yao, Jing-Xiang; Lee, Jeng-Dao

2015-02-01

This paper focuses on the design of a backstepping fuzzy-neural-network control (BFNNC) for the online levitated balancing and propulsive positioning of a hybrid magnetic levitation (maglev) transportation system. The dynamic model of the hybrid maglev transportation system including levitated hybrid electromagnets to reduce the suspension power loss and the friction force during linear movement and a propulsive linear induction motor based on the concepts of mechanical geometry and motion dynamics is first constructed. The ultimate goal is to design an online fuzzy neural network (FNN) control methodology to cope with the problem of the complicated control transformation and the chattering control effort in backstepping control (BSC) design, and to directly ensure the stability of the controlled system without the requirement of strict constraints, detailed system information, and auxiliary compensated controllers despite the existence of uncertainties. In the proposed BFNNC scheme, an FNN control is utilized to be the major control role by imitating the BSC strategy, and adaptation laws for network parameters are derived in the sense of projection algorithm and Lyapunov stability theorem to ensure the network convergence as well as stable control performance. The effectiveness of the proposed control strategy for the hybrid maglev transportation system is verified by experimental results, and the superiority of the BFNNC scheme is indicated in comparison with the BSC strategy and the backstepping particle-swarm-optimization control system in previous research.

A neural network model for non invasive subsurface stratigraphic identification

International Nuclear Information System (INIS)

Sullivan, John M. Jr.; Ludwig, Reinhold; Lai Qiang

2000-01-01

Ground-Penetrating Radar (GRP) is a powerful tool to examine the stratigraphy below ground surface for remote sensing. Increasingly GPR has also found applications in microwave NDE as an interrogation tool to assess dielectric layers. Unfortunately, GPR data is characterized by a high degree of uncertainty and natural physical ambiguity. Robust decomposition routines are sparse for this application. We have developed a hierarchical set of neural network modules which split the task of layer profiling into consecutive stages. Successful GPR profiling of the subsurface stratigraphy is of key importance for many remote sensing applications including microwave NDE. Neural network modules were designed to accomplish the two main processing goals of recognizing the 'subsurface pattern' followed by the identification of the depths of the subsurface layers like permafrost, groundwater table, and bedrock. We used an adaptive transform technique to transform raw GPR data into a small feature vector containing the most representative and discriminative features of the signal. This information formed the input for the neural network processing units. This strategy reduced the number of required training samples for the neural network by orders of magnitude. The entire processing system was trained using the adaptive transformed feature vector inputs and tested with real measured GPR data. The successful results of this system establishes the feasibility the feasibility of delineating subsurface layering nondestructively

The American College of Surgeons/Association of Program Directors in Surgery National Skills Curriculum: adoption rate, challenges and strategies for effective implementation into surgical residency programs.

Science.gov (United States)

Korndorffer, James R; Arora, Sonal; Sevdalis, Nick; Paige, John; McClusky, David A; Stefanidis, Dimitris

2013-07-01

The American College of Surgeons/Association of Program Directors in Surgery (ACS/APDS) National Skills Curriculum is a 3-phase program targeting technical and nontechnical skills development. Few data exist regarding the adoption of this curriculum by surgical residencies. This study attempted to determine the rate of uptake and identify implementation enablers/barriers. A web-based survey was developed by an international expert panel of surgical educators (5 surgeons and 1 psychologist). After piloting, the survey was sent to all general surgery program directors via email link. Descriptive statistics were used to determine the residency program characteristics and perceptions of the curriculum. Implementation rates for each phase and module were calculated. Adoption barriers were identified quantitatively and qualitatively using free text responses. Standardized qualitative methodology of emergent theme analysis was used to identify strategies for success and details of support required for implementation. Of the 238 program directors approached, 117 (49%) responded to the survey. Twenty-one percent (25/117) were unaware of the ACS/APDS curriculum. Implementation rates for were 36% for phase I, 19% for phase II, and 16% for phase III. The most common modules adopted were the suturing, knot-tying, and chest tube modules of phase I. Over 50% of respondents identified lack of faculty protected time, limited personnel, significant costs, and resident work-hour restrictions as major obstacles to implementation. Strategies for effective uptake included faculty incentives, adequate funding, administrative support, and dedicated time and resources. Despite the availability of a comprehensive curriculum, its diffusion into general surgery residency programs remains low. Obstacles related to successful implementation include personnel, learner, and administrative issues. Addressing these issues may improve the adoption rate of the curriculum. Copyright © 2013 Mosby, Inc

Surgical management of third nerve palsy

Directory of Open Access Journals (Sweden)

Anupam Singh

2016-01-01

Full Text Available Third nerve paralysis has been known to be associated with a wide spectrum of presentation and other associated factors such as the presence of ptosis, pupillary involvement, amblyopia, aberrant regeneration, poor bell′s phenomenon, superior oblique (SO overaction, and lateral rectus (LR contracture. Correction of strabismus due to third nerve palsy can be complex as four out of the six extraocular muscles are involved and therefore should be approached differently. Third nerve palsy can be congenital or acquired. The common causes of isolated third nerve palsy in children are congenital (43%, trauma (20%, inflammation (13%, aneurysm (7%, and ophthalmoplegic migraine. Whereas, in adult population, common etiologies are vasculopathic disorders (diabetes mellitus, hypertension, aneurysm, and trauma. Treatment can be both nonsurgical and surgical. As nonsurgical modalities are not of much help, surgery remains the main-stay of treatment. Surgical strategies are different for complete and partial third nerve palsy. Surgery for complete third nerve palsy may involve supra-maximal recession - resection of the recti. This may be combined with SO transposition and augmented by surgery on the other eye. For partial third nerve, palsy surgery is determined according to nature and extent of involvement of extraocular muscles.

Surgical management of third nerve palsy

Science.gov (United States)

Singh, Anupam; Bahuguna, Chirag; Nagpal, Ritu; Kumar, Barun

2016-01-01

Third nerve paralysis has been known to be associated with a wide spectrum of presentation and other associated factors such as the presence of ptosis, pupillary involvement, amblyopia, aberrant regeneration, poor bell's phenomenon, superior oblique (SO) overaction, and lateral rectus (LR) contracture. Correction of strabismus due to third nerve palsy can be complex as four out of the six extraocular muscles are involved and therefore should be approached differently. Third nerve palsy can be congenital or acquired. The common causes of isolated third nerve palsy in children are congenital (43%), trauma (20%), inflammation (13%), aneurysm (7%), and ophthalmoplegic migraine. Whereas, in adult population, common etiologies are vasculopathic disorders (diabetes mellitus, hypertension), aneurysm, and trauma. Treatment can be both nonsurgical and surgical. As nonsurgical modalities are not of much help, surgery remains the main-stay of treatment. Surgical strategies are different for complete and partial third nerve palsy. Surgery for complete third nerve palsy may involve supra-maximal recession - resection of the recti. This may be combined with SO transposition and augmented by surgery on the other eye. For partial third nerve, palsy surgery is determined according to nature and extent of involvement of extraocular muscles. PMID:27433033

Robust fixed-time synchronization of delayed Cohen-Grossberg neural networks.

Science.gov (United States)

Wan, Ying; Cao, Jinde; Wen, Guanghui; Yu, Wenwu

2016-01-01

The fixed-time master-slave synchronization of Cohen-Grossberg neural networks with parameter uncertainties and time-varying delays is investigated. Compared with finite-time synchronization where the convergence time relies on the initial synchronization errors, the settling time of fixed-time synchronization can be adjusted to desired values regardless of initial conditions. Novel synchronization control strategy for the slave neural network is proposed. By utilizing the Filippov discontinuous theory and Lyapunov stability theory, some sufficient schemes are provided for selecting the control parameters to ensure synchronization with required convergence time and in the presence of parameter uncertainties. Corresponding criteria for tuning control inputs are also derived for the finite-time synchronization. Finally, two numerical examples are given to illustrate the validity of the theoretical results. Copyright © 2015 Elsevier Ltd. All rights reserved.

Minimizing surgical skin incision scars with a latex surgical glove.

Science.gov (United States)

Han, So-Eun; Ryoo, Suk-Tae; Lim, So Young; Pyon, Jai-Kyung; Bang, Sa-Ik; Oh, Kap-Sung; Mun, Goo-Hyun

2013-04-01

The current trend in minimally invasive surgery is to make a small surgical incision. However, the excessive tensile stress applied by the retractors to the skin surrounding the incision often results in a long wound healing time and extensive scarring. To minimize these types of wound problems, the authors evaluated a simple and cost-effective method to minimize surgical incision scars based on the use of a latex surgical glove. The tunnel-shaped part of a powder-free latex surgical glove was applied to the incision and the dissection plane. It was fixed to the full layer of the dissection plane with sutures. The glove on the skin surface then was sealed with Ioban (3 M Health Care, St. Paul, MN, USA) to prevent movement. The operation proceeded as usual, with the retractor running through the tunnel of the latex glove. It was possible to complete the operation without any disturbance of the visual field by the surgical glove, and the glove was neither torn nor separated by the retractors. The retractors caused traction and friction during the operation, but the extent of damage to the postoperative skin incision margin was remarkably less than when the operation was performed without a glove. This simple and cost-effective method is based on the use of a latex surgical glove to protect the surgical skin incision site and improve the appearance of the postoperative scar. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Non-surgical sterilisation methods may offer a sustainable solution to feral horse (Equus caballus) overpopulation.

Science.gov (United States)

Hall, Sally Elizabeth; Nixon, Brett; Aitken, R John

2017-09-01

Feral horses are a significant pest species in many parts of the world, contributing to land erosion, weed dispersal and the loss of native flora and fauna. There is an urgent need to modify feral horse management strategies to achieve public acceptance and long-term population control. One way to achieve this is by using non-surgical methods of sterilisation, which are suitable in the context of this mobile and long-lived species. In this review we consider the benefits of implementing novel mechanisms designed to elicit a state of permanent sterility (including redox cycling to generate oxidative stress in the gonad, random peptide phage display to target non-renewable germ cells and the generation of autoantibodies against proteins essential for conception via covalent modification) compared with that of traditional immunocontraceptive approaches. The need for a better understanding of mare folliculogenesis and conception factors, including maternal recognition of pregnancy, is also reviewed because they hold considerable potential in providing a non-surgical mechanism for sterilisation. In conclusion, the authors contend that non-surgical measures that are single shot and irreversible may provide a sustainable and effective strategy for feral horse control.

Neural networks for aircraft control

Science.gov (United States)

Linse, Dennis

1990-01-01

Current research in Artificial Neural Networks indicates that networks offer some potential advantages in adaptation and fault tolerance. This research is directed at determining the possible applicability of neural networks to aircraft control. The first application will be to aircraft trim. Neural network node characteristics, network topology and operation, neural network learning and example histories using neighboring optimal control with a neural net are discussed.

Marfan Syndrome: Clinical, Surgical, and Anesthetic Considerations.

Science.gov (United States)

Castellano, José M; Silvay, George; Castillo, Javier G

2014-09-01

Marfan syndrome is a multisystem connective tissue disorder, with primary involvement of the cardiovascular, ocular, and skeletal systems. This autosomal heritable disease is mainly attributable to a defect in the FBN1 gene. Clinical diagnosis of Marfan syndrome has been based on the Ghent criteria since 1996. In 2010, these criteria were updated, and the revised guidelines place more emphasis on aortic root dilation, ectopia lentis, and FBN1 mutation testing in the diagnostic assessment of Marfan syndrome. Among its many different clinical manifestations, cardiovascular involvement deserves special consideration, owing to its impact on prognosis. Recent molecular, surgical, and clinical research has yielded profound new insights into the pathological mechanisms that ultimately lead to tissue degradation and weakening of the aortic wall, which has led to exciting new treatment strategies. Furthermore, with the increasing life expectancy of patients with Marfan syndrome, there has been a subtle shift in the spectrum of medical problems. Consequently, this article focuses on recent advances to highlight their potential impact on future concepts of patient care from a clinical, surgical, and anesthetic perspective. © The Author(s) 2013.

The road to restoring neural circuits for the treatment of Alzheimer's disease.

Science.gov (United States)

Canter, Rebecca G; Penney, Jay; Tsai, Li-Huei

2016-11-10

Alzheimer's disease is a progressive loss of memory and cognition, for which there is no cure. Although genetic studies initially suggested a primary role for amyloid-in Alzheimer's disease, treatment strategies targeted at reducing amyloid-have failed to reverse cognitive symptoms. These clinical findings suggest that cognitive decline is the result of a complex pathophysiology and that targeting amyloid-alone may not be sufficient to treat Alzheimer's disease. Instead, a broad outlook on neural-circuit-damaging processes may yield insights into new therapeutic strategies for curing memory loss in the disease.

The Neural Border: Induction, Specification and Maturation of the territory that generates Neural Crest cells.

Science.gov (United States)

Pla, Patrick; Monsoro-Burq, Anne H

2018-05-28

The neural crest is induced at the edge between the neural plate and the nonneural ectoderm, in an area called the neural (plate) border, during gastrulation and neurulation. In recent years, many studies have explored how this domain is patterned, and how the neural crest is induced within this territory, that also participates to the prospective dorsal neural tube, the dorsalmost nonneural ectoderm, as well as placode derivatives in the anterior area. This review highlights the tissue interactions, the cell-cell signaling and the molecular mechanisms involved in this dynamic spatiotemporal patterning, resulting in the induction of the premigratory neural crest. Collectively, these studies allow building a complex neural border and early neural crest gene regulatory network, mostly composed by transcriptional regulations but also, more recently, including novel signaling interactions. Copyright © 2018. Published by Elsevier Inc.

Vector control of wind turbine on the basis of the fuzzy selective neural net*

Science.gov (United States)

Engel, E. A.; Kovalev, I. V.; Engel, N. E.

2016-04-01

An article describes vector control of wind turbine based on fuzzy selective neural net. Based on the wind turbine system’s state, the fuzzy selective neural net tracks an maximum power point under random perturbations. Numerical simulations are accomplished to clarify the applicability and advantages of the proposed vector wind turbine’s control on the basis of the fuzzy selective neuronet. The simulation results show that the proposed intelligent control of wind turbine achieves real-time control speed and competitive performance, as compared to a classical control model with PID controllers based on traditional maximum torque control strategy.

Concise Neural Nonaffine Control of Air-Breathing Hypersonic Vehicles Subject to Parametric Uncertainties

Directory of Open Access Journals (Sweden)

Xiangwei Bu

2017-01-01

Full Text Available In this paper, a novel simplified neural control strategy is proposed for the longitudinal dynamics of an air-breathing hypersonic vehicle (AHV directly using nonaffine models instead of affine ones. For the velocity dynamics, an adaptive neural controller is devised based on a minimal-learning parameter (MLP technique for the sake of decreasing computational loads. The altitude dynamics is rewritten as a pure feedback nonaffine formulation, for which a novel concise neural control approach is achieved without backstepping. The special contributions are that the control architecture is concise and the computational cost is low. Moreover, the exploited controller possesses good practicability since there is no need for affine models. The semiglobally uniformly ultimate boundedness of all the closed-loop system signals is guaranteed via Lyapunov stability theory. Finally, simulation results are presented to validate the effectiveness of the investigated control methodology in the presence of parametric uncertainties.

"They Have to Adapt to Learn": Surgeons' Perspectives on the Role of Procedural Variation in Surgical Education.

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Apramian, Tavis; Cristancho, Sayra; Watling, Chris; Ott, Michael; Lingard, Lorelei

2016-01-01

Clinical research increasingly acknowledges the existence of significant procedural variation in surgical practice. This study explored surgeons' perspectives regarding the influence of intersurgeon procedural variation on the teaching and learning of surgical residents. This qualitative study used a grounded theory-based analysis of observational and interview data. Observational data were collected in 3 tertiary care teaching hospitals in Ontario, Canada. Semistructured interviews explored potential procedural variations arising during the observations and prompts from an iteratively refined guide. Ongoing data analysis refined the theoretical framework and informed data collection strategies, as prescribed by the iterative nature of grounded theory research. Our sample included 99 hours of observation across 45 cases with 14 surgeons. Semistructured, audio-recorded interviews (n = 14) occurred immediately following observational periods. Surgeons endorsed the use of intersurgeon procedural variations to teach residents about adapting to the complexity of surgical practice and the norms of surgical culture. Surgeons suggested that residents' efforts to identify thresholds of principle and preference are crucial to professional development. Principles that emerged from the study included the following: (1) knowing what comes next, (2) choosing the right plane, (3) handling tissue appropriately, (4) recognizing the abnormal, and (5) making safe progress. Surgeons suggested that learning to follow these principles while maintaining key aspects of surgical culture, like autonomy and individuality, are important social processes in surgical education. Acknowledging intersurgeon variation has important implications for curriculum development and workplace-based assessment in surgical education. Adapting to intersurgeon procedural variations may foster versatility in surgical residents. However, the existence of procedural variations and their active use in surgeons

Neural network regulation driven by autonomous neural firings

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Cho, Myoung Won

2016-07-01

Biological neurons naturally fire spontaneously due to the existence of a noisy current. Such autonomous firings may provide a driving force for network formation because synaptic connections can be modified due to neural firings. Here, we study the effect of autonomous firings on network formation. For the temporally asymmetric Hebbian learning, bidirectional connections lose their balance easily and become unidirectional ones. Defining the difference between reciprocal connections as new variables, we could express the learning dynamics as if Ising model spins interact with each other in magnetism. We present a theoretical method to estimate the interaction between the new variables in a neural system. We apply the method to some network systems and find some tendencies of autonomous neural network regulation.

Bacterial migration through punctured surgical gloves under real surgical conditions

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Heidecke Claus-Dieter

2010-07-01

Full Text Available Abstract Background The aim of this study was to confirm recent results from a previous study focussing on the development of a method to measure the bacterial translocation through puncture holes in surgical gloves under real surgical conditions. Methods An established method was applied to detect bacterial migration from the operating site through the punctured glove. Biogel™ double-gloving surgical gloves were used during visceral surgeries over a 6-month period. A modified Gaschen-bag method was used to retrieve organisms from the inner glove, and thus-obtained bacteria were compared with micro-organisms detected by an intra-operative swab. Results In 20 consecutive procedures, 194 gloves (98 outer gloves, 96 inner gloves were examined. The rate of micro-perforations of the outer surgical glove was 10% with a median wearing time of 100 minutes (range: 20-175 minutes. Perforations occurred in 81% on the non-dominant hand, with the index finger most frequently (25% punctured. In six cases, bacterial migration could be demonstrated microbiologically. In 5% (5/98 of outer gloves and in 1% (1/96 of the inner gloves, bacterial migration through micro-perforations was observed. For gloves with detected micro-perforations (n = 10 outer layers, the calculated migration was 50% (n = 5. The minimum wearing time was 62 minutes, with a calculated median wearing time of 71 minutes. Conclusions This study confirms previous results that bacterial migration through unnoticed micro-perforations in surgical gloves does occur under real practical surgical conditions. Undetected perforation of surgical gloves occurs frequently. Bacterial migration from the patient through micro-perforations on the hand of surgeons was confirmed, limiting the protective barrier function of gloves if worn over longer periods.

Different neural and cognitive response to emotional faces in healthy monozygotic twins at risk of depression

DEFF Research Database (Denmark)

Miskowiak, K W; Glerup, L; Vestbo, C

2015-01-01

while performing a gender discrimination task. After the scan, they were given a faces dot-probe task, a facial expression recognition task and questionnaires assessing mood, personality traits and coping strategies. RESULTS: High-risk twins showed increased neural response to happy and fearful faces...... processing. These task-related changes in neural responses in high-risk twins were accompanied by impaired gender discrimination performance during face processing. They also displayed increased attention vigilance for fearful faces and were slower at recognizing facial expressions relative to low......BACKGROUND: Negative cognitive bias and aberrant neural processing of emotional faces are trait-marks of depression. Yet it is unclear whether these changes constitute an endophenotype for depression and are also present in healthy individuals with hereditary risk for depression. METHOD: Thirty...

Surgical experts: born or made?

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Sadideen, Hazim; Alvand, Abtin; Saadeddin, Munir; Kneebone, Roger

2013-01-01

The concept of surgical expertise and the processes involved in its development are topical, and there is a constant drive to identify reliable measures of expert performance in surgery. This review explores the notion of whether surgical experts are "born" or "made", with reference to educational theory and pertinent literature. Peer-reviewed publications, books, and online resources on surgical education, expertise and training were reviewed. Important themes and aspects of expertise acquisition were identified in order to better understand the concept of a surgical expert. The definition of surgical expertise and several important aspects of its development are highlighted. Innate talent plays an important role, but is insufficient on its own to produce a surgical expert. Multiple theories that explore motor skill acquisition and memory are relevant, and Ericsson's theory of the development of competence followed by deliberate self-practice has been especially influential. Psychomotor and non-technical skills are necessary for progression in the current climate in light of our training curricula; surgical experts are adaptive experts who excel in these. The literature suggests that surgical expertise is reached through practice; surgical experts are made, not born. A deeper understanding of the nature of expert performance and its development will ensure that surgical education training programmes are of the highest possible quality. Surgical educators should aim to develop an expertise-based approach, with expert performance as the benchmark. Copyright © 2013 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

Neural Network Based Maximum Power Point Tracking Control with Quadratic Boost Converter for PMSG—Wind Energy Conversion System

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Ramji Tiwari

2018-02-01

Full Text Available This paper proposes an artificial neural network (ANN based maximum power point tracking (MPPT control strategy for wind energy conversion system (WECS implemented with a DC/DC converter. The proposed topology utilizes a radial basis function network (RBFN based neural network control strategy to extract the maximum available power from the wind velocity. The results are compared with a classical Perturb and Observe (P&O method and Back propagation network (BPN method. In order to achieve a high voltage rating, the system is implemented with a quadratic boost converter and the performance of the converter is validated with a boost and single ended primary inductance converter (SEPIC. The performance of the MPPT technique along with a DC/DC converter is demonstrated using MATLAB/Simulink.

Dynamics of neural cryptography.

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Ruttor, Andreas; Kinzel, Wolfgang; Kanter, Ido

2007-05-01

Synchronization of neural networks has been used for public channel protocols in cryptography. In the case of tree parity machines the dynamics of both bidirectional synchronization and unidirectional learning is driven by attractive and repulsive stochastic forces. Thus it can be described well by a random walk model for the overlap between participating neural networks. For that purpose transition probabilities and scaling laws for the step sizes are derived analytically. Both these calculations as well as numerical simulations show that bidirectional interaction leads to full synchronization on average. In contrast, successful learning is only possible by means of fluctuations. Consequently, synchronization is much faster than learning, which is essential for the security of the neural key-exchange protocol. However, this qualitative difference between bidirectional and unidirectional interaction vanishes if tree parity machines with more than three hidden units are used, so that those neural networks are not suitable for neural cryptography. In addition, the effective number of keys which can be generated by the neural key-exchange protocol is calculated using the entropy of the weight distribution. As this quantity increases exponentially with the system size, brute-force attacks on neural cryptography can easily be made unfeasible.

Dynamics of neural cryptography

International Nuclear Information System (INIS)

Ruttor, Andreas; Kinzel, Wolfgang; Kanter, Ido

2007-01-01

Synchronization of neural networks has been used for public channel protocols in cryptography. In the case of tree parity machines the dynamics of both bidirectional synchronization and unidirectional learning is driven by attractive and repulsive stochastic forces. Thus it can be described well by a random walk model for the overlap between participating neural networks. For that purpose transition probabilities and scaling laws for the step sizes are derived analytically. Both these calculations as well as numerical simulations show that bidirectional interaction leads to full synchronization on average. In contrast, successful learning is only possible by means of fluctuations. Consequently, synchronization is much faster than learning, which is essential for the security of the neural key-exchange protocol. However, this qualitative difference between bidirectional and unidirectional interaction vanishes if tree parity machines with more than three hidden units are used, so that those neural networks are not suitable for neural cryptography. In addition, the effective number of keys which can be generated by the neural key-exchange protocol is calculated using the entropy of the weight distribution. As this quantity increases exponentially with the system size, brute-force attacks on neural cryptography can easily be made unfeasible

Dynamics of neural cryptography

Science.gov (United States)

Ruttor, Andreas; Kinzel, Wolfgang; Kanter, Ido

2007-05-01

Synchronization of neural networks has been used for public channel protocols in cryptography. In the case of tree parity machines the dynamics of both bidirectional synchronization and unidirectional learning is driven by attractive and repulsive stochastic forces. Thus it can be described well by a random walk model for the overlap between participating neural networks. For that purpose transition probabilities and scaling laws for the step sizes are derived analytically. Both these calculations as well as numerical simulations show that bidirectional interaction leads to full synchronization on average. In contrast, successful learning is only possible by means of fluctuations. Consequently, synchronization is much faster than learning, which is essential for the security of the neural key-exchange protocol. However, this qualitative difference between bidirectional and unidirectional interaction vanishes if tree parity machines with more than three hidden units are used, so that those neural networks are not suitable for neural cryptography. In addition, the effective number of keys which can be generated by the neural key-exchange protocol is calculated using the entropy of the weight distribution. As this quantity increases exponentially with the system size, brute-force attacks on neural cryptography can easily be made unfeasible.

Novel strategy for protein exploration: high-throughput screening assisted with fuzzy neural network.

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Kato, Ryuji; Nakano, Hideo; Konishi, Hiroyuki; Kato, Katsuya; Koga, Yuchi; Yamane, Tsuneo; Kobayashi, Takeshi; Honda, Hiroyuki

2005-08-19

To engineer proteins with desirable characteristics from a naturally occurring protein, high-throughput screening (HTS) combined with directed evolutional approach is the essential technology. However, most HTS techniques are simple positive screenings. The information obtained from the positive candidates is used only as results but rarely as clues for understanding the structural rules, which may explain the protein activity. In here, we have attempted to establish a novel strategy for exploring functional proteins associated with computational analysis. As a model case, we explored lipases with inverted enantioselectivity for a substrate p-nitrophenyl 3-phenylbutyrate from the wild-type lipase of Burkhorderia cepacia KWI-56, which is originally selective for (S)-configuration of the substrate. Data from our previous work on (R)-enantioselective lipase screening were applied to fuzzy neural network (FNN), bioinformatic algorithm, to extract guidelines for screening and engineering processes to be followed. FNN has an advantageous feature of extracting hidden rules that lie between sequences of variants and their enzyme activity to gain high prediction accuracy. Without any prior knowledge, FNN predicted a rule indicating that "size at position L167," among four positions (L17, F119, L167, and L266) in the substrate binding core region, is the most influential factor for obtaining lipase with inverted (R)-enantioselectivity. Based on the guidelines obtained, newly engineered novel variants, which were not found in the actual screening, were experimentally proven to gain high (R)-enantioselectivity by engineering the size at position L167. We also designed and assayed two novel variants, namely FIGV (L17F, F119I, L167G, and L266V) and FFGI (L17F, L167G, and L266I), which were compatible with the guideline obtained from FNN analysis, and confirmed that these designed lipases could acquire high inverted enantioselectivity. The results have shown that with the aid of

Bioprinting for Neural Tissue Engineering.

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Knowlton, Stephanie; Anand, Shivesh; Shah, Twisha; Tasoglu, Savas

2018-01-01

Bioprinting is a method by which a cell-encapsulating bioink is patterned to create complex tissue architectures. Given the potential impact of this technology on neural research, we review the current state-of-the-art approaches for bioprinting neural tissues. While 2D neural cultures are ubiquitous for studying neural cells, 3D cultures can more accurately replicate the microenvironment of neural tissues. By bioprinting neuronal constructs, one can precisely control the microenvironment by specifically formulating the bioink for neural tissues, and by spatially patterning cell types and scaffold properties in three dimensions. We review a range of bioprinted neural tissue models and discuss how they can be used to observe how neurons behave, understand disease processes, develop new therapies and, ultimately, design replacement tissues. Copyright © 2017 Elsevier Ltd. All rights reserved.

Relabeling exchange method (REM) for learning in neural networks

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Wu, Wen; Mammone, Richard J.

1994-02-01

The supervised training of neural networks require the use of output labels which are usually arbitrarily assigned. In this paper it is shown that there is a significant difference in the rms error of learning when `optimal' label assignment schemes are used. We have investigated two efficient random search algorithms to solve the relabeling problem: the simulated annealing and the genetic algorithm. However, we found them to be computationally expensive. Therefore we shall introduce a new heuristic algorithm called the Relabeling Exchange Method (REM) which is computationally more attractive and produces optimal performance. REM has been used to organize the optimal structure for multi-layered perceptrons and neural tree networks. The method is a general one and can be implemented as a modification to standard training algorithms. The motivation of the new relabeling strategy is based on the present interpretation of dyslexia as an encoding problem.

A human factors curriculum for surgical clerkship students.

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Cahan, Mitchell A; Larkin, Anne C; Starr, Susan; Wellman, Scott; Haley, Heather-Lyn; Sullivan, Kate; Shah, Shimul; Hirsh, Michael; Litwin, Demetrius; Quirk, Mark

2010-12-01

Early introduction of a full-day human factors training experience into the surgical clerkship curriculum will teach effective communication skills and strategies to gain professional satisfaction from a career in surgery. In pilot 1, which took place between July 1, 2007, and December 31, 2008, 50 students received training and 50 did not; all received testing at the end of the rotation for comparison of control vs intervention group performance. In pilot 2, a total of 50 students were trained and received testing before and after rotation to examine individual change over time. University of Massachusetts Medical School. A total of 148 third-year medical students in required 12-week surgical clerkship rotations. Full-day training with lecture and small-group exercises, cotaught by surgeons and educators, with focus on empathetic communication, time management, and teamwork skills. Empathetic communication skill, teamwork, and patient safety attitudes and self-reported use of time management strategies. Empathy scores were not higher for trained vs untrained groups in pilot 1 but improved from 2.32 to 3.45 on a 5-point scale (P work-life balance, with some trained groups scoring significantly lower than untrained groups in pilot 1 and no significant improvement shown in pilot 2. The significant increase in student-patient communication scores suggests that a brief focused presentation followed by simulation of difficult patient encounters can be successful. A video demonstration can improve interdisciplinary teamwork.

Modeling the electrode-neuron interface of cochlear implants: effects of neural survival, electrode placement, and the partial tripolar configuration.

Science.gov (United States)

Goldwyn, Joshua H; Bierer, Steven M; Bierer, Julie Arenberg

2010-09-01

The partial tripolar electrode configuration is a relatively novel stimulation strategy that can generate more spatially focused electric fields than the commonly used monopolar configuration. Focused stimulation strategies should improve spectral resolution in cochlear implant users, but may also be more sensitive to local irregularities in the electrode-neuron interface. In this study, we develop a practical computer model of cochlear implant stimulation that can simulate neural activation in a simplified cochlear geometry and we relate the resulting patterns of neural activity to basic psychophysical measures. We examine how two types of local irregularities in the electrode-neuron interface, variations in spiral ganglion nerve density and electrode position within the scala tympani, affect the simulated neural activation patterns and how these patterns change with electrode configuration. The model shows that higher partial tripolar fractions activate more spatially restricted populations of neurons at all current levels and require higher current levels to excite a given number of neurons. We find that threshold levels are more sensitive at high partial tripolar fractions to both types of irregularities, but these effects are not independent. In particular, at close electrode-neuron distances, activation is typically more spatially localized which leads to a greater influence of neural dead regions. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Surgical planning for microsurgical excision of cerebral arterio-venous malformations using virtual reality technology.

Science.gov (United States)

Ng, Ivan; Hwang, Peter Y K; Kumar, Dinesh; Lee, Cheng Kiang; Kockro, Ralf A; Sitoh, Y Y

2009-05-01

To evaluate the feasibility of surgical planning using a virtual reality platform workstation in the treatment of cerebral arterio-venous malformations (AVMs) Patient-specific data of multiple imaging modalities were co-registered, fused and displayed as a 3D stereoscopic object on the Dextroscope, a virtual reality surgical planning platform. This system allows for manipulation of 3D data and for the user to evaluate and appreciate the angio-architecture of the nidus with regards to position and spatial relationships of critical feeders and draining veins. We evaluated the ability of the Dextroscope to influence surgical planning by providing a better understanding of the angio-architecture as well as its impact on the surgeon's pre- and intra-operative confidence and ability to tackle these lesions. Twenty four patients were studied. The mean age was 29.65 years. Following pre-surgical planning on the Dextroscope, 23 patients underwent microsurgical resection after pre-surgical virtual reality planning, during which all had documented complete resection of the AVM. Planning on the virtual reality platform allowed for identification of critical feeders and draining vessels in all patients. The appreciation of the complex patient specific angio-architecture to establish a surgical plan was found to be invaluable in the conduct of the procedure and was found to enhance the surgeon's confidence significantly. Surgical planning of resection of an AVM with a virtual reality system allowed detailed and comprehensive analysis of 3D multi-modality imaging data and, in our experience, proved very helpful in establishing a good surgical strategy, enhancing intra-operative spatial orientation and increasing surgeon's confidence.

Global curriculum in surgical oncology.

Science.gov (United States)

Are, C; Berman, R S; Wyld, L; Cummings, C; Lecoq, C; Audisio, R A

2016-06-01

The significant global variations in surgical oncology training paradigms can have a detrimental effect on tackling the rising global cancer burden. While some variations in training are essential to account for the differences in types of cancer and biology, the fundamental principles of providing care to a cancer patient remain the same. The development of a global curriculum in surgical oncology with incorporated essential standards could be very useful in building an adequately trained surgical oncology workforce, which in turn could help in tackling the rising global cancer burden. The leaders of the Society of Surgical Oncology and European Society of Surgical Oncology convened a global curriculum committee to develop a global curriculum in surgical oncology. A global curriculum in surgical oncology was developed to incorporate the required domains considered to be essential in training a surgical oncologist. The curriculum was constructed in a modular fashion to permit flexibility to suit the needs of the different regions of the world. Similarly, recognizing the various sociocultural, financial and cultural influences across the world, the proposed curriculum is aspirational and not mandatory in intent. A global curriculum was developed which may be considered as a foundational scaffolding for training surgical oncologists worldwide. It is envisioned that this initial global curriculum will provide a flexible and modular scaffolding that can be tailored by individual countries or regions to train surgical oncologists in a way that is appropriate for practice in their local environment. Copyright © 2016 Society of Surgical Oncology, European Society of Surgical Oncology. Published by Elsevier Ltd.. All rights reserved.

Surgical management for upper urinary tract transitional cell carcinoma.

Science.gov (United States)

Rai, Bhavan Prasad; Shelley, Mike; Coles, Bernadette; Biyani, Chandra S; El-Mokadem, Ismail; Nabi, Ghulam

2011-04-13

Upper tract transitional cell carcinomas (TCC) are uncommon and aggressive tumours. There are a number of surgical approaches to manage this condition including open radical nephroureterectomy and laparoscopic procedures. To determine the best surgical management option for upper tract transitional cell carcinoma. A sensitive search strategy was developed to identify relevant studies for inclusion in this review. The following databases were searched for randomised trials evaluating surgical approaches to the management of upper tract TCC: Medline EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), CINAHL, British Nursing Index, AMED, LILACS, Web of Science®, Scopus, Biosis, TRIP, Biomed Central, Dissertation Abstracts, and ISI Proceedings. The following criteria that were considered for this review.Types of studies - All randomised or quasi-randomised controlled trials comparing the various surgical methods and approaches for the management of localised upper tract transitional cell carcinoma. Types of participants - All adult patients with localised transitional cell carcinoma. Localised disease was defined as limited to the kidney or ureter with no gross regional lymph nodal enlargement on imaging. Types of interventions - Any surgical method or approach for managing localised upper tract transitional cell carcinoma. Types of outcome measures - Overall and cancer-specific survival were primary outcomes. Surgery-related morbidity. Quality of life and health economics outcomes were secondary outcomes. Two review authors examined the search results independently to identify trials for inclusion. We identified one randomised controlled trial that met our inclusion criteria. The trial showed that the laparoscopic approach had superior peri-operative outcomes compared to open approach. Laparoscopic was superior and statistically significant for blood loss (104 mL (millilitres) versus 430 mL, P management of upper tract transitional cell carcinoma

Capping of the radicular exposed surface (part II). Surgical and not surgical treatment

OpenAIRE

Grados Pomarino, Sixto; Estrada, Andrew Alejandro; Maetahara Rubio, Denis Miguel; Guzmán Vera, Yanina Sara; Tello Barbarán, Javier

2014-01-01

The gingival recession treatment can be made surgical1y with a high predictability of success due to the great advance during the last ones of the mucogingival surgical techniques. The use of connective grafts in coverage of recessions has obtained high rates of success reason why these procedures are common within the modern periodontal surgical practice. Knowing that all patients do not accept the surgical treatment, many investigators have come studying the possibility of treating non-surg...

Neural correlates and neural computations in posterior parietal cortex during perceptual decision-making

Directory of Open Access Journals (Sweden)

Alexander eHuk

2012-10-01

Full Text Available A recent line of work has found remarkable success in relating perceptual decision-making and the spiking activity in the macaque lateral intraparietal area (LIP. In this review, we focus on questions about the neural computations in LIP that are not answered by demonstrations of neural correlates of psychological processes. We highlight three areas of limitations in our current understanding of the precise neural computations that might underlie neural correlates of decisions: (1 empirical questions not yet answered by existing data; (2 implementation issues related to how neural circuits could actually implement the mechanisms suggested by both physiology and psychology; and (3 ecological constraints related to the use of well-controlled laboratory tasks and whether they provide an accurate window on sensorimotor computation. These issues motivate the adoption of a more general encoding-decoding framework that will be fruitful for more detailed contemplation of how neural computations in LIP relate to the formation of perceptual decisions.

e-Learning in Surgical Education: A Systematic Review.

Science.gov (United States)

Jayakumar, Nithish; Brunckhorst, Oliver; Dasgupta, Prokar; Khan, Muhammad Shamim; Ahmed, Kamran

2015-01-01

e-Learning involves the delivery of educational content through web-based methods. Owing to work-hour restrictions and changing practice patterns in surgery, e-learning can offer an effective alternative to traditional teaching. Our aims were to (1) identify current modalities of e-learning, (2) assess the efficacy of e-learning as an intervention in surgical education through a systematic review of the literature, and (3) discuss the relevance of e-learning as an educational tool in surgical education. This is the first such systematic review in this field. A systematic search of MEDLINE and EMBASE was conducted for relevant articles published until July 2014, using a predefined search strategy. The database search was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A total of 38 articles were found which met the inclusion criteria. In these studies, e-learning was used as an intervention in 3 different ways: (1) to teach cases through virtual patients (18/38); (2) to teach theoretical knowledge through online tutorials, or other means (18/38); and (3) to teach surgical skills (2/38). Nearly all of the studies reviewed report significant knowledge gain from e-learning; however, 2 in 3 studies did not use a control group. e-Learning has emerged as an effective mode of teaching with particular relevance for surgical education today. Published studies have demonstrated the efficacy of this method; however, future work must involve well-designed randomized controlled trials comparing e-learning against standard teaching. Copyright © 2015 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

The turn team: a novel strategy for reducing pressure ulcers in the surgical intensive care unit.

Science.gov (United States)

Still, Mary D; Cross, Linda C; Dunlap, Martha; Rencher, Rugenia; Larkins, Elizabeth R; Carpenter, David L; Buchman, Timothy G; Coopersmith, Craig M

2013-03-01

Pressure ulcers cause significant morbidity and mortality in the surgical intensive care unit (SICU). The purpose of this study was to determine if a dedicated team tasked with turning and repositioning all hemodynamically stable SICU patients could decrease the formation of pressure ulcers. A total of 507 patients in a 20-bed SICU in a university hospital were assessed for pressure ulcers using a point prevalence strategy, between December 2008 and September 2010, before and after implementation of a team tasked with turning and repositioning all hemodynamically stable patients every 2 hours around the clock. At baseline, when frequent turning was encouraged but not required, a total of 42 pressure ulcers were identified in 278 patients. After implementation of the turn team, a total of 12 pressure ulcers were identified in 229 patients (p < 0.0001). The preintervention group included 34 stage I and II ulcers and 8 higher stage ulcers. After implementation of the turn team, there were 7 stage I and II ulcers and 5 higher stage ulcers. The average Braden score was 16.5 in the preintervention group and 13.4 in the postintervention group (p = 0.04), suggesting that pressure ulcers were occurring in higher risk patients after implementation of the turn team. A team dedicated to turning SICU patients every 2 hours dramatically decreased the incidence of pressure ulcers. The majority of stage I and stage II ulcers appear to be preventable with an aggressive intervention aimed at pressure ulcer prevention. Copyright © 2013 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

Dissociated neural processing for decisions in managers and non-managers.

Directory of Open Access Journals (Sweden)

Svenja Caspers

Full Text Available Functional neuroimaging studies of decision-making so far mainly focused on decisions under uncertainty or negotiation with other persons. Dual process theory assumes that, in such situations, decision making relies on either a rapid intuitive, automated or a slower rational processing system. However, it still remains elusive how personality factors or professional requirements might modulate the decision process and the underlying neural mechanisms. Since decision making is a key task of managers, we hypothesized that managers, facing higher pressure for frequent and rapid decisions than non-managers, prefer the heuristic, automated decision strategy in contrast to non-managers. Such different strategies may, in turn, rely on different neural systems. We tested managers and non-managers in a functional magnetic resonance imaging study using a forced-choice paradigm on word-pairs. Managers showed subcortical activation in the head of the caudate nucleus, and reduced hemodynamic response within the cortex. In contrast, non-managers revealed the opposite pattern. With the head of the caudate nucleus being an initiating component for process automation, these results supported the initial hypothesis, hinting at automation during decisions in managers. More generally, the findings reveal how different professional requirements might modulate cognitive decision processing.

Deep Learning Neural Networks and Bayesian Neural Networks in Data Analysis

Directory of Open Access Journals (Sweden)

Chernoded Andrey

2017-01-01

Full Text Available Most of the modern analyses in high energy physics use signal-versus-background classification techniques of machine learning methods and neural networks in particular. Deep learning neural network is the most promising modern technique to separate signal and background and now days can be widely and successfully implemented as a part of physical analysis. In this article we compare Deep learning and Bayesian neural networks application as a classifiers in an instance of top quark analysis.

Energy-efficient neural information processing in individual neurons and neuronal networks.

Science.gov (United States)

Yu, Lianchun; Yu, Yuguo

2017-11-01

Brains are composed of networks of an enormous number of neurons interconnected with synapses. Neural information is carried by the electrical signals within neurons and the chemical signals among neurons. Generating these electrical and chemical signals is metabolically expensive. The fundamental issue raised here is whether brains have evolved efficient ways of developing an energy-efficient neural code from the molecular level to the circuit level. Here, we summarize the factors and biophysical mechanisms that could contribute to the energy-efficient neural code for processing input signals. The factors range from ion channel kinetics, body temperature, axonal propagation of action potentials, low-probability release of synaptic neurotransmitters, optimal input and noise, the size of neurons and neuronal clusters, excitation/inhibition balance, coding strategy, cortical wiring, and the organization of functional connectivity. Both experimental and computational evidence suggests that neural systems may use these factors to maximize the efficiency of energy consumption in processing neural signals. Studies indicate that efficient energy utilization may be universal in neuronal systems as an evolutionary consequence of the pressure of limited energy. As a result, neuronal connections may be wired in a highly economical manner to lower energy costs and space. Individual neurons within a network may encode independent stimulus components to allow a minimal number of neurons to represent whole stimulus characteristics efficiently. This basic principle may fundamentally change our view of how billions of neurons organize themselves into complex circuits to operate and generate the most powerful intelligent cognition in nature. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Neural Tube Defects

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Neural tube defects are birth defects of the brain, spine, or spinal cord. They happen in the ... that she is pregnant. The two most common neural tube defects are spina bifida and anencephaly. In ...

Residents' surgical performance during the laboratory years: an analysis of rule-based errors.

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Nathwani, Jay N; Wise, Brett J; Garren, Margaret E; Mohamadipanah, Hossein; Van Beek, Nicole; DiMarco, Shannon M; Pugh, Carla M

2017-11-01

Nearly one-third of surgical residents will enter into academic development during their surgical residency by dedicating time to a research fellowship for 1-3 y. Major interest lies in understanding how laboratory residents' surgical skills are affected by minimal clinical exposure during academic development. A widely held concern is that the time away from clinical exposure results in surgical skills decay. This study examines the impact of the academic development years on residents' operative performance. We hypothesize that the use of repeated, annual assessments may result in learning even without individual feedback on participants simulated performance. Surgical performance data were collected from laboratory residents (postgraduate years 2-5) during the summers of 2014, 2015, and 2016. Residents had 15 min to complete a shortened, simulated laparoscopic ventral hernia repair procedure. Final hernia repair skins from all participants were scored using a previously validated checklist. An analysis of variance test compared the mean performance scores of repeat participants to those of first time participants. Twenty-seven (37% female) laboratory residents provided 2-year assessment data over the 3-year span of the study. Second time performance revealed improvement from a mean score of 14 (standard error = 1.0) in the first year to 17.2 (SD = 0.9) in the second year, (F[1, 52] = 5.6, P = 0.022). Detailed analysis demonstrated improvement in performance for 3 grading criteria that were considered to be rule-based errors. There was no improvement in operative strategy errors. Analysis of longitudinal performance of laboratory residents shows higher scores for repeat participants in the category of rule-based errors. These findings suggest that laboratory residents can learn from rule-based mistakes when provided with annual performance-based assessments. This benefit was not seen with operative strategy errors and has important implications for

Abortion - surgical - aftercare

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... this page: //medlineplus.gov/ency/patientinstructions/000658.htm Abortion - surgical - aftercare To use the sharing features on ... please enable JavaScript. You have had a surgical abortion. This is a procedure that ends pregnancy by ...

A neurally inspired musical instrument classification system based upon the sound onset.

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Newton, Michael J; Smith, Leslie S

2012-06-01

Physiological evidence suggests that sound onset detection in the auditory system may be performed by specialized neurons as early as the cochlear nucleus. Psychoacoustic evidence shows that the sound onset can be important for the recognition of musical sounds. Here the sound onset is used in isolation to form tone descriptors for a musical instrument classification task. The task involves 2085 isolated musical tones from the McGill dataset across five instrument categories. A neurally inspired tone descriptor is created using a model of the auditory system's response to sound onset. A gammatone filterbank and spiking onset detectors, built from dynamic synapses and leaky integrate-and-fire neurons, create parallel spike trains that emphasize the sound onset. These are coded as a descriptor called the onset fingerprint. Classification uses a time-domain neural network, the echo state network. Reference strategies, based upon mel-frequency cepstral coefficients, evaluated either over the whole tone or only during the sound onset, provide context to the method. Classification success rates for the neurally-inspired method are around 75%. The cepstral methods perform between 73% and 76%. Further testing with tones from the Iowa MIS collection shows that the neurally inspired method is considerably more robust when tested with data from an unrelated dataset.

Short-term electricity prices forecasting in a competitive market: A neural network approach

International Nuclear Information System (INIS)

Catalao, J.P.S.; Mariano, S.J.P.S.; Mendes, V.M.F.; Ferreira, L.A.F.M.

2007-01-01

This paper proposes a neural network approach for forecasting short-term electricity prices. Almost until the end of last century, electricity supply was considered a public service and any price forecasting which was undertaken tended to be over the longer term, concerning future fuel prices and technical improvements. Nowadays, short-term forecasts have become increasingly important since the rise of the competitive electricity markets. In this new competitive framework, short-term price forecasting is required by producers and consumers to derive their bidding strategies to the electricity market. Accurate forecasting tools are essential for producers to maximize their profits, avowing profit losses over the misjudgement of future price movements, and for consumers to maximize their utilities. A three-layered feedforward neural network, trained by the Levenberg-Marquardt algorithm, is used for forecasting next-week electricity prices. We evaluate the accuracy of the price forecasting attained with the proposed neural network approach, reporting the results from the electricity markets of mainland Spain and California. (author)

Reconstruction of periodic signals using neural networks

Directory of Open Access Journals (Sweden)

José Danilo Rairán Antolines

2014-01-01

Full Text Available In this paper, we reconstruct a periodic signal by using two neural networks. The first network is trained to approximate the period of a signal, and the second network estimates the corresponding coefficients of the signal's Fourier expansion. The reconstruction strategy consists in minimizing the mean-square error via backpro-pagation algorithms over a single neuron with a sine transfer function. Additionally, this paper presents mathematical proof about the quality of the approximation as well as a first modification of the algorithm, which requires less data to reach the same estimation; thus making the algorithm suitable for real-time implementations.

Natural language generation of surgical procedures.

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Wagner, J C; Rogers, J E; Baud, R H; Scherrer, J R

1999-01-01

A number of compositional Medical Concept Representation systems are being developed. Although these provide for a detailed conceptual representation of the underlying information, they have to be translated back to natural language for used by end-users and applications. The GALEN programme has been developing one such representation and we report here on a tool developed to generate natural language phrases from the GALEN conceptual representations. This tool can be adapted to different source modelling schemes and to different destination languages or sublanguages of a domain. It is based on a multilingual approach to natural language generation, realised through a clean separation of the domain model from the linguistic model and their link by well defined structures. Specific knowledge structures and operations have been developed for bridging between the modelling 'style' of the conceptual representation and natural language. Using the example of the scheme developed for modelling surgical operative procedures within the GALEN-IN-USE project, we show how the generator is adapted to such a scheme. The basic characteristics of the surgical procedures scheme are presented together with the basic principles of the generation tool. Using worked examples, we discuss the transformation operations which change the initial source representation into a form which can more directly be translated to a given natural language. In particular, the linguistic knowledge which has to be introduced--such as definitions of concepts and relationships is described. We explain the overall generator strategy and how particular transformation operations are triggered by language-dependent and conceptual parameters. Results are shown for generated French phrases corresponding to surgical procedures from the urology domain.

[Choice of the method of surgical treatment of chronic pancreatitis].

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Vorobeĭ, A V; Shuleĭko, A Ch; Orlovskiĭ, Iu N; Vizhinis, Iu I; Butra, Iu V; Lagodich, N A

2014-01-01

An analysis of surgical treatment of 187 patients with chronic pancreatitis was made during 3-year period in the department of surgery clinic of Byelorussian Medical Academy of Post-Graduate Education. Drainage operations were performed on 28 patients, resection-drainage operations were carried out on 130 patients and resection operations had 19 patients. The laser beam technologies were successfully applied during operations on the pancreas in 43 patients. Postoperative complications (14.8%) were analyzed and structured. Methods of corrections and ways of prophylaxis of complication development were provided. On the basis of the complication analysis and new conception concerning peripheral pancreatic hypertension the authors offered the rational approaches to choice of operations on the pancreas in case of chronic pancreatitis. The authors developed the classification of pancreatoductolitiasis, pancreatic hypertension and a new strategy of surgical management of chronic pancreatitis.

Staged surgical management of gastroschisis with severe viscero-abdominal disproportion complicated by membranous intestinal obstruction

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Sliepov O.

2017-01-01

Full Text Available Introduction. Incidence of gastroschisis (GS complicated by intestinal atresia is 4.5–12.6% of cases. 80% of this obstructions are observed in jejunoileal segment. Association of GS with intestinal atresia (GIA is usually diagnosed well, but at birth, diagnosis of atresia is often controversial. There is misdiagnosis of atresia during the initial surgery in about 12% of cases. The ideal treatment model of GIA had not already been set. Different surgical approaches were described in literature: abdominal closure modalities, terms of intestinal anastomoses creation and intestinal stomas formation remain outstanding issues. the severity of congenital defects may vary thus the tactics and strategy of surgical management as well as the ability to create primary intestinal anastomosis should be considered individually. Clinical case. GS with severe viscero-abdominal disproportion (VAD in fetus was diagnosed prenatally by ultrasonography (US at 21 week of gestation. Prenatal US follow-up monitoring and examinations were conducted. The presence of concomitant intestinal obstruction was suspected at 35 week of gestation. Regarding diagnosed malformations, according to developed in our clinic "First Minutes Surgery" tactics, operation was performed in 15 minutes after birth. During the initial surgery intestinal obstruction was not confirmed. Staged surgical management of GS was conducted. Intestinal obstruction was diagnosed and confirmed by radiography only after 21 days of age, after increasing of oral intakes volume to 15.0 ml. Jejunal web was found on surgery. Following web removal diamond-shaped anastomosis was created. During post-op period the recurrence of intestinal obstruction was not observed, full enteral nutrition was reached. The good outcome after exhibited surgical management was achieved. Conclusions. The proposed strategy and tactics of surgical management found to be effective and can be applied in the case of GS with severe VAD

Long-term effectiveness of surgical treatment of ectopic atrial tachycardia.

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Prager, N A; Cox, J L; Lindsay, B D; Ferguson, T B; Osborn, J L; Cain, M E

1993-07-01

The purpose of this study was to determine the long-term clinical outcome of patients with ectopic atrial tachycardias treated surgically. Ectopic atrial tachycardia is an uncommon arrhythmia that can be symptomatic and is associated with the development of a cardiomyopathy. Management strategies are not well defined because of the paucity of data on the long-term effectiveness of pharmacologic and nonpharmacologic therapies. The long-term clinical impact of medical and surgical therapy was determined in 15 consecutive patients with ectopic atrial tachycardia. All 15 patients were initially treated with antiarrhythmic drugs (mean 5.7 +/- 2.2 drugs/patient). An effective drug regimen was identified in only 5 (33%) of the 15 patients; the remaining 10 patients were treated surgically. In each, individualized surgical procedures were guided by computer-assisted intraoperative mapping, with atrial plaques comprising up to 156 electrodes. Focal ablation was performed in four patients and atrial isolation procedures in six. The 10 patients treated surgically were followed up a mean of 4 +/- 3.2 years. Ectopic atrial tachycardia recurred in one patient. A permanent pacemaker was implanted in two patients, one of whom also required reoperation for constrictive pericarditis. There were no operative deaths. Ectopic atrial tachycardia recurred in three (60%) of the five patients discharged on antiarrhythmic drug therapy during a mean follow-up interval of 6.4 +/- 4.3 years. There was one nonarrhythmic death. Map-guided surgery demonstrated long-term efficacy in abolishing symptoms in 9 of the 10 patients with ectopic atrial tachycardia. Results demonstrate that surgery is effective for patients with ectopic atrial tachycardias who are not easily treated with antiarrhythmic drugs.

Differential theory of learning for efficient neural network pattern recognition

Science.gov (United States)

Hampshire, John B., II; Vijaya Kumar, Bhagavatula

1993-09-01

We describe a new theory of differential learning by which a broad family of pattern classifiers (including many well-known neural network paradigms) can learn stochastic concepts efficiently. We describe the relationship between a classifier's ability to generate well to unseen test examples and the efficiency of the strategy by which it learns. We list a series of proofs that differential learning is efficient in its information and computational resource requirements, whereas traditional probabilistic learning strategies are not. The proofs are illustrated by a simple example that lends itself to closed-form analysis. We conclude with an optical character recognition task for which three different types of differentially generated classifiers generalize significantly better than their probabilistically generated counterparts.

Surgical competence.

Science.gov (United States)

Patil, Nivritti G; Cheng, Stephen W K; Wong, John

2003-08-01

Recent high-profile cases have heightened the need for a formal structure to monitor achievement and maintenance of surgical competence. Logbooks, morbidity and mortality meetings, videos and direct observation of operations using a checklist, motion analysis devices, and virtual reality simulators are effective tools for teaching and evaluating surgical skills. As the operating theater is also a place for training, there must be protocols and guidelines, including mandatory standards for supervision, to ensure that patient care is not compromised. Patients appreciate frank communication and honesty from surgeons regarding their expertise and level of competence. To ensure that surgical competence is maintained and keeps pace with technologic advances, professional registration bodies have been promoting programs for recertification. They evaluate performance in practice, professional standing, and commitment to ongoing education.

A neural flow estimator

DEFF Research Database (Denmark)

Jørgensen, Ivan Harald Holger; Bogason, Gudmundur; Bruun, Erik

1995-01-01

This paper proposes a new way to estimate the flow in a micromechanical flow channel. A neural network is used to estimate the delay of random temperature fluctuations induced in a fluid. The design and implementation of a hardware efficient neural flow estimator is described. The system...... is implemented using switched-current technique and is capable of estimating flow in the μl/s range. The neural estimator is built around a multiplierless neural network, containing 96 synaptic weights which are updated using the LMS1-algorithm. An experimental chip has been designed that operates at 5 V...

Fluorescence-Activated Cell Sorting of EGFP-Labeled Neural Crest Cells From Murine Embryonic Craniofacial Tissue

Directory of Open Access Journals (Sweden)

Saurabh Singh

2005-01-01

Full Text Available During the early stages of embryogenesis, pluripotent neural crest cells (NCC are known to migrate from the neural folds to populate multiple target sites in the embryo where they differentiate into various derivatives, including cartilage, bone, connective tissue, melanocytes, glia, and neurons of the peripheral nervous system. The ability to obtain pure NCC populations is essential to enable molecular analyses of neural crest induction, migration, and/or differentiation. Crossing Wnt1-Cre and Z/EG transgenic mouse lines resulted in offspring in which the Wnt1-Cre transgene activated permanent EGFP expression only in NCC. The present report demonstrates a flow cytometric method to sort and isolate populations of EGFP-labeled NCC. The identity of the sorted neural crest cells was confirmed by assaying expression of known marker genes by TaqMan Quantitative Real-Time Polymerase Chain Reaction (QRT-PCR. The molecular strategy described in this report provides a means to extract intact RNA from a pure population of NCC thus enabling analysis of gene expression in a defined population of embryonic precursor cells critical to development.

Hidden neural networks

DEFF Research Database (Denmark)

Krogh, Anders Stærmose; Riis, Søren Kamaric

1999-01-01

A general framework for hybrids of hidden Markov models (HMMs) and neural networks (NNs) called hidden neural networks (HNNs) is described. The article begins by reviewing standard HMMs and estimation by conditional maximum likelihood, which is used by the HNN. In the HNN, the usual HMM probability...... parameters are replaced by the outputs of state-specific neural networks. As opposed to many other hybrids, the HNN is normalized globally and therefore has a valid probabilistic interpretation. All parameters in the HNN are estimated simultaneously according to the discriminative conditional maximum...... likelihood criterion. The HNN can be viewed as an undirected probabilistic independence network (a graphical model), where the neural networks provide a compact representation of the clique functions. An evaluation of the HNN on the task of recognizing broad phoneme classes in the TIMIT database shows clear...

Intermittent reductions in respiratory neural activity elicit spinal TNF-α-independent, atypical PKC-dependent inactivity-induced phrenic motor facilitation.

Science.gov (United States)

Baertsch, Nathan A; Baker-Herman, Tracy L

2015-04-15

In many neural networks, mechanisms of compensatory plasticity respond to prolonged reductions in neural activity by increasing cellular excitability or synaptic strength. In the respiratory control system, a prolonged reduction in synaptic inputs to the phrenic motor pool elicits a TNF-α- and atypical PKC-dependent form of spinal plasticity known as inactivity-induced phrenic motor facilitation (iPMF). Although iPMF may be elicited by a prolonged reduction in respiratory neural activity, iPMF is more efficiently induced when reduced respiratory neural activity (neural apnea) occurs intermittently. Mechanisms giving rise to iPMF following intermittent neural apnea are unknown. The purpose of this study was to test the hypothesis that iPMF following intermittent reductions in respiratory neural activity requires spinal TNF-α and aPKC. Phrenic motor output was recorded in anesthetized and ventilated rats exposed to brief intermittent (5, ∼1.25 min), brief sustained (∼6.25 min), or prolonged sustained (30 min) neural apnea. iPMF was elicited following brief intermittent and prolonged sustained neural apnea, but not following brief sustained neural apnea. Unlike iPMF following prolonged neural apnea, spinal TNF-α was not required to initiate iPMF during intermittent neural apnea; however, aPKC was still required for its stabilization. These results suggest that different patterns of respiratory neural activity induce iPMF through distinct cellular mechanisms but ultimately converge on a similar downstream pathway. Understanding the diverse cellular mechanisms that give rise to inactivity-induced respiratory plasticity may lead to development of novel therapeutic strategies to treat devastating respiratory control disorders when endogenous compensatory mechanisms fail. Copyright © 2015 the American Physiological Society.

NeuroMEMS: Neural Probe Microtechnologies

Directory of Open Access Journals (Sweden)

Sam Musallam

2008-10-01

Full Text Available Neural probe technologies have already had a significant positive effect on our understanding of the brain by revealing the functioning of networks of biological neurons. Probes are implanted in different areas of the brain to record and/or stimulate specific sites in the brain. Neural probes are currently used in many clinical settings for diagnosis of brain diseases such as seizers, epilepsy, migraine, Alzheimer’s, and dementia. We find these devices assisting paralyzed patients by allowing them to operate computers or robots using their neural activity. In recent years, probe technologies were assisted by rapid advancements in microfabrication and microelectronic technologies and thus are enabling highly functional and robust neural probes which are opening new and exciting avenues in neural sciences and brain machine interfaces. With a wide variety of probes that have been designed, fabricated, and tested to date, this review aims to provide an overview of the advances and recent progress in the microfabrication techniques of neural probes. In addition, we aim to highlight the challenges faced in developing and implementing ultralong multi-site recording probes that are needed to monitor neural activity from deeper regions in the brain. Finally, we review techniques that can improve the biocompatibility of the neural probes to minimize the immune response and encourage neural growth around the electrodes for long term implantation studies.

Evaluating the optimal timing of surgical antimicrobial prophylaxis: study protocol for a randomized controlled trial.

Science.gov (United States)

Mujagic, Edin; Zwimpfer, Tibor; Marti, Walter R; Zwahlen, Marcel; Hoffmann, Henry; Kindler, Christoph; Fux, Christoph; Misteli, Heidi; Iselin, Lukas; Lugli, Andrea Kopp; Nebiker, Christian A; von Holzen, Urs; Vinzens, Fabrizio; von Strauss, Marco; Reck, Stefan; Kraljević, Marko; Widmer, Andreas F; Oertli, Daniel; Rosenthal, Rachel; Weber, Walter P

2014-05-24

Surgical site infections are the most common hospital-acquired infections among surgical patients. The administration of surgical antimicrobial prophylaxis reduces the risk of surgical site infections . The optimal timing of this procedure is still a matter of debate. While most studies suggest that it should be given as close to the incision time as possible, others conclude that this may be too late for optimal prevention of surgical site infections. A large observational study suggests that surgical antimicrobial prophylaxis should be administered 74 to 30 minutes before surgery. The aim of this article is to report the design and protocol of a randomized controlled trial investigating the optimal timing of surgical antimicrobial prophylaxis. In this bi-center randomized controlled trial conducted at two tertiary referral centers in Switzerland, we plan to include 5,000 patients undergoing general, oncologic, vascular and orthopedic trauma procedures. Patients are randomized in a 1:1 ratio into two groups: one receiving surgical antimicrobial prophylaxis in the anesthesia room (75 to 30 minutes before incision) and the other receiving surgical antimicrobial prophylaxis in the operating room (less than 30 minutes before incision). We expect a significantly lower rate of surgical site infections with surgical antimicrobial prophylaxis administered more than 30 minutes before the scheduled incision. The primary outcome is the occurrence of surgical site infections during a 30-day follow-up period (one year with an implant in place). When assuming a 5% surgical site infection risk with administration of surgical antimicrobial prophylaxis in the operating room, the planned sample size has an 80% power to detect a relative risk reduction for surgical site infections of 33% when administering surgical antimicrobial prophylaxis in the anesthesia room (with a two-sided type I error of 5%). We expect the study to be completed within three years. The results of this

SAGES TAVAC safety and effectiveness analysis: da Vinci ® Surgical System (Intuitive Surgical, Sunnyvale, CA).

Science.gov (United States)

Tsuda, Shawn; Oleynikov, Dmitry; Gould, Jon; Azagury, Dan; Sandler, Bryan; Hutter, Matthew; Ross, Sharona; Haas, Eric; Brody, Fred; Satava, Richard

2015-10-01

The da Vinci(®) Surgical System (Intuitive Surgical, Sunnyvale, CA, USA) is a computer-assisted (robotic) surgical system designed to enable and enhance minimally invasive surgery. The Food and Drug Administration (FDA) has cleared computer-assisted surgical systems for use by trained physicians in an operating room environment for laparoscopic surgical procedures in general, cardiac, colorectal, gynecologic, head and neck, thoracic and urologic surgical procedures. There are substantial numbers of peer-reviewed papers regarding the da Vinci(®) Surgical System, and a thoughtful assessment of evidence framed by clinical opinion is warranted. The SAGES da Vinci(®) TAVAC sub-committee performed a literature review of the da Vinci(®) Surgical System regarding gastrointestinal surgery. Conclusions by the sub-committee were vetted by the SAGES TAVAC Committee and SAGES Executive Board. Following revisions, the document was evaluated by the TAVAC Committee and Executive Board again for final approval. Several conclusions were drawn based on expert opinion organized by safety, efficacy, and cost for robotic foregut, bariatric, hepatobiliary/pancreatic, colorectal surgery, and single-incision cholecystectomy. Gastrointestinal surgery with the da Vinci(®) Surgical System is safe and comparable, but not superior to standard laparoscopic approaches. Although clinically acceptable, its use may be costly for select gastrointestinal procedures. Current data are limited to the da Vinci(®) Surgical System; further analyses are needed.

Significance and management of positive surgical margins at the time of radical prostatectomy.

Science.gov (United States)

Silberstein, Jonathan L; Eastham, James A

2014-10-01

Positive surgical margins (PSM) at the time of radical prostatectomy (RP) result in an increased risk of biochemical recurrence (BCR) and secondary treatment. We review current literature with a focus on stratifying the characteristics of the PSM that may define its significance, the impact of modern imaging and surgical approaches in avoidance of PSM, and management strategies when PSM do occur. We performed a review of the available literature to identify factors associated with PSM and their management. PSM have been repeatedly demonstrated to be associated with an increased risk of BCR following RP. The specific characteristics (size, number, location, Gleason score at the margin) of the PSM may influence the risk of recurrence. Novel imaging and surgical approaches are being investigated and may allow for reductions of PSM in the future. The use of adjuvant treatment for a PSM remains controversial and should be decided on an individual basis after a discussion about the risks and benefits. The goal of RP is complete resection of the tumor. PSM are associated with increased risk of BCR and secondary treatments. Of the risk factors associated with BCR after RP, a PSM is directly influenced by surgical technique.